My experience indicates that when you are on a summit with an inverted Vee the nulls are not as deep nor is the gain as great as the simulation suggests. Having the inverted Vee with an included angle between 90 and 120 degrees results in some significant vertically polarised radiation. This helps fill in those nulls.
I have taken to using a 10 m flowerpot. After two activations, I will have worked most of the workable VK and ZL stations and that is it for them for the year as the rules say one contact per station per year. So nothing under 3,500 km will count. To make subsequent 10 m activations viable it is necessary to go for the best practical DX antenna, hence the end fed half wave on a 7 m mast.
Of course if I want to work the locals then an inverted Vee 20 m long and 7 MHz and 14 MHz is the choice.
I have pondered about whether the need for two short masts is worth the few dB gain of an end-fed half-square antenna for ten. It would also make a reasonable antenna for 20m as a bent end-fed half-wave. That few dB of gain might make all the difference for DX.
Its easy to see that hanging monoband EFHW10 very high gives good performance. You can better it with inv-L but this is tricky to setup and you need second mast or a tree.
That is very useful, Marek. Compared with the vertical EFHW10, the inv-L EFHW4010 seems to give 5dB gain on its main lobes, but the nulls are 8 to over 20dB down on the main lobes and would probably be deeper at a higher installation. Considering that long path signals mean that wanted signals can come from any direction, the vertical EFHW10 might be better for F2 propagation but if you expect mainly Es (during the summer months) then erecting the inv-L with a main lobe directed towards distant prospects would be the better choice, or at least that the major null at 180deg is pointed in a harmless direction!
Like you, I also tested different antennas for 10m, focusing on DX:
1 wavelength long EFHW (10m long, as inv.-7, on a 6m tall glass fiber mast).
2 wavelength long EFHW (20m long, as inv.-7, on a 6m tall glass fiber mast).
A J-pole, vertically mounted on a 6m tall glass fiber mast.
A full size vertical with a ground spike and 8 quarter-wave ground counterpoises (Marconi antenna).
I mainly compared them RX-wise, and under different conditions and then max. 3 types at a time. So no scientific comparison, only to get a gut feeling .
My conclusion until now is that “it depends”.
I also expected that Nr. 3 should be best for DX, but this was usually not the case. Maybe because on all the tests I was surrounded by tall trees? I don’t know, but I guess that the partly horizontal wire of Nr. 1 or Nr. 2 in a forrest has some advantages, compared to a purely vertical radiator.
On average, Nr. 1 performed best overall and in general should be preferred over Nr. 2 for DX.
Nr. 4 is really convenient for setup time and weight-wise when working only 20m and up, especially if there is a lot of wind (OK, under such conditions, I only extract it to 2.5m for the 10m-band). Last week in EA8, I worked the world on 10m with this handy antenna, even a S2S with Arizona was possible (10W SSB). But as we all know, conditions are much more important than the antenna…
In the future, I definitely will repeat some comparisons of the listed antennas.
I have used the WSPR beacon app on my last few activations and, while the results are interesting, I find the time involved really frustrating. Each WSPR transmission is just under 2 minutes. To run two WSPR tests on one antenna then two tests on a second antenna is a minimum of 8 minutes, more likely 10 or 12 minutes allowing time for the antenna changeover.
Along with the low number of WSPR reporters that are using half-decent antennas, I found the number of meaningful results quite small.
An alternative for antenna comparisons could be to use FT8 where one could call CQ while being monitored by many more stations who generally have better antennas as they too want to make QSOs.
The time for each FT8 cycle is shorter, just under 30 seconds, and you may get one or two QSOs in the log as well.
I don’t have a great FT8 set up for SOTA yet, but something involving an Android tablet and Bluetooth connection to my FT817 would be good.
Certainly the better approach, Peter. I initially thought of WSPnet. But FT4/8 is actually the better choice at the moment because there are significantly more reception points. With the FT8CN app it has become very easy to activate digital on a summit.
Or if you’re not interested in working the digital modes, you could use the SOTAmät App to place your spot for an SSB or CW QSO and then later take a look at pskreporter to see what strength you were received by all of the SDR receivers that got your FT8 signal. If you don’t want to place a spot, you could use the email generating option and send yourself an email, the generated request signal will still go via FT8 to PSK Reporter to the sotamat.com server. Of course less SDRs pick up the special format packets from Sotamät than pick up the standard CQ FT8 packets so as always YMMV.
I’ve done six 10m activations so far this year - all with 10W CW from a KX2 with internal ATU - and all from G/LD summits. The first five were with a 40/20/10 EFHW configured as an inverted-L or inverted-7 (not inverted-V) and today (on G/LD-037) with a Chameleon MPAS Lite vertical with two 8m counterpoises (yes, I know that’s longer than needed for 10m but I was working 30m afterwards).
(C) Google Earth 2024, radio paths courtesy www.adif.uk
Some of the six US chasers today were the same as on the previous 10m activations. I would be hard pushed to say whether the reports I gave (mainly 529 – 569) and received were any different with the vertical than with the EFHW. Unlike before I didn’t get any west coast chasers but that’s almost certainly because I activated more than an hour earlier (1323 to 1333 utc) than previously.
The S0 noise on 10m made it a joy to work even the weaker N/A stations despite my frozen fingers. With freezing temperature and a dusting of light snow today I certainly appreciated the quicker setup (with gloves on) of the MPAS vertical.
with only one “radial” you have more or less a preferred direction, with 3 (really) radials you should have no difference over 360 degrees. One “radial” is really a radiator. It affects the fare field.
Thanks - That makes sense, I sort of figured that its more a V dipole, the way I mount it. (Pic below) I normally point the radial in the direction i’m most interested in (USA). Question I have is whether there is any meaningful performance difference in this direction or should i increase the mountain ‘faff’ and put two more radials on ?
Tim, Looking at your picture, the “radial” seems rather high and slopey. Have you tried keeping it parallel to the ground 1m up? This should exhibit some gain in the direction of the horizontal wire.
Hi Fraser,
I certainly could try that. Yes, its high, must be about approx 3m high on a 6m mini, maybe sloping at 30deg down from the horizon. Feels so much more of a dipole than a GP maybe.
Had so much fun on 10m with this antenna, its all I had to start on 10. but guess most of that is conditions
[later]. BTW, The radial is about 10% longer than the vertical.
Well it does feel like a bit of wet string will get 10m contacts at the moment, however a more efficient and directional antenna will get you better ones!
Tim,
Stick with the high single radial. Height is your friend, always. By pointing it in your preferred direction you are getting a bit of gain thataways albeit with a reduction in the opposite direction.
Yes it is more closely related to a dipole than a ground plane but it’s working AOK.
For 10 m I am using a flowerpot type half wave vertical. Simple. Functional. Unidirectional. Small footprint. No ATU.
Monoband is fine with that one as it is pretty quick to deploy and then replace with something else.
I’m thinking of a linked 12m/10m EFHW that I could use with my existing auto-transformer and run vertically up a 6m or 7m mast. Will be a simple build. Anyone done this?
Despite reading articles and searching the internet (on more than one occasion) I can’t find consistent definitions for ‘radial’ and ‘counterpoise’ and the distinction between them if any. Many of the sources contradict each other leaving me bewildered. One says they are the same thing; others imply they’re different.
I think the three short metal rods on the base of my V2000 6/2/0.7m colinear are radials because a) Yaesu call them that, b) they are a ‘tuned’ length (one of them is for 6m and is much longer than the other two), and c) the radials are ‘raised’ (about 5m from the ground).
I think the two ~7m-long wires I lay out on a rocky summit and attach to the ground spike of my MPAS Lite vertical are counterpoises because a) Chameleon call them that, b) they’re not a tuned length but (apparently) act as a capacitive connection with the ground below (the latter being the other ‘pole’ for my 17-ft monopole whip), and c) they are not ‘raised’ by much (well, only by a cm or two).
Any antenna grounding experts, feel free to un-bewilder me or point to some reliable resource.
BTW: I don’t understand why anyone would spend the time and effort to raise two or more wire radials off the ground for a temporary portable antenna particularly in wintry weather. It would seem less effort (and probably gain more performance) to erect a centre-fed dipole (e.g. inverted V).
Andy, Your BTW is an interesting point. In winter (specifically wintry weather) you probably only want to put one wire up. With all of the 10m activity this year, that could be a monoband. Likely to be vertical because of the short lengths involved. You get your points, hopefully some 10m challenge new ones and almost certainly some DX.
Personally and because of my knowledge of GM/ES summits, having been fortunate enough to climb them all, I would consider antenna type based on the type of summit (in wintry weather). A shelter with a trig in the middle is screaming out for a dipole, supported by a mast strapped to the trig. That way, everything apart from the antenna ends are inside. The downside is un-doing links to change band. Or do I just need to build a 10m one, to live up to my statement in the previous paragraph? Probably. Some summits suit an EFHW/EFRW/W3EDP and coax because of nearby fence posts or trigs some distance from shelters.
However, you may have seen in my recent report that running an EFHW 3m up a pole as a vertical and sloping away from the cairn achieved the same result (operator comfort, simple to erect) and allowed more bands to be enjoyed, with DX on three of them.
The monoband (with radials) and gain antennas that may be more time consuming and difficult (in wintry weather) to erect may not be needed at this time of high SFI.
Ultimately the question is, as always, what do you want to get out of your activation?
Hi Fraser, perhaps you activate at some very remote summits and are undisturbed by other walkers during your activation but I find, even when I think no one else will show up at summits I do (mainly G/LD and G/NP), someone does and wants to stand at / sit next to / touch / have lunch at / take photos of / the trig point so I avoid even sitting there not alone tie my antenna pole to it.
Re doing 10m only during adverse weather, I’ve done that (because my fingers got too cold to paddle any longer) but I feel bad if I don’t also do 30m so that regional and EU chasers can ‘bag’ the summit too. As I said at post #35 above, that’s why I chose to use my MPAS Lite vertical and got 8 (mainly N/A) 10m contacts in 9 mins and then 13 (mainly EU/UK) 30m contacts in 14 minutes. That’s about as long as I can take sitting on a sub-zero un-sheltered summit albeit wearing 5 top layers.
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