Siltronix 90-3 VFO in the bench

Just doing a walkthru with a Siltronix model 90 VFO on the bench. The most commonly used of these were the number 3 which had 16mhz output and was used with the Browning Golden Eagle Mark 3 radios. The other variant models, 1-9 had different frequency outputs and were used for other radios. The number 7 VFO had 15mhz and could be converted fairly easily. Siltronix also made the model 80 VFO's but these had only one frequency band and covered around -8 to +40 range. The 80's also did not have any Xtal/crystal slots while the 90 models had 3 slots. One would normally remove the channel 23 crystal from the radio and plug the VFO into the channel 23 slot. With the 90 only, one would then insert the removed 23 channel crystal and place it into the 90's Xtal/crystal slot. Now if one wanted to go to channel 23, they would place the radio's channel selector on 23 and then place the VFO to the Xtal position. The 90 had 3 Xtal slots so if you hadd a favorite channel, say Super-Bowl 6, one could get the correct crystal, install it in the VFO, and could access the channel directly thru the VFO. The 80 did not have this feature at all. Also while the 80 had one band, the 90 had an upper frequency band too. With the 90 on 'CB', you would have the same VFO frequencies that the 80 had, -8 thru 40. However, the 90 added a 2nd band. Turn the CB switch to 'HF' and now you would be on the upper band/upper dial, High frequencies. These would start at around channel 35 and take you up to 85 if the radio could go that high. Most Brownings were not that wideband though. The Siltronix VFO's put out about 1v which is not quite enough to drive some radios. Nowadays, they make and sell VFO amplifiers for pretty cheap. Also, Siltronix VFO's are not crystal controlled. They use a cap/coil combo to get the oscillator to work. Of course cap/crysal oscillators are not as stable as a crystal, PLL or modern DDS VFO is. However, the size and looks of the Siltronix is similar to the Brownings and old vintage radios and many old timers prefer the vintage old school over the modern new school stuff.

[keithweiss]

Excellent explanation! You know that Siltronix is simply Swan, who made ham radios. The funny thing is that hams like to call the Swan 350 the “drifty fifty”. But my Siltronix (Swan) VFOs aren’t very bad. Neither is my 350. I think in the day of sophisticated PLL circuits we have gotten too used to rock solid stability. In the tube days, that you and I are from, drift was simply something we dealt with. I love my MkIII with my 90 #3 on it. I do have a modern programmable frequency counter on it though. A $17 luxury!😊
Thanks Doc!

[EricTechstuffs]

This was very cool to see them side by side ! BIG difference from and 80 to a 90 ! I wonder what retail was back then...

[CatboxWA]

Thank you for another fine show-n-tell . Also sorry about your poor experience with paypal and shipping . I would definitely do business with you again as you have earned my trust .

[CatboxWA]

I have a small siltronix "23 channel " VFO . Its supposed to work on Lafyette CBs and some others . Had it for years and never hooked it up . I have a couple of radio's that it is supposed to work on . One has a bad final and the other works poorly. I doubt I will get around to pairing them up . They need a good home .

[xabeque]

Siltronix also made smaller versions of their VFO's. I have one that is labeled 40 and on the back it has 2. I could not find any documentation for a number 2 version Silytronix. Then on your video, I saw that you have a detailed Siltronix guide that shows a 80 that has version number 2. I grabbed a quick screen shot of your book showing the versions and their frequencies. I assume 80 and 40 version 2 are the same. Correct me if I am wrong. Also I have a Siltronix the size of a 40 but just labeled VFO by Siltronix but also showing a version 2 on the back of the VFO. I assume it is also the same as the 80 version 2. But again, correct me if I am wrong. Thank you for your video.

[CatboxWA]

I'm looking for a crystal sets for a Radio Shack CB. Channels 6/11/17/26/28 . Ch6 is the one I most want .

[bblod]

At 3:00...What are the circular ceramic things next to the crystal mounts?
Thanks for the video.

[Ohm-]

"Hey Mr. tramdr it looks good.... how much? 😃

[rogerfl]

You don't happen to have a siltronix 90-6 would you tram doctor for my realistic TRC 48??

[frankc]

Does that control the receive or does that control both the receive and transmit?