Do the radials actually have to be a physical 5/8 wave to get this benefit,
or can loads be chucked in to just give the 1/4 radials-5/8 electrical
lengths?

Warmest regards,
John

Cecil Moore wrote:
I'm considering putting up a 1/4WL vertical for 30m
with four slanted elevated 1/4WL radials. I looked
at all the bands, 40m-10m. Take a look at the
performance of this antenna on 10m where it is
an omnidirectional 5/8WL, 4.28 dBi at 10 deg.
Note the four radials are also 5/8WL.

Keep the 5/8WL vertical on 10m and shorten the
radials to 1/4WL (8.25').
0.57 dBi at 10 deg.
3.5 dBi at 24 deg.
4.4 dBi at 53 deg.

Looks like 5/8WL radials may work better for a
5/8WL vertical than 1/4WL radials.

Sure...Old news to me....
http://web.wt.net/~nm5k/acompari.htm

I've used that exact antenna...was designed mainly as a 5/8
for 10m, but also used it as a 1/4 on 30m.. I used 3/4 wave
radials the last time...."10m".
I also did the same thing on 40/17...My full size 40m GP
doubled as a 5/8 on 17m. I used a 24 volt relay to switch
in a loading coil for the 5/8...In modeling those,
I found the 5/8 should have more gain than the 3/4 radials,
but seems to me, the 5/8 radials would need to be tuned to
work properly...IE: think dual 5/8 radiators...One up, one
down...The 3/4 radials are a good match as is, being the
reactance is tuned out with that length...
BTW....Vuuuurrrrryyy important...If you dual band it, you
must use an ungrounded series matching coil. There can be
no dc connection to ground, if you want it to work on 30m.
MK

wrote:
BTW....Vuuuurrrrryyy important...If you dual band it, you
must use an ungrounded series matching coil. There can be
no dc connection to ground, if you want it to work on 30m.

I guess I forgot to say I plan to use it on 40m-10m driven
by an SGC-230 which will match virtually anything. The
resistive impedance and the reactive impedance are less
than 1000 ohms on all bands so I think the SGC-230 will
not be extremely lossy.

I once forgot to attach the Hustler coil to the Hustler
bottom section so the antenna was about four feet long
with no loading. The SGC-230 faithfully loaded that
four foot long vertical on 75m. But please don't ask
about efficiency.
--
73, Cecil, http://www.qsl.net/w5dxp


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