For radials lying on the ground or shallow-buried, the soil detunes them. The near field of shortened vertical antennas is more compact, so making the radials longer than the antenna is tall won't help much. If you could set up the transmitter (or ATU) with 102" whip antenna atop a 200" - 210" wide copper or copper foil square (or circle) and ground the unit to the copper, that should give excellent results. One or two *resonant* elevated radials (up 10' high or more) cut to 1/4 wavelength may work better, but they are illegal for Part 15 AM use. -- Jason
> >> Is anyone using 1/4 wave length radials with their LPAM
> transmitter?
> >> What transmitter are you using and what kind of range are
> you getting?
> >> I have a potential site that has plenty of room for 140
> foot radials.
>
>
> > Since I build these things, here is my advice: I have
> had exactly two
> > customers ask for "LONG" radials. I suspect that, over
> the long run, a little > bit longer is cool, and if you
> have a damp area to install them in, could be to > your
> advantage...........However, you don't need 1/4 wave
> radials; your antenna > is 102" long, and you certainly
> don't need 360 or 10 or whatever!....Try it, but > our best
> guess is that after 50 (and that is stretching it!!) more
> won't help
> > you.
>
>
> I appreciate your advice Carl, you have done a lot for this
> group. My thought is that the antenna is "tuned" (even
> though it is only 102" long) for resonance at 1.670 Mhz. The
> "other" half of the antenna is the ground and the radials.
> 102" is the resonate frequecy (1/4 wavelength) for 27MHz,
> not broadcast AM. A radial at resonace (234/1.67) 140 foot
> long, would dramatically improve the signal or so it would
> seem. Perhaps this is why belltowers, watertowers and metal
> billboards have the best results.
>
