[Lowfer] " XR " WSPR

[Andy - KU4XR]

Hi all:  First; Thanks to Lloyd, Jay, and Laurence for looking 
for the WSPR signal. My best guesstimate for power output right
now is about 500 Milliwatts on the air. I am running completely
Class " AB " at the moment; but it's the only thing that will
work.. I tried to run the radios output thru the Class " D " amp,
and for whatever reason; that's unknown to me, it would not 
show any output over about 50 Milliamps of RF. The drive from 
the radio itself feeding straight into the 50 Ohm LPF into the
matching coil was higher than that. So I tried the TDA7052B,
and got a respectable output level. The RF current continues to
rise as the ground dries from Sat's. rain and is up to 115 mA.
For the 1 watt in Class " AB " 125 mA will be the max on RF " I "

For a good dose of laughter, here is the setup that gives best
performance so far. The TDA7052B is a BTL amp, and trying to run
it single ended never gave much output, so I connected a small
8 Ohm speaker to its terminals, and am tapping output from the
speaker terminal that gives the best output into the 50 Ohm LPF.
I tried bypassing the LPF, but the output is better thru it.
I'm sure that if I had a filter designed with an 8 Ohm input,
to a 50 Ohm output, that would be even better.. I am feeding the
radio thru a .3 µF cap into the amplifier input. The drive level
is MUCH too high. I have everything backed down to almost off,
to keep from driving the audio amp out of its mind... Again;
this is a crude, throwed together setup to get on the air.

If I'm thinking correctly; I really need to put a squaring
circuit in the line so that it will " hopefully " drive the
Class " D " amp. 

Doug: Thank you for tieing up your equipment.. You have shown
as Jay mentioned that it is working.. Your spots on the 
database give me a feeling of accomplishment.. I can finally
say that I have successfully ran a digital signal, copyable
past my driveway, on 1750 meters. I really appreciate your time.

Until I can do better;  73 to all for now:


Andy - KU4XR - EM75xr - Friendsville, TN. USA

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