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
The other tuner worked and your new MFJ didn't. Sounds like whatever you are trying to match is outside the range of the MFJ, but OK with the other tuner you put in line. Without further data, that's
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
Author: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Thu, 01 Jan 2015 17:39:26 -0500
Have you checked the toroid? It's been a few years since I had one, but IIRC the toroid is always in the circuit on the 989C. If not, how about the output selector switch? I've purchased more than on
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 po
Hi Roger. Yes, I did try that. I disconnected the torroid from the circuit. I think it is something getting hot but just can't feel anything that gets overly warm inside. It does drift faster at high
Hi Dave I did spray the bearings in the caps with some cleaner. Forgot to mention that. The caps are not grounded in this circuit. On 1/1/2015 12:18 PM, David Robbins wrote: Well, lets see... you byp
Just a thought, BUT, why not use an inexpensive laser temp meter that will save the "pinkies"? On 1/1/2015 3:55 PM, Kim Elmore wrote: Even at low power, large currents can flow in certain components.
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 An inexpensive remote reading thermometer, like the one
Hi Robert. Thought about that, but when the tuner is not in the 'tune' mode, it works fine just straight through. That is still a good idea. Will check it out tomorrow. 73 Tom W7WHY Sent from my iPad
Hi Bob No, it matches the antenna just fine. SWR goes to zero. Then it starts to creep up after a few seconds. Then I can re-tune it back to zero again, but doesn't stay there. Thanks and 73 Tom 73,
Has same behavior on dummy load? Try getting rid of all coax switches, surge suppressors, anything in the RF path to antenna, then swap out jumper cables & connectors. I am thinking cable/connector i
Author: mike repinski via TowerTalk <towertalk@contesting.com>
Date: Thu, 1 Jan 2015 23:58:51 -0500
Could the antenna be changing somehow? Mike Has same behavior on dummy load? Try getting rid of all coax switches, surge suppressors, anything in the RF path to antenna, then swap out jumper cables &
I'm puzzled that no one has mentioned the FIRST and most helpful trouble shooting test-- substituting a dummy load for the antenna. BillW4BSG an OCF dipole, or is it a dipole fed with open wire line,
What band and what type feed line? What antenna? You may need to shorten or lengthen the feed line to avoid an extreme low of high impedance point along the line. Running 40 meters on an 80 meter dip
Put a different SWR meter (not a tuner) in front of the MFJ-989C so you can see if it's simply the meter circuitry in the 989C that's acting weird. Dave AB7E Hi I picked up an MFJ-989C tuner that has
I haven't been checking every message... but has anyone noted that what is driving it could be the problem? Tuners act as a rather narrow bandpass filter in most cases so if the radio/amp driving it
Author: Patrick Greenlee <patrick_g@windstream.net>
Date: Fri, 02 Jan 2015 09:06:06 -0600
I recently had a problem where the SWR would "go crazy" frequently but seemingly at random. After "getting lucky" in a trouble shooting session I found a defective RG-8X jumper. In the middle of its
I have 7 antennas here. It will drift on every antenna. There seems to be some confusion on my first posting. This is what I asked: "Hi I picked up an MFJ-989C tuner that has a problem (don't want to
Author: TexasRF--- via TowerTalk <towertalk@contesting.com>
Date: Fri, 2 Jan 2015 12:25:34 -0500
So Tom, did you replace the SO239 rivets with screws yet? I think I saw two posts saying they had seen that problem/solution. 73, Gerald K5GW In a message dated 1/2/2015 9:11:20 A.M. Pacific Standard