Every Tuesday evening, we have a local VHF net in Cork and a few of us get together for a chat. We use the the 6m, 4m, 2m and 70cms bands and which one we use depends on which Tuesday of the month it is.
It usually covers the first four Tuesdays of the month and if there happens to be a fifth Tuesday then we gave it a skip. A few weeks back, we thought it might be a good idea to use the fifth Tuesday in a month for experimentation, to try something that we don't usually do.
From this concept came the idea to try the 23cms band, i.e. 1296 MHz.
Denis, EI4KH near Watergrasshill has a Yaesu FT-2312 23cms transceiver running 4 watts on FM only and his antenna is a 26 element Yagi horizontally polarised.
A sked was organised with Don, EI8DJ who was located in a car at Camden near Crosshaven at the mouth of Cork harbour, a distance of 22 kms or 13.8 miles.
While the path wasn't line of sight, both Denis and Don were in good high locations. EI4KH was about 120m above sea level while EI8DJ was at a spot about 45m above sea level.
As the plot shows below, any obstructions on the path were several kms distant which made them less of an obstruction.
For EI8DJ's portable set-up, he was using a scanner for receive with a home made Bi-Square antenna shown below which was sitting on the dash of his car.
Using a frequency of 1290.000 MHz, EI8DJ managed to hear the FM signal from EI4KH at an estimated S'4' signal strength and a successful 23cms to 2m crossband contact was completed.
EI8DJ found the Bi-Square to be suprisingly directive and later peaked the FM signal from EI4KH to a maximum of an estimated S'7' signal strength.
The experiment was repeated with EI8DJ back in his driveway which is some bit lower than his portable location. From his home location, EI8DJ couldn't hear any sign of the FM signal from EI4KH.
While the distanced achieved were nothing special, it was interesting to see some local activity on the lowest of the amateur microwave bands.
Notes:
1) The beam heading for Denis was 170 deg.
Oh God! Now you've whetted my apetite for 23cm! I can actually see the Mourne mountains from my QTH in Wales, so the prospects of some 'DX' are quite good, I think!
ReplyDeletehaha! I'm laughing at your comment John :)
ReplyDeleteThat's the problem with reading other people's blog... the exchange of ideas and the slippery slope.
During the VHF net last night, I was telling the other guys about a story I had heard a while ago. Back in the 90's, there was supposed to have been a very active group on 23 cms around the Isle of Man. I think there was a repeater there and there were people from Northern Ireland, SW Scotland, NW England and N Wales using it.
23cms was very popular in Japan and there was a supply of FM only rigs for that band. I think a lot of people were using those.
I don't know what became of the repeater or the activity?
GI6ATZ is very active up in GI on VHF. I'm sure if you work him on 2m, he could let you know of any 23 cms activity.
The BIG problem of course is the lack of overall activity and is it really worth buying some gear? There is a big difference from being on the west coast of Wales and being say in Norfolk and beaming across the North Sea to the Netherlands and Germany.
Nice to see someone using a bisquare antenna.
ReplyDeleteBiquad ( closed loop) as opposed to bisquare (open ends).
ReplyDeleteThere is a guy makes and sells them for 2M and 70cms in the North at rallies. No reflector on his though. Serious gain for the size with a reflector.