Great video I just came across last week actually. I found this interesting enough to watch several times also. Sunday morning while at the Toledo Hamfest I came across a BC-122F. All aluminum case and appears complete except for the fact it has been converted to 120 VAC mains. The seller was happy to be rid of the "old anchor" and I was thrilled to carry the gem home. As it appears basically original I'll be doing a lot of research and restoring before the old gal will be ready for power. Thank you for the great videos you are producing and may you continue for years to come!
This is a fascinating video! Years ago I saw the BC221 mentioned in QST many times. It was very popular for those interested in the frequency measuring contests.
MIKRO, An interesting video and great to see the BC221s and the other kit you have in the background. However you did not cover the calibration procedure using the corrector control inthe video. You might find that the 170Hz error is a lot less if the instrument is corrected at the nearest crystal check point to the required frequency. Its still not bad oscillator linearity for an instrument which is probably 70 years old. Thanks for taking the time to make the videos, and keep them coming!
Fantastic! I hope this stuff (and radio in general as we know it) doesn’t go away any time soon. That’s a big fear of mine, now that I’m seeing the apparent slow but steady extinction of AM radio…
Don't underestimate the NAB lobby. They will not give it up it up easily. They may even allow more low power "hobby" AM stations access to the band, before relinquishing it.
Thank you for this video...My old friend W9UOI, Charlie Dickinson SK, introduced me to the BC221 and it is indeed a wonderful and most useful piece of equipment...Bill, WB9NYI
Thanks for the excellent video. I just thought that the BC-221 was just an early version of a frequency counter - It appears that is much more than that. I am especially interested in the fact that you can use it to spot your transmitter/receiver combo on net frequencies. I'll be looking for this unit at next hamfest.
Most of the BC-221's that you find were converted to AC operation either by hams or by the military themselves. Typically you will find a small power supply in the battery box. Look at the typical 6.3 VAC and 150 VDC PSU schematic here: radionerds.com/index.php/BC-221 and here: radionerds.com/images/4/4d/TB_11-300-3_RA133_power_supply.pdf
Thank you for another very interesting video. You probably already know this but to lower the tendency to lock of your regenerative receiver you can lower the mutual coupling on the transformer. That will also lower the overall gain but there's always a tradeoff. I've never used valves so I'm not sure but lowering the anode voltage should give the give the same result.
Yes Vic was a good friend and he was a regular in the Old Military Radio Net CW Edition on 3570 kHz on Sunday evenings at 9PM EST. Vic disappeared a couple of years ago from the airwaves and I fear that he is SK.
I have 2 of these as well,, one is a zenith, with a really nice power supply, so nice it wouldnt surprise me if the military did because the quality of work is amazing,, if memory serves me right it had a germanium rectifier..
hi i remember having a bc221 in 1968 i remember that the calibration book has a serial number which should match the serial number on the frequency meter to ensure you have the correct cal points Peter N.
A great video showing and BC-221 Frequency Meter. Can you give me a diagram of the coil you used to receive CHU Canada time stamp using the Frequency Meter
Thank you for a fascinating video. Mine just showed up today :^) I'm curious about the function of the beam filter in the tuned circuit demonstration - to limit the bandpass to the amplifier? Also, what would be an alternative approach with discrete components?
i like to put my scope on my bc-221 to see how accurate it still is. i have a BC-221-T. But i do not know where i could tap in to measure it. i have never worked with tube equipment so this would be my first. i think my scope would not really like a 135v dc on the input. could you give me a few tips?
These meters were calibrated by computers. It took 16 hours to calibrate each meter. By the end of the WWII they were deemed useless by the military and sold for as little as $5.00. The Russians copied the designe and used them well into the 1970s. Great video. Thanks for posting. I hope you post more. I also like your ARC-5 videos as well. 73. KF0XO
I have one that I bought 30 years ago when I was into radio. On the shelf since then but was working well when I had it. No use to me if anyone wants if for say £25?
Great video, how did you connect the frequency counter to the meter? I’m interested as I would like to check and adjust the crystal frequency if required. I’m thinking that the harmonics may make it difficult for the counter.
As with all your military radio/equipment videos, I am fascinated. These are excellent tutorials and references -- and entertaining! This time, however, I come to you for assistance. I have the good fortune of scoring a BRAND NEW IN THE BOX TS-323. This, of course, is the 20-450 Mc version of the above. It is pristine and packed without batteries or manual (save for the calibration book). I would like to get it back "on the air" and wonder if you might help me? I would ask your guidance in waking it up, building a power supply for it, forming the caps, etc. (I believe the A+ and B+) rquirements are similar to the SCR-211. Any guidance would be greatly appreciated. I am k6whp and I am a member of the ARRL. (Nudge, nudge, wink, wink.) Thanks in advance! ~Bill, k6whp
Hello Mikrowave1, Thanks for posting the video of the BC-221-AN frequency meter. Are these rare at all? Reason I ask, I just recently bought one of these at a yard sale and I am looking to sell it, but don't know anything about it, or its value. While I did look online for some info on the 221-na, I have found there is MUCH more info on the "BC-221-N" or "BC-221-A", but much less on the "BC-221-AN". What's the difference? Any info would be great! Thank You in Advance!
Nice video on the frequency meter. I have a TS-175U unit that oscillates from 85 to 1000 megacycles and has a type N connector. It missing the 66/u antenna. It is in good condition and for auction price of $5 not a bad deal. No doubt this unit was for testing early radar units on ww2 aircraft. Inside it has a 5000kc crystal and a tube rack with spare tubes. Crystal check points on the final pages of the chart are 200,400,800 and 1000. To get to 1000 megacycles you need to work on the 5th harmonic. A schematic shows a set of 135v and 6v batteries. How do you power your unit? I need to get it running and check on the spectrum analyzer. Have you checked the harmonic output on your unit?
I just got a couple of these on luck. I could tell right away that they were very well built equipment, and it looks like they are unused. they work, but I have no need for them, as I don't know anything about radios other than speaking into one. if anyone wants to give one a home, I am willing to part with them.
well theyre in California, I would need at least 30 bucks a piece for them, and we could arrange shipping after we strike an accord. let me see if I can message you my info
hello i own an ww2 SCR-211-AJ / BC-211-AJ. its looks to be pretty good condition. the wooden exterior is not so great. paint peeling, wood peeling. but the dial panel and everything behind it is absolutely prestine. however it appears the back battery compartment was modified by someone ? it now has installed a tray with transformer and tubes with an electrical cord. one tube glass is broken. i have not attempted to use it or anything. but a search online found this video! i am in NJ would be nice to meet someone like you who could give mine a little a love back to life!
That is the "standard" AC Power conversion done right by the book. The set was made to run on batteries, which nobody wanted to do. Now those old power supplies are suspect in many ways and need to be gone over!
Nothing was said about how the set is powered. I assume that batteries are not used, instead the power comes from a power supply. It would be nice to see that, too.
Someone asked this 3 years ago: Most of the BC-221's that you find were converted to AC operation either by hams or by the military themselves. Typically you will find a small power supply in the battery box. Look at the typical 6.3 VAC and 150 VDC PSU schematic here: radionerds.com/index.php/BC-221 and here: radionerds.com/images/4/4d/TB_11-300-3_RA133_power_supply.pdf
Bit puzzled by the 3750 test. The charts are not in focus so it was hard to see which you chose. You spoke 3824.9 which is not the 170 hz error to which you referred. Where did I go wrong? 73 G3NBY
So I have one of these frequency meters, a bc-221-t. My problem is that it has a hefty requirement for electricity at a capacity that I cannot reach. Without the original batteries from 1941, and the strange power supply cord, how would I power this piece of equipment. A better question might be, how did you manage to power it?
Apparently MIKROWAVE1 went to sleep on us so let me see if I can help. If you Google "BC-221 Power Supply" You'll come up with some simple classic circuits. You will need about 127-135 VDC B+ @ about 100 mA and 6.3 VAC @ 1 Amp for the filaments. You can get the transformer off of eBay and the HV caps and resistors and diodes at a local parts house. Should cost about $20 total unless you have a good junk box. I posted something about my restorations of these units on righthandofzod.blogspot.com - take a visit.
Thanks for the reply. I did get the machine to work just fine by buying 9 volt batteries in bulk. This technique has also helped me restore a scintillation counter from the 50's. I managed to wrap the bc-211's antenna around the stock antenna of a dirt cheap and terrible shortwave radio. I was able to get it tuned so well, I love this machine. I do need a better power supply because the 9 volts only lasted me 4 hours.
+William Phinizy I took a look at what you had posted on your website and found it entertaining. I loved my 4 hours with my bc-221-t. I didn't find much information on exactly how your dad put the power source together. I was wondering If you would mind opening it up and sending me pictures or even a schematic. I have managed to find other schematics for power sources, but the more the merrier. I only had 4 hours with it working and I know that It holds more mysteries than what I was able to learn about it. Any help is much appreciated.
Hello there !!Looks like a good video, but sound quality is poor can hardly hear you with volume up 100% and earphones on, suggest usinga lapel microphone !! but keep up the interesting videos !!!
BC221 Top left/h corner of panel. Ant and Ground terminals. Are these retro -fitted? Mine doesn't have them but single antenna on the top (not centred) of the case. There's no obvious place to connect an RF ground. Doing (or Trying to do) what you suggest is a messy business. 73 G3NBY.
Can someone give me their email?! I have a Knight-100A receiver and a BC-221AH that I just picked up. I don't really know what I'm doing but I can send pictures and I'd like to learn what else I need and how to operate it. Any help would be appreciated
