Earlier in the year, Andy @MM0FMF got in touch. The SOTA MT had received a few antennas of a novel design, for testing purposes. Would I like to put one through it’s paces?
Fast-forward to early December, Andy and I met up, failed to erect the antenna due to a lost or forgotten adaptor, and so it came up the road with me - untried.
On Wednesday, I had the opportunity to nip out and give it a go. Craiglich GM/ES-068 can be put on the air within 40 minutes of leaving the house and is an ideal summit for testing stuff, so off I went.
I won’t say too much about the antenna here, as that is all in the video. All I’ll say is, it was a still December afternoon, with superb clear air. I could see snow capped Cairngorm summits over 70km away. The pics that follow, hopefully potray the serenity. Once I’d completed the test and disassembled everything, I lingered for some time, soaking in the atmosphere. One of those days where I just didn’t want to come down.
I watched the video earlier Fraser, thanks for doing these videos.
I was trying to remember the story behind the inflatable antennas and piece it together. Interesting that they’re branded as Shakespeare these days. A bit of help from Google led me to Scottish based company Air Antennas, run by Tom GM3HNN. Air Antennas rebranded to RadioGeeks and ran for a couple of years and then it seems to have stopped trading. Comparing the RadioGeeks offerings and the Shakespeare antenna in your video, they’re definitely related.
On the picture it looks like there is a fibre class pole up to the highest point. That kind of defies the idea of the inflation element replacing the mast.
You are, of course, correct Colin. They have been around for a while. Someone commented that there was also an HF version available from Radio Geeks. Sadly they are no longer trading.
There was someone I used to work on 2m when activating who had some sort of inflatable antenna he used when out portable. I can’t remember his call and I don’t think I’ve spoken to him for a while.
From his description, I thought his was one that you pumped up with a bike pump and was 5-6m tall and achored to the ground? Maybe it was a different antenna, or maybe I got my polarisation crossed.
Hi Fraser,
Thank you for the report. I wondered about one of these as an emergency antenna for the boat.
Sorry we missed you on Wednesday but we were coming down from a similarly beautiful day on White Coomb by the time you were on air.
Hope you feel better soon.
Andy
MM7MOX
How long can you keep it up with the CO2 canister? I was looking at CO2 for my mountain bike tyres, but I’ve read that it seeps out overnight, so you have to use a manual pump anyway. Is this similar, or does it retain the gas for longer?
Yes, but it needs to be supported at the top if inflated manually. Using the gas vastly increases rigidity meaning it can be supported at the base only.
Geoff GM4WHA using Colin the Caterpillar inflatable antenna on Castle Crag LDW-214 it worked well on a back to back test with a flower pot antenna and Jpole
Having read the discussion here, I don’t see the point of a blow-up VHF antenna, emergency or otherwise. Is the ‘emergency’ for when you are in trouble or when your proper antenna breaks in situ / is accidentally left at home?
They seem to compare unfavourably with my 2m and 6m roll-up antennas on purchase price, ongoing cost (gas), stowed volume, complexity (things to lose / forget to bring), robustness (punctures?), wind profile (use in windy condx), RF performance(?) and maybe setup & pulldown times.
The space needed is not much considering you don’t need a pole.
The one Fraser had has the feeder attached. The thing lost was the adapter for PL259-SMA (found under our fridge last week). If you actually owned one you would fit the connector to match your radio and then the worst thing would be no gas bottle should you want instant deployment.
A possibility with much use. Depends on handling care but the material is not like a party balloon but feels somewhat strong.
They designed for use at sea originally. So they will survive hilltops. Bigger than wire antennas, they’ll catch more wind.
There’s more comparison work to do. Swapping the RG174 or reducing the length would probably be a good move.
It takes longer to fold and put in its bag that to inflate with a gas bottle and hang on something.
The full story behind these antennas will emerge in time.
Someone wrote above that you need a pole if you inflate one by mouth, presumably because there’s insufficient air pressure (without using the gas cylinder) to make it erect on its own.
It’s also not clear how you would get the party balloon antenna at a reasonable height at most summits without a pole. If someone wants to say, well you can hang it on a tree, then so could a roll-up antenna.
