homemade external/internal antenna for handheld.

("RST Engineering" wrote)
You could have saved yourself half the price of the "commercially
available antenna base" by using a bulkhead BNC female connector, mounting
it to the same piece of aluminum and feeding one side with connector/coax
to the radio and the other side with a BNC connector on the other side
with a brass brazing rod of your choice in diameter for the radiating rod.


(John Smith wrote)
"A length of stainless steel rod cut to mid-frequency length was inserted to
serve as the antenna. This was on a 7AC. The antenna coax entered the cabin
at the leading edge/canopy junction."


1. With a standard handheld, what would the average length be (approx) for
the rod(s)?

2. Should the rod be insulated, at any contact points within the wing? If
yes, with what?

4. If no, does the rod cantilever away from the BNC connector, without ever
touching anything else inside the wing?

5. Does the length of the coax (running to the radio) matter,
significantly?

6. Is there a benefit to having one wing 'tuned' to receive and the other
wing 'tuned' for transmitting? g


Montblack

"Montblack" wrote in message
...

1. With a standard handheld, what would the average length be (approx)
for the rod(s)?

It is a function of rod diameter. With an infinitely small diameter wire,
the length for each rod would be about 23.2" for a geometric (*) band center
of 127 MHz. With a half-inch diameter rod, that would reduce to 20.2 and in
between is in between. (*) The geometric center of the band is the square
root of the (bottom end of the band times the top end of the band).



2. Should the rod be insulated, at any contact points within the wing? If
yes, with what?

Electrically, no. Mechanically, probably. A nylon cable clamp would work
well.



4. If no, does the rod cantilever away from the BNC connector, without
ever touching anything else inside the wing?

It can. However, vibration will eventually take its toll.



5. Does the length of the coax (running to the radio) matter,
significantly?

It does not matter at all. An old wive's tale says that there is a "magic"
coax length. Put an orange in the center of your house and start running
around the outside. You can see differences in the orange depending on what
window you look through, but you never get any closer to the orange no
matter where you are relative to it.



6. Is there a benefit to having one wing 'tuned' to receive and the other
wing 'tuned' for transmitting? g


Why? They are both on the same frequency.

Jim

("RST Engineering" wrote)
1. With a standard handheld, what would the average length be (approx)
for the rod(s)?

It is a function of rod diameter. With an infinitely small diameter wire,
the length for each rod would be about 23.2" for a geometric (*) band
center of 127 MHz. With a half-inch diameter rod, that would reduce to
20.2 and in between is in between. (*) The geometric center of the band
is the square root of the (bottom end of the band times the top end of the
band).


Thanks for the answers.


Montblack