Re: 10GHz World Record


marcuswalden@...
 

Richard,

 

Assuming that you are talking about 3 September 2013 (VHF/UHF column in RadCom November 2013), I looked at some radiosonde data at 1200 UTC for this date.

 

There was an elevated duct over Camborne (UK) with its top at ~770 m and a depth of ~350 m that might support frequencies down to ~37 MHz. Above Funchal (Madeira), the elevated duct top was at ~640 m with a depth of ~140 m, while above Guimar (Tenerife) the top was at ~950 m and its depth was ~600 m.

 

From this radiosonde data, one might assume that there was a continuous elevated duct extending from the UK to the Canary Islands, albeit one where the characteristics changed with distance.


Weather charts for this time period indicate a high pressure system over the Bay of Biscay, which suggests the elevated duct was a subsidence duct.

 

I believe your station is at ~60 m altitude so there would have been a sizeable coupling loss into the elevated duct (~60 dB?). There might have been sufficient link budget to establish a contact on 430 MHz but the additional loss at 1296 MHz could just have been too much.


How do the conducted powers and antenna gains for your system compare at 430 MHz and 1296 MHz?


Do you know the station details at the other end of the link?


If you and/or the other station had been closer to or within the duct, the coupling losses would have been much lower. I wonder if you then might also have established the contact at 1296 MHz or even higher frequencies. Obviously, there are physical/practical limitations to getting the station higher to take advantage of these elevated ducts.

Hope this is of interest.

 

Marcus G0IJZ

Join UKMicrowaves@groups.io to automatically receive all group messages.