I'm looking for a single antenna solution for my IC-R3 receiver. Could a
discone antenna cover 500KHz to 440 MHz with usable signal? (This is receive
only.) Would a ramdom length wire be my best bet?

--
Bob D.
ND9B

On Thu, 31 Aug 2006 16:58:43 -0500, "Bob D."
wrote:

I'm looking for a single antenna solution for my IC-R3 receiver. Could a
discone antenna cover 500KHz to 440 MHz with usable signal? (This is receive
only.) Would a ramdom length wire be my best bet?

Radio Shack has a discone that receives from 25 mhz to 1300 mhz. Maybe
you could combine that with a random wire for the lower frequencies.
(The arrl antenna handbook has a discone for 7-30 mhz, but it is 62
feet tall -- you could check their formula for what it would take for
500khz to 440 mhz)

bob
k5qwg

I'm looking for a single antenna solution for my IC-R3 receiver. Could
a discone antenna cover 500KHz to 440 MHz with usable signal? (This is
receive only.) Would a ramdom length wire be my best bet?



Here is my spur of the moment opinion... think of the frequency you
want to monitor and thing of the antenna. Then realize that to get a
reasonable signal you need an antenna that is substantially large in terms
of the wavelength of the signals you want to capture.

If you want to monitor HF, MF, and even lower frequencies, a standard
VHF discone such as the diamond D-J130 is such a tiny fraction of the
wavelength of HF signals that there is very little HF signal captured by
it.

You need wire, and plenty of it, if you want low frequencies!


Ed K7AAT

Hi Bob

There isnt a simple answer to your question! You havent really defined
what "usable" really means either.

As a gut feel however a discone would probably be "usable" over a 10:1
frequency range (say 44-440MHz) There will be some tradeoffs however,
the most troublesome (in my view) being non optimal radiation pattern as
you go higher in frequency. (ie the antenna pattern tends to sky) It
will never work as well as an antenna designed for a specific frequency.
Your only real option is to try it and see.

Below about (say) 20MHz you'll probably get better performance just
using the feedline to the discone. You might even consider separately RF
earthing the R3 and then only connecting the centre conductor of the
discone coax. You will of course encounter local noise issues but it
does work.

Its a hard call to find an antenna to do what you want unless a lot of
compromises are accepted. If I was in that situation I'd probably grab
one of those motorized car radio antennas type designs so I could adjust
the length remotely, or look into some kind of (remote adjust) magloop
design for at least the HF end.

Apologies for not being much help

Cheers Bob W5/VK2YQA



Bob D. wrote:
I'm looking for a single antenna solution for my IC-R3 receiver. Could a
discone antenna cover 500KHz to 440 MHz with usable signal? (This is receive
only.) Would a ramdom length wire be my best bet?