Austin Spectra Antenna, Best Reception Possible

[rob2262]

I have a question about the Austin Spectra Antenna. Do most of you have to do cut off some of the antenna to receive the best reception ? If so how do you know how much to cut off ? Thanks !

[ka3jjz]

It only makes a slight difference on VHF lo - and you can cut the very top whip from the bottom, and reinsert it so you can't even tell you cut it.

There is a chart that shows how much to cut it, and the last time I bought one (years ago) it came with the antenna. There is a version floating around the web somewhere...Mike

[Redneck0410]

Don't forget to double check your antenna once you get it cut to make sure it's resonant at the frequency you want it to be resonant at. When you cut, make sure to cut it a little long to allow for fine-tuning.

[bigmattyl]

here you go

[k7ng]

Just to make sure it's clear:
You don't cut anything anywhere if you are not going to be listening to Low Band.

There is really not a huge difference in reception on Low Band without any adjustments.

Make very sure you have tightened the allen screws REAL tight after any adjustments or you won't have that piece after a while.

[prcguy]

There's not a huge difference if you don't consider 20 or 30dB of loss huge but I do.

The Austin Spectra comes factory tuned to about 33MHz and I measured the loss at 43MHz without tuning at around 18dB. At 50MHz its almost 30dB down compared to untuned so if your going to listed more than a few MHZ either side of 33MHz you would want to tune it.
prcguy

Originally Posted by k7ng

Just to make sure it's clear:
You don't cut anything anywhere if you are not going to be listening to Low Band.

There is really not a huge difference in reception on Low Band without any adjustments.

Make very sure you have tightened the allen screws REAL tight after any adjustments or you won't have that piece after a while.

[rubicon05]

so i was wondering how bad is it if you cut it a little long, i just bought one and cut it @ 40 mhz, just to cover 42-44 mhz for the chp. just curious?

[ka3jjz]

Any antenna that is this short is bound to have problems on VHF lo (and that would include 6 meters as well). Loss figures notwithstanding, I have been very pleased with mine on VHF lo, even tho I didn't expect to have it work as well as it does.

A little background - I had this antenna on a Diamond NMO trunk lip mount on my 2001 Camry (since got rid of the car), and used this antenna with a Uniden BCD396T and 245 (yes the venerable analog Uniden trunker...). Our local Md. State Police runs mostly on 39 Mhz (where I cut the top whip). I made certain I had a decent connection between the base of the mount and chassis by scraping a little paint and testing with a VOM (the other end of the VOM was on a mounting bolt for one of the seats).
Admittedly not particularly scientific, but it worked.

The terrain here is hilly and urban - but I still managed to hear the Glen Burnie barracks from my parking lot in Bowie (scratchy, but it was there)- a good 1/2 hour or more drive. I've had similar success hearing the Golden Ring barracks from Howard County (similar distance, roughly). I've even heard mobiles - not just the barracks base (it's primarily a simplex, not a repeater, system)

So don't let the loss fool you. It's not going to replace a 6 foot or so whip (and I wouldn't be so silly as to claim that it would), but it does work surprisingly well on VHF lo. There are practically no 6 meter repeaters here to speak of, so I can't comment on how it works there.

Mike