So I was convinced for my new mast I would use a SCAM12 after seeing G4ERO’s installation (picture on his QRZ page). I had done some antenna work round at Colins QTH and seeing how simple it was to erect (BINGO!) and take down. The mast is approx 3m when down (with antennas on) and the top of the SCAM12 is 12m when up. The SCAM12 is pneumatic and requires about 22PSI of pressure when fully up and mine stays up for days. The SCAM12 is fully rotate-able and sits within a swivel base/mount but I use a rotator at the top which you can see below the 6m/4m antenna so you can work out and see the SCAM12 is low when down. I do plan to move this to the bottom when I get round to working out how best to do it.
And when up:
Mounting the SCAM12 I again took advice from Colin G4ERO and dug a hole about 100cm x 30cm x 30cm, bought a 2.5m long 178mm x 102mm x 19mm universal beam, modified it, (see below) put it in the hole and aligned it for vertical. I then concreted the bottom 50cm of it, let it set and filled and packed the rest with mud.
As the SCAM12 is able to rotate, there is a bearing in the bottom of the mast so it is not a good idea to mount it direct onto the ground. So I welded a bracket on the bottom to hold the SCAM12 off the ground. I then used threaded bar and some angle iron to hold it against the universal beam with some wood between both to tighten against. Since these pictures were taken I’ve repainted the universal beam Hamerite ‘Highland Green’ which is more similar to the SCAM12 colour.
As the mast is pneumatic I got a small compressor for 30EUR at a Dutch Radio Rally which take 2 minutes 40 seconds to put the mast fully up. I’ve fitted it with a remote control and pressure switch to it automatically switched off when at the correct pressure. The SCAM12 comes with a key to allow the air out and it takes a minute to come down.
There are guying points for 4 guy ropes on a slip ring but so far I have not guyed the mast at home and it’ has been up in quite strong winds, if I’m worried about the wind I only put a few sections up. The sections can also be locked off if the SCAM12 is planned to be up for an extended period of time.
The hole doesn’t sound very big and only half filled with concrete. How are you finding stability when the mast is extended and not guyed?
This sounds like a very good solution to my antenna problems in a restricted space and have been inspired to look at a couple of Scam 12′s next week.
73 de Jim
Hi Jim,
I agree it doesn’t sound alot but I’ve had no issue with it. If I give the bottom a shove it’s very solid and the SCAM12 is still vertical after being in for 15 months or more. The design can be changed to allow for a larger hole or more concrete I guess.
Gav.
I don’t like to create any unnecessary work! If that all that is required it is fine with me. Just been pricing up a Universal Beam. They’re not cheap but don’t want to cut corners with that I think.
Many thanks, Jim
I know what you mean! Also check eBay for universal beams, http://goo.gl/r9O55 there maybe someone selling the right length in your area?