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How to Test a Transmitter's Power Output?

 
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How to Test a Transmitter's Power Output?
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endgame
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Post How to Test a Transmitter's Power Output? Reply with quote
How to Test a Transmitter's Power Output?
Wed Sep 19, 2007 11:12 pm View user's profile Send private message
pcs
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By using SWR/POWER meter. Best done into dummy load as antenna may not be
a perfect match and power meter often does not show correct value under such
conditions.

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Marko - PCS Electronics
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Thu Sep 20, 2007 8:37 am View user's profile Send private message Visit poster's website
nay27uk
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Joined: 08 Jun 2009
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marko is ther anyway of doing this with a volt meter, was just wondering as i have had lots of troble tuning my VFO home built transmitter. I would get it so i thought it was on the proper frequency (or at least it sounded like it in the house) when i went for a walk 500 yards away the transmision is on another frequency.

Anyway i managed to get the frequency i wanted but could only recive it for around 1 mile, so i knew it was somthing to do with either SWR or output power, so i went back home determined to get the thing out further and being as tho i had no power meter or swr meter i had a bright idea of using a volt meter on the antenna and final, in the end the black - lead of the volt meter was resting on the earth of the SO239 with the antenna conected, and the red lead of the volt meter was resting on the emiter of the 2SC1971 transister that is also conected to earth, then using the three 40pF variable capacitores in the final stage i tuned them finely untill i got the highest volts reading i could with the meter set to 200VDC the final and highest reading i could get was 03.50V or 3.5 volts if you like.

After doing this i went for a walk and hey presto the transmition halted at 4 miles because of another stronger station.

So back to my question is ther anyway of tuning a transmitter using only a volt meter, it seems to have helped me, but did i do it right, is ther another way of doing it using a volt meter
Sun Jul 05, 2009 11:14 pm View user's profile Send private message Visit poster's website
pcs
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You could do something like this:
http://www.ab4oj.com/pwrmeas.html

Calibrating this versus a real power meter
would be nice.

I think a swr/power meter is something you'll
need sooner or later so why not invest in one.

If nothing else to tune antenna.

_________________
Best regards,
Marko - PCS Electronics
--------------------------------------------------------
Turn your PC into a FM radio station!
http://www.pcs-electronics.com
fax +386 4 2316 128
Mon Jul 06, 2009 1:08 am View user's profile Send private message Visit poster's website
nay27uk
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thank you pal
Mon Jul 06, 2009 10:30 am View user's profile Send private message Visit poster's website
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