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Using a vhf antenna on a low band portable

Posted: Sat Dec 15, 2007 1:24 am
by tylercnty316
Hello,I'm looking to settle a debate between myself and 2 friends.We run on low band(46...mhz)and they are saying you can use a vhf portable antenna(150 mhz) on the low band portables.I'm no radio guru,but I dont think that is possible.If someone could help me settle this,I would appreciate it.

Re: Using a vhf antenna on a low band portable

Posted: Mon Dec 17, 2007 8:30 pm
by n9gik
Can you? Sure! SHOULD you? Probably not. Your antenna will not match the transmitting frequency of your radio, resulting in an impedance mis-match.

Best case scenario: It works great

Worst case scenario: It damages the radio

Most likely scenario: It works ... sort of ... but not very well

Re: Using a vhf antenna on a low band portable

Posted: Mon Dec 17, 2007 10:51 pm
by mike m
I didn't look at the date on this thread and I don't check this group that much so if I revived an old thread I'm sorry but before someone ruins a good Low band hand held I had to say something.

It will work like crap. Been there tried it.

The result is an antenna with about 30 dB lower gain than a true tuned low band duck antenna would provide.

I'd bet your friends are refering to the recent topic on another radio users group about using a VHF high band 5/8 wave antenna for 50 MHz mobile work.

This works just fine as some mfg's 2 meter, 146 MHz, 5/8th wave mobile antennas are also electrical 1/4 waves on 50 MHz.

In fact the above method comes from an old antenna MFG's application note from the early 70's about using a 2meter 5/8th wave mobile antenna as a 1/4 wave 6 meter mobile antenna, a very early simple dual band antenna system.


As for the above 5/8th wave antennas use on a handheld, hey if you can get a decent ground plane or a wire counterpoise and can put up with a 50 inch long antenna then go for it but personally I find a 10 inch or longer top slug tuned low band antenna to work great.



Mike
WB8VLC/7