“Convenience antennas” have their place in the SOTA antenna arsenal: usually that place is in a drawer at home. More often than not any set-up time gained by using them is more than offset by the increased time taken to make any contacts.
Coincidentally I read that Elecraft will be making their own version of a short whip antenna.
I agree with everyone about those types of antennas I can’t see taking a cumber-son tripod up a summit easier than carrying a 7 or 8 m squid pole to support a dipole antenna that gives the chasers a signal they can hear makes no sense to me .
200 summits done 63 more to old goat
Ian vk5cz …
Richard, maybe it would be worth re-running your WSPR antenna experiment with some of these compromise antennas versus a 1/4wave GP ?
Agree with all the comments. I did many activations with an Alex Loop. I liked it in the winter because it was FAST to set up. But it is SEVERAL s-units down from a simple wire antenna supported by a pole.
Barry N1EU
I have used the MFJ-1899T antenna on several summits where there was limited space and/or no trees and as a compromise antenna I was successful working chasers in multiple states from 1 point summits in California. I believe having pre-cut counterpoises for individual bands has been the key to having a modest success with this antenna. I mount the antenna on a camera tripod. I have noticed that signal reports when using this antenna are generally significantly lower.
However, this antenna is not my first choice. I prefer an end fed wire into a 9:1 balun - a 33’ wire supported by a 30’ PackTenna pole is my go-to antenna on a summit. I have tried throwing the antenna up into a tree and also using it strung from a large bush to a nearby rock, and that wotks, but the end fed wire set up as a sloper seems to be best. I do want to try changing to a 53’ wire and I suspect that will work better than the 33’ wire!
My HF rig is my KX3 with the built in antenna tuner.
I will probably try the Elecraft AX1 when it is available just to have one more antenna choice available.
I used a MFJ 20m whip with the tuned counterpoise with no luck on my first SOTA attempt. It could work and is useful for when you cannot erect a full size vertical or dipole.
I have done wspr tests with the wsprlite appliance with everything from a mag loop to an end fed and various others in between.
I then sold off some short compromise antennas and am sticking to a dipole, end fed and mag loop.
My first successful SOTA used the Chameleon Hybrid Micro with a 60 foot radiator and 30 foot counterpoise. This is an end fed design.
Worked very well. I did bring a Packtenna and a Sotabeam but due to time did not deploy.
We have lots of choices and there are advantages to the short compromise antennas but their biggest disadvantage is they will be several s units down in signal and at a few watts it will push your signal into the noise.
Cheers
John
You can use the 17m mfj sntenna on 20 and 15 as well with a tuner
The more wire the better and the better matched the better the signal output…
Hi Mike,
I have used this antenna for my first SOTA HF activations and it was working quite good on 20m in central Europe (up to about 2000km distance). Also made contacts on 80m and 40m with it. I was using a metal measuring tape as adjustable counterpoise.
The drawback that I have identified was that I always had to adjust a little bit on the antenna length and counterpoise for good SWR depending on the soil/rocks on the summit.
For summits with very limited space I think it is still a nice option.
73 Joe
I have the 20M model of the MFJ whip. I’m going to try it with FT8 mode once I get a portable FT8 setup sorted out. I think it might be okay.
Hi Mike,
I’ve used one on a few activations. On Mount Hopkins I used it and made 14 QSO’s, mainly on 40m, with CA, AZ, and CO. I also used it on a couple of small Phoenix peaks as well, much to my surprise I worked as far as Maine on 40m with it, with 5 watts out from the rig. And even more surprising was making a few 80m QSO’s with it (although only with local Phoenix guys and spotting help).
However, the contacts definitely were not easy and I have pretty much decided against using it very often. It’s fun to use such a simple antenna, and I agree that the key is the counterpoise, but I think most other options will be better. And it’s actually heavier than some of the most simple antennas (such as a packtenna mini or homebrew endfed). Sometimes I do carry it as a backup antenna to use in case something goes wrong with my primary antenna.
I saw your spot and was hoping to catch you - sorry it didn’t work out, I’ll be looking for you to return to that peak!
73,
Keith KR7RK
Indeed a last resort emergency antenna … it will never beat a wire antenna of any kind (dipole, endfed …)
I would not advise it for serious SOTA activating, but it is fun to see where it can get you a contact …
In the picture a home made copy of such an antenna , it cost me virtually nothing.
The coil is some magnet wire on a PVC electrical conduit, at the top is a bajonet type fuse holder, which can hold different “plug in” telescopic whips.
With the KX3 on internal AA’s, so at 5W, I worked DB7MM/P on 20m SSB.
With the longer telescope seen on the left (72"/1.8m from RadioShack) I can use it on 40m, with the shorter telescope, it tunes on 30m and 20m.
I worked an EA7 in FT8 on 40m with it on a club night, from INDOOR the clubhouse.
73 - Luc, ON7DQ
Mike,
Just go with a single band link dipole and feed it with RG174 coax (really small light 50 ohm coax). Ten feet of that coax weighs next to nothing. You can carry a 20 meter dipole only and will be hard pressed to not work twenty stations from most summits.
Hang the dipole from a tree or a rock if u don’t want to carry a short center pole…even a few feet off the ground works very well (especially 40 meters for NVIS). My 40 meter dipole is 13 feet off the ground sloping down to the ground on the ends…works great! Put it up as an Inverted Vee, a classic horizontal dipole, a sloper…whatever…it will work well.
On pinnacle style peaks (cliffs all around u) u can just run throw dipole down over the cliff…a vertical dipole (don’t forget to hold onto one end Hi Hi).
Even Wally World sells cheap telescoping crappie poles or fishing poles tall enough for a dipole. I see them on sale for $10, or u can go online and find ones that are under 18 inches long when collapsed.
No need for a heavy tripod base (or almost any base for that matter) with all of the rocks we have in Arizona.
73
Pete
WA7JTM
Thanks for all the replies and tips.
I need to go back to my roots. My first SOTA activations were with a Rockmite 20M kit and an inverted V on a painters pole; and that did pretty well on <1 watt. I have since tried to “streamline” the operation with mixed results. The 817/buddistick combo works well, but the KX1 being what it is, presents some challenges that the 817 does not.
So I am going to break out the inverted V again and grab a cheap fishing pole and give that a whirl.
Thanks again.
All,
One of the more subtle things not mentioned so far is multi-band operation, and fast band changes.
With the better small rigs, it’s possible to jump from band to band to catch S2S contacts that would otherwise be missed. Even with an auto-tuner, some antennas work a lot better than others on the more popular 40-30-20-17-15M bands.
Any simple coax-fed dipole will have mismatch problems and coax loss on some bands if fed with RG-174 or other small line. Using traps is one way to reduce the mismatch loss.
One of the big advantages of the end-fed wires is that because there’s no coax feeder, there’s no coax loss. The feed impedance depends on the main wire length, the counterpoise length (if used), and other factors, but good tuners can easily match these wires on all the 40-30-20-17-15M bands and more.
These days I often carry two different antenna systems on most activations.
66 feet of #24 silver-plated teflon wire with a link (jumper) at 52 feet. Usually I use no counterpoise with this. My support pole is about 18 feet high, so about 48 feet of wire remain to be run out to another support.
52 feet of the same wire, with links at 46 feet and 33 feet. Usually I use a 12-foot counterpoise with this. The support pole is 18 feet high, so about 34 feet of wire remain to run out to something. This more compact antenna helps when space is limited. I cannot detect any reduction in performance compared to the 66-foot wire.
I use a homebrew manual tuner with both systems, and I can easily tune 40 through 15 meters with either antenna.
Some of the matches are resonant high-Z matches, such as the 66-foot wire on 40, 20, an 15M. The 52-foot wire is resonant with the 12-foot counterpoise on 40 and 20M, but the impedances are moderate, requiring use of different taps on the tuner’s tank circuit. The 52-foot wire presents a high-Z match on 30M and 17M, so the counterpoise has little effect on those bands.
By opening a link, I can have other matches available if I like. One of the nice features of the end-fed-on-a-pole is that you can often just tilt the pole to lower the wire, so it’s easy to open or close a link. There is just one link to change, instead of two as on a dipole.
When activating high, alpine summits far above timberline - sometimes above 4000M - with strong gusty winds, the end fed is the only effective antenna that I am able to deploy. Wires blow in the wind, along with everything else, but many times a single wire can be strung in the direction of the wind, or opposite, to great advantage. Often a pole can be supported by rocks, or 2 or 3 simple guys, and the wire helps stabilize it. I have run these simple systems in winds so powerful that I feared the pole would gyrate to destruction - and well it might - but anything else would have been long gone!
It is almost magical to hear the flying wire singing with the gusts, and the pole humming loudly as it dances, and sit in a hole down in the rocks and work station after station as they call from all over!
With these systems I usually don’t have to get up to change bands, so looking for S2S activators is pretty fast. A perfect match is not needed to listen with these wires. Once you know where your matches are for each band, preparing to transmit just takes a few seconds. A good LED bridge in the tuner is the key.
73
George
KX0R
I’m going to hook up my MFJ-1820T 20M whip, mounted on a hiking pole with one or two radials and see how many spots I get with 5W on FT8. I’ll post results when I get around to trying it.
Barry N1EU
This is why I advocate using a W3EDP antenna, with mine I can operate on any of several bands without having to leave the operating position, and only need a short length of coax.
I have the MFJ-1699S model which is somewhat similar. Bandwidth is very restricted and it needs fine tuning. Works better with a counterpoise wire off my copper backpack frame but it can be tuned without it. Have only worked stations on 40 and 20m when propagation was good as well as 2m. Lightweight, I classify it as a mobile backup only. I prefer wire antennas even if it means carrying heavier.
Try Cabela’s for the pole, link below. I use the 16.5’ pole when I need lightweight and it works well. Considering the flex in the tip you get about 14 to 15 feet height depending on tension of the antenna wire. $12 + shipping - hard to beat.
http://www.cabelas.com/product/Cabelas-Classic-Crappie-Pole/738689.uts?slotId=0
I tried the MFJ-1820T on 20M FT8 with 5W and the resulting spots were few in number and way, way down from the dipole antenna. I guess this isn’t surprising. My conclusion is that the MFJ-1820T isn’t quite up to the task of a SOTA activation, even when using the FT8 weak signal mode. Perhaps if there were FT8 chasers specifically looking for me it would work.
Barry N1EU
In the top post, I was not impressed with the antenna; I was actually pretty disappointed with it. However, when I use it with my 817ND it does pretty well, even at 2.5 watts.
So it does have a use after all, just not with the KX1.
Hi,
Good to hear of some success. Conditions have been good the last week so that might need to be factored in.
I built a Dumtenna for very short range stuff, like in the back yard and just out of the AZ to work someone inside. It uses two 1.2 m telescopic whips and a 100 ohm resistor. and gives less than 2:1 SWR from 1.8 to 440 MHz. Screws into the SO239 socket on the back of the 817. Definitely inferior to the MFJ-1899 but no fiddle to change bands except for 2 m and 70 cm where the whips have to be 1/4 wave each. Best dx to date, 400m.
73
Ron
VK3AFW
