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Author Topic: TS-480SAT + G5RV + MFJ-934?  (Read 4788 times)

Posts: 7

« on: October 20, 2009, 08:29:35 AM »

Got the TS-480 a few weeks ago, great rig, but the internal ATU has problems with my G5RV (half-size + 80m coils), particularly on 80m.

I don't really want to go to the expense of a multi-band vertical (don't really want to over advertise the fact I am a ham), and the G5RV seems to work well (had a FT-110ZD before with FC-902 ATU and I could get the SWR to a reasonable level on all bands).

I am thinking of getting the MFJ-934 tuner + aritifical ground (I operate from my 'office' on the first floor = upsatirs!) so long distance from a 'real' ground.

Comments seem positive about the MFJ unit, any thoughts? Pros, cons, etc???

I don't run too much power (normally try to keep below 50w and have worked South Orkneys on 15m SSB).



Posts: 805

« Reply #1 on: October 20, 2009, 09:14:42 AM »

I have not been too happy with the lower-power MFJ tuners. Consider picking up a used heavier duty tuner. Their 948 worked, but it was prone to arcing and a bit touchy. There is a world of operating difference between it and, for instance, the Heathkit SA-2040. Little more than the small MFJ. A lot less than new heavyweights. Big devil, but a breeze to tune and nicely overspeced for 100 watts and will tune most anything, a nice thing when you're keeping a low profile. Same could be said for a number of the older heavy tuners.

I can't address the artificial ground issue, as I've never messed with them, having used balanced antennas. I suppose that there are situations in which an artificial ground device on a counterpoise is the only way out, and maybe you have one of those. I really think I'd have whipped up a balanced loaded dipole and fed it with ladder and a real tuner before I fiddled with "G5RV" tweaked antennas and had the attendant issues. But likely someone who's used one can contribute. I just suspect the setup is going to test any tuner and that a more robust one will do a better job.

Posts: 2086

« Reply #2 on: October 20, 2009, 12:35:18 PM »

The MFJ-934 as most MFJ tuners works just fine. The problem usually starts when someone consistently tunes at high power (100W) when the tuner is seeing high SWR. The MFJ-934 is a 300W tuner, initial tuning should be at 10W then touched up at the operating power. Even an expensive legal limit tuner will arch at 100W under some conditions. Have fun!

73 de Lindy

Posts: 691

« Reply #3 on: October 21, 2009, 08:39:51 AM »

Hi Mick....

Well, first off, the price of that tuner and the artificial ground adds up to the cost of a decent multiband vertical.  You are talking about $300 (US).

G5RV's can be good antennas, but depending on the installation, they can also be a real bear to get them to work on all bands.  A good, wide-band tuner is almost a necessity.

A simple ground mounted vertical over as many radials as you can fit would be my choice. And once installed, and tuned, the internal tuner in the 480 will take care of any mis-matches due to frequency excursions around the bands.  Also note that a ground mounted vertical does NOT require quarter wave radials, anything you can put down will usually do the job.  Just try to keep the radials themselves as long as the antenna is tall.

Just an opinion....

73, Jim/k7unz
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