| Author |
Message |
    
Perrym1962
Member
Username: Perrym1962
Post Number: 51
Registered: 11-2002
| | Posted on Monday, March 17, 2008 - 10:51 pm: | 
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What is the reason for backward swing on receive on a lot of different cobra models? I have had various ones with this characteristic, ie 142gtl, 89gtl, 1000gtl. Thought some of you Cobra guys may know, Thanks, Perry... |
Kabar
Member
Username: Kabar
Post Number: 61
Registered: 6-2003
| | Posted on Wednesday, March 19, 2008 - 6:44 pm: |
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Do these radios swing backwards on receive on all received signals or just on some?
Sometimes tranmitted signals swing backwards due to being overdriven and they will show up at your receiver swinging backwards which is the true meter reading.
UNIDEN PC-78 ELITE RADIOS SEEM TO HAVE THIS PROBLEM ALL THE TIME On RECEIVE.Tried two of these radios right out of the box new recently and both had this problem.Who wants a new radio that swings backwards on receive?
To your question the best I can come up with is that it is possibly a problem in the AGC circuit. |
Perrym1962
Member
Username: Perrym1962
Post Number: 52
Registered: 11-2002
| | Posted on Wednesday, March 19, 2008 - 10:12 pm: |
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I tried turning the rf gain down a tad and I can get them to swing forward. It does it with anyone with a 9 or greater signal. Also almost every 89gtl I have owned did this and a couple of 1000gtls. Also on the 87gtl. Never have saw this though on a 148gtl or 2000gtl. |
Starface
Senior Member
Username: Starface
Post Number: 1845
Registered: 1-2005
| | Posted on Wednesday, March 19, 2008 - 10:57 pm: |
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Reverse swing happens when you add modulation and the result is a loss of average power..Negative modulation usually happens when the carrier wattage is too high and not enough headroom to balance a peak to carrier ratio..
STARFACE
CEF#Ø476
KI4NBE
HAM#181
CVC#Ø14
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