Continuing the discussion from HF Naive: Kit update. (Part 1) - #100 by G5OLD.
Previous discussions:
Continuing the discussion from HF Naive: Kit update. (Part 1) - #100 by G5OLD.
Previous discussions:
@MM0FMF The examples work. I modified a Moxon design many times and the answers were encouraging. The antenna works as promised.
When I try to model one of these low antennas that things go awry. I have also been influenced by a EZNEC guru on another forum who dislikes these compromise antennas but also says EZNEC isn’t good with low antennas.
I will just drop EZNEC for this and experiment with wire.
@G5OLD. Thanks for your comments and photos of hiking poles and your antenna lengths. That first antenna is already on my radar but the second sounds more handy. I have enough wire for both and more.
Fair enough Dave. I looked and at present I have MMANA-GAL only installed which uses Mininec as its engine. Does it give more correct answers than EZENEC? Pass.
I have 2 antennas I use of HF that need a tuner, everything else is resonant (10m delta loop, 1/4wave GP or centre fed dipoles.) One is a commercial 40/30/20m trapped EFHW. The original matching unit seemed to get awfully hot on 40m with just 5W CW so I use a manual AA5TB style parallel tuned high impedance match. Or if I have a radio with an ATU, either 49:1 or 64:1 unun. The designs are on here for assorted ways of winding and ferrites to use. With either fixed unit the KX2 tuner has no problem matching to 50Ohm. The AA5TB cannot match this on 17m unless a link is opened.
The other antenna is a “41ft random” and counter poises. I made it to see if / how it worked. The antenna and its 9:1 unun takes up so little space in the bag that it stays in there as a backup antenna i.e. I always carry it and normally add in other antennas because I have some reason to use something else. With the 9:1 the measured match was: 7.035MHz 3.6:1, 10.118MHz 8.3:1 14.03MHz 3.5:1, 18.085MHz 2.1:1, 21.06MHz 2.5:1, 24.9MHz 4.3:1 & 28.058MHz 3.7:1 Playing with the length may improve those figures but they are all trivial for a KX2 tuner. Without the 9:1 they will be higher but should probably still be in the range of the KX2’s tuner. But why make life harder for it?
The dimensions/setup I use are here along with Heinz’s suggested improved counterpoise / radial lengths.
Initial description: Testing Antennas during an M5 Flare
Suggested improvements: Testing Antennas during an M5 Flare - #11 by HB9BCB
You can stick the measurements into EZENEC and see what you get.
If you want even shorter there’s the 5.5m radiator and 2x 4.5m counterpoise, that matches 20m and higher frequencies with the KX2 tuner (a transformer is needed for 40m). The Xiegu G90 can match it on 40m and I have made many contacts with it on 40m even if it’s quite compromised.
It’s a nice length to put on a 6m pole and be a vertical - so no guying or pegging etc. of the antenna. Plus if you’re doing the PVC tube in rocks then even faster!
As seen on Fraser’s, @MM0EFI video - and he credits learning it from @GM0GAV Gavin.
and
Clearly, choice of antenna (and supports) depends greatly on where you are operating.
Most of my portable operation has been around trees and I’ve used some version of my portable dipole kit, as it permits operation on multiple bands without needing a tuner. (My old HW-8 had neither tuner nor SWR meter.) Basically, dipole wires for each band, plus a center insulator with coax that any combination of them can be connected to. Recent trips to KH6 added the potential for operation near salt water, so I’ve added ground plane wires to each band package: I use the two dipole wires for the radials, then cut a third wire (often of a different length) and tune it as a vertical when fed against the radials.
That gives me a lot of options - not only for vertical or horizontal polarization, but I’ve also used the wires other ways when circumstances permitted. A 40m dipole wire makes a full wave loop on 10m (with the addition of one 45cm (18 inch) clip lead for SSB or two for CW). On one peak (long before SOTA) that was the remnants of an old volcano, I used the 20m wire as a doublet and the 40 and 80m wires for a balanced feedline (I did have a tuner that time), and with some effort and all my rope I was able to string it between two rock crags with 100m of drop beneath it.
For speed I can leave it set up with the 40m and 20m wires attached, or whatever bands I expect to use most often. Then it’s a simple matter to hoist the center and tie off the end ropes to whatever is handy (even a clump of grass).
So many choices - antennas, radios… glad to have at least made a start.
Pleased with the ‘budget’ kit so far - it’s making contacts and activating summits…
1- G106: £205 delivered.
2- EFHW: £36 delivered.
3- 5m Caperlan Pole: £18 delivered.
4- 12v lipo with charger: £31 delivered.
4- BNC connectors, coax, torroid, nicknacks: £40.
Under £350 total, I can’t complain. It’s a way in.
Next on my list - to try Tim’s 10m 1/4 wave vertical antenna. Thanks @G5OLD - a gentleman.
PS That figure of 8 winding thing/technique is rather confusing for the neurodiverse (dyspraxia)… so I tried with the guy line and not the antenna wire in case I ruined it.
Maybe you need a little song to sing whilst doing the motions to keep everything on track.
Over the top at the top,
around and back underneath,
over the top at the bottom,
around and back underneath,
(repeat till no more wire)
Thanks Andy - will give that a go.
I can do all of my climbing knots & coiling ropes etc with no problem. I think that’s because I was taught by person rather than trying to figure it out from a video or description.
I’ve noticed my antenna and counterpoise wires are getting little kinks if I wind them back onto the winder in exactly the same way every time. So, now I vary it, e.g. a mixture of figure-of-eight and straight winding. It doesn’t seem to affect the winding/unwinding time nor take up more space when stowed in the rucksack.