It is my opinion that very low dipoles that are much less than 1/4
wavelength are efficient radiators but most of the radiation is straight
up. So they are not good for long distance but work well at low HF
frequencies for short distances where straight up is fine since it
refracted right back down in the ionosphere.
Does anyone have any real data to either support this or refute it?
Carl Moreschi N4PY
58 Hogwood Rd
Louisburg, NC 27549
www.n4py.com
On 7/18/2016 6:15 PM, Darrell Bellerive wrote:
How do you know this? Did you make comparisons with dipoles at greater
heights? Low power enthusiasts (QRP'ers and QRPp'ers) make lots of
contacts with very little power, so just because you made contacts
doesn't mean your antenna was efficient and not affected by ground losses.
100 watts into an antenna system with 13 dB loss is 5 watts effective
radiated power (ERP).
100 watts into an antenna system with 20 dB loss is 1 watt ERP.
Either case will still make lots of contacts. Any antenna is better than
no antenna. Just don't think that a very low antenna height is helping
your transmit signal. You are succeeding in spite of it.
73, Darrell VE7IU
On 16-07-18 03:02 PM, Stuart Rohre wrote:
Surprisingly, we found the ground losses to NOT affect adversely our
use of 100 watt transmitters at Field Days for NVIS to our target
areas in state of TX and nearby states.
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