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Author Topic: MFJ 998 vs LDG 1000pro  (Read 1567 times)
KE7EOZ
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Posts: 117




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« on: January 29, 2011, 08:20:33 AM »

Hi all I need to buy a tuner for a ampl AL80B that I ma going to run with a G5RV I want to go auto so would like to hear which of this two tuner would be better option thanks
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K0BG
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« Reply #1 on: January 29, 2011, 12:33:59 PM »

The choice is yours, but there are a few things to consider.

First, neither tuner will take the full output of the 80B, unless the load is within reason. For example, you might (?) be able to load the G5RV on 17 or 10, even though the reactance is rather extreme. However, dumping full power into either coupler on either of these bands will likely zap the coupler.

Both are switched LC units, and they just don't have the matching range a decent T match will have. Nonetheless, they have the same limitation when matching loads of about 25 ohms or less, especially highly reactive ones. It is just the nature of matching networks.

You might want to do a search on http://www.w8ji.com for G5RV so you have a better understanding of the conditions mentioned above.

Oddly, the MFJ mentions that is has an amplifier bypass relay, which they say is an exclusive feature. That's not so, as 2 of the SGC units have had the feature for at least 10 years.

In any case, if it were me, I'd sans the auto coupler, and buy a decent T match.
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N3JBH
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Posts: 2358




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« Reply #2 on: January 29, 2011, 12:38:18 PM »

I totally agree with Alan I had a auto tuner the LDG-!000 it was kind of ok Huh?sold it bought a Palstar and loved it no more auto tuners for this shack. Jeff
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AD5X
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Posts: 1426




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« Reply #3 on: January 29, 2011, 04:08:05 PM »

I've had a MFJ-998 since it first came out, and it has been a great autotuner.  It has an L/C limit algorithm that limits the L and C values based on matching, power and frequency to keep from damaging the unit though I've never seen this kick in.  I've used my MFJ-998 with a maximum power of 1200 watts, though my normal use is at 600 watts with my ALS-600 amp.  Antenna is a 43-foot vertical.  The amp bypass function works great - it takes the amp off-line before the MFJ-998 starts tuning.  Firmware updates are easy - I've done this twice in the three years that I've had the unit.  Anyway, as you can tell, I like this autotuner.

Phil - AD5X
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WX7G
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Posts: 5920




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« Reply #4 on: January 29, 2011, 04:28:24 PM »

From what AD5X says the MFJ will do the job and do it well. 1500 watts and 12 to 1600 ohms is the spec.

Tuning an AL-80B and then a manual tuner each time you change bands sounds like a chore. The autotuner will be nice.



« Last Edit: January 29, 2011, 04:49:14 PM by WX7G » Logged
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