tnx for the suggestions. I will look all of them.
I never use more than 500w as i live in a city with lots of neighbors (hi
hi). I usually run rtty contests and i have learn a gold rule teached to me
by f6irf. If you want to be sure on rtty, use components capable 4 times
your power. So 4x500=2kw.
In my own designs i prefer this limit to be much bigger. So my ant has a 2kw
balun , my amplifier is rated for 1500w, my switches, my coaxial, my
bandpass filters, my antenna tuner, etc follow the same rule: all are rated
on these power limits. Jim teached me so much (i have read 4-5 times his rfi
tutorials), so no problem my friend Jim. I am also very unhappy with all the
----- Original Message -----
From: "Martin" <email@example.com>
Cc: "rfi reflector" <firstname.lastname@example.org>
Sent: Tuesday, April 28, 2009 5:37 AM
Subject: Re: [RFI] where to buy FairRite?
> Jim Brown napsal(a):
>> 2-3kW? Is someone cheating on the rules? If you want to cheat, do your
>> designs and stay out of contests and DXing!
>> My chokes are designed for 1.5kW. See my "Choke Cookbook" in
>> http://audiosystemsgroup.com/RFI-Ham.pdf Note that #43 material is as
>> good or
>> slightly better ABOVE 5 MHz. #31 is much better on 80M and below.
>>> I sent an email to lodestone but i had no reply.
>>> Do you know where to buy them for a cheaper price or is there anyone to
>>> to buy them and send to me in Greece?
>> Everything I know about buying them is in Appendix One of the latest
>> of the tutorial. Make sure you get it directly from my website to get the
>> latest. I don't know if any of those vendors do business outside the US.
>> Fair-Rite has distributors worldwide. See their website for listings and
>> Jim Brown K9YC
> Oh, I would beg for stopping talks about cheating. BTW we in OK are
> allowed to run 750 Watts any time, 2 kilowatts in contests and 3
> kilowatts in contests if you are operating out of any densely populated
> This K9YC's explanation is very true:
> > The key to not overheating them is to make the total resistance in the
> common mode equivalent circuit very large, so that the current is very
> small. In the case of the vertical dipole, which was really a method of
> trying to push the choke hard enough to cause overheating, a single
> choke did not provide enough resistance to achieve that, but two chokes
> in series did. And remember, this test is FAR more severe than anything
> the choke would see on an antenna that wasn't seriously broken! In my
> test, it's the end insulator of a resonant half wave dipole that's
> transmitting 1.5kW.
> Anyway I made my worst experience with _commercial_ products run up to
> its nominal rating. Obviously a 1 kW rated part is good at 100W. I can't
> keep quiet if I use my own design at its limit, a bad joint on the
> antenna can change the things quite dramatically so an overrated part
> (3-4x) makes me quiet :-) For commercial parts, at least made by
> manufacturers, an overrate factor of 10 is not bad.
> Martin, OK1RR
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