Towertalk
[Top] [All Lists]

[TowerTalk] MFJ ARTIFICIAL GROUND

To: <towertalk@contesting.com>
Subject: [TowerTalk] MFJ ARTIFICIAL GROUND
From: K7GCO@aol.com (K7GCO@aol.com)
Date: Sat, 17 Nov 2001 06:35:44 EST

     In a message dated 11/15/01 7:33:34 AM Pacific Standard Time, 
     w8ji@akorn.net writes:< 
      Let's try this again. The message bounced, and I don't keep 
      copies, and I hate to retype the same thing twice.
      
      The MFJ artificial ground cannot make a 1/4 wl ground lead 
      grounded at the far end into anything "good". 
      
      The only thing the artificial ground does is cancel reactance in the 
      ground lead. It will NOT make a 1/4 wl ground lead or any other 
      poor ground lead length look like a low impedance, because it is a 
      two terminal device and can't "stretch" the line.
      
      While there are cases where it can help, there are just as many 
      cases where it will not help. It might do the trick in some 
      situations, but certainly will not in all of them.
      73, Tom W8JI
      W8JI@contesting.com 
       >>
     In a message dated 11/15/01 1:14:39 PM Pacific Standard Time, 
thompson@mindspring.com writes:<< 
      
      The advice from K7GCO is good.  I would add that my first shack at my
      present location was a second floor bedroom.   The Artificial Ground 
works
      well.  I moved to the basement and it still did a good job there.  I 
have
      three (multiple) paths to ground but found on 10 and 17 there was a poor
      enough ground for the MFJ to work.  I made a good ground for both but 
found
      that it was best to switch the MFJ out when working the other 
bands...as the
      MFJ caused say 20 to be detuned.  It does affect loading which in this 
case
      caused SWR to appear higher so my transceiver would balk (but not the
      amps..so go figure).
      73 Dave K4JRB
      >
      > In a message dated 11/14/01 7:22:58 PM Pacific Standard Time,
      > aa0cy@VRINTER.NET writes:
      >
      > << anyone used this device, which sounds like an "antenna
      >  fooler" for the ground system?  Good?  Bad?  Indifferent?
      >  I've got a good 35' run to where the water line enters the
      >  basement...
      >  Thanks. >   73
      >  Bob AA0CY
      >
      >  Yes it works.  It's a series circuit that alters the length of what 
ever
      > it's connected to, to a 1/4 wave (or 3/4 wave) that's a low Z path 
for RF.
      > I'd try hooking it to the wire to the ground, some other lengths and 
the goal
      > is "maximum RF cooling."  The internal meter measures max RF current 
just
      > before the terminal you connect a wire to your rig or whatever you 
want to
      > cool.  K7GCO
       >>
     Tom:  No one said it worked all the time and/or without some 
modifications of wire length. You say it works and then you say it doesn't 
work.  Which is it?  Few things work every time.  Just because it doesn't 
work in all your cases you have to do your "TT Flame" for reasons best known 
to you.  I specifically suggested different lengths on it's tail end so that 
it works most or all the time as the MFJ unit has some limit's in what it 
does.  Dave above "verifies EXACTLY what I said" and he had the ability to 
try different lengths to make it work for him satisfactorily--you didn't.  
I've found it cooled the chassis of a tuner one time indicating it presented 
a Lo-Z to it and as indicated by the internal meter, RF current did indeed 
flow typical in Low Z's.  I inserted a RF Ammeter in series just to see how 
much current was flowing--2 A..  Tom you will have to speak to the MFJ 
Artificial Ground directly as it can't read TT about what you say it can't 
do.  
  
  Dave also noticed it affected the unit it was connected to also.  It's got 
some "RF Hooks" in it if adjusted right.  How it does it no one really give a 
damn and if you approve or not.  Every piece of equipment is not all bad or 
are all the new ideas bad you can't understand.  
     
  Now the MFJ Artificial Ground can present a Lo-Z to what ever it's 
connected to if the wire length on the tail end is fairly compatible for the 
MFJ, MOST OF THE TIME.  If it doesn't, change the length.  The built in meter 
tells you when "it's doing it's thing."  It works great on "second floors" as 
Dave above suggests (even the basement) and can prevent TVI on 6m--I know.  
In ham radio one must be creative enough to solve "simple problems" to 
accommodate practical limits of any equipment or it's not ethical to "Flame 
It" anywhere.  You must have a lot of technical helpers with your station 
there to get things to work for you.  Tom what useful purpose did your post 
serve?  I clearly stated it didn't work every time with certain lengths of 
wire.  Why was it ncessary for you to say it again and not provide a 
solution--as I did?  
 
 Something that works deserves the proper recognition.  I just invested over 
$1000 of my own Retirement Money and a lot of time to give a FREE PLUG to 
Raibeam and it's beam design (that you don't think works.) in the Dec 73 Mag. 
 Have you ever done that?   Mfgs often invest large sums of money to market 
gear.  There is a lot of equipment in Ham Radio that didn't survive Critics 
like you--that couldn't make it work.  Many Mfgs lost big sums of money as a 
result.  I've got 5 E-mails telling of how the MFJ worked for them.  They 
didn't care for your comments either.  They are going to continue to use it 
regardless of your technical inability's.  
     
  The MFJ Artificial Ground like the Match Box works just fine when "properly 
used"--please leave them alone or learn how to properly use them.  I wish the 
Artificial Ground was still made.  Tom, you have this "Total Misconception 
and Delusion" that every thing or new idea has to be approved by you to be 
useful, worth trying or you get on your "TT RF Negative Soap Box."  It's not 
a W8JI Ham Radio Police State as yet but it's getting there.  The rest of us 
still reserve the right to use what we want although appreciate legitimate 
info on equipment deficiencies.  Lets support equipment that works and new 
ideas even if you didn't think of them.  If you need some help on how 
something works, I'll be glad to help you.
  
Dave,  I thank for your support.  You get the "K7GCO Good Samaritan Award" 
for "Defending What Works."  I'm all alone sometimes supporting equipment and 
proven ideas that work.  MFJ appreciates it also.  Wait until Martin F Jue 
hears of this.  K7GCO 
   

List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 100 feet for under $1500!!  http://www.anwireless.com

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com


<Prev in Thread] Current Thread [Next in Thread>