I'm puzzled that no one has mentioned the FIRST and most helpful trouble
shooting test-- substituting a dummy load for the antenna.
Bill--W4BSG
-----Original Message-----
From: Charles Farr
Sent: Thursday, January 01, 2015 5:50 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Tuner SWR won't stay down
An inexpensive remote reading thermometer, like the one from Harbor
Freight would be a less invasive, and less likely to result in an RF
burn. Sounds like capacitor to me.
Chuck, W6AJW
Even at low power, large currents can flow in certain components. This
sounds like something is heating up and changing value. A giveaway would
be if the match drifts faster at high power than at low power. Assuming
that's the case, can you get inside and, while running low power, feel
around for anything getting warm?
Kim N5OP
"People that make music together cannot be enemies, at least as long as
the music lasts." -- Paul Hindemith
On Jan 1, 2015, at 14:09, Tom Osborne <w7why@frontier.com> wrote:
Hi
I picked up an MFJ-989C tuner that has a problem (don't want to hear
about 'mitey fine junk).
The problem is that the SWR goes down and then slowly creeps back up.
I got a new roller inductor and installed it and the SWR still doesn't
stay low, even at low power.
I took the roller inductor out and put in a switch/coil combo to
eliminate the coil problem. SWR still climbs up.
Bypassed the SWR circuitry and ran the input from the antenna directly to
the capacitor. Still won't stay low.
I thought it might be the SWR circuitry but I put another tuner in front
of this one and when I tune the SWR down with the other tuner, it stays
down, so don't think it should be the SWR circuit.
This really has me puzzled. Can't see anything left to check. Any
ideas? Thanks and 73
Tom W7WHY
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
---
This email has been checked for viruses by Avast antivirus software.
http://www.avast.com
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|