and most important how to fabricate a bottom mast connector.
The purposes of these pages is not to modify the AS-2259
antenna system but to use it in its original configuration.
The AS-2259 was initially set up and tested for a week. Some data was exchanged with Gene Smar, AD3F who made some initial Smith Chart and feed line calculations but I decided that actual field testing would be better and to see how the antenna could be utilized on amateur frequencies. I became frustrated with the PRC-47 base mount that I had used previously and decided to put the antenna back up and fabricate and test a different mount. Additional measurements were made and successful matching was accomplished on 80,60, and 40 meters.
The
kit weights 16 pounds and is easily carried on foot or tied to my M151A1
fender. Most kits do not contain a base connector/mount. I fabricated
a connector using common plumbing items, see link for page 2 at the bottom.
The TM for this antenna is available from LOGSA and MARS sites as of February 2007. Down load or do a search for AS-2259. TM 11-5985-379-14&P The manual is based upon use of the PRC-47 and contains a lot of NVIS information as well as info on the AS-2259.
I inspected the antenna kit and was surprised that it was just two different sized doublets with equal lengths sides fed with a hard line type mast. I had expected some sort of secret creative design with different wire lengths.
The mast was a possible mystery as it was a coaxial feed line, Gene and I were curious about its possible use as a matching transformer as the characteristic impedance was not published.
Inner mast dimensions.
The mast dimensions work out to be approximately 50 ohms.
Using a dielectric constant value of 1(air) I arrived at:
(138/1)log2.34=50.9 ohms
But most "foam dialectic (polyethylene) has a
a dielectric constant of around 1.3.
(138/1.14) log 2.34= 45 ohms, which is close enough to 50 ohms for government work. So the mast mystery is solved, it was nothing special but a 14 foot feed line with an approximate value of 50 ohms.
Four
wires attach to the top of the mast in dipole configuration, A short and
long "hot"wire attach to the top of the insulator and then the
other short and long wire attach to the rest of mast. Be
sure and clean and tighten all connections. A lot of corrosion
was found inside the brass clamp.
Here is an interesting quote from the the TM, page 38.
" In order to provide an acceptable impedance to the tuner of the AN/PRC-47, it is necessary to make the sloping dipole fat. This is done by using two wires for each half of the dipole. The four wires are equally spaced about the mast and serve as guys as well as radiators."
You will need a space clear of trees etc. that is approximately 60X60
feet. The dipoles are erected 90 degrees to each other. Each leg of the
short dipole is equipped with an extra long guy line so that the sloping
angles remain the same on both antennas. 
Setting
up the antenna is fairly easy, each guy line is marked with a crimp on marker
to indicated the proper length for attaching to the stake.
Bottom of mast
The basic antenna requires some sort of base unit for
connecting the coax feed line to the inner conductor and outer portions
of the feed line mast. NOTE: Most AS-2259 kits do
not have this base connector
I happened to have a PRC-47 adapter that KG2BL,Jeff
gave to me at the 2005 MRCA meet at Gilbert. So initially I used a PRC-47
mobile mount as an antenna base. The adapter is basically a connector
with a 3/8-16 1/2" stud.
The adapter slips into the bottom mast section.
The adapter is a direct connection, there are no transformers or baluns.
It screws into the top of the PRC-47 radio antenna mount or onto the mobile
mount.
Here is the real deal. Dean KK1K operating his PRC-47 with a stock non-modified AS-2259. Dean gives the antenna an excellent review.
The
PRC-47 mobile mount was satisfactory but was too large and is rare. Very
few were saved during the destruction of the Marine Corps vehicles .
. 
There
have been numerous base mounts manufactured for the AS-2259 antenna, several
for vehicles, and ground mounting. The one shown here was for the PRC-104
and used a BNC connector.
The power rating is 50 watts and there is a 1:4 transformer(voltage
balun) imbedded in the base supposedly for HF equipment that was designed
to operate in whip antennas that offered a low impedance value of say
10 to 20 ohms. These photos were taken from Steve Haney's store on Ebay.
Link at the end.
The A3023293 is a nice tilt over base with direct feed. The tilt over feature is really not needed as the AS-2259 mast is only 15 feet tall.
Note: Brooke Clarke , N6GCE has an excellent summary of the adapters and mounts for the AS-2259 on his web pages and includes a home made mount for the PRC-47 adapter.
Link at the end
Mount
Fabrication
I fabricated a direct feed mount which did not have any power restrictions.
Cost was minimal as off the shelf plumbing hardware was utilized.
The base was plywood and the connector utilized was a standard SO-239.
See links below for page 2 on details of construction of the mount.
Continue
with:
Page
2 Fabricating a Mount
Page 3 Testing and Matching the AS-2259
Matching tools page
Links:
Haneyelect
Ebay
Brooke
Clarke AS-2259 adapter info
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