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RE: Receiver desense problem



George

It seems that the problem comes from your preamplifier.
I personnally use an ICOM 821H with a 9el 145 MHz Yagi
and a 21 el 435 MHz Yagi.
Both Yagis are installed on the same boom, in a X configuration.
It does mean that each antenna is pretty close to the other.
I dont use any preamp and have no problem when transmitting
at full power (about 40 W RF).

73 de Jean-Louis F6AGR
JN18DQ
 ----------
De: o=INTERNET;p=THOMSON;a=ATLAS;c=FR;dda:RFC-822=owner-amsat-bb(a)amsat.org;
A: o=INTERNET;p=THOMSON;a=ATLAS;c=FR;dda:RFC-822=amsat-bb(a)AMSAT.org;
Objet: Receiver desense problem
Date: samedi 27 juin 1998 01:44

My 146 Mhz transmitter at 5 watts or more is heard in my 435 receiver while
accessing the satellites. Although I can hear my downlink the sound is
distorted and in CW follows the keyed rf.  This only happens when using a
preamp which I need with the IC-821and KLM 18 el beam.  My transmit antenna
is a homebrewed 4 element quad, both separated by about 5 ft on a PVC boom
and operating in horizontal polarization.  If I mount my KLM antenna in the
X configuration would it make a difference?  The quad is tuned to 146Mhz
and the SWR is flat.  Are filters commonly used to get around the problem?
If so can anyone recommend one that worked for them?

Thanks in advance

George, W2CID



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