My latest activation of GW/MW-036 Pen-crug-melyn is up on the blog. http://www.gw4vpx.blogspot.co.uk/
Photo shows my set up for the day…3 element 2m beam, 2m dipole and the Band Hopper 3 linked dipole on 7m fishing pole…not for a windy day
73 Allan GW4VPX
Interesting activation, Allan,
You say you are using a ‘Band Hopper 3 linked dipole’, which bands are the links set for please? I’m in the process of deciding on doing something similar myself and I noticed you said you’d used 60M and, as I have the NoV still, I might give it a go as well.
60/40/20 and also you can work 15m when set up for 40m…I made 2 short lengths (22cms approx) of wire to attach to the 40m links to keep the FT817 happy (no atu).
73 Allan GW4VPX
I’d never tried my 40m dipole on 15m till today. I’d earlier used my 15m vertical but had taken that down and had the inverted V for 40m in place. On 15m, the match is acceptable, 2/3 blobs on the 817 SWR meter. I called a few times but got no takers and went back to 40m.
I’ve just checked now looking at the RBN spots, I was spotted by KM3T. So my 40m dipole was radiating something when on 15m sufficient for me to be heard across the Atlantic.
Thanks for the information Allan,
I’ll have a go at something similar. I might also put a link in at either 10M or 12M. I think that the internal ASTU on the KX3 might allow 10M off a 12M dipole. Worth trying anyway even if I just have to cut back to 10M dipole and do your pigtail trick for 12M after all.
Yes, I got rid of the ‘blobs’ by adding the short extension. Several ‘across the pond’ contacts on ssb with the 817 and South America so it does work when conditions are favourable.
73 Allan GW4VPX
I used to have some “danglers” for my old 30m dipole that flattened it out. I remade it and cut it the right length on the next one!
I think the SWR was perfectly fine for a 40m dipole cut for 7.100 on 21.062. It means I can flip to 15m CW without having to do diddley. If only I can remember to do this now.
A 40m halfwave dipole is a bit short as a 3/2 wave dipole on 15m, but pretty close. You can add some capacitive loading dongles to tune that. There is an example in the ARRL handbook.
The pattern is different from a halfwave. The halfwave radiates broadside. The 3/2 wave has smaller broadside lobes with the four main lobes at 45º angles from the wire. That pattern is blurred when close to ground.
Found a reference for the capacitance loading for 15m. Look at figure 3 in this article. The capacitance hats do not need to be loops. You can clip on short lengths of wire and let them hang.
The use of a 40M dipole on 15M does work but, as is often said, it’s an approximate match and the radiation pattern is not the same as for a true dipole.
Having said that, most of our antennas don’t operate in an ideal setting. Houses, wiring, other antennas, all make what happens different to the ideal. Out on top of a hill we are usually unlikely to worry about lobes of maximum radiation on HF and, if we do, it’s often not too difficult to move the mounting pegs round a bit.
It’s the same situation between 80M and 30M. Instead of a nice 3/2 relationship it’s a bit messy.
Back in the day, a PI tuned output would cope but now we all either want a ‘good’ match, so that the internal circuits don’t draw back the output, or else that the built in tuners can cope.
Some can, some were designed only to match within a short range, expecting almost a 50 Ohm output within a few Ohms, which is why we now put tuners in front of tuners and Baluns where Baluns should not go… IMO, of course.
I’m as bad as everyone else. I’ve bought things that, on reflection, were never going to work but it’s an interesting learning curve I guess.
I’ve used a 40/20/17/12/10 metres fan-dipole for 15 metres quite successfully from Kenya on several holidays. However, the 40 metre element is cut for the bottom end of 40, as the first time I visited Kenya only allowed 7.0 to 7.1, and fan-dipoles have a habit of picking and choosing depending on frequency. Used it last night to catch GW2HFR/P on GW/NW-053.
Obviously, fan dipoes aren’t much use for activating…
73, Rick 5Z4/M0LEP