[Elecraft] Monitoring transmitted signal waveforms

Wed Apr 7 02:15:01 2004

Paul, the place to start is with one of  your scope probes. Next you need a
very low capacitance connection to the center conductor of the coax feeding
your antenna output system. I make my connection at the input to the Bird 43
wattmeter which connects to the antenna selector switch.

Actual connection is with a T- connector in the coax line. Take a PL-259 and
solder a short piece of #12 copper wire in the center pin about an inch or
so long. Cover the wire with plastic tubing or "spaghetti."

Clip the scope probe around the insulated wire in the PL-259 which is
plugged into the T-connector. Connect the probe ground to the PL-259 shell.

This will give you more than enough signal pickup even with 5 watts QRP.
Where the scope probe is grounded is important in picking up a clean signal
uncontaminated with r-f from broadcast stations, RFI, etc.

Unfortunately, just using a length of wire connected to the scope input or
probe has never worked for me. The approach described above has worked best
for me to give a clean sample of the transmitted r-f envelope or carrier
signal, depending upon sweep frequency of the scope.

I also used the SB-610 for many years and still have it, but my Goldstar 20
MHz dual-trace scope is far superior for monitoring.

Let me know how you make out.

73, George W5YR
Fairview, TX
[email protected]
http://www.w5yr.com

----- Original Message ----- 
From: "PAUL WEBB" <[email protected]>
To: <[email protected]>
Sent: Tuesday, April 06, 2004 7:00 PM
Subject: [Elecraft] Monitoring transmitted signal waveforms

> Gentlemen,
>
> I am hoping that someone can help me out with information on how to use an
> oscilloscope to monitor transmitted signal waveforms.  Many years ago I
had
> a Heathkit SB-610 monitor scope which allowed one to "see" the shape of a
> CW waveform and the little "Christmas trees" on SSB.  I could tell if I
had
> any key clicks on CW and if I was overdriving (flat topping) on SSB.
>
> I think there should be an easy way to do this with a regular
oscilloscope.
> But I don't know how to go about it.  I have a BK Precision 30MHz dual
> trace scope.  Any ideas will be most appreciated.  Thanks in advance.
>
> Paul, K5HKX
>
> --- PAUL WEBB
> --- [email protected]
>
>
>
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