List Etiquette (was [Milsurplus] mast poles "Really" long

Wed May 28 01:38:46 EDT 2008

Well,
Since I am back to being subscribed after ISP change, I will expound on
the subject of the mast poles.

The "Antenna Assembly" that immediately comes to mind is the AB-85/GRA-4.
This antenna is one of several used with the AN/GRC-46 and the AN/GRC-26(*)
radio systems (yes I said systems, don't get me started)!

The AB-85 is contained in the assembly known as MX-1116/GRA-4.

Now on to the Mythos, The AB-85 is a vertical antenna, the sections are
continuous from the "base insulator top" to the cap 35 feet up (apprx.) at
the cap, which is internally threaded there is a provision for the MX-series
antenna sections to be added to the overall length(height) of this base-fed
isolated from ground vertical. With the right "MS" elements and the full
number of AB-85 sections, you can build a 40 ft. vertical antenna, fed at 
the
base with a single wire, which would be connected to the AN/GRC-26
system TX/RX thru the TN-339 antenna "COUPLER", it is not a tuner.

The AB-85 sections in the downward portion has a spread of fingers inside
to make a good contact with the previous section. Also to insure continuity
between the sections. In some cases you can also use the AS-3577 antenna
from the same support (insulated) an also has a counterpoise and a (Ahem)
Balun to facilitate operation with a 50 ohm output, as in "Coupler" not
required. The AS-3577 covers (Somewhat) 1.5 to 30 Mhz. in operational
range, and is an NVIS antenna system.

The Fiberglass poles Don't stand up to the additional weight very well of 
the
addition of the AS-3577, or for that matter the installation of either a 
long wire
or center-fed dipole. For Dipoles and excessively long wires, the mast is 
the
AB-86 which is of taller sections, to reach the forty foot height and three
sets are used for a center-fed dipole, be it 50 ohms or open-wire feed.

For further clarification, see http://eshop1.chem.buffalo.edu/an-gra-4.html
For the manual on the AS-3577 in PDF go to
http://eshop1.chem.buffalo.edu/images/Antennas/AS-3577.pdf

For descriptions of various uses of the systems here at WB2FCN go to
http://eshop1.chem.buffalo.edu/600-Meter-Ant.html

The Masts that most folks remember using in the 60s - 80s is in fact this
system. Another caveaut of the fiberglass poles is when the AB-85/GRA-4
is assembled and raised, an operator can shimmy up the pole as it were
and within reason NOT worry that it will break or come down, not true
with the fiberglass type which tend to shatter like a hand grenade at the 
slightest
external pressures. FWIW, this most likely won't make it through.
But here goes anyway.
Jim
WB2FCN
MILTFD-J1
----- Original Message ----- 
From: "Don Davis" <dxguy at earthlink.net>
To: "Don Davis" <dxguy at earthlink.net>; <WA5CAB at cs.com>; 
<milsurplus at mailman.qth.net>
Sent: Wednesday, May 28, 2008 12:44 AM
Subject: Re: List Etiquette (was [Milsurplus] mast poles

>
> ----- Original Message ----- 
> From: "Don Davis" <dxguy at earthlink.net>
> To: <WA5CAB at cs.com>; <milsurplus at mailman.qth.net>
> Sent: Tuesday, May 27, 2008 9:26 PM
> Subject: Re: List Etiquette (was [Milsurplus] mast poles
>
>
> OK Robert:  Here's some new dope.  I bot a bunch of 30 - 75 MHz military 
> log periodics from Murphy several years ago.  They have a lanyard about 30 
> feet long (black nylon cord) that flips the ant from vert to horiz 
> polarization.  Also has coax about the same legth with BNC conn.  The 
> hinge assy has a pintle that slips inside the fiberglass mast end.  The 
> other end of the fiberglass mast fits into the aluminum masts.  I bot a 
> ton of the masts from Murphy as well.  Fiberglass on the top section so 
> that the antenna works properly in vert polarization.  I'll look up the 
> nomenclature of these as I get access to the ants, and post it to the net. 
> This set-up makes a dandy portable 6M antenna set-up.  If you're into that 
> sort of thing.
>
> 73 de Don  AD6PB
>  ----- Original Message ----- 
>  From: WA5CAB at cs.com
>  To: milsurplus at mailman.qth.net
>  Sent: Tuesday, May 27, 2008 9:10 PM
>  Subject: Re: List Etiquette (was [Milsurplus] mast poles
>
>
>  I guess this can be my pet peeve rant for the month.  I'm quite sure, 
> when I signed up, I read somewhere in the fine print that we were allowed 
> one a month.
>
>  This morning someone (who is not germane to my point) posted a question 
> about fiberglass and aluminum mast poles currently being sold at hamfests 
> and other venues.  By Noon it had been well established that the poles 
> were originally procured by USA/DOD for the purpose of supporting 
> camouflage netting.
>
>
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> 