Pro-96 Strange Antenna Problem

[SAR923]

I've got an RS dipole on a 30 foot mast and a Pro-96. I originally had a PL-259 with a BNC adapter and the reception on weather channels was lousy. I even had to use the attenuator to hear a few channels. I can hear them all fine with the standard rubber duck. UHF and 800mHz reception was very good though. I though I might have a problem with loss from the adapter so I cut off the PL-259 and soldered on a BNC. Huge improvement in the weather channels and VHF-Hi in general. Only problem was that my UHF and 800 mHz reception went right down the tubes. I cut off the BNC and went back to the PL-259 and BNC adapter and it was back to the way it was before -the weather channels were terrible but UHF and 800 were strong again.

Anyone have an idea as to what might be the problem and what I can do so I get VHF as strong as the other bands?

 

[LarrySC]

To me the problem seems to be OVERLOAD. All PRO-series scanners will lock down in a Metro area when connected to an outside antenna. In my area a 1/4wave 3" commerical rubber duck is a good replacement for the stock antenna on a 95 or 96, of which I own both. My office is 21miles south of the Metro area and I use a MAXSCAN1000 tri-band base antenna on my PRO-96 at work. Not this works fine as I am outside of the RF Hell area. We have a lot of UHF in the area and I install a Stubby 3" VHF rubberduck on any older 10.7 IF scanner overloaded with UHF. Using the wrong antenna is a good thing. Good Luck, Larry

 

[SAR923]

Larry,

I'm sure that overloading must have something to do with it or the weather channels wouldn't improve if they are attenuated. I'm far enough away from San Francisco that I don't don't have any major RF problems and never hear any intermod on the Pro-96. Attenuating other VHF-hi frequencies degrades their performance, even relatively close stations. I'm sure the BNC adapter is inducing the loss but I'm still confused about why it would make 400 and 800 do better while 150-174 gets so much worse.

 

[KA5UUN]

To SAR2401

You never mentioned your feedline. As you increase in freq. your feedline loss goes up as well. While this is not usually a problem for RX only systems it could be whats bugging yours. Get some Beldon 8214 or 9913 if you've got the coin. At least RG-8.
On the connectors, I'd stay with whatever your antenna terminates with. BNC, PL-259 or whatever. Adapters are also 'lossy'.
Make sure your antenna is well grounded, for safety as well as RF reasons.
Hope this feeble attempt helps!