[ADXA] FW: Question about wire mesh ground system

[EJ]

Thanks Jay!  Great articles.  I've been considering trying to do some
receiving on 630.  Like Joel said everybody has their own opinions about
ground systems

 

EJ

 

From: adxa-bounces at mailman.qth.net [mailto:adxa-bounces at mailman.qth.net] On
Behalf Of Jay Bromley
Sent: Monday, September 23, 2019 10:14 PM
To: adxa at mailman.qth.net
Subject: [ADXA] FW: Question about wire mesh ground system

 

Ej and all interested in an update on Chicken wire and or mesh wire ground
system.  Please see below and attached.  Like I mentioned before your
mileage may vary.  We have different soil here than Rob does, but anything
is better than trying nothing!  Still Rob knows his stuff and how to  make
it work!  I always learn something new from him.  

 

There are two attachments with this email I am forwarding from Rob and if
they don't get through the ADXA reflector and if you would like a copy, just
let me know and I will send them direct.  One about 630m using the wire mesh
and sort of a updated version of the Ham Radio May 1977 article on the wire
mesh ground screen.

 

All are very interesting, including the below!  Many thanks to Rob for
allowing me cross post!  73 de w5jay/jay..

 

From: Rob Sherwood. <rob at nc0b.com <mailto:rob at nc0b.com> > 
Sent: Sunday, September 22, 2019 11:13 PM
To: Jay Bromley <jayw5jay at cox.net <mailto:jayw5jay at cox.net> >
Subject: RE: Question about wire mesh under antenna

 

Hi Jay,

 

Nice to hear from you again.

 

My HR Magazine article used chicken wire simply because it was cheap, and I
could cut it up, make measurements with different layouts of the screen and
then throw it away.  My permanent ground screen that went down beside my
house in 1971 where I still live part of the time is dip galvanized hardware
mesh.   It is 3x30 feet, or there about.  I don't operate on 160m in Denver
any longer due to the vastly higher noise level than in the 1970s.  

 

The dip galvanized hardware mesh is steel, and is easy to solder to until it
gets wet once.  If you have very acid or caustic soil I can see that the
mesh I have been using for decades could be a problem.  

 

99% of my operating is now at my rural QTH 35 miles east of Ft. Collins, CO.


 

I just gave a presentation on my 630 meter operation at the Duke City
Hamfest / Hamcon.  Attached is a PDF version, and you can see the mesh in
one picture.  It is several pieces tied together mechanically and
electrically.  It is approximately 650 square feet, in more or less two
lengths 7x50 in and X.  Roger VK4YB and I currently hold the distance record
of over 8000 miles on 475 kHz. We used WSJT X JT9, and we  have had three
complete QSOs on 630m, in November of last year and March of this year, so I
can say my ground system is pretty good.  

 

The mesh wasn't new when I put it down 12.5 years ago, and it has sense been
covered with soil after a flood washed away a pile of dirt in my pack yard.
Also there is now native grass in the back yard, so it is not possible to
see the mesh any longer.  A few years after I installed the Marconi T
antenna at my rural QTH, I also added forty 100-foot radials, as covered in
the Dayton Hamvention Antenna Forum circa 2009.

 

I don't know anything about high power shortwave stations, but I have used
stainless mobile whips since the 1960s.  There would be more loss in
stainless, so I suppose if one is transmitting at 100 KW this could be an
issue.  I doubt it is an issue at 1500 watts.

 

While there may be copper mesh, the cost would likely be astronomical.  

 

The 630m presentation shows my current tuners for 160 and 630m.  The old
picture of the ground screen had a fixed L network in a blue case that was
not remotely tunable.  Now I can tune the L network from the shack.  Rotary
inductor and a vacuum variable.   I don't presently remotely tune the 630m
tuner. 

 

Rob

NC0B

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