A random collection of objects and subject I am interested in… or as my wife
would say obsessed with !!
Antenna Projects 1
Mag loop experiment
John 2W0OSG and myself had a go at building a loop antenna Heath Robinson style which was born out of an idea that John had for a very cheap and simple version of this type of antenna.
Information on this type of design can be found all over the Internet. so we set about assembling this very basic antenna and were really surprised by the results.
The basic loop is approx 12” of aluminium ventilation tubing from Wicks DIY
Now when I said Heath Robinson I really meant Blue Peter sticky tape and plastic
John Likes to keep his hand in, and gives the Cap a bit of manual tuning
What do you think? shall we go for it? we have not even soldered the wires to the aluminium tube section, we really did stick them on with tape !!
Well we were really made up by the way the Mag loop worked John got the idea to fit a small motorised gear from Maplin and that really made a difference. John took the plunge and had a brief QSO with and Italian amateur on the 20 metre band who reported 57 contact even though it was not fully tuned in at that point.The next stage is to make a more permanent arrangement with cross supports and a housing for the motor drive and capacitors. I can see the next week or two is going to be busy...
The FMW Magnetic loop antenna
After realising the extraordinary properties of the mag loop antennas and trying out an Alex Loop on loan from Ian M0ODD I wanted one for myself, yes I could have built one myself but I stumbled across this little beauty on Ebay. I paid the princely sum of £85 for it.
It is fully collapsible and covers 40m to 10m very comfortably. It even came with the tripod. I have not had chance to take it out up the hills or to the coast yet but that is the plan. The saving I have made on buying this antenna from Ebay has allowed me to buy a new antenna analyser.
The first thing I did with the Sark 110 antenna analyser was to see what the FMW loop was like across the bands 10,12,15,17,20,30,40 metre’s. The SWR on some are very good, others are not so good but the are all under 3:1 so they are workable.
Below are the plots for those ranges.