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MFJ-948 Tuner help/problems

Jun 22nd 2015, 18:47

KA0RSN

Joined: Jan 23rd 2015, 19:42
Total Topics: 0
Total Posts: 0
Thank you for any information or guidnace you have on this. Please bear with me as a newer operator trying to figure things out and get set up. I have an MFJ-948 Antenna Tuner that I am unsure that it is working properly. It is connected to a G5RV dipole antenna that I built myself. The overall length is 102', with the feedline length being about 35'. I am using an Icom IC-7200 transceiver. While attempting to set up the tuner for certain bands, such as 20 and 40 meter, when I try and see what my reflected power is, both needles on the tuner never move. I have used the recommended starting adjustments from MFJ but I never see a difference. I am using the lowest power setting (30 watts) and have adjusted the setting extremely just to see if I could get any change, but nothing.
Any assistance would be appreciated!!

KA0RSN
Jun 22nd 2015, 20:20

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Is your IC-7200 putting out 30 watts and measuring SWR according to the manual? I'd first do testing on 20M, where the SWR is normally best for a G5RV--and I'd do it without the MFJ in line--run the coax from the antenna straight to the rig.

Once I know that is working, then I'd hook up the MJF--being very careful to use the right connectors on the back panel.

Zack W1VT
ARRL Senior Lab Engineer
Jun 23rd 2015, 04:04

KA0RSN

Joined: Jan 23rd 2015, 19:42
Total Topics: 0
Total Posts: 0
Thank you Zack! It ended up being the mode I was trying to use to tune. I was using SSB. I switched over to RTTY and it worked perfectly! Embarrassed to admit it, but it tells you to do that right in the set-up portion of the manual. Sheesh. Thanks for your help!

KA0RSN

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