> I was wondering therefore, on the feasibility of using a WW2 US aerial
> base such as the MP48A or AB15 types which are still readily available
> and can, I think, be fitted with co-axial leads. I do not have a great
> understanding of radio but believe that an aerial has to be tuned to the
> frequencies used by the radio etc. Would it be only a matter of adjusting
> the length of the whip aerial(and if so, by how much?) or is there much
> more to it than this? Has anyone actually done this before???
Hi Dave.
The aerial you'll need for the band in question will be very much shorter
than any aerial used by radio equipment during WW2. But once you've got the
base and a longer whip than neccessary in place, the tuning proceedure is
relatively simple, though a little time consuming. You'll need some kind of
a cutter to cut the whip, an SWR/Power meter to check the forward/reverse
power and standing wave ratio, and an extra metre or so (preferably as short
as possible) of co-ax.
Connect the swr meter to the radio using the short length of coax. Connect
the other end of the swr meter to the aerial using the aerial coax. Press
the transmitter PTT while the SWR meter is in the Power mode and calibrate
the instrument according to the manufacturers instructions. When this is
done, switch to swr mode. A perfect match is 1:1. However, most vehicle
radios cannot match this, so a ratio of 1.2:1 or at worst 1.5:1 will be
acceptable.
Clip the whip with small bits at a time until the swr is the lowest
possible. If your whip is much longer than neccessary, it may be a while
before the meter needle begins to drop. When it does begin to drop, it
normally does it very quickly. So once it begins to drop, cut smaller
bits off it.
Regards
Gerry Davison - Denmark - Europe