[Amps] Alligators

[Peter Voelpel]

Hi Jim,

I do not think that K9AY loops are of any help on 20m,
there I prefer yagis which are quite useful to supress qrm from some
directions.
Most are using groundplanes or dipoles here as the have no permit for large
antennas,
few have multiband yagis 

All the antenna projects you mention are useless against qrm from other
stations near your frequency within the passband of the if-filters.

Again, the receiving problems have nothing to do with electrical
interference or electrical noise.
I have used the Orion in contests and use myself a pair of IC-765s and
modified drake twins.
The R4C and the 765s make use of smaller roofing filters.
In large contest qrm is tremendeous, especially when using 100W you will
hold no frequency.

Very few people are able to run high power (750W) in Germany with all that
electronic junk in their neighbourhood.  

73
Peter



 

-----Original Message-----
From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
Behalf Of Jim Brown
Sent: Montag, 5. März 2007 23:21
To: amps at contesting.com
Subject: Re: [Amps] Alligators

On Mon, 5 Mar 2007 22:29:06 +0100, Peter Voelpel wrote:

>You should come over and try to run a frequency with 100-400W.

I spent 50 of my 51 years as a ham in a city (mostly Chicago) on a tiny lot
with low dipoles. For all but the last 3 years, I ran 100 watts. I really
doubt that the QRM is a lot different between EU and North America. There
are many very big signals here too. :) 

>What receive antenna do you suggest to suppress S9+ qrm in Europe?

There are many excellent receive antenna projects in books like the ARRL
Antenna Book, ON4UN's book, and books published by EU radio societies (for
example, RSGB). There are antennas you can build, and products you can buy.
There is a tutorial on my website that shows how to use ferrite chokes and
other filters to minimize receive noise. W8JI has some great stuff on his
website. Also google for K9AY. 

There are also huge differences between the receiver sections of low cost
transceivers and more expensive ones. The better receivers have far less
overload and spurious noise generation from stations on adjacent
frequencies. For example, search the ARRL website for an article by an EU
ham on "The DX Prowess" of ham transceivers. It was written about 5 years
ago. 

73,

Jim Brown K9YC


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