Change of plan

My plan a few days ago was to build a maypole-style antenna supported in the center with inverted vee antennas coming down around it.  I was worried about the wires coming down all over the place and I also realized that there must be another cheaper and more easily implemented solution.  I have done some reading in the ARRL antenna book and also done some youtubing and now have a new plan.  Now my plan is to install a single wire, centre-fed, with balanced window line.  As long as I am at least 1/2 wavelength long from end to end, on the lowest frequency I plan to operate on,  I can feed it to a simple tuner for multi band use.  My tuner of choice will be the QRPguys Multi Z tuner for 10-40M.  I like the way this tuner has an LED that dims as a match is obtained eliminating the need for an SWR meter which is a huge benefit if I take this tuner to the field.  I have watched a great Youtube video on the building and testing of this tuner and I really like what I see.  For $40 US plus shipping I don't think it can be beat.

My existing long wire can be used for an end fed half wave (EFHW) antenna on 80 meters.  My first option is to adjust the length and try and use my 9:1 Unun to make it resonant on 80.  Failing that I can feed this into a QRPguys EFHW mini-tuner for 80M.  I may need to add some length to the existing wire since the recommended length for 80M use is 135'.

If I cannot get it working well enough on 80 with the LDG Unun I will likely order both kits at the same time so I can save on shipping costs.  

Less than favourable results...sort of

So I installed my random wire antenna from my barn out to a very tall poplar.  I used #10 wire so that the strong winds at my QTH wouldn't break it and I have about 130' of wire up in the air sloping up towards the top of the tree with the last 50' or so being para cord over a branch and down to the ground where it's tied off.  At the shack end I am using a ceramic egg insulator to a rope tied through a pulley attached just above the barn window to a bucket of bricks so that strong winds won't break the wire.  I then have another wire soldered to the antenna wire which comes into the "shack" to my LDG 9:1 random wire unun.  From there I connect straight to the radio.

I used the Agilent Field Fox to look at the resonance points on the antenna and saw that it wasn't really well resonant on any band but it wasn't too bad on a couple.  I added some radials on the ground of varying lengths and according to the Field Fox this made things worse.  What I really need is a MFJ-16010 L-network tuner to finish things up for me.  As it stands now, when I hook up the FT-817, the only band that presents no SWR issue is the 30M band.  30 has always been one of my favourite bands (along with 17 and 12) so I'm not extremely upset by it.  We are in a dismal part of the propagation cycle and I was still able to have a few QSOs on Sunday (Jan 12th) including a QSO with Ron, K5WLT, at almost 1700 miles in Texas and a 2xQRP with Alan, KR4AE, in Cleveland Georgia which is almost 900 miles away.  It's certainly not as good a distance as I can get with far less power during better propagation periods but I like the fact that I can still make QRP contacts, albeit with 5 watts.

Of course, as with many hams, I'm thinking of other antenna ideas.  The one that interests me at the moment is the Maypole style antenna.  I am a proponent of the fan dipole antenna and this is a variation on that.  The problem I have at my QTH with wind can best be defended against with stronger wires but thicker wire is heavier making supporting the center more challenging.  What the Maypole antenna does is use a non-conductive centre support with the inverted-vee antennas equally spread out in all different directions around the circle (looking from above) acting as guy wires and also not interacting with each other as much as with the standard fan dipole.  This antenna can be fed with coaxial cable but you'll want to keep the run as short as possible to reduce losses.  You could use a 1:1 balun or choke at the feed point to reduce feed line radiation but I don't think it's really that necessary, especially at QRP power levels, based on my use of dipoles in the past and from what I've read on the topic.  The leg pairs will all be of different lengths making the "V" angle different on each band but this shouldn't change the feed impedance too much.  The legs should not touch the ground but can be attached to stakes or pegs with non-conductive guy ropes.  Since I am operating QRP power levels I am not worried about RF burns but at higher power levels you should keep the antenna elements out of reach of people.  The key now is to choose which bands I want to operate on and figure out the best type of centre support to use.  There's PVC piping but the strength is suspect if it gets too tall and there's also wood or fiberglass.  I'm not quite sure yet which is the best choice.  As it stands now, this antenna will take up a fair bit of real estate and cutting grass around it will be a pain but if it works well it will be worth the extra effort.