After much testing and procrastination I think I may have stumbled across the right length for an End Fed Random Wire antenna for 40/20 metre bands plus some higher bands. Those who have been following my SOTA activities will know I thought I already had it right long ago but we can’t sit on our hands with antennas. I needed it to be light weight and to tune easily using the You Kits MT 1 tuner which it now does with ease. I messed with some lengths and using the web page put up on Ham Universe and the calculations done by Jack VE3EED [sk] to avoid having a length close to any half wave of the frequency I want to use or multiple there off. I wanted or thought maybe some where close to a 3/8 wave on 7.030 would be a good starting point at around 50 feet but I ended up making it 53 feet . The reason I arrived at this length was the influence the MT1 tuner had trying to tune the 50 foot length. For starters it would match ok but VSWR was not as close to 1 t 1 as I liked and I had to use two different counter poise wires when swapping bands and it was too much to remember . Using 50 foot as a starting point and keeping with 9 feet of counter poise I used educated guess work and slowly increased the wire length right out to 58 feet with changes but still not good tuning results. Thinking I had gone too far I juggled with some shorter add on pieces of wire and found at 53 feet long the antenna tuned really easily on 7.030 and went right down to 1 t 1 and I could achieve that result in the SSB part of the band as well. I talk in feet as my method of measuring because it is in line with Jacks calculations on the net. I do convert to metres to measure things as I have a long passage in the house and every 3 floor tiles equal 1 metre. I can run out 17 m of wire from the garage door to end wall in a bedroom so even rainy days I can still make up antennas.
I set up all these measurements using the MFJ -269 AA then did a test using the You Kits HB-1B CW rig in line with the MT1 tuner to make sure the VSWR meter on the little tuner was reading right. The VSWR is tuned easily on 40m and 20m but being a bit sharp on 30 it is touchy but seems to tune ok. I got it to tune on 17/15/12/10 metres as well but not sure how it will go using a rig I have not tested it with the kx3 yet. Added bonus it tuned it on 3.6 MHz but I have not checked it with RF there either I run out of time. It will also be interesting to try the kx3 tuner on it as well when I get a chance.
Well the chance arose today and the KX3 does tune it on most bands but not that good on 30/10 metres possibly a bit close in relation to wave length of wire. But the MT 1 tunes it nicely on all bands so the HB1B rig will be good to use in combination with the MT 1. I noticed using the MT1 with the kx3 its best to disable the auto ATU in the rig but still watch the VSWR read out on the rig as well as the tuner they are much the same as one should expect.
I did swap a quick report to vk2 on 20m cw and a qrp 2 qrp into vk3 on ssb using the KX3 on 40m .
That’s all for now watch this space for further activity Ian vk5cz ..