At 12:03 PM 4/27/00 -0700, g w wrote: >Hi, >Well I had my handheld hooked to the nav antenna. It didn't work real well >and sometimes when the plane was turned, it would not work at all.
Ah. Well, a couple of things are not in your favor. First of all, if the nav antenna really is a NAV antenna, its center frequency is apt to be on the lower end of the frequency spectrum. Thus, it will exhibit a high SWR. That in itself isn't a terrible problem except that your solid-state handheld may be sensitive to it, and be protecting itself by reducing its power output accordingly. The mismatch on the coax doesn't help matters, but the big problem with solid-state radios is that they really don't like to transmit into a high SWR. >The >problem I am having now is that the com antenna on top simply doesn't work >with it. It is probably worth while to try and diagnose what is going amiss with the COM antenna. If you have a ham radio friend who has a VHF SWR analyzer, he may be able to help you understand what's up with that. Coaxial cable absorbs moisture and deteriorates over time, and corrosion plays hell with connections between the copper coax braid and the aluminum aircraft skin which serves as a ground. > I flew the plane down the road the other day and was flying around >flashing the lights trying to get the tower's attention. The antenna had a >nav/loran mixer box which I removed and I was wondering if anybody knows if >the antennas with those are a special kind that only works with the box >installed or if there is some way of tuning the antenna. Without seeing the specific antenna it's hard to be sure, but it is indeed likely that there is some sort of tuned circuit in the NAV/LORAN mixer box which helps make it a good antenna on those widely dispersed frequencies. Without the box, it may be a lousy antenna on both frequencies. Even if it's an acceptable receiving antenna for the VOR, it may be too far off to make the transmitter happy. Of course you can't use the mixer splitter to transmit through! Not designed for that kind of power. Check the Avionics West catalog or web site. I seem to recall some 'emergency' antennas made for hand-helds which should work pretty well inside a coupe cockpit. Another option is to get the cheapest whip antenna you can find and install it just behind the rear window. Again, Avionics West has some basic ones for pretty cheap. Greg __________________________________________________________________________ ______ To unsubscribe from this list please send mailto:[EMAIL PROTECTED] ________________________________________________________________________ Start an Email List For Free at Topica. http://www.topica.com/register
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