[50mhz] 6 meter performance on Icom 756

[Gordon Couger]

If your serious about weak signal work on six you will need a
preamplifier. At least you don't have to put it up on the antenna
like on 450 and up. A high Q cavity or some narrow filter will solve
the selectivity problem but they are a bit bulky on six.

http://legitimate.org/iook/sixduplex.html is a cavity made from
Heilax I don't know how good the noise figure would be on it but it
would cut out the crap from out side the area of interest. It should
be good enough to let you use a lot of gain with out bringing in
every TV in the neighborhood.

I have seen 2 meter cavity pre amps that used the best amps and 1/4
and 1/2 wave cavities. The half wave had the best noise figure but
were a pain to make and a bigger pain to test.

If your are really serious I can chase down the guy that builds
them. He will build you one or tell you how to build it. He shares
very well but 50 MHz is way below his usual working area. He is more
likely to be playing with 5 and 10 GHz or higher if he can get the
stuff to go there. I still see him but he does not have much in the
way of pre amps at hamfest anymore as they don't sell.

73

Gordon W5RED


Gordon Couger
Stillwater, OK
www.couger.com/gcouger
----- Original Message ----- 
From: "Lance Collister, W7GJ (DN27ub)" <w7gj at bigskyspaces.com>
To: "John Geiger" <johngeig at yahoo.com>
Cc: <50mhz at mailman.qth.net>; <vhf at w6yx.stanford.edu>;
<6meter at yahoogroups.com>
Sent: Wednesday, October 06, 2004 5:04 PM
Subject: Re: [50mhz] 6 meter performance on Icom 756


: John Geiger wrote:
: > I wonder if anyone on the reflector could give me some
: > feedback as to the 6 meter performance of the Icom 756
: > original.  I am assuming that it will do much better
: > than what I have now for 6 (icom 706), but are there
: > better non PRO 6 meter rigs out there also?
: >
: > 73s John NE0P
: >
: >
: >
: >
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: Hi John,
:
: As far as I know, the IC756 is a very good rig, and puts out a
clean signal.
: However, it is my understanding the the noise figure of the front
end is around 5
: dB, which makes it pretty hard of hearing.  Turning on the
internal preamplfiers
: does nothing to improve this front end noise figure - they just
amplify the noise
: coming from the insensitive front end.  Like many modern rigs
(including the more
: recent versions such as the IC756 Pro II), the design has
sacrificed sensitivity for
: strong signal handling capabilty.
:
: If you are interested in using it primarily for weak signal work
on 6m, I urge you
: to get a good low noise external preamplifier, such as the CA50T
model from
: (http://www.lnatechnology.com/).  The IC756 is very well suited to
this, since it
: has a connector in the back that you can use as an auxiliary
receive only antenna.
:
: GL and VY 73, Lance
:
: -- 
: Lance Collister, W7GJ (ex: WN3GPL, WA3GPL, WA1JXN, WA1JXN/C6A,
ZF2OC/ZF8)
: P.O. Box 73
: Frenchtown, MT  59834  USA
: QTH: DN27UB
: TEL: (406) 626-5728   FAX:(406) 626-5728
: URL: http://www.bigskyspaces.com/w7gj
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