What is the best TR antenna changeover switch for your Ham Station n6tlu has performed a test decide 

I knew beforehand that the needle on the field strength meter would be pinned. LoL! Good test. Everything must be shielded.

I have one of those. I suggested he put the relay inside the box 10 years ago. He told me the CBers like to see and hear it click. Most of the time I just build my own or use the Johnson TR switch. I don't use dowkeys. I lost two radios to them. They are old and can stick and when they do, they dump the rig into the reciever. If you could get new 120v dowkeys, that would be one thing. Sounds like it's time for you to come up with a solution Terry. An enclosed TR relay. Small vac relays are best. NO and NC terminals for station accessories and a slow release delay. That is very important for these rigs. They all benifit from a slow release on return. I use the Johnson circuit in my TR switch. Simple diode and cap.

Great video thank you for posting. I just went through T-R relay replacement on a homebrew HF RF amp . I found most standard relays that place the coil perpendicular to the contacts also have an unshielded wire to the switched reed that lengthens the RF path and is usually pushed up against the coil itself: Yikes! Now when I build (

Terry great demonstration the ice cube relay is Junk, I had one not worth buying and no specs. Dow key is the only way to go.

A good demonstration, Terry! You show why you can't treat RF signals like DC, just like you need to properly handle high voltage or high current each in their own way. Using that "ice cube" relay offered no shielding. Oh, and I liked the fact that you made a point about not caring who made the "ice cube" unit; you weren't trying to put down anyone in particular, mainly just showing the problems inherent in the design. I'm looking forward to the follow-up video. 🙂👍

Thank you Terry.

Thanks

Very good information sir thank you so much.

I’ve been using a VersaTR board with my Ranger and SX-99 and this works very well. It’s not ‘period correct’ but it works.

That's great information. I would think the octal socket, assuming a quality socket is used, will be just as good/bad as the socket on the outputs tubes. The long conductor relay contacts in an unshielded housing, though, do seem like EMI waiting to happen. AC7JC

Wow, no thank you, I will stick to the tried and true Dow key. Let's keep the RF where it belongs, in the coax and out of the shack. Thank you Terry for the testing of the two. P.S. I'm liking the new shop extension and I'm sure you are too.

Thanks for bringing up the name Dowkey. An eBay search found a new old stock, sealed-in-bag unit for $13 total. Probably had a value in the hundreds of dollars originally. Has SMA connectors though. For small signal use only. Will work great for antenna and receiver comparison. Has a very high isolation figure. I wasn't familiar with Dowkey before your video.

I used a slightly beefier relay plus I put a baking powder tin lid upside down and held by the octal socket and them put the baking powder can onto the upside down lid and over the relay.

I will always use the vintage dial key relay. W8DMX Kevin

I have been using vacuum relays from jennings or killovac and mounting them in a die cast case i have a conventional relay inside the housing for muting contacts. they take a lot of RF and never fail and the "flight time" of the vacuum relay is much faster.

I have used both kinds for years , no problems here. I tried the same test on mine , as soon as the wire loop was 2 inches away I couldn’t pick up anything. I wonder if we should try the same test on open wire feed line or ladder line. Remember the term skin effect. 73

This problem is real, but it is because of a socketed control relay and really poor wiring in the box. The problem has nothing to do with relay shielding or the relay's internal design inside the plastic cover. The problem is almost exclusively from the wire path lengths and routing from the relay to the connectors. The relay internal construction is perfectly fine if not socketed and if someone is mindful of wiring, shielded or not. The Ameritron RCS-8V and a half dozen others from a variety of manufacturers I designed are well over 50dB worst possible case isolation and cross talk loss up through 30MHz, and that is worst case. It has no shielding at all and the case leakage is almost unquantifiable across HF. It is actually perfectly functional to 150 MHz with its open frame relays. I have designs using $1 wholesale cost cube relays with almost no bump at all measured at 400MHz, and they will handle several kW at HF. Every commercial Ham amplifier made uses either an open frame relay or little cube relays. I've measured 40-50 dB crosstalk loss from input to output in a properly wired relay. We can take a good relay and screw it up with how we route wires and the ground paths through sheet metal. That eBay switch is a great example of how to screw up a design.

Great video. But I think a question might be is that if you can’t get a Dow key how can the ice cube relay be made to be as good as the Dow key or have a similar rating as one?

ok.. but what if that relay was mounted internally in that case instead of sticking up out of the box? if i were to build my own system the relay would definitely be enclosed in the case .... the Doy key is pretty expensive for what it is.

I had the same concerns when I saw this relay at hamfests, regarding RF shielding. This was a fair test. I also wonder how the ice cube relay would react under high swr conditions. I built my own relay years ago, and still use it. It is in a shielded box, with a heavy duty relay, (ker-chunk!) and external contacts for receiver mute. I also use the standard dow key relay for my other stations. The hillbilly relay is a great idea, but in my opinion the implementation leaves a lot to be desired.

what does TR mean?

I think this test is skewed because of the way you wrapped the two devices differently. You really did need a seperate loop from the field strength meter placed exactly in the same position for both tests.

I built a few Ice Box types and have run 350 watts AM on a consistant basis for years. Dow Key do the still make them? Why would I want to search out old junk? Yes a vac relay would be best. I however don't run a commerical station. The relay on the ice box goes I slap in another one. FYI never had to do it. I will take my chances on the newer stuff plus I can pick a higher quality relay to slap on the box.

I gotta laugh at this. I have built and have in use 3 "ice cube" relays. Zero problems ever. In fact I run a bc610 through one thats legal limit AM not some little ranger. Zero issues folks. I think Mr. D lab has run out of things to do to on his channel. But you want to send me some of your dow keys because your so worried about it I will put it inline. But when I key the transmitter I have no worries and do sleep just fine at night.

Sounds to me like you're just hating on the hillbilly RF relay. Maybe investigate and offer methods of improvement for those unable or unwilling to pay the price for a vintage relay.