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<DIV><FONT face=Arial size=2></FONT><FONT face=Arial size=2>17W is more than
enough drive to satisfy any legal output for just about anywhere in the world.
Its all about what type of linear you want to drive and how you develope the
drive power. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The 50W your Elmer's talk about only applies to a
Triode linear amp, if its a Tetrode then 50W will drive it silly. I
can drive a pair of 4CX250B,s on 144Mhz to over 500W with just 2 watts of
drive.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you want to use some of the typical Commercial
1kw linears then your best way forward is a combination of a little
Attenuation on Pennywhistle and one of Granbergs Motorola AN designs from CCL in
Ohio, to give you a 100W output from the HPSDR set up. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you are not the typical appliance operator then
the 17W could easily drive a home brew tetrode amp using 4CX1500 or the RU
equivalent.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The set up here uses Pen to drive a pair of
2SC1969 to around 8-9W then into a a Modified AN762 amp <A
href="http://www.communication-concepts.com/appnotes/AN762Sharp300.pdf">http://www.communication-concepts.com/appnotes/AN762Sharp300.pdf</A>
with a pair of SD106 transistors.</FONT></DIV>
<DIV><FONT face=Arial size=2>My external linear uses a pair of GI7b to give
around 1KW.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The System has been fully operational since 31
January 2009 and I have logged over 2,500 contacts with possibly as many
reapeats and regulars that dont appear in the log. The Rig averages an 8 Hour on
time 7/12 so when people do get operational with Alex they can look fwd to a
well enginered set up.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Shel CT1IZU</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<P></P>I just came back from my digital group showing what I have been
assembling here and the biggest answer I got was pretty much "that's a lot of
money for a qrp rig". This would be my second radio beyond a 5W triband
HT, so 17W did seem like a lot in comparison, but they're saying that it takes
a minimum of 50W to drive an amplifier and 100W is the minimum target in order
to get good transmission on HT. Plus my wanting to explore heterodyning
into higher frequencies cutting into the signal power and this starts to feel
a bit on the weak side.<BR><BR>So... we have Pennywhistle that does 17W.
Other than linking to a second radio, can I get some suggestions as how to
amplify the output from this thing?<BR><BR>Erik KE7YOA<BR>
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