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frequency counter question

loosecannon

loosecannon

Sr. Member
Mar 9, 2006
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just bought a new freq. counter and im wondering if anyone knows any tips or tricks to get a steadier reading from it.

its fine when tuning the clarifier circuit at 34.XXXXmhz, but when i try to tune the SSB IF at 7.8mhz, it just jumps around steadily, like changing the display every second.

yes, i realize this can usually be corrected with the proper gate setting, but i cant seem to get it right.
it is a VICTOR VC3165. paid about 120.00, yep, ebay.
it has continuously varible gate time from 100ms to 10s.

so, is it just junk? or can i help it along?

ive only owned two other counters, both were old, a bit off, but steady.
thanks for any help,
loosecannon
 

i am very sorry to have wasted anyones time.

i do not think this is a counter problem as i just tried it with another radio and it worked fine.
back to the ol' drawing board.
sorry for the waste of space.
loosecannon
 
loosecannon,
It's not really a waste of time, just didn't see the question till now.
For a frequency meter to measure correctly it has to have an input signal to measure. Nothing new there. For modes with a carrier, that 'signal' is constant. For SSB or modes that do not have a constant carrier, the frequency meter is still reading correctly, it's just that the signal it's reading is jumping at the same rate the 'voice' in that signal does. Not very useful, huh? So the 'cure' is to check frequency with a constant signal source, a carrier applied. To make it just a bit more complicated, the direction the frequency changes is determined by the type of SSB, upper, or lower, which sort of go away from the 'dial/channel' frequency in different directions (higher, or lower). And then there's FM. Sort of 'fuzzes' out in both directions from the center frequency.
Unless you can tap into the radio's circuitry at a point where you get a constant signal (with SSB) your freq.meter isn't going to tell you much that's going to help you. It'll work fine on modes with a carrier, just not so fine on all those 'other' modes.
Certainly wish I hadn't found that out by experience...
- 'Doc
 
I thought he was tapping the oscillator circuits.

I was suspecting he was adjusting and finding some very touchy circuits, or perhaps the level was just very low, at the threashold...
 
qrn is correct.

i am tapping into the oscillator circuits.

i am using the test points laid out in the service manual. (sams)

i am using the BNC on the front. there are no SO-239's on this counter.

the radio i am having a problem with is a 2000gtl.
it has been completely re-capped, and is assumed to be working fine, except for not being able to get the IF into spec.

i gave my 139xlr an alignment, and the 7.8mhz IF tuned up perfectly.
no fluctuation on the counter.

problem has to be with the 2000gtl, but i dont know what it would be.

thanks for the responses guys,
loosecannon
 
this is when you need a spec. an. to see what's going on.

How do you go from the BNC to the TP? 10x probe?
 
i am just using the BNC to clip leads cable that came with the counter.
the counter has a X1 and X20 attenuator on it.
LOL on the spec. analyzer.
im not in the bizz, so i cant see myself getting one of these unless i hit the lotto.

i do have access to one, but its an audio type.

like i said, worked fine with the 139xlr, just not the 2000gtl.
im thinking its the radio.

not a tech here, just a die hard do it yourselfer.LOL
loosecannon
 
I've seen issues where that oscillator didn't drive a counter enough to get a steady reading, but worked fine in general radio operation. Tune everything that you can, and then if need be, tweak that last section by "ear" using a test radio. Better yet is to get some kind of signal booster/conditioner for the input of your counter. I don't know where to point you for that offhand, though, I've never looked for one myself.
 
thanks very much moleculo and DTB,

not enough signal eh?
that gives me a place to start.

just so i can use the radio while finding a solution, i tried tuning the 7.8mhz IF cans while transmitting with no modulation.

on the built in freq. counter in the 2000gtl, turning these cans will change the TX freq. so i tuned them until TX was right on with RX per the counter.
havent used the radio yet,
think this might work for now?

i know, kinda cheap and dirty, but this radio works so well usually that i hate having it down.

i will now begin my search for ways to increase the signal to the counter.
thanks,
loosecannon
 
well, i got it fixed, sort of.

the test point for the 7.8 if in this chassis is at the SSB detector end of the cable connecting the two circuits.

i placed the probe on the coupling cap right off of the 7.8 xtal and got a steady reading.

i think the test point should have been at the other end of the cable.
who knows, not a tech here. just a hobbiest.

thanks for the help guys,
loosecannon
 

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