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N4XM Tuner

Subject: N4XM Tuner
From: ni6t@scruznet.com (Garry R. Shapiro)
Date: Wed Jul 31 03:51:14 1996
Jim Reid wrote:
  The roller inductor is on a ceramic
> core;  MFJ's
> new inductor is air core,  and will be higher in Q than were it on ceramic.
> I went to
> the XMatch tuner after melting my earlier MFJ inductor core while on 160;
> that was
> the earlier MFJ design which had a plastic inductor core of some type.  I
> did also
> become very frustrated with the poor quality of construction of the MFJ
> controls:
> the switch shaft would slip,  not turn the switch because the internal shaft
> coupler
> was slipping;  the turns counter would slip on the inductor drive shaft,  etc.
Every man chooses his own tradeoff points, I guess. After five or six
years of constant maintenance and tinkering with the TenTec 238 I bought
used, not knowing any better, I would probably agree that the XM is a
good choice--if I had the money, which I do not.

TenTec and MFJ each put the lie to "American craftsmanship,"--although
in fairness each targets a wider market than N4XM or Nye-Viking. The
TenTec is a marvel of cost-cutting from a company that basically makes
boxes. The cost-cutting is clever, but not confidence-inspiring:

* couplings made of  plastic
* extension shafts of phenolic or fiberglass or some other fiber
* a cheap meter of translucent plastic that serves to diffuse the light
from a 12V bulb that also sits in front of a piece of aluminum angle
stock that serves as a reflector--careful:-the bulb easily melts the
* a rotary inductor with a ceramic core--but with end plates made of PC
board stock and a roller wheel that wobbles on a floating shaft. It
squeaks a lot and is as smooth as---sand in your crotch.
* a sliderule dial-cord assembly whose tensioning elastic was an early
and chronic failure
* coax connectors riveted at two holes of four--badly--necessitating
replacement with screws
* disc ceramic padder caps;
* the obligatory, generally worthless 4:1 balun, smoked early-on when
presented with the ridiculous impedances not infrequently seen with
balanced lines
* a TT case with the cutesy plastic side trim pieces, whose plastic
nipples break off after the second or third removal--not to mention no
RF  sealing where those pieces mount.
* cheap knobs

The roller inductor and its cheezy dial finally got me--this weekend I
yanked both and installed an old  BC375E roller inductor and counter,
purchased most reasonably at a flea market, years ago. The impulsive
decision to do surgery came after I saw--too late--a Nye-Viking MV5-A
offered on PacketCluster for $350. It went in a microsecond. I needed to
cut a lot of big holes in the 238's inner and outer panels and extend
the spacers and couplings. But it is brass, ceramic and cast metal that
cost us taxpayers a mint decades ago, perhaps when I was still in
diapers. It's not an XM or an MV5-A---but it's sure better than it was! 

The circuit? Series L, shunt C, with the C switchable between eingang
and ausgang. That part I like: CONTEST tuning is quick and easy.

"Alternating currents are dangerous. They are fit only for
                                powering the electric chair."
                                         -- Thomas A. Edison
Garry Shapiro,
Editor, "The DXer" 
        --monthly bulletin of the Northern California DX Club

>From neader@centuryinter.net (Scott Neader)  Wed Jul 31 06:41:06 1996
From: neader@centuryinter.net (Scott Neader) (Scott Neader)
Subject: Free ham classified ads on the web!
Message-ID: <v02140b05ae249deb360d@[]>

>I don't know if this is appropriate, but I am looking for an Amp.  Something
>that runs 160 through 10 meters from 1000 to 1500 watts......

If you're looking to buy or sell equipment, especially stuff used during a
CONTEST, check out this FREE service via the web:

   Ham Heaven Classified Ads

73 - Scott KA9FOX

Disclaimer: Trey said it was OK to post this.

INTERNET SOLUTIONS - Affordable web page design and storage
Scott Neader (608)788-1234 / FAX (608)787-0100 / neader@centuryinter.net
Internet Solutions web: http://www.QTH.com/is   Ham web: http://www.QTH.com

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