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Re: [TowerTalk] Distance from exciter, amp, tuner, dummy load, antenna

Subject: Re: [TowerTalk] Distance from exciter, amp, tuner, dummy load, antenna
From: "Roger (K8RI)" <>
Date: Mon, 09 Aug 2010 15:28:00 -0400
List-post: <">>

On 8/9/2010 1:51 PM, Jim Brown wrote:
> On Mon, 09 Aug 2010 13:10:01 -0400, Roger (K8RI) wrote:
>> I think I can get around this by adding a coax switch (Alpha Delta - 2)
>> between the amp and tuner, so instead of selecting the dummy load on the
>> aux position, I just use the coax switch. It means two switches instead
>> of one and I've been trying to keep it simple.  The original Alpha Delta
>> - 2 switch between the exciter and amp that allows selecting the exciter
>> or antenna analyzer would stay in place. I've had very good luck with
>> these switches.
> My results have been mixed. When they work, they're fine. I have five
> 1x4s. I One came with a mfg defect that made the #4 position not work,
> and it could not have made it through final test if there was a final
> test, so there must have not been a final test. :)  I have another that
> went bad, again with a position that doesn't work. 40% failure rate puts
> them in MFJ territory. :)  On the other hand, when they do work, the
> signal path is good enough for 2M. Maybe even on 440 -- haven't measured
> it carefully.
I have used them (the 2 port version with lightning arrestor with 
grounding center position) in a mixed 144 and 440 set up with good 
results, BUT your results make this truly one of the YMMV cases which I 
find to be scary indeed.  Again, I've not measured the isolation or loss 
carefully. OTOH neither created a problem with two rigs running at the 
same time.
It's scary because here is a piece of equipment to which few give second 
thoughts, yet it's ability to carry power, voltage, current, isolation, 
and lifetime/reliability is, or rather can be very important (depending 
on the use.)  Your results with a 40% failure rate albeit such a small 
sample make it anecdotal, but it's an anecdote that's certainly worth 
paying attention to.


Roger (K8RI)
> 73, Jim K9YC
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