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<p>DL4YHF@aol.com wrote:
<blockquote TYPE=CITE><font face="arial,helvetica"><font size=-1>Hello
Jim, Markus, and group,</font></font>
<p><font face="arial,helvetica"><font size=-1>Some on-air testing of Stewart's
implementation of WOLF took place on sunday</font></font>
<br><font face="arial,helvetica"><font size=-1>evening, which was partly
successful (tnx Markus, DF6NM and Jim, M0BMU for</font></font>
<br><font face="arial,helvetica"><font size=-1>their patience and to Stewart,
KK7KA for the new software).</font></font>
<p><font face="arial,helvetica"><font size=-1>Here is the new setup used
at DF0WD:</font></font>
<br><font face="arial,helvetica"><font size=-1>- An LF-transverter which
was once intended to be a linear transverter</font></font>
<br><font face="arial,helvetica"><font size=-1> (until I blew the
first set of matched MOSFETS a few months ago).</font></font>
<br><font face="arial,helvetica"><font size=-1> Transverter mixes
10.136MHz down to 136kHz and vice versa.</font></font>
<br><font face="arial,helvetica"><font size=-1>- An oven-controlled 10MHz
XO which feeds the transverter</font></font>
<br><font face="arial,helvetica"><font size=-1> and synchronizes
the 30MHz 'master' oscillator inside the IC706</font></font>
<br><font face="arial,helvetica"><font size=-1>- An old IC706 shortwave
TRX, slightly modified</font></font>
<br><font face="arial,helvetica"><font size=-1> (30MHz clock 'voltage
controlled').</font></font>
<br><font face="arial,helvetica"><font size=-1>- WOLF signal taken from
soundcard, fed to IC706 in USB mode</font></font>
<br><font face="arial,helvetica"><font size=-1> (to test amplitude
shaping of new WOLF software by KK7KA).</font></font>
<br><font face="arial,helvetica"><font size=-1>- TX output power about
10 Watts (a little more later with "rough keying")</font></font>
<br><font face="arial,helvetica"><font size=-1>- Antenna 200m horizontal
wire (no straight line), end fed,</font></font>
<br><font face="arial,helvetica"><font size=-1> about 8..10 meters
above ground.</font></font>
<br><font face="arial,helvetica"><font size=-1> EIRP once estimated
by PA0SE about 80mW with max. drive,</font></font>
<br><font face="arial,helvetica"><font size=-1> depending on WX (see
www.qsl.net/dl4yhf/lf_index.html).</font></font>
<p><font face="arial,helvetica"><font size=-1>I received the WOLF signal
with the IC706 in "CW" at (10MHz+)137.500, using a</font></font>
<br><font face="arial,helvetica"><font size=-1>the narrow CW filter.</font></font>
<br><font face="arial,helvetica"><font size=-1>To transmit, the IC706 runs
in "USB" at (10MHz+)135.500. The audio frequency</font></font>
<br><font face="arial,helvetica"><font size=-1>should have been 2000.000
Hz, so the transmitted WOLF carrier should have</font></font>
<br><font face="arial,helvetica"><font size=-1>been on 137.500 kHz (but
it wasn't, see below). The soundcard's A/D</font></font>
<br><font face="arial,helvetica"><font size=-1>conversion rate was once
measured as 7938.086, this value was passed to WOLF</font></font>
<br><font face="arial,helvetica"><font size=-1>as command line argument
(because this is quite 'far off', I will verify it</font></font>
<br><font face="arial,helvetica"><font size=-1>later with the 10MHz-ref
divided down to audio freq. Thanks Markus for the</font></font>
<br><font face="arial,helvetica"><font size=-1>point).</font></font>
<p><font face="arial,helvetica"><font size=-1>To Jim, M0BMU: The "test
carrier" was transmitted "CW", so it was not</font></font>
<br><font face="arial,helvetica"><font size=-1>generated the same way as
the WOLF signal. This may explain the problem.. I</font></font>
<br><font face="arial,helvetica"><font size=-1>don't know how you generated
the "leading carrier" before your WOLF</font></font>
<br><font face="arial,helvetica"><font size=-1>transmissions a few weeks
ago.</font></font>
<p><font face="arial,helvetica"><font size=-1>One intention for the test
was to compare the new 'amplitude shaped' WOLF</font></font>
<br><font face="arial,helvetica"><font size=-1>signal. I found that with
the amplifier currently use here, I can not</font></font>
<br><font face="arial,helvetica"><font size=-1>generate such a 'crystal
clean' WOLF spectrum like the one shown on Stewart's</font></font>
<br><font face="arial,helvetica"><font size=-1>updated WOLF page (<A HREF="http://www.scgroup.com/ham/wolf.html">http://www.scgroup.com/ham/wolf.html</A>).</font></font>
<p><font face="arial,helvetica"><font size=-1>It seems that each MOSFET
(IRF540) in the PA needs an indivudual carefully</font></font>
<br><font face="arial,helvetica"><font size=-1>adjusted bias point, and
a little more source resistance (as negative</font></font>
<br><font face="arial,helvetica"><font size=-1>feedback) to make the small
PA work linear. Each FET carries a different</font></font>
<br><font face="arial,helvetica"><font size=-1>current, especially when
the driving power is very low. Result: the damn</font></font>
<br><font face="arial,helvetica"><font size=-1>thing looks like a linear
when the power is 10%...70% of the output, but it</font></font>
<br><font face="arial,helvetica"><font size=-1>does not behave linear when
drive is less than 10% (because of different FET</font></font>
<br><font face="arial,helvetica"><font size=-1>behaviour) or more than
70% (compression point). The low-power linearity ot</font></font>
<br><font face="arial,helvetica"><font size=-1>the PA was better, when
I used the 4 "best-matched" FETS which I selected</font></font>
<br><font face="arial,helvetica"><font size=-1>from a bundle of 50 low-cost
FETS. I blew two of these 4 FETS a few months</font></font>
<br><font face="arial,helvetica"><font size=-1>ago when was experimenting
with a slowed-down variant of PSK31 (which</font></font>
<br><font face="arial,helvetica"><font size=-1>produced the sample modulation
spectrum as WOLF with the option 't 1').</font></font>
<p><font face="arial,helvetica"><font size=-1>The best way to drive a high-power
BPSK transmitter is the way M0BMU</font></font>
<br><font face="arial,helvetica"><font size=-1>described (do the phase
reversal by "XOR-gating", and do the envelope shaping</font></font>
<br><font face="arial,helvetica"><font size=-1>by "modulating the PA supply
voltage" or similar). On the other hand, a</font></font>
<br><font face="arial,helvetica"><font size=-1>'completely linear' concept
will allow low-power experiments with QPSK, MT</font></font>
<br><font face="arial,helvetica"><font size=-1>HELL etc. As long as I am
still resctricted to the crazy power limit in DL, I</font></font>
<br><font face="arial,helvetica"><font size=-1>don't have to care for a
highly efficient TX design (there's enough "spare</font></font>
<br><font face="arial,helvetica"><font size=-1>power" to compensate the
losses in the ATU and in the cable which I consider</font></font>
<br><font face="arial,helvetica"><font size=-1>as part of my transmitter
hi).</font></font>
<br>
<p><font face="arial,helvetica"><font size=-1>Hope I'll have better luck
next time, and thanks to everyone involved.</font></font>
<br><font face="arial,helvetica"><font size=-1>Also thanks to all stations
active in fast CW, which will remain my favorite</font></font>
<br><font face="arial,helvetica"><font size=-1>mode. Nice to meet you again;
no matter if in CW, any kind of BPSK or</font></font>
<br><font face="arial,helvetica"><font size=-1>whatever.</font></font>
<p><font face="arial,helvetica"><font size=-1>73's Wolf (DL4YHF).</font></font>
<br> </blockquote>
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