Mission: Convert an OTS* commercial 27 Mcs handheld antenna to 50.1 Mcs**
* Off The Shelf or as they say here in Chickenland
"Store bought"
** Only Megacycles are recognized on this site. I mean what was wrong with them anyway.Why do we have to rename everything.
Overview: Short Helical wound Citizens Band hand held antennas* are readily available and are easily converted to six meters.There are very few six meter(51.0Mc) handheld antennas available on the commercial market and their cost is prohibitive.
* For some reason these short handheld antennas are referred to as Rubber Duck's. Trying to determine the relationship between an helical wound antenna and a Duck is bewildering.
The MAXON model
WTA-2 BNC mount handheld antenna was converted
from 27 Mcs to 51 Mcs. The photo shown above is after the conversion.
There was no change to the
BNC mount or to the 10
inch length of the original antenna. The antenna is the long skinny
thing without the cord.
NO, of course not, there is no free lunch, however this conversion is an an excellent hamfest or military meet antenna. Especially if you have acquired a military radio without the accessories and you need an antenna. If you are cheap like me , you never get all the accessories so you spend many of your adult hours fabricating things to go with the radio. So maybe you should get the radio with the stuff in the first place.
NOTE: There are several pages of conversion information presented here, try to review all of the information before beginning.
The
MAXON antenna is a very rugged steel helical wound short antenna with a
center loading coil. The steel coil is copper plated. Use the razor blade
to cut open the center section to expose the coil.
On the original loading coil the coil winding direction was
wound "opposite" to the top and bottom helical sections. I assume
this was done to try and prevent any self resonant tendency of the coil.
I wound the center section both ways and could not detect any major difference
in relative field strength test or bandwidth. Of course this is only a ten
inch antenna and relative measurement might me a little off in a non- test
range environment. QUICK AND DIRTY 
The quickest way to modify the MAXON WTA-2 antenna is to
cut open the center loading coil covering and remove
turns. Just remove a bunch of turns and check for resonance.
I wound up with 34 of the original turns remaining
but really didn't like this configuration as the wire was very small and
hard to keep positioned on the center coil form. Moving the turns , or
spacing the turns changes the "center frequency".
Later I used a larger size wire to try and increase the Q slightly and to provide a more manageable and rugged coil. This is shown on the later pages.
A grid dip meter can be handy. If you don't know how to use one skip on to the next paragraph.
For
trial tests I mounted a BNC mount on a chassis,using the chassis to simulate
the radio's ground plane. I fed this system with a 3 foot section of RG-58.
Keep your test antenna several antenna lengths away from other objects.
Final tuning can be accomplished outside. The pencil was not used and is
shown for scale.
AN
Antenna analyzer or grid dip will make things easier.
The
PRC-70 was utilized for the medium power tests. 
Easy
to check reflected using the URM-182. I used several
different lengths of RG-58 during testing. 
Coat the loading coil with coil dope or cement and cover with heat shrink
or using the KISS principle just wrap one layer of electrical tape around
it to hold the coil in place. 
Looks good on the FSE 38/58 perfect for the Dayton or the Gilbert meet.
Price should be around 12 bucks plus shipping.
Go To page two for more conversion information
Gilbert
MRCA Meet