| Author |
Message |
    
Slicker
| | Posted on Thursday, August 08, 2002 - 5:09 pm: | 
|
can anyone tell me how to calabrate the siltronix model 90-3 vfo, and also i have a siltronix freq counter FC-1A is there any way to hook this directly to the vfo so i don't have to key up to get a freq reading or is it possible that i could hook it between the transmitter and receiver of my markIII to get a reading with the spot button
Thanks and 73's |
2600
| | Posted on Friday, August 09, 2002 - 12:04 am: |
|
I think the model FC-1A is an inline-only counter with two SO-239 sockets, meant to be jumpered JUST behind the radio's antenna jack. It may also have a jack on the front. It isn't a programmed display like the "FD-1011" that went with the Siltronix 1011 radio. It reads the carrier coming out of the radio's antenna jack. This will cause it to jump around erratically when you modulate.
One thing that probably will work is to tap off the driver tube, feeding to a jack added to the rear of the transmitter. I don't remember if it worked on "Spot" or not, but it would hold steady with modulation because the carrier coming out of the driver tube is steady and not being modulated. This requires that jack added to the back of the chasis, a cable (short as possible) with a plug to match the (usually a BNC) front-panel counter jack to the one now on the back of the transmitter. A small-gauge insulated solid wire soldered to the center pin of the new jack stretches over to the wire coming out of the driver tube plate to the driver coil, and wraps AROUND the short bare wire. YOU DON'T SOLDER TO THIS SPOT. The small coil of insulated wire provides what the textbooks call a "gimmick" capacitor borrowing just enough carrier from the driver tube to make the counter read. If your counter isn't that sensitive, or if it doesn't have that front-panel jack, you may not want to pay what it costs to have somebody modify one that old. If the counter is sensitive enough, and you keep both the wire INSIDE the radio AND the shielded cable to the counter BOTH AS SHORT AS POSSIBLE this one works pretty well. Not every counter with that front-panel socket is sensitive enough, but a lot of them are.
73 |
|
