| Author |
Message |
    
Therealporkchop
Intermediate Member
Username: Therealporkchop
Post Number: 405
Registered: 11-2002
| | Posted on Tuesday, September 20, 2005 - 8:28 pm: | 
|
I had to title it that, so I would make sure the right person read this.
OK, I got an S9 in my truck. A two pill Dave Made hooked to it. The jumper going from the radio to the amp is about 1ft long and the big RG8/U type. Connected for an anetenna is a Wilson 5000.
OK, when I key up the radio with the amp off, I'll use a round number, the meter shows say "6". OK, when I cut the amp on, radio still keyed up, the needle moves backwards, to like 4 or 3 or so forth.
OK, I changed the coax jumper to a piece about 6ft long. Did the same test, the needle moved up from "6" to like 8 or so.
What is going on with this setup? I had the same thing happen on the bench in the shop, with another radio, a Galaxy 77.
I also noted that the SWR was higher with the 6ft coax jumper installed and saw the SWR rise when I would whistle into the mic versus either a stand still with the short jumper or a slight fallback.
With either coax, SWR is about 1.1:1, but with the longer jumper it goes up to about 1.6:1 when talking, so I removed it.
But I'm puzzled as to why the radio shows different movement when you change the jumpers?? I also NEVER see the S needle swing fully when talking or whistling, regardless of what jumper I am using or whether the amp is inline or not.
Pat, what's up with this buddy?? |
Kid_vicious
Advanced Member
Username: Kid_vicious
Post Number: 670
Registered: 9-2004
| | Posted on Tuesday, September 20, 2005 - 11:22 pm: |
|
i know you want pat's input, and i'm sure he'll be able to help, but here's a couple of thoughts to ponder until you get his response.
it sounds like the input tuning of your 2 pill is not 50ohms, or the radio is putting out a lot of harmonics.
on the test bench, try putting a low pass filter in between the radio and amp.
if this cures the problem, then it's one of those two things.
dont know what the permanent fix is though.
hope this helps some,
matt |
|
