Antenna usage???

[adss023]

Hope someone can help me out here. I am currently in possession of an old Antenna Specialist(?) base antenna. It has a model number of ASPF700 (ASPRF700 according to a web site), and has a frequency range of 460-470MHz. The antenna is approximately 13 ft long and is fiberglass. It looks like an old base antenna that police would use. My question here is, can this antenna be used for scanner monitoring. Most of my scanner monitoring is UHF, VHF, & 800's. If this antenna is "usable" would I receive distant stations OK? Thanks

 

[ermin]

Hope someone can help me out here. I am currently in possession of an old Antenna Specialist(?) base antenna. It has a model number of ASPF700 (ASPRF700 according to a web site), and has a frequency range of 460-470MHz. The antenna is approximately 13 ft long and is fiberglass. It looks like an old base antenna that police would use. My question here is, can this antenna be used for scanner monitoring. Most of my scanner monitoring is UHF, VHF, & 800's. If this antenna is "usable" would I receive distant stations OK? Thanks

It would work good on UHF. Depending on how far away your VHF & 800 systems are they might not do so good. If you get nothing on UHF I'd suspect a problem with the antenna.

73
Ermin

 

[jackj]

From your description, this appears to be a collinear array. A bunch of 1/4 and 1/2 wave length pieces of copper tubing that are phased and end-fed. The fiberglass tube gives it structural strength and shields the antenna works from the weather. This antenna will work good at its designed frequency but not at any other frequency. I don't think you would pick up much VHF or 800 MHz signal using this antenna. Because of its construction, they have a tendency to develop high reflected power when one of the internal feed wires between sections breaks due to repeated flexing in the wind.

 

[m3ojt]

JUST BUY A DISCONE, ANT, THEY WORK.
M30JT LONDON, 73s

 

[benbenrf]

Hope someone can help me out here. I am currently in possession of an old Antenna Specialist(?) base antenna. It has a model number of ASPF700 (ASPRF700 according to a web site), and has a frequency range of 460-470MHz. The antenna is approximately 13 ft long and is fiberglass. It looks like an old base antenna that police would use. My question here is, can this antenna be used for scanner monitoring. Most of my scanner monitoring is UHF, VHF, & 800's. If this antenna is "usable" would I receive distant stations OK? Thanks

T

ads023

I don;t think it'll be worth it - that antenna offers 7dB gain, apparently across the entire 10Meg bandwidth - I doubt that in reality - but in any event, that's the same as 4dBi (iso) in theory.

Put it to use outside of it's design frequency bandwidth, and yes it will work, and yes, gain is not the only criteria which determines how well an antenna works, but my personal feeling is that as this is a omni-directional antenna, and more than likely as jackj notes, of co-linear design, use it outside the the original design frequency band-width and the performance spec is going to plummet like a stone to the left hand side of 0dB - and while co-linears can indeed be used on multiples of antenna resonant frequency, their sensitivity degrades more so off-frequency than a di-pole type antenna would.

... and I'll tell you what else is going to go out the window: it's the lobe/radiation pattern at 90degrees (horizon)

This a carefully designed pro-type antenna (as is any rf product which carries an "Andrew" affiliated trademark) which is going to appeal to someone who's on the hunt for a good quality 450-470Mhz omni - my guess is you'd be better off to stick it up on eBay, and then put the proceeds towards purchasing or constructing a broad-band trapped (i.e. coil loaded type) vertical antenna.