UHF Mobile Antenna Search

[svfd1243]

Is there such an antenna that covers 430-470? Ive seen 430-450 and 450-470 but nothing that hits the 70cm ham and the public service band all in one and has a spring base to it. Can someone suggest an antenna? This is going on a trunk lip mount.

Thanks

[Tom in D.C.]

Try this site to start:

http://www.eur-am.com/com-nmo.htm

[txshooter]

Is there such an antenna that covers 430-470? Ive seen 430-450 and 450-470 but nothing that hits the 70cm ham and the public service band all in one and has a spring base to it. Can someone suggest an antenna? This is going on a trunk lip mount.

Thanks

From experience, I would say pick the area of the band you are most likely going to be transmitting it. For recieve purposes out of band is not perfect, but it will work well. You are really not that far off. The more critical area is where you will be transmitting the majority of the time.

[kf4sqb]

Even with the antennas Tom suggested, you still won't be able to cover that whole range with a single antenna. The antenna may cover that whole range, but it will only cover app. 5 MHz at a time. You may be able to help your match at the radio by using a tuned, open 1/4 wave stub in parallel with the radio. You would do that by coming out of the back of the radio with a coax "tee" with the coax to the antenna on one side and a piece of coax slightly longer than 1/4 wavelength at the lowest frequency needed on the other side. You will be much better off with an antenna analyzer, like the MFJ-269, for the tuning. Tune just the antenna, without the stub, toward the upper end of the desired coverage area. Hook the stub to the analyzer, and tune it for the lower part of the desired coverage area. Put the stub and antenna in parallel, and the SWR should cover a little broader area than the antenna alone. Make sure you keep the center conductor and braid at the end of the stub separated, and use heat shrink or something to cover the end to keep it from touching anything metal. Keep in mind that this isn't the most efficient system, but it will allow a better match for the radio. Radiation efficiency will be best in the area where the antenna is actually tuned.