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Re: [Amps] MFJ products

To: "Gene May" <gene-may@hotmail.com>, "Amplifier Mailing List" <amps@contesting.com>
Subject: Re: [Amps] MFJ products
From: "Carl" <km1h@jeremy.mv.com>
Date: Mon, 10 Sep 2012 18:44:57 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
With the cover off it might annoy bugs, birds, and 4 legged rodents. OTOH it might decide to self destruct on its own.

Carl
KM1H


----- Original Message ----- From: "Gene May" <gene-may@hotmail.com>
To: "Amplifier Mailing List" <amps@contesting.com>
Sent: Monday, September 10, 2012 6:12 PM
Subject: [Amps] MFJ products



I've had experience similar to that described below with their products, of which I have a number, some active, some passive. I've learned the following:

(a) don't believe their CCS and max ratings; IMHO they've been somewhat optimistic. (b) the same sentiments re QC that are expressed below. I open and examine them the same way I would examine an early HeathKit or DynaKit that I was resurrecting, one which I made before I had much experience in assembly and soldering,.

Along these lines: I just got an MFJ 998RT, the 1.5 KW, 1.8 - 30.0 MHz, remote antenna tuner. I found one of the bolts that is supposed to hold the cover to its base with its head stripped off. I also found that they used wire at least two gauges smaller than I would have used to wind the coils.

QUESTION: I plan to use the 998RT in my attic right now, not outside, and am thinking of running it with its cover off so that it runs cooler. Their instructions say not to do this, although this seems to relate to safety issues (high RF voltages) rather than function. The cover is made of plastic, not metal, and therefore not a shield against harmonics radiating. Does anyone else have any experience with running this or any other of their remote tuners without covers (indoors, obviously)? Comments or suggestions?

I do like their value, and as below, will probably continue to buy their stuff, with the cautions above. I also particularly like their not cancelling the warranty if you open the device, since I always do.

Ref SWR meters: I like the "computing" type of SWR meter, like first described in QST by Fayman W0GI about 30 years ago. This displays SWR directly, computing it from forward and reflected power and not requiring one to either read some obscure needle intersection, or switch back and forth between forward and reflected power. I still have one of his design I made back then. Grebencamper has described an updated version (in the ARRL Antenna Book - haven't tried it, but the circuit is similar), and Autek Research in FL makes and sells them. I have one of these also and like it. These are VERY handy instruments for Field Day, or for people who have to squeeze their antennae into small attics.

Tnx es 73,

Gene May
WB8WKU


RECENT RELATED POSTINGS:

Date: Mon, 10 Sep 2012 04:00:26 -0400
From: k8ri@rogerhalstead.com
To: amps@contesting.com
Subject: Re: [Amps] SS Amp questions

On 9/10/2012 12:53 AM, Jerry Kaidor wrote:
*** My impression of MFJ is that they do have some pretty decent engineering in their stuff, but their quality control is strictly to meet
a price.

They do make some handy equipment that works fairly well, they make some to a price and stretch the power out beyond reliability limits, but you only need to look at the QC on the same items built under their control and without to see what building to a price can do.
I still use their products, but pay attention to what I get.

73

Roger (K8RI)
open the> >
> - Jerry Kaidor, KF6VB

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