On Sun, 30 Oct 2005 15:27:34 GMT, "Jeff"
said in rec.radio.scanner:

"Al Klein" wrote in message
Four things you should be aware of:

1) A discone is a negative gain antenna - that is, it has less gain
than a dipole, which is the standard by which 0 gain is measured.

Name 1 "scanner" antenna that does have gain? Not an
amatuer antenna a "scanner" antenna.

Since we never covered "scanner antenna" in antenna theory, define
what you mean.

Dipoles (or ground planes) have, by definition, 0dbd gain. A discone
has negative gain, vis-a-vis a dipole.

With trunking a
fact of life nowdays most people want to listen anywhere from
100 to 900Mhz. There are only 2 antennas that work well all
the way thru that area, one is the discone

The discone operates, at best, over a 4:1 frequency range, not exactly
VHF-hi to 850.

Actually a nice link, very informative and agree with it
totally. I use Quad Shielded RG 6 with only about a 25' run. Im good
up to about 1 Gig. Not much above that to listen to anyway.

I'll go along with 2.3db loss being ok, but what is quad shielding
buying you with an unshielded scanner?

Actually a good discone is closer to a 10: 1 ratio.

When are they awarding you your Nobel prize?

Most antenna engineers will quote you 3:1 for real world antennas.
Some claim that they can actually achieve 4:1, but I suspect the
machining costs would make the antenna unaffordable.

Most, without
the vertical stinger are good from 100-1000Mhz. I have transmitted
on mine on 52, 144, 440, and 904Mhz with anywhere from excellent
to good results.

I can do the same thing with my R7, but that doesn't make the antenna
an antenna at those frequencies. Conductors don't accumulate signal,
they radiate it.

The math for a discone is totally different than the math for
a dipole. They just dont work the same way.

Yep - the rule of thumb is that the lowest frequency is that at which
the radials are 1/4 wave and the highest frequency is 3 times that for
a good design that's been well implemented.

You're getting carried away here again with the grounding thing.
Nobody, and I mean nobody puts a grd system in as you describe here.

No one you know - okay. Many people I know have and do.

It simply isnt needed.

Not unless you want a good ground. I'm not talking about not having
the mic bite you, I'm talking about not living in a hole in the ground
after the pole pig on the pole in front of your house suffers a direct
strike.

I'm not making this up - read the National Electric Code on grounding,
or ask an electrician. This is important - people are killed every
year by bad antenna installations. Not many - but if you're one of
them, it doesn't matter how many there are.

The people that do get killed are the idiots that put up a mast
and an antenna 10' from a power line, and when it goes down and lands
on a power line bad things happen.

I'm talking about those killed by lightning. You don't run a ground
system to blow breakers on a 440 line that are located a few miles,
and a few transformations, from the ground.

Rule No. 1, do not put ANY
antenna even remotely close to ANY power line and you wont have
any problems.

Until the clouds gather.

I hope you sleep well when someone actually takes your advice and it
results in his death.

*N*E*V*E*R* take *A*N*Y* chances with lightning. 50 million volts
can't be "handled" by anything man can do when it has tens of
thousands of amps available behind it.