| Author |
Message |
    
Sideband
New member
Username: Sideband
Post Number: 9
Registered: 10-2004
| | Posted on Tuesday, October 26, 2004 - 9:35 am: | 
|
I just installed an IMAX 2000 and I also replaced my feed co-ax with RG213 terminated with gold plated connectors. I measured the SWR and it indicates 1.9 on an Autek analyzer with confirmation on the meter on the radio. After a bunch of futzing around I went back to the original feed and VSWR dropped to a more manageable 1.4.
When I soldered the connectors on I was carefull to fill all four holes and not leave a cold solder joint. I first tinned the shield I could see through the holes but I will say though, I wasn't sure if I got much solder in otherwise. End to end both shield and center conductor meter to < than 1 ohm with no short.
I'm puzzled. Can anyone shed some light on this?
Thanks
Mark
CEF412 |
Tech808
Moderator
Username: Tech808
Post Number: 3931
Registered: 8-2002
| | Posted on Tuesday, October 26, 2004 - 11:53 am: |
|
Sideband,
Your Meter should read ""0"" or NOT even move the needle when testing the Center to the Shield of coax.
When testing the Shield to Shield it shoud read FULL Scale and the same when testing Center to Center
What is your SWR on Channel 1 / Channel 20 and Channel 40? |
Sideband
Junior Member
Username: Sideband
Post Number: 10
Registered: 10-2004
| | Posted on Tuesday, October 26, 2004 - 1:23 pm: |
|
Tech808,
Sorry my sentence about my meter readings on my first post wasn't clearer. It is less than 1 ohm end to end on both shield and center conductor and infinity (within the meaning of the act) between center conductor and shield. This is what it should be.
I didn't check SWR's at both ends of the band. Will do so tonight.
Thanks,
Mark
CEF412 |
Sideband
Junior Member
Username: Sideband
Post Number: 11
Registered: 10-2004
| | Posted on Wednesday, October 27, 2004 - 9:21 am: |
|
OK,
I measured SWR's at channel 1, channel 20 and channel 40 with the RG213 in place and these are the results:
Channel 1 1.9
Channel 20 1.9
Channel 40 1.8
With the RG8 in place the results were:
Channel 1 1.4
Channel 20 1.3 to 1.4
Channel 40 1.3
Higher than channel 40 the results trended upward again so it's obvious the cable/antenna combination center tune is a bit higher than channel 20.
Whatever the center tune point is though, it still puzzles me why the RG213 provides enough of a mismatch to increase the VSWR by an average of .5 Help!!!
Thanks,
Mark
CEF412
|
