Hi Art,
I would be very interested in seeing how you engineered your pipe, if you
don't mind sending me the pictures.
73 de Mark N1UK
----- Original Message -----
From: <atrampler@att.net>
To: "Richards" <jruing@ameritech.net>; "Roger (K8RI)"
<K8RI-on-TowerTalk@tm.net>
Cc: <towertalk@contesting.com>
Sent: Sunday, 28 December, 2008 7:25 PM
Subject: Re: [TowerTalk] Hy-Gain AV-640
> James,
>
> My counterpoises droop more than the 1-2 feet mentioned, perhaps due to
> repeated icing.
>
> However, the slope of the counterpoises impacts the impedance of the
> antenna. From what I recall, the impedance rises as the counterpoises
> slope
> downward, up to a point. So I would advise against lifting them in any
> way.
>
> This antenna is a 3/8 wave radiator with a nominal feedpoint impedance of
> about 200 ohms. In this regard it is SOMEHWHAT similar to an OCF dipole,
> in
> a sense "similar" to a 1/4 wave vertical acting similar to a dipole with
> half of it buried in the ground. My main point here is that I believe
> letting the counterpoises slope naturally is an important element in this.
>
> As for mounting, I had one on a 1.75" pipe, about 8' long, and during the
> big Ozarks ice storm two years ago it came down: the pipe folded over; the
> AV640 was largely intact. So be careful about what you put it on.
>
> For mine, I have about 11' of 4" pipe with a hinge on it, buried in
> concrete. Dummy me...I over-engineered and could have it up higher...but
> never mind. Then there is the hinge and another 8' or so of 3" or 2.5" OD
> heavy wall pipe. I could likely mount a small yagi on it, but at least
> I'm
> not worried about the mount falling apart.
>
> Write off the list if you want pics or anything.
>
> 73,
> Art
> ----- Original Message -----
> From: "Richards" <jruing@ameritech.net>
> To: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
> Cc: <towertalk@contesting.com>
> Sent: Sunday, December 28, 2008 5:23 PM
> Subject: Re: [TowerTalk] Hy-Gain AV-640
>
>
>>I have yet to install my AV-640 which remains in the box -- I am
>> STILL all unsure, worried, and obsessing over how I can install
>> it over the front corner of my attached garage or other location
>> in the yard. (I have a big 43 foot monopole vertical in the middle
>> of the back yard...) and have been considering:
>>
>> 1) 20 feet of RG type lightweight tower (e.g. two sections)
>> braced against the house/rafters/eaves
>>
>> 2) A twenty foot 1.75 inch heavy galvanized iron water pipe,
>> set in a couple feet of concrete at the base, and braced
>> against the house/rafters/eaves
>>
>> 3) a 3-5 foot roof tower and 5-foot mast set in the middle of
>> the garage roof. (Wife does not favor holes in the roof...
>> but is OK with options 1 and 2 - but will not cry about this
>> option if it is best and can be done safely and securely -
>> and I share these concerns... especially after the 50 mph
>> wind storm last night that shook the house all night....)
>>
>> 4) A ten to 15 foot 2-inch galvanized water pipe set somewhere
>> in the yard far enough away from the house and the big
>> vertical in the back yard... I can put it AT MOST about 50
>> feet from the big vertical if I put it in a corner of the back
>> yard, but I have rather narrow side yards (avg sized
>> suburban lot)
>>
>> 5) ???? (Any other options I should consider...)
>>
>> ISSUE = How to mount it so it can tip down and I can access
>> it for tuning? Can I stand on the roof to tune it if it can be
>> tipped over on the mast or tower section?
>>
>> ISSUE = How high must it be over the roof (and gutters) if I
>> brace it against the side of the garage? How much do the
>> counterpoise radials droop (and can I suspend them
>> with light rope to keep them from drooping without causing
>> a wind loading or other problem?
>>
>> ISSUE = How should I guy it if I mount it over the roof
>> (and gutters) if I brace it against the side of the garage?
>> I can tie off to the garage sides and roof on three sides
>> of it, but then the side away from the house/garage needs
>> something... or does it? Are three quarters sufficient?
>> Does not seem balanced that way. Again, I have a narrow
>> side yard and do not want a problem with the neighbor kids
>> or lawn mower service... I do not have quite the space Roger
>> has for guys... DO I NEED TO GUY IT... really? (Yeah... I know
>> an ounce of prevention...)
>>
>> ANY IDEAS GREATLY APPRECIATED. I WOULD LIKE TO GET
>> THIS UP SOON...
>>
>> I admit to obsessing, but my big vertical sustained 60 mph winds
>> last night with no problems, so I am 1) able to finish the project
>> if assured by good plans, and 2) get good results by good
>> planning.
>>
>> ============= James // K8JHR ================
>>
>> Roger (K8RI) wrote:
>>
>>> I've used an AV640 for a couple of years now
>>>
>>> As for guying I'll just include the link:
>>
>> =============================================
>> _______________________________________________
>>
>>
>>
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