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.
Yes, me too if I don’t do 40m. Some of those chasers have helped me get my 4th contact on many an occasion. Sometimes I’ll only take VHF gear with me (if I know I can make it work) and I don’t have the same guilt trip.
Yes. Originally a counterpoise was the name given to an alternative to an earth connection. I always consider a radial a form of counterpoise.
However, when it doubt ask Kraus. Counterpoise Systems There is probably something on Rothhammels Antenna Book but I only have a German PDF of that and have not delved deeply.
Normally because they have perfected an almost zero effort way to doing so. I find old broken wooden tent poles with metal tips make ideal distant supports for about 1m AGL. Frozen ground is an issue of course.
Yup… I review what I think the ground will be like and choose antennas that will be deployable even if some other antennas may be better for the propagation.
My 1st EFHW was for 10m, so just 5m long. As I didn’t have the right toriodery stuff in the shack at the time I made an AA5TB match which would let you tune the 5m long wire to be 50Ohms on also 12 and 15m. It worked well in that I was able to work US chasers from GM summits.
As much as possible. Ah but then realism creeps in and I match the activation to the WX and summit. Hence little 13cms in deep Winter when doing up SMA connectors is so very difficult.
The fun part is every POTA or SOTA activation is different.
I have a vertical with 4 ten foot wires, another uses 4 32 ft wires and one that uses a raised elevated wire. I make contacts with each no problem but I have been sad when I missed completing the activation.
Not enough power, poor antenna choice or not enough sunspots
John VE3IPS
SOTA in a refugee location,? Buddihex Beam of course
Mount Everest? The North Face Denali vertical with 10 ft wires
A park? A inverted vee on a mast
Chameleon MPAS 2.0…not hiking too far
Wires = counterpoise = radial = the other half of a vertical
Lets build a GP antenna and start with imagine a vertical dipole in free space and feed in the middle. Field lines of electrical field are starting rectangular from the surface of one half of the dipole end ending rectangular on the other half. On the way they are bent. In the horizontal plane through the middle of the dipole all these field lines are rectangular to this plane. Now put a large metal plate in this plane. It doesn’t effect the electrical field (rectangular).
Now remove the lower part of the dipole and feed between metal plate and remaining half of the dipole. The metal plate didn’t radiate. You have a monopole, a GP antenna, a radiating monopole over a GROUND PLANE.
Now important: along the field lines there is a so-called displacement current (established by Maxwell). On points this displacement current is touching a conductor it is continued by a “normal” (convection) electrical current. All the current through the field from the monopole is flowing through the metal plate to the feed point (or back). All the losses on this way are reducing the efficiency.
It’s possible to reduce the metal plate to some wires mounted RADIAL to the feed point. (As more as better up to a saturation.) The effect to the electrical field is nearly the same. For most cases (in SOTA) 3 or 4 radials are enough, 2 are possible.
The metal plate/ the alternate wires don’t radiate, only the monopole is radiating. If you use only one horizontal wire (one “elevated radial”) this wire is also radiating. You have again a dipole (in a special configuration). If this wire is close to the ground (earth) much of the radiated energy is consumed by the ground. This is the reason for elevated mounting.
A L/4 monopole shows a low impedance at the feeding point, the current is high. Low resistance in the metal plate (in the radials) is important. A L/2 monopole shows a high impedance, losses in the GROUND PLANE are less important. This is the advantage of HW (or n * HW).
If you feed an antenna, you have to drive a current in to the antenna. Connecting your generator only to the monopole allows no current. You need a second connection. This is the counterpoise (like Andy wrote). In some cases the counterpoise should have a low resistance and in some it’s not so important. (And the “resistance” of the counterpoise contains also the coupling to the environment.)
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