At 6/2/2009 05:22, you wrote: >All that glitters is not gold... > >If you sweep the typical Comet, Hustler and Diamond Multi-band >antennas... you'll find they are fairly limited in band width >and rarely cover an entire Amateur Band Segment with decent >SWR (reflected power, return loss) values. They work fairly >well for many people in casual FM service but you might find >your repeater operates at one portion of the band where the >SWR value is not pretty... > >As an example, the SWR of a Comet & Hustler Multi-band Antenna >I have here is not a decent, what I deem a usable value at the >low end of the 440 to 450 Amateur Band... Even with a decent >circulator / isolator panel in for protection I would be >wary.
Not sure what you consider "usable", but I haven't had any bandwidth problems with Comet antennas. I just checked my GP9 antenna at home & the return loss is <=20 dB (1% reflected power) from 444 to 450 MHz. It does go up a bit from there: 3% @ 443 MHz, 4% @ 442 MHz, & 5% @ 441 & 440 MHz. 2 meters is similarly good: <1% from 146 to 148, 2.5% @ 145 MHz, 4% @ 144.5 MHz. BTW, it's being fed with 30' of 1/2" Heliax so negligible loss between the Bird & antenna. I once bought a "Comet knockoff" at the swap meet a few years ago that was obviously a 430-440 cut antenna even though it was labeled 440-450, as it had very high reflected power at the top end of the band. Perhaps that is what you had. Bob NO6B
