On 21 Mar 2006 13:23:26 -0800, wrote:

The claims
for
this antenna seem streached abit, they claim 26dB gain from just wire
and a few resistors
and claim its 435mhz design can work up to 890mhz, theres even a quad
rhombic shown
also. Sounds to good to be true, so i wandering if anyone has had any
experience with
actually building & using one of these antennas. I would like to build
some kind of high gain recieve
only antenna to see if its possible to get a decent signal from some
of the ATV repeaters.

Hi OM,

It's as good as any other.... Good being highly qualified, especially
as the construction details are so shy of description here. Barring
those details, rhombics are not a mystery.

If it works on the 440 Band, you can scale it down for the 900 band if
you want it shorter, or just use the instructions provided. How good
it performs remains to be tested. You would have to test anyway to
confirm any antenna claim for gain.

73's
Richard Clark, KB7QHC

Also I would check to make sure the gain is listed as 26 DBd instead of DBi.
Back in the day, allot of companies inflated their specs by stating the
DBi gain instead of DBd.
DBi being gain over an isotropic and DBd being gain over a dipole.

--
RoD
KD0XX
PG-6-29404


"Richard Clark" wrote in message
...
On 21 Mar 2006 13:23:26 -0800, wrote:

The claims
for
this antenna seem streached abit, they claim 26dB gain from just wire
and a few resistors
and claim its 435mhz design can work up to 890mhz, theres even a quad
rhombic shown
also. Sounds to good to be true, so i wandering if anyone has had any
experience with
actually building & using one of these antennas. I would like to build
some kind of high gain recieve
only antenna to see if its possible to get a decent signal from some
of the ATV repeaters.

Hi OM,

It's as good as any other.... Good being highly qualified, especially
as the construction details are so shy of description here. Barring
those details, rhombics are not a mystery.

If it works on the 440 Band, you can scale it down for the 900 band if
you want it shorter, or just use the instructions provided. How good
it performs remains to be tested. You would have to test anyway to
confirm any antenna claim for gain.

73's
Richard Clark, KB7QHC

Stargatesg1 wrote:
Also I would check to make sure the gain is listed as 26 DBd instead of DBi.
Back in the day, allot of companies inflated their specs by stating the
DBi gain instead of DBd.
DBi being gain over an isotropic and DBd being gain over a dipole.

At 26Db there isn't enough difference between dipole and isotropic to
matter.

Dave WD9BDZ

To get 26 dB over a dipole would require rhombic leg lengths of about
125 wavelengths, or about 275 feet at 450 MHz. The overall length would
be around 500 feet. The beamwidth would be so narrow you'd have
difficulty getting it aimed toward one station, even if you were able to
turn it somehow.

Roy Lewallen, W7EL

David G. Nagel wrote:
Stargatesg1 wrote:
Also I would check to make sure the gain is listed as 26 DBd instead
of DBi.
Back in the day, allot of companies inflated their specs by
stating the
DBi gain instead of DBd.
DBi being gain over an isotropic and DBd being gain over a dipole.

At 26Db there isn't enough difference between dipole and isotropic to
matter.

Dave WD9BDZ