KCBS 740 AM San Francisco Transmitter Tour Part 1 

Hi. Thanks! I keep promising to do Part 2 and maybe this summer will be the time I get to actually get back out to the transmitter and do it. Things have changed a bit in the four years that I have been retired. Big fan of your channel. Thanks for all of the nice restoration videos and tips and tricks. I have a large collection of old broadcast gear that I want to do a series of videos on but I just haven't had the time or figured out the best way to actually record what I am doing. Hopefully soon. I want to bring some old audio consoles back to life. Thanks again and looking forward to your next video! Man, you have a lot of test gear! Yikes! Take care, Dave

Hi Brent. Thanks and glad you enjoyed the tour. Having our transmitter sites become storage areas was one thing we fought very hard to prevent. It also helped that we had a staff of four engineers. This meant I could be at the transmitter twice a week. That really helped with keeping the place up. My generators always started but occasionally I would have to brave the weather because, even though they were serviced twice a year and tested once a month, something would happen and I would find myself out in the rain. My three generators on Mt. Beacon in Marin County only had 150-gallon tanks. If the power was out for more than a day, we would refill them with 5 gallon cans filled from the local Chevron station Nothing I loved more than standing next to a running generator with a 5 gallon can in high wind and rains. Glad those days are behind me. Take care, Dave

Thank you! Dave

Daniel, Thank you. I only wish I had had time to do the videos on the FM transmitter sites before I retired. Dave

Richard, thanks for the nice note. No, I didn't get in trouble. I actually called downtown and let the chief engineer know I was going to do the pattern change and why. When we would be working at the transmitter, we would change pattern or transmitters without letting the newsroom know. The only time we really let them know we were doing something was when we would drop to a lower power or go non directional, which was only 12,500 watts, because then we would get calls from listeners who were farther away. Wow, I am impressed that you can occasionally hear KCBS in Hawaii! I'm thinking about going to Oahu for my 67th birthday in September. Maybe I'll take a radio and see if I can DX the station. Take care, Dave

Do not worry. This sound engineer is a well-desired professional, and he is well-favored. His reputation is outstanding.

Hi Larry, yeah there is a lot of stuff in those racks. Fortunately, while I was there, I installed 90% of that so I knew the signal path for audio and RF like the back of my hand. It has changed quite a bit in the almost four years that I have been retired though. Dave

Walt, good to hear from you! Sorry the reply took a while, but I was in Arizona chasing trains with a friend. Thank you for the nice words about the site. Mike and I took great care in the upkeep of the plant. It was the best transmitter plant I ever worked for, hands down. When I retired in June of 2019 one of the things that bothered me was how was the plant going to be maintained. Unfortunately, after Mike retired 3 months after I did, the new chief they got was, well, to put it nicely, not as interested in quality as we were. Too bad. The new, new chief is thankfully. Andy retired in 2013 and is living the good life in Oregon. Mike is still in San Francisco and like me, does not miss radio. I much prefer spending time with my granddaughters and chasing trains than being on call 24/7 but I wouldn't trade my 45 years in radio for anything. Take care. Dave

I couldn't agree more and you couldn't have said it better. On behalf of all the other broadcasters who never made it out of the small markets, I am jealous!

As an audiophile, I am longing to see Part 2. I had never seen a broadcast radio station very organized and neat like this one in America.

Kev, interesting about Hawaii. Think I'll try to pick it up the next time I go there. DAve

Hi Ann. Thank you. It was a fun place to work. I am going to try and work it out with the new engineer to see if I can get up there and record the video I need to do part two. Here's hoping. Dave

Michael, Thank you. I wish I had had the time to do tours for my FM sites as well. Dave

Hi. Thanks. It's a shame you didn't get to see the old GE BT25A transmitter. That was a truly gigantic beast. I never really got to work on it much. It came out in 1990 or so when the tower fell down and the building was remodeled. We installed the Nautel in 2017 I believe. It gave us a third xmtr for emergencies and could use it for any non DA operation that might go longer than a day. Dave

Terrence, thank you! I still want to see if I can get out there again and do part two of the tour. Maybe this summer. Dave

Hi, glad you liked the tour. KCBS was a lot of fun to work at and maintaining a big 50KW site like that was one of the best experiences I had in radio. Dave

Thanks! I wish I had had the time to do the other sites. I just have still pictures and I will eventually get all of them up on my steampoweredradio.com site. My AM broadcasting in retirement will probably be limited to playing with a LPB 10 watt transmitter I have to restore and building a power line coupler for it. It's only 50,470 watts lower than what I used to do. Dave

Hi, glad you liked the tour. Our chief engineer and I always worked hard on not only maintaining the equipment but trying to keep the plant as clean as possible. As you know dirt can really mess with electronic equipment. I suspect my philosophy is a bit different than yours. I believe in maximum antenna current! Take care, Dave

Hi, Thanks. Yeah, that Kintronics panel was cool. Also helped us diagnose the rare problem that popped up with the switching. Wish I could have done the videos on my sites at Mt. Beacon in Marin County. They were really nice. Dave

MIchael, Thank you! Glad you enjoyed it. Dave

Jeff, thanks! I do have more Anyrail videos planned but I have slowed down a bit to take care of other things. The KCBS transmitter was, emphasize was, very clean. We were out there twice a week and besides our maintenance of the equipment, we would always vacuum or clean some part of the building, tuning houses or gen shed. Over the years I found that that is the best way to catch impending disaster. I could tell just by the sound of the transmitter or phasor or tuning house components if something was just not quite right. Try explaining that to new engineers. I had a lot of fun working at KCBS, Alice@97.3 and KFRC-FM but I much prefer being retired. Dave

Thank you. Dave

Charlie, thank you! I hope to be able to do part two this year. Dave

Rick, thank you! Hope to do part two this year. Dave

Hi, Those are big towers and you can see them from all over the North Bay. Years ago I was able to walk out into my backyard and see the tower lights at night. Then the trees in the schoolyard behind my house got too big. At night, KCBS redirects the power we would send east and north during the day to the south. At night when KBRT in L.A. lowers their power from 50 thousand watts to 190 watts, KCBS just wipes them out. I once heard KCBS while driving at night in Arizona. It's a massive signal to the south. Lot of fun to take care of the site but I think I enjoy retirement a lot more. Dave

Thanks! Unfortunately I don't have much usable footage for a part two just now. I hope to be able to convince the new engineers to let me go out and shoot some video so I can make part two sometime in the future. Dave

@@steampoweredradio2981 its all good! Keep up the good work

@@steampoweredradio2981 Please do make part 2

Michael, thanks! I loved that DX50 transmitter. Had very few problems with it. If I was still working, I could do a video on the array and the monitoring setup, but I don't have access to the site like I used too. I'll think about it though. I am going to turn my attention to doing some restoration of my collection of Sparta equipment that I have. Sounds like a wintertime project. As for part two, I discovered that the amount and quality of material that I have is not quite good enough. Maybe I can talk the current chief into letting me go out there with my camera sometime. Dave

Thank you! It was a fun job! Dave

Thank you! Dave

Spanky, thanks! The audio wiring at a transmitter would be very similar. Though I have watched videos about telephone CO's wiring and switching and it amazes me how anyone could trace a signal through all of that wiring. Take care, Dave

Hi. Being a broadcast engineer was great fun. I got to go to a lot of places doing remotes or sports and when I started working with CBS, our main station was all news so I got to help cover news stories as well. Biggest was the 1989 SF earthquake. Of the 4 million people who claim to have been at Candlestick Park for the World Series, I was actually there and then all over the bay area helping to cover the damage. Met lots of personalities too. But as with all things, you can grow tired of it, especially being on call 24/7/365 and in 2019 I called it quits. If I was 20 again, I would probably do it all over. Dave

@@steampoweredradio2981 I’m looking forward to “part 2”! 😉

Hi Autumn. That Gates board has always been a favorite of mine. I was lucky to be able to get it for a song a couple of years ago. Wish I could of had one for my high school station way back in the early 1970's.

Mark, Glad you liked the tour. CBS Radio was a fun place to work. I spent 31 of my 45 years in radio with CBS. Nice thing about being an engineer in radio is it means you pretty much survive all of the regime changes. I can't tell you how many program directors, morning shows and DJs came and went in those 31 years but engineering stayed the pretty much the same. I never got into ham radio but I almost got myself a Bauer 707. It was the same one I had at KTIM in San Rafael in the mid 70's and I was going to fix it up and put it in my living room and fire it up occasionally into its built in dummy load. I decide not to get it, my daughter has enough of my electronic equipment to get rid of when I die, and it went to a ham. At least it will be cared for and still used. The Symetrix 528E is a really good processor. Our Chief Engineer and I had a really good setting for it for use with Electro Voice RE20 microphones. The one thing you have to watch out for with them are the IN/OUT switches. These are the schadow types and the get dirty and noisy. We eventually took all of our 528s and removed the switches and replaced them with jumpers. No more audio dropouts. There is a famous and true story here in San Francisco radio about an infamous 528 switch caused audio dropout. When Barry Bonds hit his record breaking home run the audio on KNBR dropped out during the call. It was because of one of the switches on the 528E. The chief engineer lost his job over that which was not right. He's a good guy. Oh well, it's radio. When I make a comment on AnyRail not doing something, I do it because I hope it will eventually get back to David at AnyRail and will be used in an update. I have always had terrible luck with suggestion sections on forums. Guess I just ask for something no one else ever has. With all of the videos I am making I still haven't completed my railroad design but I will sure know a lot of tips and tricks when I do get back to working on it! Dave

The generaor was spec'd to run the old GE transmitter, which was a power hog. When we installed the DX-50 we found it was large enough to run it and the MW-50 transmitters at full power without breaking a sweat. Maintenance was contracted out to a company that also maintained the diesel engines on the Golden Gate ferries.

One of the really fun parts of being a transmitter tech was the fact that you not only got out of the studio regularly, you also got to go to some really nice mountain tops with great views of the San Francisco Bay area, or L.A. basin when I worked for KFAC Am&FM in the late 70's and early 80's. Now that I am retired, I miss the views but not cranky transmitters. Dave

Hi. Yeah, KCBS had the fastest pattern change of any AM I ever worked at. It is amazing how many people work at a radio station for years but never want to go see the transmitter. Of course I have seen some sites that I wouldn't care to visit either but it sort of rounds out your radio experience to see what the engineering people have to do to keep you on the air, at least in my humble opinion. The Nautel XR12 we installed worked pretty well. We had one issue early on that Nautel was less than helpful about but it was many years ago and I forget now what it was. The combiner in the Harris was a large copper buss bar. We had three AC units on top of the building providing clean air and we never had any corrosion issues. Part of our maintenance cycle was monthly shutdowns of the DX and a thorough check. One thing we really started looking at as the xmtr got older was the condition of the toroids on the combiner. We had heard of other CBS stations having the toroids crack. Never had that problem and I wouldn't have wanted to try and replace one. Hopefully I will be starting a series of videos this winter on restoring some of the equipment I have collected over the years. Lots of Sparta consoles and a Harris MSP100 audio processor that has more meters and lights than any self respecting processor should have. I really want to make it live again. Glad you liked the tour! Dave

David, Thank you! I wish I could have documented all of my sites before I retired, Dave

Hi, Thanks. Yeah, the solid state transmitters sure did away with a lot of the heavy iron, though in some ways, I kinda miss that part. Big transformers and if you're really old like me, mercury vapor rectifiers! That blue glow that danced with the modulation was really cool. Wait, come to think of it, solid state stuff was a lot easier to maintain. I have a website, also called Steam Powered Radio, and on there, I have a picture of the KCBS plant being constructed with a photo of some of the heavy iron stuff being installed. It's under the Radio Station section. Go to KCBS pictures and then the Original 1997 Tour. It's a web page I had up long ago. I really should update the coding for it but I thought it was fun to show it in the original HTML4 version. Dave

Michael, thanks for the note. I guess I could use the 5000 watt line. My first job was KDFC-FM and KIBE-am. KIBE was a 5000 watt daytimer. It was not in the best of neighborhoods and there were lots of holes in the walls of the transmitter building with corresponding dents in the transmitter from bullets. We were fired upon one time in the middle of the night and had to be escorted out by three patrol cars. Ah, radio is fun. I started including TV manuals and catalogs on the site. Always interested in anything you might have that would be of interest. If you do have some items, contact me thru my Steam Powered Radio website. Have fun in retirement! I'm over three years into it and don't miss radio at all. Take care, Dave

Pattern change times are spelled out by the FCC on the station license. It is the monthly average sunrise and sunset times at the transmitter site rounded off to the nearest 15 minutes.

Thom, Glad you liked it. The actual really real reason I made the video was because I wanted a record of all of my CBS transmitter sites so that when I retired I could look back at them and think "boy am I glad I am not getting any more 3AM phone calls to go out and fix something there). And, I did want to be able to let the people at the studios get a look at the sites. A lot of the office staff and sales people really don't care about the transmitter sites. The sales people only are aware of them if something goes wrong and one of their spots don't air. We had a complete studio and sleeping/survival area at the KCBS transmitter in case there was an earthquake or fire or other disaster in San Francisco that rendered our studios there useless. We did bring out news directors and on air staff to the site and showed them what we had, how to work it, and for those who were designated as primary on air in an emergency, how to get in and get on the air. It's a shame I was never able to shoot the final video for them. When Entercom bought CBS Radio we were just so busy trying to combine the two groups and build new studios that the project fell by the wayside. Combine that with my decision to retire because I really didn't like Entercom, I never got the other six site videos shot. As for part 2, well, I looked at what I had and realized that there really wasn't enough video there to make a coherent tour. Add in the fact that I was trying different wireless mics and I got some really atrocious audio on some shots. Maybe I'll do one where I combine the video with a lot of stills that I have of the site someday. Happy to know you are a listener. KCBS directs its power south both day and night so we ( I say we, guess I should say they now) put a really strong signal in your area. You can hear KCBS in L.A. at night, it comes in like a local after the station on 740 down there shuts off, they're a daytimer. At dusk before they would shut down, KCBS would usually overpower them. Fun place to work, all news. Got to go out on a lot of interesting stories with the reporters in the days before cell phones. Earthquakes (I was at Candlestick when the quake hit in 89), fires, troops returning, beached whales, etc. Prefer babysitting my granddaughter though to work. Take care, Dave

Agreed. I was in radio for over 20 years, but I *was* one of those who befriended a lot of engineers and DID accompany them to transmitter sites and assisted in various tasks that I was qualified to do. There weren't many transmitter sites I didn't go to. The thing is, while employed at a radio station, the office, programming, promotions, and sales staffs aren't required to go to the transmitter site as the engineering staff is. Nevertheless, as part of the programming/operations crew, I STILL found transmitter sites fascinating. And yes, I had radio stations in my bedroom as a teenager. My AM transmitter was an "AM Broadcaster" kit from Radio Shack, and my FM transmitter (without a stereo generator) was built by a buddy in my neighborhood who was an electronics buff.

@@wannawatchu66 Your hobby was more interesting than model railroading. I became an audiophile in 1978 when I bought my first high-fidelity system of components and enjoyed reproducing music. That hobby enhanced my interest in sound reproduction. That is why I wanted to see a radio station and a recording studio to compare if the music sounds the same as from a high-fidelity components system. I am pleased to know that you had radio broadcasting as a hobby.

Hi Jason, you can usually find some good stuff on EBay but the prices being asked right now are kinda high. I thought about making another home studio but I would rather use the space for my model railroad. Do you work out of Sparks for the UP?

Ebay is definitely high right now, especially for gear that is 20/30 plus years old. Unless you have a inside on the industry, people think they have gold when it comes to old gear. Especially Orban stuff... Yes, Sparks out of the Roseville service unit.

Thank you. One of the things I do miss since retiring is hanging out at the KCBS site. It was a great way to spend a work day. Dave

@@steampoweredradio2981 You are welcome.

Justin, thank you. It was a fun place to work for over 30 years. Dave

Hi Robert. Thanks. No, there was no problem switching patterns. I did call my boss and alert him before I did it because it was a day off for me and I wanted to alert the engineering department that I was there and going to switch patterns. Typically, we did not alert the newsroom when we would do something like that. We protected morning and afternoon drive times, meaning anything from 6A to10A and 2P to 7P was pretty much off limits for messing around like that but any other times, we could do what we wanted pattern wise. If we were lowering power, we always let the newsroom know so when they started getting the 'we can't hear you' phone calls, they could tell the listener what was going on. Dave

Well that's cool that you did that. I like watching videos about this stuff. I was a student DJ back in the day at a 100 watt radio station in Chicago. One of the building engineers showed me where the transmitter is and how it was hooked up to the tower. And it was a bit noisy. And from what I gathered it has to been super super noisy in that giant building. And those buildings don't look too big but there's a lot of stuff in there. I like the part where you showed the kitchen. That is important to have a kitchen because you're probably in there for a few hours on end and you have to have some snacks. I like the Pepsi and the mountain dew and the water.

Yeah, I bet an on channel 50KW and a 60KW 10 kHz away does make it a bit tough. The farthest I ever heard KCBS was in Arizona on at night on the radio in my 1990 Ford Taurus station wagon back in 1996. I was pretty amazed but really happy that my transmitter was doing that. Dave

@@steampoweredradio2981 Thanks for the comment Dave! At a mexican DX group I know 2 guys that were able to pull the signal in Mexico City One of them getting KCBS once in a while and the other guy only one time

Thank you! It was a lot of work keeping it clean but it paid off in reliability. Dave

Hi Bob, Getting KCBS in New York would be quite an achievement. The pattern is basically to the south of the transmitter site in Novato, Calif. KCBS pulls the power in from the north and east at night, in fact we get complaints from listeners in the Sacramento area in the winter when we are still in night pattern. Since I am retired from KCBS I don't know when they will be doing any ND tests, but the ND power is limited to 12.5KW. I once accidently went to ND with the xmtr at 50KW. To put it mildly, the tuning components in the phasor sang very loudly. I realized my mistake after about two seconds and went back to DA-D. A quick look at everything confirmed no damage but I got a very funny look from our chief engineer who was standing next to the phasor when I switched. Should you ever get KCBS in Florida, let me know. The farthest away I ever heard the station was in Arizona back in the 90's, just after sunset on my 1990 Ford Taurus wagons radio. Dave

At night the major lobe is to the south. I forget the exact field strength intensities but at my house, which is to the southeast 15 miles, I can hold my scope probe between my fingers and watch the modulation of KCBS on my scope. I think I once measured 750 mv/m at my house. It's a great signal. Someday I'll try and borrow a field strength meter from KCBS and measure what I have again at my house. Dave

Thank you! I just checked out your channel (and subscribed) and watched the KNX tour. My friend and ex-boss, Mike Smith, worked there for years as the west coast DTO for CBS. I am going to send him a link to your video. I also watched the Mt. Wilson party video. I was happy to see you guys go into the post office. I was an engineer with KFAC AM&FM from 1978 to 1981 and made many many trips to the transmitter site in good weather and bad. I wish you had identified the xmtr plants a little more, the interior of the building has changed just a tiny bit in the last 40 years. When I was there we had a Sparta 620 that had been upgraded to a 625 (that's a long tale of woe) and a RCA FM5B that we got from KMPX (my first job as a chief engineer) in San Francisco. There are pictures of KFAC in 1979 on my website steampoweredradio.com. Check it out. Also, when I was with KFAC there was a postmaster at the post office. He and his wife lived there and he just loved it when any of the stations would call him and ask him to go look at a transmitter and tell us how much smoke was boiling out of the cabinet. I think he secretly wanted to be a broadcast engineer. I forget his name but he was a real nice guy. Also enjoyed the short view of Red Box Road. I loved that drive. I lived in Sepulveda and when I went to Wilson for the day I always made a stop at Apex electronics. Went there for the first time in 30 years two years ago and saw a lot of the same parts that were there in the eighties. Is there still a red box at the base of Red Box Road? Unfortunately I don't have much usable footage for the second part of the tour so I am hoping that maybe I can convince the chief at KCBS to let me go out and do a little filming. He'll be OK with that I think. Just out of curiosity, what stations do you work for? L.A. was a lot of fun for a 23 year old in 1978 but after three years my girlfriend and I both wanted to get back to Northern California but, KFAC was a lot of fun. Take care, Dave

@@steampoweredradio2981 Thanks! I’m starting to get more comfortable with filming. The Mt Wilson tour was early on. I’m a tad more “aggressive” about asking questions on camera. There is still a red box, but as usual no one really knows what’s in it. We have plans for this year’s Mt Wilson “Christmas Party” but the date hasn’t been secured yet. Probably September or early October. At that point I’d love to do more of a tour of Mt Wilson and get more detailed. My (now) normal haunts are Santiago Peak in Orange County and outside of Palomar in San Diego County. We sold our stuff in the Las Vegas area and outside of Barstow. Your part 1 video is great and something for those of us who have smaller facilities to try to emulate in the cleanliness and beauty of your facility. Now that I don’t have sites outside of Southern California anymore I should have more time… as soon as I can finish this network infrastructure project at the studio. That’s a career in itself! - Marcos

Hi Paul. Those are just straight out of the box Kintronics contactors. Nothing special was done to any of them and some of them are now 30 years old. The RF kill on the Harris DX and 3DX is so fast we have never had any arcing issues since the system went in in 1990. Several times a year we would go ND and I would go out to each ATU and check the contactors. I found that over time, some of the hardware would loosen up a bit especially on the bar that holds the buss bar contacts. It also gave me a chance to observe up close how the finger stock was and how well the bar was seating in them. I did transmitter maintenance for 20+ years and I think I only had one microswitch fail because it was loose. Part of the maintenance when in the ATUs was to wiggle them and see if they were tight. We also shutdown twice a year and went thru the phasor from top to bottom doing the same thing and checking all of the connections. I also got pretty good at changing out the contactors in the ATUs in record time after we would take lightning strikes. Sometimes the arc gaps and balls would save a switch and sometimes it would rip right past and take out contactors and other components. Worst part was cleaning the soot out of everything. My director of engineering and I had a system down of, I would replace the switch and he would bend the replacement copper tubing and fit it into place. Ah, transmitters and lightning. 2 1/2 years of retirement and I don't miss that part at all. Glad you liked the tour. I hope to start some videos this winter on restoring some old broadcast equipment. Should be fun. Dave

If you think about it, being able to modulate the signal 100% at 10 Khz means the array's residual "flywheel" energy storage dissipates in less than 0.1 uSec. Killing the RF drive squelches the transmitter's output almost immediately and the Kintronics contactors have more mechanical inertia than that before the contacts start to move. What takes longer is if you turn off the High Voltage to kill the RF. Then you have to wait for the power supply capacitors to discharge before the power decays to zero. When I was at KFAC the remote control sent a Plate Off command to the transmitter at the same time it called for the contactors to switch and we were getting visible arcing across the phasor contactors. These went away when I modified the old RCA 5F to kill the RF drive instead of the high voltage during pattern change. Bob Smith at Hammett and Edison came up with the same idea when he designed the KCBS phasor - leave the high voltage on and mute the RF drive when you energize the contactors, then unmute it as soon as the new pattern's interlocks line up. The logic was quite simple - as soon as pattern change is requested the transmitter reacts to the opposite pattern's interlock chain. It will be open until the last contactor falls into place.

Hi, that is a problem in the broadcast industry right now. Most kids are more interested in coding than learning electronics. I think the fact that a broadcast engineer works long hours, usually makes less money, is on call 24/7/365 and generally not looked upon as a professional by a lot of management types in radio also contributes to reasons why the job doesn't look appealing.

@@steampoweredradio2981 Hours suck, job is dangerous, the pay sucks and the learning curve is steep. Something is going to have to change if they want any talent but honestly working on some of the new nautels you don't really need an engineer anymore. It's just module swapping.

Alex, that box was a custom design by the engineering department. It used some off the shelf components and also some custom circuitry and circuit boards designed by us. It was pretty handy to have. Dave

The introduction of high frequency mos-fets really helped the solid state scene, especially for FM transmitters. The DX50 that KCBS uses was introduced around 1990. There were several other earlier solid state am transmitters but I don't really recall the exact history and they weren't very successful. There were also some early, 1970 or so, hybrid solid state. The Gates Vanguard 1 comes to mind. It had transistors all the way up to the final output section which was a tube.

Hi, the shape of the tower arrangements is simply whatever the design engineer needs to get the pattern to go where they need it to go. In addition to parallelograms, I believe there may be some rhomboids out there. In the case of a five tower array, it can be in line or a parallelogram with a tower in the center. There are 9-10-12 tower arrays out there and they will have different configurations depending on where the power needs to go. A lot of three tower arrays that you see are actually dog-legs, where one of the towers is slightly offset to the other two towers. All of the design for directional arrays involves math that is way beyond what I can do. Dave

@@steampoweredradio2981 So essentially, the polar response can be very accurately tweaked to provide any pattern that’s required. Very interesting.

@@davba2 Yeah. The pattern is derived from the tower spacing, the amount of power applied to each tower and the phase between the respective outputs of the phasor. This is done so you can have two or more (many more) stations on the same frequency or adjacent and have them direct the power from their antenna arrays in different directions to cover areas they need and protect in other directions. KCBS pulls the power in from the north and east at night, due to different propagation at night, and then we would let the power out during the day. One of the jobs of a engineer at a directional station is to go out every month and make measurements at are locations called 'monitor points'. You would take your Field Intensity Meter out, get the reading and compare it to what your license says you should have for a value at that point. You could not go over whatever the pattern called for, if it was a higher reading it meant that either the array was having problems or something in the area had changed and maybe was reflecting power or something and that was causing the higher reading. We had one point go out at KCBS and we determined that was due to a new irrigation system installed in a new vineyard right next to the point. We had to apply to the FCC to change the point. Nice thing about doing monitor points was you could get paid for driving around the countryside for a day. At least that was the way it was at KCBS. Dave

Hi Paul, AM radio stations use ground radials buried in the, well, ground. The radials are typically as long as the tower is high and spaced every three degrees. Where you have a directional station, like KCBS, where the radials from the towers meet, they are bonded together with a large copper cable or sometimes copper strap. Some stations, like KCBS, also use what is called a counter-poise. This is a raised copper screen or wires, that extend around the base of the tower 40 feet or so and then the buried ground radials attach to the end of the counterpoise. The counter-poise tends to reduce changes in the resistance/reactance of the tower itself under varying weather conditions of the soil around the tower. Dave

MArk, the 3DX50 had some growing pains and also didn't work well with the AM HD at first. We got that straightened out and when I left in 2019, we were running the two transmitters on a rotating weekly basis. Dave

Hi, that was not as uncommon as you might think. The newer transmitters will kill the RF quickly without killing the high voltage. In the older transmitters it was a plate off command to kill the RF. Then you had to initiate the switch in the phasor and then issue a plate on command. Years ago at KKHI AM, I had a Harris MW10 (worst transmitter ever) and it would kill the RF quickly but because I didn't trust it, I built in a little time between the RF kill and pattern switch and RF back on. Figured it would save me a trip or two to the transmitter at dinner time. Dave

@@steampoweredradio2981 Appreciated your response. I'm familiar with the location of the KKHI transmitter, as it was just east of the Bayshore Freeway. I wondered at times if that transmitter shack would have been waist-deep in water as a result of a exceptional high tide, or as some would refer to it as a "king tide," as that area always seemed marshy with the San Francisco Bay being there.

@@bloqk16 Hi, your comment about the water levels is pretty true. Sometime in 1985 or so, the City of Belmont opened up some long clogged up drainage pipes that were around the land that KKHI sat on. They did this for the new developments that were being built to the east of the site. Well, the water started pouring in and it was getting right up to the floor of the building. Never got inside thankfully. Buckley Broadcasting being the cheapskates that they were, did not want to follow my idea of putting in a raised, pre-fab building. So, I had to remove the old RCA standby transmitter, raise the phasor on blocks, have someone come in and pour a new concrete floor that was one foot higher. We did this on one side of the building. I then moved the main xmtr over to the higher side and had the concrete folks raise the floor on the other side. Then my brother (who was a carpenter) and I redid the inside with new walls and ceilings, new tile, etc. We then bought a used Collins 820F 10KW transmitter from KRVN in Lexington Nebraska and shipped it out as the new back up. We also had to have electrical work done as well as other items. By the time we were done we spent twice as much as it would have cost to buy and install the pre-fab but the bean counters at Buckley patted themselves on the back because for some reason, they thought they did the right thing. The road would sometimes disappear under water. When it did this, I would pull my car up to the water, line myself up with the high ground point at the other end by the transmitter building and drive slowly and straight. If you veered to either side, you could end up in a ditch. A later engineer, after I left, did just that in his brand new 4 wheel drive. I came out to meet him and his car was at a 30 degree angle in the ditch with the inside totally drenched. I don't miss those days at all. Dave

@Bloqk-16 Hi, I was the transmitter tech at KCBS before Dave took over. Back in the late '60s to early '70s KFRE had the same massive GE BT-25a transmitter as KCBS. When KCBS had the old GE and phasor they would also pause twice a day to switch from day to night pattern and vice-versa. The announcer would say "We now pause 5 seconds for technical adjustments", the engineer would hit the pattern change button and everyone would wait for the transmitter to come back up on the new pattern. It was exciting to be inside the transmitter building during pattern change, there was lots of clunking and thumping as massive power relays dropped out and then re-energized. The GE wasn't that old, it was purchased new immediately after WWII and the building was designed around it. KNX got the next generation GE transmitter, which was about a third the size of the 25a. When KFRE replaced their GE with a Gates MW-50 in the late 1970s KCBS was still using theirs as the main transmitter and since GE was no longer in the transmitter business, they sent a crew to Fresno to gather up everything they could for spare parts. KCBS had a new MW-50 in the building but Corporate wouldn't let them install it until Gates figured out why the MW-50s at other CBS stations were catching on fire. Something to do with dust, moisture and a 100Kw, 26Kv high voltage supply. When the KCBS MW-50 was finally placed in service it included a positive pressure, double filtered air delivery system and massive Halon fire extinguishers. These mostly solved the internal arcing problems. The room that's now the Engineering Office at the KCBS transmitter originally held all of the GE's high voltage iron, a massive 8 ft tall modulation transformer, reactors, high voltage transformers, etc. and there was a duplicate of each from KFRE standing next to the originals. They contained gallons apon gallons of PCB oil so it doubled the disposal cost when the GE was removed to make room for the DX-50 and Kintronics phasor. I remember the changeover happening in 1989 because we had the crew on site and were scheduled to chop down the 3 remaining old towers (one had previously fallen and was replaced) the day after the Loma Prieta earthquake and we had to remove the GE and install the new DX-50 transmitter and phasor before that. It was a year long game of Jenga - how many pieces can we remove today without the whole house of cards collapsing in a heap? The earthquake and the all the excitement following it delayed the tower replacements until the field dried out the following summer. All of the new tower steel was on site and had to be placed on wooden platforms to ride out the upcoming winter. BTW, the old towers rode out the earthquake just fine.

@@louschneider6806 Hey Lou! Thanks for the information. Lou was the transmitter tech for many years before the job was forced upon me. Lou got to work with the BT25A on a daily basis. I think the extent of my experience with the GE was helping to replace a final or modulator tube one time in the middle of the night. Lou was also the one mostly involved with the 1989 rebuild of the transmitter site. I occasionally had to go out there and supervise the CBS supervisor who was supervising the construction people when the company would give Lou a day off from his 20-hour days. I also helped do the wiring of the new DX50 (still love that transmitter) and maybe some audio wiring too. If you would like to see photos of the old GE, go to my web site steampoweredradio.com/New%20Tour/historical/oldam1.html There are photos of the building of the site from the 1950's. This is part of a web tour I did of KCBS and KRQR back in 1996. Dave

Hi, directional antennas in the AM band are very common. I couldn't find anything about what percentage of stations use them but here in the San Francisco Bay Area, by my rough count, there are 19 AM stations and only four of them are omni-directional single stick types. Dave

@@steampoweredradio2981 I meant beamforming obtained by means of delays/phase shifts and not just placing directors and reflectors in the right place of the antenna field.

@@dktr2 Hi, that is the way it is done in AM. For FM stations, if a directional pattern is required, you'll see screens and reflectors behind the individual elements that make up the FM array.

@@steampoweredradio2981 And even more amazing that these delays or phase shifts are done at high power and not in front of separate power amplifiers. :)

@@dktr2 I have a promotional ad from sometime in the mid 1970's from, I believe it was Westinghouse, showing the directional AM radio station of the future. It mentioned that there would be a transmitter of the appropriate power in each tower base tuning house. I assume that each transmitter was fed by a phase shifted signal from a low power oscillator in the main xmtr building. Interesting concept and maybe it was tried at various locations but for me, I would prefer one big transmitter and let my phasor do the power dividing/phase shifting. The idea of having two, three, four, or for some stations, 16 separate transmitters would be just a bit too much. Plus, if one dies in a bad storm, you will find yourself sitting out in a cold tuning house trying to repair it and running back and forth to the main building to get parts, tools, etc. Even if I was in my 20's that would be a royal pain. Sometimes brute force methods are the best.

Joel, KCBS is required to change patterns between day and night to protect other stations on the same frequency. At night KCBS pulls the power in from the north and to the east and redirects it to the south. Many directional stations do this to protect other stations. Some stations drop their power at night, say, 5000 watts to 1000 watts and some are only daytimers. The time we change patterns depends on what month it is. In the wintertime we used to get a lot of complaints from people in the Sacramento area who were commuting to San Francisco. The signal was weaker to the east and commuters would sometimes here noise that they didn't hear in the summer months. We had many people threaten to report us to the FCC for our 'poor engineering practices'. The power from the transmitter goes into the phasor and from there it is transferred to the towers via 3" coax. Dave

@@steampoweredradio2981 I'm no electrical engineer, but I'm familiar enough about AM radio to think that a KCBS daytime pattern at night, the station could probably be heard as a 'local' in Barrow, Alaska.

Peter, It is not as bad as it sounds on the video. Besides, we had a really nice office that we could go into and shut the door for important work like eating lunch. Also, when you have been in radio for a long time, you just sorta ignore the noise. If you think the KCBS site sounded loud you should have heard Mt. Beacon where all of our FMs were. Now that was loud! Dave

@@steampoweredradio2981 I've worked in a computer data center for 20+ years. The noise actually relaxes me. In fact, I sleep with a fan on regardless of the temperature.

Hi, When KCBS says HD1 they are talking about the FM. FM hd consists of several things. The first is the standard analog signal, just like everyone has been receiving forever. On top of that, we add a digital signal. The digital signal allows us to allocate a certain amount of bits per second to each of the audio channels we wish to add. The HD1 refers to the first digital stream which mirrors the analog audio. This way if you have a digital radio, it will switch to the HD1 signal, away from the analog, but, if the digital fades, the radio will blend the audio back to the analog signal. It will stay on the analog until the signal strength on the digital is strong enough and it is receiving enough digital data to decode properly. The digital signal has a lot less power than the analog. If I remember right, KFRC FM was 80,000 watts and the digital was in the 1500 watt range. Been 5 years since I worked on those transmitters. In addition to the HD1, you can have other audio channels as well, HD2, HD3, etc. There is also room in the data stream for information like artist, song title and album artwork. But each time you add a HD channel you use more of the data. The most we ever had on any of our stations was an HD3 and this was at 16kbps, so the audio bandwidth was only 8khz mono. Not high fidelity but good enough for the programming.

Hi Steve, after I posted the first video, I found that most of my material for the second was unusable. I hope to get out there this spring and shoot what I need for part two. Dave

Hi. That's right. It is a 210KW gen. We could run both 50KW transmitters at full mod without having to do any load shedding in the building. It's an old generator too. I started there in November of 1988 and it was there then and it is still going strong today. We were very careful about regular maintenance on all of our generators. Dave

Hi JR, yes it is a 210 Kw Caterpillar diesel genset, a real beast of a generator. When the site was built after WWII KCBS only had the 50Kw GE transmitter and no backup transmitter or generator. Then around 1960 they installed a 10Kw Continental transmitter and a 50 Kw diesel generator to run it. The generator was replaced in the late 1970s by the 210 Kw Caterpillar so they could run the 50 Kw GE transmitter (it was a real power hog) instead of having to cut back to the 10 Kw transmitter during power outages. It had a 4000 gallon fuel tank that would run the GE transmitter for about two weeks, When the MW-50 delegated the GE to backup status it used less than half as much power so the generator just loafed along and used considerably less fuel. In the early 1990s FEMA chose KCBS as one of the EAS Primary Entry Point stations. They built a fallout shelter with a studio inside by adding 12" thick concrete walls and ceilings to one of the back rooms. They wanted to replace the generator but we turned them down since the Caterpillar was far better than the lowest bid generator they wanted to install. FEMA said having 4000 gallons of fuel on site wasn't enough (they wanted the generator to run for a full month at maximum load) so they installed a second 4000 gallon fuel tank next to the first one. Since the generator runs at less than half load those tanks now hold about 2 months worth of fuel.

That second tank is the only one still in use. We decommissioned the original in 2014 or so. 5000 gallons of fuel is still enough for KCBS to run for about a month. The original tank was a single wall with a containment wall around it. The newer tank is double walled.

Hi, I checked with my former boss and he told me that the bills ran from $8000 to $10,000 a month. A little higher than what I pay at home. Dave

@@steampoweredradio2981 That power bill is not unreasonable given the station is running 24/7. Out on the desert regions in the US, households can run up electrical bills over $500/month in the heat of summer with running the AC units.

Hi. Yep, both stations are power houses. KNX is an omni-directional station whereas KCBS directs its power south at night. KCBS is stronger in L.A. at night than KNX is here in the Bay Area. Never been worried about low frequency RF, either in the AM or FM bands. Cell phones near my head for a long time though....... Dave

I visited the KNX site (walking around the field and park) in April. Always wanted to visit KCBS. The gate off the road was as far as I got of course. You can definitely pick up KCBS in LA at night. Would love to see the 4 towers one day Dave. What a wonderful site. Just like I thought it would be - a class act!

Hi, I posted the video with the 'Part one' in the title and then discovered that I didn't have enough material to do a part two. I will try to convince the current chief to let me out there sometime and shoot the video I need for a part two. Sometime next year when the fields and road dries out. Dave

It's a secret ancient trick known only to the cabal of broadcast engineers. Dave

It's called video editing. 😁

Hi. I imagine we were a pain for DXers. But it was a LOT of fun to push that button that brought us up to 50KW. There is an old Outer Limits episode called the Galaxy Being (I believe). In it the DJ disobeys the engineers warning not to turn the power up or horrible consequences will occur. Of course he does or you wouldn't have a story to tell. Anyway, after he increase the power to maximum he walks over to a map of the U.S. and waves his hand over most of the country thinking 'This is my audience! I am the most powerful DJ in the World! (or something like that)'. That's how I always felt when I hit that button for 50KW. We only went off the air every six to eight months for routine maintenance. Normally just to get into the phasor to check the tightness of connections. The phasor had plastic covers and we could see inside and check seating of switches or look for signs of heat. I have no idea what the new engineering regime is doing about off air times. I know we got some DX reports from South America and also Norway. Those people are crazy. They put up mile long antennas on mountain tops and sit in the snow and DX. I used to get reports from them when I was chief at KKHI in San Francisco in the eighties. It was a 10KW station and they would send me recordings they made. Wish I had them today. Glad you liked the video. Dave

KCBS didn't get as many DX reports as you would think a 50 Kw station would get. It doesn't send much power to the north or east where most of the people in North America and Europe are. The main beam is aimed towards the southeast at the expense of power in other directions. KQW (KCBS's predecessor) was licensed to San Jose on 1010 and when they filed to move to 740 KHz they had to provide 25 mv "City of License" coverage over San Jose. San Jose is about 60 miles from the Novato site and they were able to provide this signal by sending about 200 Kw ERP in the main lobe down the length of San Francisco Bay, taking advantage of the Bay's salt water conductivity. Usually a station's 25 mv contour only extends about ten miles or less away from the transmitter. This gives a killer signal over Los Angeles but after LA most of the power goes down Baja California and along Mexico's west coast before being lost out to sea. It doesn't hit land again until it comes to Equador on the west side of the Andes Mtns. One time I was visiting Hawaii and took a rental car to the windward (eastern) side of Oahu. I parked in a beachfront parking lot a few hours before local sunset and was able to clearly hear west coast stations on every frequency on the dial. KCBS wasn't any stronger than the majority of them. Interesting, if you went even a quarter mile inland the signal strengths drastically reduced and you couldn't hear any of them in Honolulu or anywhere on the western side of the island.

Especially the mercury vapor rectifiers dancing with modulation. Dave

Yes in deed- like early disco lights pulsating with the music. Visitors were always impressed with that. @@steampoweredradio2981

I found that I really don't have enough material for a Part 2. Maybe I can get out to the XMTR and get what I need but I just haven't gotten around to it. I should change the title card. Hopefully someday there will be a part 2. Dave

@@steampoweredradio2981 please make a short video for the antennas

Hi Dale, At about the 25:50 mark, I have two graphics that show the pattern. The major lobes for both day and night are pointing around 150 degrees. Dave

A few reasons. Because an AM/FM radio is included standard with almost every new car (except Tesla, FM only). And most 50kw AM stations continue to make money for their owners. They may carry pro sports games, news/talk, or ethnic/foreign programming. For example, 770 WSB in Atlanta Georgia billed $30 million for 2020. Why change a good thing? In general, AM is dying, nicknamed Ancient Modulation. In large cities the noise from modern electronics makes many weaker stations impossible to hear. For every profitable 50kw AM station, there's probably a dozen low watters who are barely hanging on. And often, the land the transmitters are located on is worth more than the station itself, causing some AM stations to diplex or even tripleplex onto one tower site. Digital FM (marketed as "HD Radio") is still included in some new cars, but never really caught on. The US (and by default Canada and Mexico) use a completely different standard than Europe, mostly due to the fact the 200MHz frequency band used for DAB was already in use (1.25m amateur). Our solution was to cram the digital signal into the regular 88-108 MHz FM band. The standard is called IBOC for In-Band/On-Channel, but branded HD radio. It works by adding digital sidebands. For example, a station on analog FM 102.7 will have digital info on 102.5 and 102.9. The pair of digital signals are the same, just redundant for recovering from interference. The digital signal is usually broadcast with 10% of the analog's ERP. Unlike DAB which multiplexes a dozen stations to one transmitter that covers an entire city, IBOC results in a patchwork of stations of varying strengths. If the digital signal gets too weak, it falls back to analog FM. Often the two will be out of sync by a few seconds which is very annoying. Just shows how few people are listening to the digital signal.

@@derek20la I understand the technical details and find quite interesting how DAB is mixed with FM in North America. However, FM offers much better quality than AM. I dont feel any incentive to switch to AM with all the static when there are so many FM stations. What kind of people do listen to AM in US?

Hi, Derek is right. I don't know your age, but I would bet you could put your hands on an AM radio in an emergency. AM has the ability to travel farther than any of the other mediums you mention. Yes, it is susceptible to noise, especially now-a -days when everything has to be connected to the internet including your toothbrush. Speaking of emergencies, when there is a disaster, AM radio is right there. Here in California, we are subject to horrendous wildfires and earthquakes. During the last several events, guess what wasn't available? The internet. Cellphones were down due to towers burning and no power. People in out of the way places had no way to use their cellphones to get info but they all had an AM radio and that signal was able to get into the valleys and other hard to reach areas and provide information they needed. I can't tell you how many times over the years that I worked at KCBS that I had people tell me that, when the disaster struck and there was no cell service or internet, KCBS and other AM stations were there to help them. And FM? Northern California is considered one of the worst FM signal markets in the country because of its terrain. A lot of KCBS listeners listen to the FM side, KFRC 106.9, but when they are on the road and that signal fades away, remember FM is pretty much line of site, they tune to the AM. And DAB? In bad terrain it is even worse than FM. Error correction can only do so much and then you get silence or your radio falls back to a noisy FM signal. In Europe I believe that there are many more transmitters to handle coverage but, in the USA, we still have independently owned radio stations and radio companies so radio here is a more local thing. That's the way radio should be but the trend here is to move away from local radio. A bad call but what can you do? Way back when, AM was for music but that has pretty much gone away now. FM and HD Radio do provide better quality, but it is not perfect. FM has multipath and fades away and noises up just like AM. Internet radio? Well, that's great if you have unlimited data service. Not everyone has or can afford that. Not sure what it is like where you live but here in the USA that's a concern. I like to go to the Sierra Nevada mountains and my 5G drops in and out constantly. AM stations are still there. A little noisier maybe but listenable. What kind of person listens to AM? Probably old people like me. Also, those who like news and talk radio. Those are the two prevalent formats for AM. A lot of AM radio stations have become foreign language stations as well. The future of AM? I suspect the USA will turn off AM in my lifetime. Maybe FM as well. I think we should keep some powerhouse AM's around for emergencies, but government is usually not that far sighted. The internet is the shiny object that catches politicians' attention. Don't get me wrong, digital is great but a good analog recording will outshine a digital one no matter how high the sample rate is. That said, everything I listen to is digital now. That's my thoughts on AM radio. Not everyone will agree with me nor should they. I do hope you enjoyed the tour of the KCBS facility though. Take care, Dave

@@cvetomircvetkov5670 English AM stations are listened to by an older group, generally aged 40+. Exceptions for foreign language and pro sports games. In many large markets, popular AM stations are simulcast on full power FM. Examples are 740 KCBS & 106.9 KFRC San Francisco, 1070 and 97.1 KNX AM & FM Los Angeles. In other cases AM stations can apply for a 250 watt FM translator (secondary service, subordinate to full power stations). This increases their reach to younger audiences. Many simulcast stations brand themselves with only the FM frequency, briefly mentioning the AM signal during the top-of-the-hour ID. While far from their first choice, FM is still listened to for short periods by teens and 20s, usually while in cars or retail stores. Often they only know the frequency for one or two stations (they don't even understand the concept of frequencies). It's doubtful they would tolerate the noise and fade outs common with AM. One final consideration. All of the big 50kw AM stations were built 70 or 80 years ago, before the rapid growth and sprawl of cities. There are cases where the nighttime pattern misses huge chunks of the modern city. Add in the all noise, and this further reduces their usefulness as a commercial business.

@@steampoweredradio2981 It is very different to Europe, even the reasoning for the emergency situations. We had floods and also wild/forest fires in Europe this year. I am located in Bulgaria. I never experienced any disaster situation very close but FM are generally available. About internet radio, I find it very very shortsighted from policymakers. Here in Bulgaria, they constantly prompt people to use their online platform and services. Firstly, elderly people have difficulties with that. On a second note, in case of a disaster, war or political upheaval, internet is completely unreliable

Frank, right now there is no part two. My material for part two was largely unusable. I hope to go out there this spring or summer and shoot what I need. I really should change that title card but I think I talk about part two in my introduction. Bad planning on my part. Dave

Hi. Unfortunately, when I made the first part, I thought I had enough material on the outside of the plant to make another video. I found I didn't but I do hope that someday I will be able to go up the xmtr and get the footage required for part 2. Dave

Yeah, but you would need to have a really big backyard to handle the footprint of the tower and the guys. But it would be cool! Dave

Hi, they're great relays but I should have included a shot of what they look like after a lightning strike. Dave

Hi, transmitters will still do odd things like that. The most common problem at KCBS was PG&E having a leg on the three phase power coming ingoing either high or low. Transmitter would shut down and have to be restarted. Rare but it did occur. Dave

Hi Rick, good advice but in the 24+ years or so that I was the transmitter tech, I only had one time someone came out unannounced to the building. I know, that could have been one time too many but the road was so long and many times in such bad shape that people just didn't want to come out there. Besides the burglar alarm, we had lights at the editors desk, in the studio and in the rack room that let people at the studio know someone was out there. Now Mt. Beacon in Sausalito where three of my FMs were was another story. The road to the building was also part of a hiking trail and occasionally someone would stick their head in the door and shout hello. Gave many tours but never had a problem. Laid back Marin County residents I guess. Dave

Thank you! My Director of Engineering and I were very proud of the site and the condition we kept it in. Ah yes, the programming. I have been away from the company for three and a half years now, but I do know that it is not quite the same place that I left all that time ago. That's as much as I will say though.

@@steampoweredradio2981 The place is not the same since the retirement of Al Hart.

I like that. Never thought about it before. They could use it in the top of the hour ID. 'KCBS, All news 74, the lowest station in the nation'. Audacy would just have to hope that the 'lowest' part doesn't apply to the ratings.

@@steampoweredradio2981 The only station in the US bringing you news from below sea level. hope you have fun with it. I love station ID's I wonder if anyone collects them.

if we were any lower our transmitter would be underground.

Hi Jeff, when I recorded the intro I thought I had a lot of footage that I could use for part two. Unfortunately I didn’t and I hope to get permission to go out there some day and shoot what I need. Since I’m retired from KCBS I just can’t run out whenever I want. Hopefully I can get what I need sometime. Dave