Jim's Antique Radio Museum

Real radios glow in the dark and are warm to cuddle up next to!..

This is the Radio Work Shop page

This page will show you my radio work bench and some of the test equipment I use to work on radios.

Part of the radio room is also my "operating" ham shack where I operate my ham radio on the HF bands and on 2 and 6 meter bands. A picture of me and the ham shack operating position can be seen on the Amateur Radio page.

The above picture shows you "where it all happens" on the radio bench. That nice radio just to the left of center is an HRO-500 that I just bought. This radio and I go back around 35 years when I worked at National Semiconductor and the HRO was a piece of Lab test equipment.  I have used the radio "way back when" as an oscillation detector for semiconductor test decks and it worked very well.

On the bench, just to the right of center, is a Knight R-100 receiver I was working on until the HRO showed up. The Knight is a very good receiver and the audio in the headphones is very sharp and clear.

On the far right is a Zenith model 600 Transoceanic radio similar to the one we had in our radio van in Korea so we could hear all the news from home.

BTW the work bench and the hutch on the back were built by me. Another of my MANY hobbies is wood working. The hutch was actually built to go with a desk I made for my son, but he decided he didn't need it so I said, cool, I know just where to put it.


This is a Jackson RF Signal Generator.

I can use this to troubleshoot any of the RF circuits in the radio. Just inject an RF signal (like at the antenna terminals) and see if that signal makes it through the RF stages.

This is an Audio Signal Generator.

Like the RF generator, you can use this device to help troubleshoot any of the Audio stages in a radio.

A much more useful tool is this RCA Sr. VoltOhmyst.

This is a VTVM and is a high input impedance volt meter that can be used at sensitive points of the radio without loading down the signal you are trying to measure.


I haven't worked on any FM sets yet, but I have this generator when needed.

It is nice to have a well rounded set of shop tools because you never know when you will need this instrument.


Probably the single most important piece of test gear in a radio shop is a tube tester. This is a WWII military model I-177.

To test antique radio tubes you need an antique tube tester. Part of the reason for this is some of the oldest tubes had only 4 pins and any tube tester made after about the 60's-70' s probably won't have a 4 pin socket.

Also, there are two types of tube testers. One is the Emission type and the other is the Dynamic Mutual Conductance, or Transconductance type. This one is the latter.

If anyone is looking for the manual for this model tester it is TM 11-2627 and copies are still available from sources found on the internet. I used to know who manufactured this one but I have forgotten....so if you know please drop me an email.

This tester is one of 5 that I own and some of them even work. You see a tube tester has a couple of tubes itself, so what do you test those on if they go bad?  Therefore you need a second tube tester......at least that is what I told my wife!


This is just a tiny view of STUFF on the work bench.

You see WD-40, the all purpose lubricant, anti-rust spray can. Next to that is a VARIAC, which means a Variable AC transformer, or Autotransformer.  This allows me to bring up the voltage slowly on an old radio so the surge current of full voltage doesn't do damage.

Next you see a magnifying glass on a stand and that is probably a clue that I am almost as old as some of my radios.

Adjacent to the WD-40 is an oscilloscope that I can use to "SEE" the signals when all other methods fail.  Sometimes the signal you SEE, is not what you expected to see and that helps a great deal in understanding what is wrong.


Another piece of test gear I will probably never use is this Weston model 799 insulation tester.

This is basically a leakage tester and it might be able to test for leakage in a capacitor. However, it is not a breakdown tester because it only uses 50 volts for the leakage test.

The case has provision for two batteries. The "A" battery is 1.5 volts and the "B" battery is 67.5 volts.

The calibration sticker on this unit shows the last time it was calibrated was in 1972. I suspect this is WWII vintage equipment based on the packaging.


I have had this equipment at least 45 years, long enough that I have forgotten its history.

The equipment looks home brew, but the meter dial face on the left has a National Radio Co. logo on it.  Perhaps National made a kit for the home brewer to use. It is both a Grid Dip Meter (GDO) and a Wavemeter.

The outfit includes 10 plug in coils, starting with a coil with just one heavy loop on it. I assume that coil is for the wavemeter, but not sure.

The paper in the lower right is calibration data I took years ago which shows the frequency range for each coil. 

I wish my mind worked a little better in remembering how to use this unit, but if you have more interest, I found this web site that seems to be very informative on the subject: http://www.qsl.net/n4xy/gdos.html

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