[UK-CONTEST] 144mhz UKAC 3/11

[Andy Swiffin]

>>> On 05/11/2009 at 21:56, in message <B628722E1D814BEEBFC23EA50476B6D1 at OCH1>,
"Darrell G0HVQ" <g0hvq at talktalk.net> wrote:

> 
> The last time I worked IO72 or IO73 on 2m was around 1986, when I had my old 

73 used to be pretty regular - aren't there quite a few active folks on Anglesey?

> Just goes to show, it's always worth a look on VHF. Given the weather, I was 
> convinced there was no chance of any tropo.

Depends what you mean by tropo Darrell.   Do you mean Tropospheric ducting or Troposcatter?  They're very different.  Troposcatter will give pretty much the same signal 24/7.

Julian Gannaway published what I think is a seminal paper on troposcatter in Radcom in the late 70's /early 80's.   I have it scanned on a web server if anyone is interested (am I allowed to do that??).  Which gave some nice graphs for calculating the expected troposcatter signal from 50mhz up.   

I did a test once to anglesey with, I think it was, Steve gw0gei (or was it Tony, can't remember the call) and we got pretty much the expected signals simultaneously on 50mhz and 144mhz, calculating the values for our stations.  Interestingly taking into account the smaller aerials that are usually around at 50mhz but the lower path loss most people will have the same signal strength of 50mhz that they do on 144mhz, Steve and I did.

Basically, on troposcatter I should be able to work up to about 600kms to an equivalent station at any time.

73
Andy
gm8oeg


The University of Dundee is a registered Scottish charity, No: SC015096