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Message |
    
Skifly
New member
Username: Skifly
Post Number: 6
Registered: 10-2004
| | Posted on Sunday, November 14, 2004 - 5:54 pm: | 
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I'm trying to tune two Fire Sticks on my big truck,Grounded,changed mounts ,changed coax ect. I finally got my Cobra 25 to 1.3-1.05-1.3, when I hook up my MagnumS3 it goes to 3.2-2.8-3.5.
Lost and confused, any help would be apreciated.
Thanks
Mark |
Bc910
Intermediate Member
Username: Bc910
Post Number: 188
Registered: 7-2004
| | Posted on Monday, November 15, 2004 - 2:49 am: |
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Simply put, the more power being fed to the antenna, the more gets reflected. Reflected power being what SWR is, this is your problem. The S3 almost positively puts out more power than the 25, therefore, higher SWR. Just hook up the S3 and tune the antennas accordingly to it and you should be fine.
Every radio is different; every radio and antenna combo should be tuned to each other!!!! Don't expect one to perform the same as the next even if it is the same make and model even.
BC
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Skifly
New member
Username: Skifly
Post Number: 9
Registered: 10-2004
| | Posted on Monday, November 15, 2004 - 9:26 am: |
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Thanks Bc910
Mark |
Patzerozero
Intermediate Member
Username: Patzerozero
Post Number: 207
Registered: 7-2004
| | Posted on Monday, November 15, 2004 - 12:33 pm: |
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look what time it is, bc, shouldn't you be in bed? you're not thinkin' straight here.(just messin' wit ya!!) it's quite possible, if both radios are unmodified, the S3 is KEYING 1 watt and the 25 is KEYING 4 watts. i usually test my swr's with an UNMODULATED signal(unless of course i had that autek research meter...). and my sx100 won't calculate swr with less than 20 watts dead key...
'Just hook up the S3 and tune the antennas accordingly to it and you should be fine.
Every radio is different; every radio and antenna combo should be tuned to each other!!!! Don't expect one to perform the same as the next even if it is the same make and model even.'-maybe so, but that much of a difference, something's not right. just ran out and swapped my 148 for my grant xl, internal swr meters and maco swr meters read the same, 1.3:1 on 26.835, with 3 watt dead key...
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Bruce
Senior Member
Username: Bruce
Post Number: 1765
Registered: 9-2003
| | Posted on Monday, November 15, 2004 - 2:51 pm: |
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hummmm if your SWR meter is calabrated corectly they should be the same no matter what power you run. NOW if the S-3 has been peeked and tweeked and is putting out trash that could change things.
DECREASE the output power of the S-3 to 4 watts and remeasure ...... if the readings become the same i would try another SWR meter if the 2 nd meter reads the same put a good lowpass filter on the radio before the SWR meter and try it again TRASH comming out of a transmitter will rase a SWR reading. |
Bulldog369
Intermediate Member
Username: Bulldog369
Post Number: 211
Registered: 2-2004
| | Posted on Monday, November 15, 2004 - 9:58 pm: |
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it should not change the vswr that much if it has been P+T.. i hook my 142 up i have a 1.2 i hook my ts-5010 i have a 1.4 and that going from 4 watts to 12 on the 5010.. are you useing an external meter or the ones on the radio?.. if its the one on the radio then it could just be that the s3 is out of alignment on that pot. |
Skifly
Junior Member
Username: Skifly
Post Number: 10
Registered: 10-2004
| | Posted on Tuesday, November 16, 2004 - 10:23 am: |
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The radio is converted, Tuned , external meter
I hooked up both to a single RG58 20' with a dummy load,(S3 Turned down 4wt) both have 1:1 across the channels. (1.15:1 on Mag with antenna full power across)
The cophase coax I am using in the truck is 18' wilson product with Beldin RG8X? they say 72 OHM cophase harness, I thought RG8X was 50 OHM?
with 2 dummy loads the cophase cable I get 1.3:1 across the channels both radios.
The only thing I did now was rplace the stud mounts and cleaned ,retightened everything getting SWR down but not like the single setup.
Thanks for all the help
Mark
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