Freq Counter to display Transmitting Freq?

Freq Counter to display Transmitting Freq?

Post by mark.a.mccuisti » Fri, 14 Jun 1996 04:00:00

I've got this Ramsey Frequency Counter, good up to 600 Mhz.  I use it with
my MFJ SWR analyzer, and it works pretty good.

How can I (or rather, Can I) use the Freq Counter to display the transmitting
freq of my transmitter?  I've built a little FM transmitter with a Coil and
Trimmer, but I'm having a real time figuring out what freq it's broadcasting
on.  And yes, I've done the math on the Cap/Coil, so I'm in the right range.

Thanks.  I hope the answer isn't so simple as "Connect the Freq Ctr to the
antenna output.

--Mark KB2els

 
 
 

Freq Counter to display Transmitting Freq?

Post by Howard Ginsbe » Fri, 14 Jun 1996 04:00:00



writes:

Quote:

>I've got this Ramsey Frequency Counter, good up to 600 Mhz.  I use it with
>my MFJ SWR analyzer, and it works pretty good.

>How can I (or rather, Can I) use the Freq Counter to display the transmitting
>freq of my transmitter?  I've built a little FM transmitter with a Coil and
>Trimmer, but I'm having a real time figuring out what freq it's
broadcasting
>on.  And yes, I've done the math on the Cap/Coil, so I'm in the right
range.

>Thanks.  I hope the answer isn't so simple as "Connect the Freq Ctr to
the
>antenna output.

>--Mark KB2els

The answer is kind of like your last sentence.
Simply capacitively couple the RF to the frequency counter.  Depending
on power output from your transmitter, a cheap and dirty trick is to
hold the freq counter probe out a little from the transmit antenna.  If
the transmit power is 25 watts or so, try 3-inches.  You could also
hold the probe way out, like a foot or so, transmit and move probe
towards (BUT DO NOT TOUCH) the antenna until you see the frequency.
Alternatively, you could sample the frequency at the low power stages.
Howard Ginsberg
NW1N/4
 
 
 

Freq Counter to display Transmitting Freq?

Post by Frank Ding » Fri, 14 Jun 1996 04:00:00



Quote:> I've got this Ramsey Frequency Counter, good up to 600 Mhz.  I use it with
> my MFJ SWR analyzer, and it works pretty good.
> How can I (or rather, Can I) use the Freq Counter to display the transmitting
> freq of my transmitter?  I've built a little FM transmitter with a Coil and
> Trimmer, but I'm having a real time figuring out what freq it's broadcasting
> on.  And yes, I've done the math on the Cap/Coil, so I'm in the right range.
> Thanks.  I hope the answer isn't so simple as "Connect the Freq Ctr to the
> antenna output.
> --Mark KB2els

 =================response GM0CSZ / KN6WH
 Mark, If you switch on the tx ,do you receive a carrier on a receiver ?
If so you can place a freq counter with a simple pick up antenna near
the tx antenna in the hope the freq counter's sensitivity is good
enough to receive the signal.
If you connect the output of the tx directly to the freq counter the
tx might no longer work due to its simple circuit . A second (buffer)
stage following the simple oscillator will be very helpful.
Have fun with your homebrew circuit !

Frank Dinger , Inver by Tain , Ross-shire IV20 1RX - Scotland UK