[TowerTalk] Tower-mounted preamps
spelunk.sueno
spelunk.sueno@mci2000.com
Mon, 21 Sep 1998 20:10:56 -0400
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When one has preamps for V/UHF on the same tower as QRO HF antennas, =
must one take any special precautions to keep the high power HF out of =
the preamps?=20
I am planning a single-tower installation with some kind of HF Yagi plus =
144 MHz, 435 MHz and 900 MHz parasitic arrays. I'm also thinking of =
feeding the HF Yagi boom on 40 Meters. I expect to have preamps for all =
3 V/UHF bands in the feedlines (for ATV and weak-signal 2-M work), with =
the preamps mounted near the top of the tower. =20
I understand from N4KG that I could measure coupled power with a =
Wattmeter at the end of each coax jumper, before it enters its =
respective preamp (Thanks again, Tom). But that means I would have =
already spent the $$ for the V/UHF arrays and might not be able to use =
them. Plus, putting high-pass filters before the preamps will have an =
impact on the noise figure of the array on receive.
Does anyone have experience in using V/UHF preamps with HF arrays as =
I've described? Thanks
-Gene Smar AD3F
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<DIV>When one has preamps for V/UHF on the same tower as QRO HF =
antennas, must=20
one take any special precautions to keep the high power HF out of the =
preamps?=20
</DIV>
<DIV> </DIV>
<DIV>I am planning a single-tower installation with some kind of HF Yagi =
plus=20
144 MHz, 435 MHz and 900 MHz parasitic arrays. I'm also thinking =
of=20
feeding the HF Yagi boom on 40 Meters. I expect to have preamps for all =
3 V/UHF=20
bands in the feedlines (for ATV and weak-signal 2-M work), with the =
preamps=20
mounted near the top of the tower. </DIV>
<DIV> </DIV>
<DIV>I understand from N4KG that I could measure coupled power with a =
Wattmeter=20
at the end of each coax jumper, before it enters its respective preamp =
(Thanks=20
again, Tom). But that means I would have already spent the $$ for =
the=20
V/UHF arrays and might not be able to use them. Plus, putting =
high-pass=20
filters before the preamps will have an impact on the noise figure of =
the array=20
on receive.</DIV>
<DIV> </DIV>
<DIV>Does anyone have experience in using V/UHF preamps with HF arrays =
as I've=20
described? Thanks</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV>-Gene Smar AD3F</DIV></BODY></HTML>
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