So for the 1/4 wave (81mm) section of the antenna the loss would be
about 0.05dB ? at 915 MHz.

I typically have between 150mm (When antenna mounted on enclosure) and
2m length (when antenna external to enclosure) cable between transmitter
and Antenna. (Around 1.2dB max. loss in coax between transmitter and
antenna). Would this usually be acceptable or do you aim for much lower
loss in the transmission line ? Max. power is 1 Watt. Most of the
transceivers I play around with are around 10mW.

Thanks

Cecil Moore wrote:
David wrote:

If I scale that up to 915MHz, the dimensions are almost perfect for
using RG58 coax ...


I wouldn't use RG58 for anything above HF. It has 20 dB
matched line loss per 100 ft at that frequency.

"David" wrote in message
...
So for the 1/4 wave (81mm) section of the antenna the loss would be about
0.05dB ? at 915 MHz.

20dB/100' MATCHED line loss.
W4OP

David wrote:
So for the 1/4 wave (81mm) section of the antenna the loss would be
about 0.05dB ? at 915 MHz.

Depends upon whether you leave the insulation on the radiating
part or not. But what I was concerned about is the transmission
line. You lose about half of your power every 15 feet. Until
your last posting, you didn't tell us the length of the
transmission line but personally I find 1.2 dB matched line
loss in six feet to be unacceptable. Any SWR above 1:1 and the
losses are even greater.

Cecil Moore wrote:
I wouldn't use RG58 for anything above HF. It has 20 dB
matched line loss per 100 ft at that frequency.
--
73, Cecil http://www.qsl.net/w5dxp


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