Re: Quarter-wave whip earth plane

On 3/11/25 2:56 AM, Liz Tuddenham wrote:

Joerg <news@analogconsultants.com> wrote:
 

[...]

For example, you could get another of those hinges from a vehicle
junkyard, have someone weld a piece of steel to it and then mount the
antenna on that. If you ever sell the van you could mount the hinge you
took off.

 I have never seen or heard of one of these being scrapped in the UK,
they are all exported to third-world counties and converted into lorries
and buses.  (The engine and transmission is reputed to outlast three
sets of bodywork.)  Perhaps a hole could be drilled through the hinge
strap to take a bolt - that could be removed later and the hole might
not be noticed.  I can do my own welding, but that is much harder to
disguise.
 

Even the best vehicles occasionally become smashed in an accident such as a head-on collision or a T-bone. Then the whole chassis is toast. Someone will take out the engine and transmission but one of the door hinges could become yours.

 

One thing you might consider is to drill or machine three big holes into
the steel plate and sink the magnets into it so they are flush with the
bottom surface. That way the whole steel plate could make surface
contact with the roof (with a thin protective plastic layer in between,
of course). That should increase the capacitance substantially.

>
That's an idea, I won't be able to do it with the existing plate, but I
do have a bigger piece that might work.  My lathe only has 9" radius
swing (with the bed gapped), so I might have to trepan the holes
instead.
>

>
Or maybe ask a friend who has a bigger lathe.

 I have a contact in a heavy engineering factory (I sorted out one of
their CNC machines a few years ago) but another approach might be to
drill a lot of smaller holes and buy a lot of smaller magnets.  A sheet
of polythene damp-proof course material or adhesive-backed neoprene
sheet across the whole underside would prevent scratching
 

That sounds like a lot more work than using one of the hinges.
--
Regards, Joerg (AJ6QL)
http://www.analogconsultants.com/