[NLRS] DEMI 10GHz transverter concern
Robert E. Wesslund
[email protected]
Wed, 22 Oct 2003 17:46:47 -0500
Hi Chris,
Yes! That is the LO. It is enough to drive my counter with just a 7 db
horn on the input. Gary, W0GHZ, is putting a filter between the
transverter out and the power amp. I have noticed it for some time It
could cause some problems depending on how you switch the pa.
73 Bob W�AUS
-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of Chris Cox, N0UK
Sent: Wednesday, October 22, 2003 3:00 PM
To: NLRS
Subject: [NLRS] DEMI 10GHz transverter concern
I was just playing with my new (old) HP141 analyser and having had enough
of seeing which 144MHz repeaters produced a signal strong enough in the
living room to register on the display (surprisingly quite a few!) I
decided to take a look at the 10GHz transverter. As most of you probably
realise, that was the main driving force behind investing in the beast
anyway!
So, with it running keydown, it produces a very nice, single-source
carrier on the desired frequency. Yippee!
However, with no drive applied, but transmit enabled on the transverter,
it produces a full-power signal approximately 150MHz down from the desired
output - the LO frequency. Note, the LO leakthrough disappears completely
in the presence of 144MHz drive. This anomolous response is present on
both SSB and CW.
There are no other spurs within +/- 500MHz of the desired output strong
enough to register on the display, although there were two spurs evident
about +/- 800MHz of the desired output, but they could be sporadic mixes
with other signals in the low to mid UHF region - I was measuring across
the room from the dish to an open waveguide transition on the analyser.
Has anyone observed this strong LO leakthrough in the absence of 144MHz
drive?
I'm going to try fitting a pipecap filter between the transverter and the
PA to try and squelch the badness.
--
73 Chris Cox N0UK, G4JEC, ex-AB0CN, ex-G8PTC RNARS #1157 EN34jv33
[email protected] Ping Jockey's do it until they HEAR the burn...
WWW Home Page: http://WWW.Chris.Org/ http://www.pingjockey.net
Cultural observation:
Europeans think 100 miles is a long way;
Americans think 100 years is a long time!
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