Antenna considerations

Right, if you’re going to do it properly you need to have a sensible antenna otherwise you’re wasting your time.

At present I’m playing with my 30 meter 1/4 wavelength counterpoise antenna, which was lashed up firstly for my WSPR receiver project and has worked well in that role and with my Ultimate3 QRSS beacon.

I need a multi waveband antenna to do the SoftRock justice, so I set about working out the pros and cons of planting a permanent, fit for purpose antenna on the house.

For a long time I’ve been keen to explore the idea of Stealth Antenna’s after getting hold of a copy of the RSGB book by the same name. For a residential property it certainly widens the mind to ways of erecting an antenna for radio work without attracting undue attention.

My brief is for a multiband, discrete or stealth antenna for QRP work, maximum 5W at present.

After lots of research I plumped for the idea of a long wire covering 40m to 10m. The reasoning for this was it’s cheap, something I could make myself and could conceal in a variety of locations either inside, outside or alongside the house.

I was just about to embark on the build when I realised how much it was going to cost me to source the necessary components and hardware to build the thing and realised I was being silly. The combined cost of the ferrite ring and waterproof enclosure for the 9:1 transformer alone was 2/3 the cost of a complete antenna system, built, tested and supplied.

Now as hardcore as I want to be, at some point common sense steps in!

My weapon of choice was a Model 728HFA limited space antenna from Alton Antenna Arrays.

http://aaa001.webeden.co.uk/#/limited-space-hf-antenna/4578141933

I was fortunate enough to meet Mike Parkin (G0JMI) back in the summer when I had all of 3 weeks knowledge and was about to take my Foundation Licence exam. Mike gave a lecture on his Mini Beam antennas and he absolutely blew my mind. He made a potentially complicated topic so easy to understand it was captivating and I was able to hoover up a tiny fraction of his knowledge when I got chance to speak with him later.

Mike has made the 728HFA as a special with an extended length of feeder to allow me to test various cable routing options before finalising the fix.

At the moment all my options revolve around sighting the antenna to the rear aspect of the house / garden

Screenshot 2014-11-30 18.47.08

Option 1 – route the antenna beneath the fascia and guttering, feeding the co-ax into the shack/man cave with other pre-existing cable runs on the back wall of the house

Option 2 – run the antenna from the house to a purpose built mast at the end of the garden. The antenna will be parallel to and 2.5m above a boundary fence to adjacent scrub land

Option 3 – run the antenna from the house, immediately outside the window of the shack room/man cave diagonally across the garden to the antenna mast at the end of the garden

Option 4 – loft fit

 

Option 1

PRO’s – it’s a semi covert fit avoiding undue attention and the antenna is sheltered to a degree from the elements

CON’s – relatively long feeder run, potential building effect / ground effect from the building

Option 2

PRO’s – there will be less ground effect / building effect on the antenna as it will be suspended in free space, rather than against a brick structure as in 1)

CON’s – despite the similarity to a washing line (and there’s plenty of those around) it’s a more obvious placement, added cost of erecting an antenna mast, I have no control over the vegetation to the west of building and although recently cut back by the owners it has the potential to grow into and over my antenna causing it damage

Option 3

PRO’s – there will be less ground effect / building effect on the antenna as it will be suspended in free space, rather than against to a brick structure as in 1), the deployment is completely within my boundary and won’t be subject to extraneous vegetation action, shortest feeder run of the 3 options

CON’s –  like option 2 it’s more obvious, requires a mast, potentially impacts more on the regular use of the garden

Option 4

PRO’s – a true stealth fit, the antenna is inside the house and protected from the weather

CON’s – I don’t have an uninterrupted run within the loft space to accommodate the antenna without removing some brickwork, there’s already a whole host of electrical and data cables snacking their way around the loft space so the potential for interference is greater, I’d need to punch a hole through the ceiling to run the feeder to the radio as I don’t have any risers or the ability to lift floors to route the cable. Admittedly conduit could be fitted, but there’s the inherent grief and the need to decorate/patch afterwards.

So with that lot in mind we’ll be going with Option 1 in the first instance. The antenna should be here sometime next week and with decent weather should be fitted relatively quickly.

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