To improve the ground plane of my roof mounted HF verrtical I plan on lining
the flat roof of my house with chicken wire (wire mesh) which comes in rolls
6' (2M) wide. As this is fabricated from fairly thin galvanised steel wire
I am not sure how to join the strips of mesh or make ground connection to
it. Can it be soldered?
I also plan on retaining the radials which run from the base of the antenna
to the edges of the roof and down to ground level. Should these be above or
below the mesh?
Thanks de Dick G4BBH

Hello Dick,

Whether you can solder the chicken mesh depends on the amount of
oxides. When it is very glossy (like a fresh soldered PCB), you may use
solder with a flux core (as you use for normal electronic assembly or
rework). I do not like this method for large solder jobs.

However, when it looks dull, you should use the aggressive paste or
liquid flux in combination with solder without flux (as used by
plumbers). The liquid flux (I think zinc solution in hydrochloric
acid) works well (I'm still using it) However, after soldering, you
have to clean thoroughly with abundant warm water with soap to avoid
corrosion. The aggressive flux stays active, also at normal
temperature.

I prefer the aggressive flux in combination with cleaning. After
cleaning, you can use normal flux core solder.

When I solder several pieces of mesh together, I first strap them
together with metal wire (in their final position), so I can fully
concentrate myself on the soldering.

I do not know your radial arrangement, but when the mesh will replace
the radials, I would remove them.

When the existing radial wires are not insulated, you may get
unreliable contact between the mesh and the radials. In combination
with small mechanical movements (wind), this may generate noise.

As the conductivity of wire mesh is not that good and somewhat
unpredictable, you may put (solder) small radial (about 30cm) wires
from the point where you ground your coaxial feeder.

I hope this will help you.

Wim
PA3DJS

Thank you Wim

I have in my household toolbox a good supply of a very agressive flux which
I often use as a final attempt to solder to some modern PL259 connectors.
I just tin the surface with the aid of agressive flux then clean it all up
before soldering normally. I think this and plumbers solder may work. When
the roll of ckicken wire is delivered I will try a test run.

As the ground mat will be of a lossy material I am hoping the large number
of effective rf paths in parallel will mean that losses will be reduced. My
present radial system is four insulated wires that run to drains at four
corners of the roof and the down inside the plastic drain pipes to ground
level. Approximately 16 metres each. There are a futher four radials which
onle go to the edge of the roof but are only about 4 metres long each. I
would lose these four short radials but keep the longer ones. The wire mesh
mat would be 6M by 7M and would be much better than those short radials. I
can solder a few radial wires from the base of the antenna to the mesh.
However if I solder each wire to the mesh at, say, 500mm intervals I could
end up with more galvanic corrosion particularly as the air is very salty in
Dover.

The weather is changing and I think I chose a bad time to start this :-(

Dick G4BBH

ferrymanr wrote:
To improve the ground plane of my roof mounted HF verrtical I plan on lining
the flat roof of my house with chicken wire (wire mesh) which comes in rolls
6' (2M) wide. As this is fabricated from fairly thin galvanised steel wire
I am not sure how to join the strips of mesh or make ground connection to
it. Can it be soldered?
I also plan on retaining the radials which run from the base of the antenna
to the edges of the roof and down to ground level. Should these be above or
below the mesh?
Thanks de Dick G4BBH



Once you have a mesh size of about 1 ft square it looks like a solid
copper sheet to RF. Putting your radials underneath will achieve nothing
they will be screened by the mesh.

Its also doubtful if they will have any value with such a high density mesh.


Galvanised wire wont last long laying on the ground. You can buy some
mesh at some places which is actually coated with copper. Its plated
with copper. Bird breeders seem to be demanding this stuff more and
more, which is very convenient to say the least.

You will have to solder mesh. The problem is that after the galvenising
process there is a nasty muck left on the wire thats hard to remove.

I would use a general purpose flux and use a pain brush to apply the
flux and leave it overnight to eat this crud away. I would then solder
the next day using heavy flux. Just watch your soldering tip, i would
wash it regularly because the flux is so aggressive it will eat away
your tip doing such a big job. I would use a very cheap solid tip iron
that you can file away and wash.


To me the job is such an horrendous thought that laying down 60 clean
copper wire radials looks like a simple job!

To each their own.


Greg

Continue to use the radials on top of the roof... Install the mesh
under the roof (attic I assume) and lap it over the rafters and just
twist the free ends to each other so that the mesh is relatively one
piece... Don't bother with solder.. Don't waste your time connecting
the radials to the mesh... The radials will couple with the mesh
electromagnetically...

If you are planning on putting the mesh out on the roof ( I would not
because it will rust and disintegrate in just a few years.) It has to
go underneath the radials, not over them... Again, do not mechanically
connect the radials to the steel... Just the proximity will couple
them... Think twice about putting the mesh outside... You will have a
nasty mess very soon...

denny / k8do

"Denny" wrote in message
ups.com...
Continue to use the radials on top of the roof... Install the mesh
under the roof (attic I assume) and lap it over the rafters and just
twist the free ends to each other so that the mesh is relatively one
piece... Don't bother with solder.. Don't waste your time connecting
the radials to the mesh... The radials will couple with the mesh
electromagnetically...

If you are planning on putting the mesh out on the roof ( I would not
because it will rust and disintegrate in just a few years.) It has to
go underneath the radials, not over them... Again, do not mechanically
connect the radials to the steel... Just the proximity will couple
them... Think twice about putting the mesh outside... You will have a
nasty mess very soon...

denny / k8do


Thanks Denny but unfortunately the flat roof has no access under. As far as
I can judge the ceilings have about a foot of insulation and beams above
then (probably) timber and is covered in several layers of heavy duty
bitumen based roofing material. The mesh will have to go on top as I think
the XYL would complain if I stapled it to the lounge ceiling.
The chicken wire will have a secondary function of deterring the large
number of seagulls that plague the town (Dover) :-)
Dick G4BBH

Dick, the usual galvanised, chicken wire available in the USA is good
for 3 seasons near the ocean, tops... Then they turn into rust balls...
Unless your chicken farmers there near the coast have better materials
available I would be wary...
The gulls that hang around my boat will stand on anything, I doubt that
chicken wire would bother them... I also doubt that putting the mesh on
the roof will make a major improvement in signal strength, especially
if it is above the radials... First your radials are already elevated
above the ground a significant fraction of a wave which reduces ground
losses... Putting your money/energy into having 6 or 8 quarter wave
radials for each band is more likely to show a better result...

cheers ... denny / k8do