UHF channel scanning
Submitted: Thursday, Dec 01, 2005 at 14:03
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ChrisB
Have just installed a GME 3400 in my 4by. When on scan mode, it always stops on channel 20 when near home. There is no one speaking when the scan stops however and it does not continue to scan after 5 seconds.
I know I can remove this channel from the scan memory to avoid this happening, but it only happens around home. What could cause this? There is a garden supply place near by; I’m wondering if they may be using this channel to direct their forklifts and loaders around the yard using low power radios that cause my UHF to stop scanning but I can’t hear what they’re saying. Could this be? Or, what else could cause this?
Reply By: Member - MrBitchi (QLD) - Thursday, Dec 01, 2005 at 14:06
Thursday, Dec 01, 2005 at 14:06
Try turning the squelch up a bit. Probably picking up some interference from somewhere. Source could be anything at all....
AnswerID:
141950
Follow Up By: joc45 - Thursday, Dec 01, 2005 at 14:18
Thursday, Dec 01, 2005 at 14:18
Agree with John. Many household appliances, eg, TV sets,, videos, garage door openers, have small oscillators which can radiate on UHF, albeit only a short distance.
If you're living on or near a hilltop, there may be a group site for commercial VHF/UHF mobile radios, and some small interference could be radiating from there. I get that problem where I live.
You could set the radio to only open channel 20 with the CTCSS feature, but then anyone calling on 20 would have to have the CTCSS operating as
well.
Crank the squelch back a bit, just remember to readjust when you head off.
Gerry
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Follow Up By: ChrisB - Thursday, Dec 01, 2005 at 14:59
Thursday, Dec 01, 2005 at 14:59
The 3400 only has 3 squelch settings. It evan stops scanning on squelch 3. I think Alan has the best solution, to use group instead of open around home and open when away. Just wondered if it was something I did wrong when installing the unit.
I have it connected directly to battery, but when ignition was turned on I was getting interference even when just on ACC. I put extra insulation around coax by means of electrical tape for the distance it runs in engine bay, I then put it in that split casing stuff. Interference stopped.
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Reply By: Sand Man (SA) - Thursday, Dec 01, 2005 at 14:24
Thursday, Dec 01, 2005 at 14:24
I would have to disagree, unless the GME scan mode acts in a peculiar way.
The Uniden unit will stop if it picks up any sort of transmission signal, but unless one subsequently presses the scan button to stop auto scanning, it will continue on.
Would have thought the GME units would perform in a similar fashion.
AnswerID:
141952
Reply By: Alan S (WA) - Thursday, Dec 01, 2005 at 14:33
Thursday, Dec 01, 2005 at 14:33
Chris
You have 2 scan modes, open & group. Program you group scan to scan all channels except Ch 20.
It is covered in the manual how to delete & add channels to your group scan.
Alan
AnswerID:
141954
Follow Up By: Utemad - Thursday, Dec 01, 2005 at 18:05
Thursday, Dec 01, 2005 at 18:05
You should be able to delete channels from group or open scan. If you use group scan it will check the priority channel every four seconds which is a PITA if you don't want it to keep doing that.
However as Sandman said it should continue scanning once the channel is clear after a few seconds. So it is more likely that their is interference from electronic sources than some other UHF user.
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Reply By: Banjo 1 - Friday, Dec 02, 2005 at 09:00
Friday, Dec 02, 2005 at 09:00
Modern HF scans often stop on channels that traffic can't be heard on - just hash - so some of those systems just respond to "any activity" of sufficient strength on that frequency. Re your UHF, a blip of noise (not heard by the user) might open the channel - as others have said, the airwaves in our lives are full of radio waves, over a huge spectrum, all of the time. Variable interference like this is to be expected IMO. As an aside, my HF set puts out a signal that interferes with channel 35 on my UHF ....... HF and UHF produce fundamentally different signal types but the HF box manages to generate something that the UHF recognises as traffic on 35 !
AnswerID:
142089