multiband receiving v/uhf antenna 1

[Martintin]

I want to use some v/uhf multiband antennas for mobile use, low altitude - tripod installation.

Do you know any company that provides multiband antennas for V/UHF radios for using in harsh environments?

 

[VEBill]

This question might be better if it were posted in the 'Antenna & Propagation engineering' forum (on this same website).

Mobile usually implies installation on a vehicle. Tripod installation would be better termed as portable.

The military (the Army to be specific) makes extensive use of portable V/UHF antennas in the range of 30 MHz to as high as 512 MHz. Harris is one vendor for example.

Don't expect excellent RF performance with those other requirements.

 

[Martintin]

Thank You VE1BLL

You have a point - i should have posted it on the other forum, my mistake.

Anyway, i used some Harris products and i was very satisfied with them but now I am searching for a low cost/small dimensions/good performance antenna - sorry for not being clear from the beggining.

Thanks for your post and perhaps Harris could be THE solution after all (the price could be an issue though).

 

[VEBill]

If you just need a receive-only antenna, you might be able to get away with a home-made coaxial dipole in a PVC tube.

If you're transmitting over the entire V/UHF frequency range and you need to provide a reasonable match for the transmitter, then one old trick is to add a 3dB power attenuator in line with the mismatched antenna. The 3dB pad will provide 6dB return loss (or more when normal cable losses are considered) and 'only' affect the transmit and receive functions by 3dB each. If you can get around 8 to 10dB of return loss, that's acceptable for many transmitters (check your manual).

Some people would shudder at the concept of using a pad in-line with the antenna, but then they purchase an expensive 'wideband' antenna that may be designed to be just as lossy to provide the same effect (but hidden, not explicit). One clue can be the relatively low power rating of many wideband antennas.

Radio Shack used to sell consumer/hobbiest V/UHF antennas for use with scanners. One was a three-element ground plane, another was a whip with two loading coils/isolators, one was a discone.

There are also some "EMC Antennas" that can provide low loss and wide bandwidth. Look for birdcage dipoles. Bring money - lots of money.