[TZ] Elevated radials vs buried ones

[Rolf Sandmeier]

Dear Braintrust

An AM station, 40 kW, 910 kHZ, single tower 330 feet had half the radial wires stolen.

To worsen the situation, vegetation including 10 to 30 ft slim trees have grown long time ago. The station owner cannot cut trees because of new environment regulations.

I'm wondering about the amount of absorption  that could result from the trees top leaves, possibly affecting the interaction between the tower  H field and the radials E field. Or is it negligible at that frequency?

I told them if they could avoid cutting the trees by trimming the top ends to clear partially the "vision"  between radials and trees.

On the other hand, some guys came with  elevated radials suggestions.
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 Of all what I've heard and read about these, I never saw a neat conclusion about the the relative efficiency of the elevated wires systems, wether using 4, 8 and up to 60 radials wires, compared to a "healthy" properly laid 120 AWG 10 gauge wires, buried at a shallow 10 in.

I'm not too keen about trying this, as the costs in this case are much higher than the buried system repairs.

Any clue about this?

Thanks a Thousand for any suggestion!

Rolf Sandmeier
Consultor autonomo em radiodifusão, sistemas irradiantes AM/FM
Broadcast CE, Brazil
13 / 99776 0150
sistemasradio.hd at gmail.com