Date: Thu, 11 Apr 2013 10:14:39 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: amps@contesting.com
Subject: Re: [Amps] Date: Thu, 11 Apr 2013 10:14:39 -0700
From: Jim Brown <jim@audiosystemsgroup.com>
To: amps@contesting.com
Subject: Re: [Amps] Look at this Custom 10kW Amp
> who has a higher ERP, the 10KW to a vertical in a restricted subdivision
The resulting RFI to home entertainment systems would make that a recipe
for a lynch mob! Fair-Rite would love you!
## say what? It doesn’t put a dent on any equipment of the
owners of 10 kw amps, so why would it wipe out the neighbours ?
The biggest cause of rfi it turns out is the use of lousy baluns at the
feedpoint.. The secret is to use type 43 at the feedpoint, then a type 31
line isolator at the input of any remote switchbox, which is also at top
of tower. . What else that works superb is to use a physical 1/4
wave coax, – 2%, from top of tower to feedpoint, or 3/4 wave, 5/4 wave.
Run coax down the inside of the tower. At base of tower, ground the
shield, then off to the spg in basement + another
line isolator made from type 31. More Type 43 or 31 directly on output of
10 kw amp.
10 kw lp filter on spg. RFI, what rfi ? Ok, tutorial now over.
On 4/11/2013 5:16 AM, Jim Thomson wrote:
> How about all you olks with 200 foot towers
Which folks are you talking about? My highest gain antenna is a 3-el
SteppIR, and although I live in the heart of contesting country, I don't
know of any 200 ft towers, nor do I know about any 3-el 80M Yagis at any
height, let alone 200 ft!
## You don’t need a 200 foot tower, you are already up 2200 feet, so your 100
foot
tower is ample. What is your noise level on the low bands ?
### And you live on the west coast ? You must be brain dead. You are
surrounded
by 80m yagis’.;..and super tall towers, loads of em.
> reduce your power by 15 db, so the playing field within the sandbox gets
> leveled for the 1st time in 30 years.
Although I do most most of my contesting with a legal limit amp, I
recently ran ARRL SSB DX and CQ160CW QRP (5 watts). I've also worked
some DXpeditiions QRP. That will give you a different perspective. :)
It will also give you greater respect for the guys who have put together
good RX capability, both by working on their antennas and by chasing
down and killing local noise! And it will make you a better operator.
### I will donate $1000.00 to the 1st guy who can solve my 160m noise
problem...
at that point you will get some respect.
Are you suggesting that someone who has to have a monster amp to make
him feel big will be satisfied with anything less than a monster antenna?
73, Jim K9YC
### The end justifies the means. Always has. I view it as an engineering
challenge myself, whether it gets used or not is a moot point. Monster
antenna’s + muscle amps is the ultimate combo. Call once, bam, in + out
in just a few seconds. Far more efficient than yelling for an hr or more with
some rinky dink table top toy amp.
Later.... Jim VE7RF
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