BobS wrote:
Anyone using the PAR Electronics EF-SWL Antenna please advise if a
ground is necessary. Will using the PAR without a ground be any better
than a 50' random wire? I live on the second floor of a condo and only
can use a very thin hidden wire from my receiver to a nearby tree. No
ground available. I read all of the glowing reviews of the PAR but all
of them are using a ground. Unfortunately I don't have that luxury. Any
other recommendations appreciated.


Bob, a friend of mine has the ham radio transmitting version. It's half
a trap dipole with a proprietary matching coil. We have some theories of
exactly what the coil is, but they are speculation, so I'll leave it
out.

As a dipole, you need two sides. PAR accomplishes this with the ground side
of the dipole being ground. Since it connects to a coax cable, the feed
is unbalanced, and so is the antenna.

In short it needs a ground to operate. Otherwise it is just a wire (with
a loading coil) stuck at the end of a coax.

If I were you, I would make a ground at the receiver end of your wire.
The best would be a tuned counterpoise, such as 50 feet of wire connected to
a cheap antenna tuner. Second best (but maybe not very different in actual
performance) would be a multi conductor wire, such as a rotor cable, cut
at various wavelengths.

From what I have read, the best length for a counterpoise wire that is not
on the ground is 28% of a wavelength. Since you are receiving and not
transmitting, length is not all that critical, nor is insulation.

The wire can be run around the floor of your room, even looped around if it
is a smaller room.
The far end of the wire is a voltage node if you are transmitting and
therefore needs good insulation. For reception, enough to prevent it from
causing a short if it ends up in the wrong hole is good enough.

Since it will be "cold", it can be under a rug, etc.

For electrical saftey, I recommend that some sort of grounding (a wall
outlet near the window is fine) is used when not receiving to prevent
static build up or a nearby lightening strike damaging anything.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge or
understanding, as in he has a sub-wikipedia understanding of the situation.
i.e possessing less facts or information than can be found in the Wikipedia.