Rik
My advantage is Location. I am only 2 miles from the sea to the East across
countryside, to my south there is a river, which probably helps and I am
sorrounded by thousands of hectares of green fields in all the other
directions. The only obstacle if any is the town of Scarborough to my SE.
Therefore, my transmitted signal has a good take off and the same applies on
receive. I have maximum advantage with the permitted power.
Measuring or comparing signals at a distance is impossible, it depends how
the signal is launched, in an urban environment/middle of a housing estate
the signal is likely to be attenuated dramatically.
Air calibration at various distances from the TX is the only reliable
solution. Hardly worth the effort.
The German beacons on 505 khz are strong with me during daytime as well as
night time, and as a matter of interest I can work most EU stations on 160
metres daytime when they are active. Antenna on 160 is a one wave inv L at
over 100 ft vertical, this is one leg of 4 legs for 137 khz.
de G3KEV
----- Original Message -----
From: "Rik Strobbe" <[email protected]>
To: <[email protected]>
Sent: Sunday, August 24, 2008 10:33 PM
Subject: Re: LF: 500khz rtty
Based on the antenna description given by Mal ("1/4 wave inv L for 500
khz, 100 ft vertical and rest horizontal") simulation reveals a
radiation resistance of 5 Ohm and a directivity of 1.5 dBd. This means
that only 375 mA antenna current is needed to radiate 1 W ERP.
It is hard to tell from here, but such a big antenna should have a
loss resistance of 20 Ohm or less. So in the worst case 2.8 Watt TX
power is needed to get 1 Watt ERP.
I can only dream of such a situation ;-)
73, Rik ON7YD - OR7T
From: "mal hamilton" <[email protected]>
Sent: Saturday, August 23, 2008 8:18 PM
To: <[email protected]>
Subject: Re: LF: 500khz rtty
ANYTIME . If you saw the fet in my PA you would'nt bother.
G3KEV
----- Original Message ----- From: "John Pumford-Green GM4SLV"
<[email protected]>
To: <[email protected]>
Sent: Saturday, August 23, 2008 7:39 PM
Subject: Re: LF: 500khz rtty
On Sat, 23 Aug 2008 18:14:23 +0100
"mal hamilton" <[email protected]> wrote:
I thought that would be the response from you. Why no ID?
I will let OFCOM decide if necessary
G3KEV
Perhaps we could ask them to check your ERP at the same time?
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