<LONG>QRP+MOD FOR W1AW TROUBLE

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From: ERNEST GREGOIRE (GREGOIRE@VALLEY.NET)
Date: Sun Aug 27 1995 - 09:32:44 EDT


        Hi All, I have completed a modification for fixing splatter on 80
meters regarding the W1AW code practice signal. For a quick catch up on the
problem: W1AW broadcasts on 3.581.5 for buletins and code practice. A
problem in the local oscilator of the Index Labs QRP+ rig was made accute
due to the strong signal on this particular frequency. The spur was found in
other bands as well, according to tests done at Index.

The fix was to move the braid on the L.O. from one place to another on the
third board down in the rig.( Not as bad as it sounds).

It worked, for the most part. I believe that this is the frist step in
cleaning up the receiver. Other minor problems exist. I can now hear the
W1AW signal on 3.581.5. I could not do that before.(The audio had a buzz to
it and was very much attenuated, even though the signal was 60 over 9). I
can also hear it at several spots down the band, but not as bad as before.
Using the 20 db pad, and a narrow C.W. filter setting is the key to
listening to W1AW. Using the norrow filter can eliminate the spill over on
the rest of the band.

Now for the rest of the problem. A whistle can be heard on certain
frequencies. Can any one else duplicate this ? I'm wondering if this whiltle
is unique to my radio.

Here are the results:

This test was done with no antenna connected to the radio and
using the C.W. filter set to .2 KHz . A whistle was heard on the
following frequencies:

80 meters 40 meters 30 meters 20 meters
                                                                             
                                            13.999.2
3.518.8 7.027.8 10.113.4 14.083.2
3.570.6 = s 1.9 7.036.2 14.125.1
3.580.0 7.050.3 14.188.2
3.623.1 7.080.0 14.158.8
3.665.1 7.142.1 = s 3.2 loudest of all
3.709.7 7.160.2
3.749.1
3.752.6
3.780.6
3.793.8 very low level here

17 meters 15 meters 12 meters 10 meters
     

18.094.8 21.077.5 24.921.1 28.076.8
18.134.3 21.161.5 28.244.9
               21.250.6 28.418.3
               21.418.7

The volume on the radio had to be turned up loud to hear the
higher frequencies whistle. The lower frequencies could plainly
be heard.

Bruce sent me a hand written diagram of the board and where to move the
braid from and too. I will get that digitized and have it available as an
attatched file soon. Write to me directly and I'll send it to you.


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