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?