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Customer Reviews for the MFJ-931.

From: Marty KB0QZ
Purchased the MFJ-931 Artificial Ground Tuner after failing to find a workable HF antenna solution for a second story apartment. Always have had access to full size dipoles and short earth ground connections do this was a challenge especially since I was wanting a solid signal on 80 meters. Without the MFJ-931 any antenna (tried a ham stick on a metal balcony and an attic 35ft dipole) but neither were effective and had RF evident at the Transceiver. With the MFJ-931 I was able to increase my signal strength at the receiving end and no RF was observed at the Transceiver.
More antenna tests will be tried but the MFJ-931 will be used in future antenna systems. I am convinced that it solves remote grounding issues, maybe not as good as a short connection to a solid earth ground, but when one is not available it is better than even using a Balun based upon my experiments. The Manual is vague on the wire counter poise - my experiments show two is better than one especially if they are different lengths. In future tests I intend to have several lengths that are approximately quarter-wave lengths for my favorite HF bands.

From: Gary W Long W1GWL
The MFJ-931 added the final touch to the remedy for an issue I was having. Operating from a second floor shack and using an end-fed multi-band antenna made for some interesting problems. RF grounding is a problem with operating an end-fed and more so when the station is well above "earth," so compensating for this is precisely what the 931 assists. After installing a full-length counterpoise under the sloping end-fed wire, a line isolator on the coax near the feed-point, bonding all radio and power supply elements, and bonding all earthing rods (at the mast, at the end of the counterpoise, and below the shack window), I installed the 931 in series between the HF radio and the grounding lug of the MFJ-4602 window feed-thru. This complete system removed all noticeable RF from the shack.

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