[VHFcontesting] [VHF] Antenna Coupling Issues

[George Sintchak/WA2VNV]

Jim - you're right on the money. Les has the disease and just doesn't know 
it yet - still in denial, as you said.

YMMV, keep on trukin' Les.

73's,
George
P.S. I don't thnk 2304 will work very well from inside the attic. Much 
better on your future new rover vehicle !!!

----- Original Message ----- 
From: "Jim Worsham" <wa4kxy at bellsouth.net>
To: "'Les Rayburn'" <les at highnoonfilm.com>; "'Stan, W1LE'" 
<stanw1le at verizon.net>; "'VHF Contesting Reflector'" 
<vhfcontesting at contesting.com>; <vhf at w6yx.stanford.edu>
Sent: Friday, July 11, 2008 10:45 PM
Subject: Re: [VHFcontesting] [VHF] Antenna Coupling Issues


The DCI filters work well.  We use them at W4NH on all of the bands from 6
through 432.  Famous last words on that TX power.  I started on just 6 and 2
meters with 100 Watts.  I thought the same thing.  You don't even want to
know what I have now and have spent on this stuff since then.  The first
time you try to make a Q and just miss the other guys call or grid or he
misses yours it will drive you insane.  Frankly, you already have the
disease but you are in denial.  How much stuff have you bought in just the
past few months (we have all been watching you with a knowing smile on our
faces!) and now you want to buy DCI filters (which we know are not cheap).
I predict the antennas in the attic will not last a year.  I predict you
will be buying some property someplace or a big vehicle to mount antennas
and go roving before long.

73
Jim, W4KXY

-----Original Message-----
From: vhfcontesting-bounces at contesting.com
[mailto:vhfcontesting-bounces at contesting.com] On Behalf Of Les Rayburn
Sent: Friday, July 11, 2008 2:43 PM
To: Stan, W1LE; VHF Contesting Reflector; vhf at w6yx.stanford.edu
Subject: Re: [VHFcontesting] [VHF] Antenna Coupling Issues

Along with Stan, several folks have mentioned using tight bandpass filters
on both TX and RX. I looked over DCI's filters today, and saw a few that
might fit the deal. I'm curious has to what others are using.

The bandpass filter option appeals to me as I think it would provide the
added benefit of reducing my interference levels, and providing some
additional protection for the pre-amps and front ends. I can't imagine that
I'm ever going to even seriously consider running more than 200-300 watts on

any band given the indoor antennas. It will be easy to become an "alligator"

and certainly will only cause issues with TVI/RFI, including the potential
to interfere with the President of the HOA who lives next door.

So, sources? Prices? Anything to avoid?

73,


Les Rayburn, director
High Noon Film
100 Centerview Drive Suite 111
Birmingham, AL 35216-3748
205.824.8930
205.824.8960 fax
205.253.4867 cell

--------------------------------------------------
From: "Stan, W1LE" <stanw1le at verizon.net>
Sent: Friday, July 11, 2008 11:08 AM
To: "Les Rayburn" <les at highnoonfilm.com>
Subject: Re: [VHF] Antenna Coupling Issues

> Hello Les,   My comments are added.....
>
>
> Les Rayburn wrote:
>> 1. At what power levels (typically) does this begin to be an issue?
>>
> Too many variables that need controlling to comment, you are on thin ice.
> destruct level of the preamplifier,
> preamp isolation (filtering) for out of band signals,
> TX power levels,
> quality of coax being used, braided shields leak, solid shields like solid

> copper on superflex or hardline are betrter,
> Bypass relay isolation,
> antenna proximity, near filed issues.
> polarizations used,
> Coaxial cable losses,
> etc.
> etc.,
>
>> 2. Are there steps that I can take to minimize the coupling, and protect
>> the
>> pre-amps and radios?
>>
> Coupling is proximity. Either I disable all preamplifiers not used, except

> for the band I am playing on or
> I have tight bandpass filters and leave the preamp on for other RX bands.
> Tight bandpass filters for RX AND TX.
> Another alternative is to disable all preamps on ALL bands,  when I
> transmit on any band. including HF.
>
> All preamplifiers default to a bypass mode, when the system is not used.
>> 3. What do rovers in similar situations do to prevent problems?
>>
>
> Rovers usually go thru a few preamplifiers until they take the previously
> mentioned actions.
>
>
> Stan, W1LE   Cape Cod
>
>
>
>
> ZZZZZz
>>
>>
>>
>
>

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