Question About Opek HFT-306 6m Antenna

[ThomasMcKean]

I affectionately call this my "snow plow" antenna, because I bought it for the express purpose of monitoring snow plows on the road. They would be in the 47mhz range. If anyone knows of a better antenna with a BNC on it for 47mhz, please provide link.

As I wait for the snow, I notice this antenna does a great job on 2m and VHF aviation. It also does fair on 11m CB bands. All well and good.

But I also want to monitor the 70cm band. I am wondering if there is a way to "tune" this antenna for the 2m/70cm bands, by adjusting the height of the antenna?

Actual antenna is seen here:
OPEK HFT-306 - 6-Meter Band - Telescopic Ham Radio Antenna - BNC

As yew can see, it has a "heavy duty loading coil" and ten sections. I am wondering if, taking the loading coil into consideration, there may be a simple mathematical formula by which I may compute height for frequencies so I can keep this antenna on the scanner while waiting for the snow plows?

Thanks in advance.

 

[dksac2]

I'd go for an outside scanner antenna. Try to find one that is strong on the 50 band or buy an outside transmitting antenna to listen with. Good, low loss coax run as short a distance as possible with an outside antenna above roof height should make a world of difference. Don't forget a good ground.
An antenna stuck on the top of your scanner will never come close to the signal you will pull in with a quality outside antenna.

John

 

[LtDoc]

Is there a simple formula to do that adjusting? No, I'm afraid not. One method would be to find a length that does well for some particular frequency/band. Multiply that length by the frequency, then divide it by the 'new' frequency. That should give you a sort of 'ball-park' length to start from. Then you can do all the 'tweaking' you feel you should.
The suggestion to get that antenna outside and as high as possible is a good one. That typically 'helps' even a 'bad' antenna.
Good luck.
- 'Doc

 

[ThomasMcKean]

Is there a simple formula to do that adjusting? No, I'm afraid not. One method would be to find a length that does well for some particular frequency/band. Multiply that length by the frequency, then divide it by the 'new' frequency. That should give you a sort of 'ball-park' length to start from. Then you can do all the 'tweaking' you feel you should.
The suggestion to get that antenna outside and as high as possible is a good one. That typically 'helps' even a 'bad' antenna.
Good luck.
- 'Doc

Already done. Sorta. The scanner upstairs IS connected to an outdoor antenna. Right now a Comet DX-333. Pondering adding a discone or a scantenna when I put the ham rig on the comet. This is the scanner downstairs. I am a bit limited as I rent and don't own the property.

What I am trying to do specifically is pick up 440. I have multiple antennas here but none of them seem to do as well on 2m as the 6m antenna. Go figure?