[RFI] IN-band Filters
hamradio at oz.net
Wed Nov 8 12:30:40 EST 2006
I sure agree with Jim. I have an IC746Pro and an IC756Pro3, both of which I
use a lot and like really well (ordinarily). But last field day on 20 cw
there was a constant S-9 level of hash between signals on the 746Pro
(overload, intermod, etc. from all the big signals on the band at the time)
but switching over to the 756Pro3 the background hash between signals
dropped to about S-1 on the same frequency/antenna. Signals levels remained
about the same. A very impressive comparison for anyone who heard it.
Except for this sort of extreme situation the 746 is great, but there is a
de Randy, W7HR
Port Orchard, WA
From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com] On
Behalf Of Jim Brown
Sent: Tuesday, November 07, 2006 4:31 PM
To: RFI List
Subject: Re: [RFI] IN-band Filters
On Tue, 7 Nov 2006 17:00:14 -0800 (PST), Bryan Swadener wrote:
>We have use of a site that will allow up to about 1000' separation.
That is by far your best solution.
As the architect of some competitively scoring FD stations, I agree
with others who have noted that stubs dont have nearly enough Q,
and that heroic measures are needed to achieve even a little in-band
Your choice of 100 watt radios like the K2 that are relatively clean
and have very good receivers is the right approach. TS850s make
good FD radios too. Avoid cheap radios (FT100, IC706, IC746, etc.)
like the plague. Their receivers overload easily, and their
transmitters are broad as a barndoor too.
Likewise, having high flat dipoles for stations on the same band at
right angles to each other helps a bit. So do baluns, IF they are
good enough to take the transmission line out of the picture. But
dont expect much help from low dipoles or inverted Vees.
Jim Brown K9YC
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