Other SOTA sites: SOTAwatch | SOTA Home | Database | Video | Photos | Shop | Mapping | FAQs | Facebook | Contact SOTA

What would you do 3 acres & some antenna wire?


#1

Ladies & Gents,

As I have mentioned in other posts, I am in the process of trying to set up a remote (internet controlled station) on a piece of farmland which I own (approximately 2 1/2-3 acres). Up until now the project has been delayed by internet/networking issues, but I now have sorted that, so it’s time to decide what antennas to put up…

Obviously in an ideal world, I would stick up a 100ft tower with a rotator + beams and be done with it. Unfortunately this just isn’t possible (planning regulations, restrictions on budget and other practical restraints prevent this).

I primarily plan to use it for chasing SOTA stations, but will also use it for other amateur related activities.

Basically the question is “what would you set up if this was your land?” I’m looking for some collective group wisdom.

I have attached a rough drawing of the site. Don’t laugh; drawing was never my strong point!

The measurements are not exact (I took the measurements from Google Earth, so they could be a few meters out either way) but I’ve drawn it to a very rough scale (as best as I could with the measurements available to me) and it should give you a very rough idea what space I have available to play with.

The requirements/criteria are as follows:-

  • Looking to work NVIS mainly on 80m & 60m.

  • 40m for SOTA contacts.

  • If I can also get good results on 160m that is a massive bonus (I know that there isn’t much SOTA activity on 160m but I’ve always wanted to play on 160m. I’ve just never had the space for a big enough antenna to make it work).

  • Need to be as discrete as is physically possibly because:-

  1. The land is classed as agricultural so I won’t be able to get planning permission & I don’t want to draw the attention of the local planning department.

  2. Possibly more of a concern is security. Given that I can go a couple of weeks at a time without getting down to the field, I don’t want it to advertise the fact that there is expensive radio equipment on site!!!

  • Note the power cables running across the field (pink line). UK government HSE guidelines recommend a minimum safe distance of 10m horizontally (along the ground) from underneath the cables. Other guide lines (aimed at boom lift operators) suggest 9m safe operating distance from wooden pylons (which this is) and 15m for other (very high voltage metal) pylons. Either way I really don’t want to get too close. My approximate measurement of 30m between the power cables & the tree should be safe.

  • Want to work a bit of DX on 20m and possibly 40m, so may add a vertical later, but for now my main goal is to get on 80m, 40m, 60m & 160m (probably in that order of priority).

As far as I can see, I have 3 options:-

Option 1:-

Use the 40m/80m trapped dipole which I already have. This should give good NVIS on 80 & would also be usable on 40 (if I can get it high enough)

Unfortunately it means sacrificing the 60m band. It also means that 3 masts/supports are required (one in the middle & one at each end).

Option 2:-

Looking at my measurements on the plan, I reckon that I could squeeze in a full wave loop for 160m (which as far as I can tell from looking on the internet, should also work on 40m & 80m with slight gain). Should also be able to tune 60m with a tuner? Would probably do what I do with my current 40m loop at home (feed using 50ohm coax via a 4:1 balun).

On the plus side, this antenna would probably give the best performance out of the three options.

The negatives are that it requires a minimum of 4 masts/supports to keep it up in the air. Hence not particularly discrete, and there is also the cost of buying mast sections to build it.

Option 3:-

Just put a long wire up (which was my original plan, as shown in my diagram). Probably around 6-10m high mast to support it at one end and use the tree at the other end. It’s about 90-100m from the mast to the tree, which means around 100-120m of wire (when you factor in the height of the mast). I would probably use a 9:1 unun (or maybe even a 4:1) with a decent radial field.

I’m guessing that this would give reasonable NVIS results on 80m & 160m? I’ve heard of people running an earthed ground wire along the ground (directly underneath the radiating element) to give an improvement in NVIS performance (apparently it’s quite a noticeable difference of between 3 & 6 dB).

This is probably the cheapest & also the most discrete option (less noticeable from the road). Only needs one mast (as I can use a tree at one end) and should give fairly good performance as long as I have a decent amount of radials.

To my understanding, the theory would suggest that it won’t perform as well as a full wave 160m loop, but it may be the best compromise of the three options.

The thought did occur to me that I could use an aluminium mast to support the antenna and cut it to length to make it resonant on either 20m or 40m with a radial field underneath it, giving me a vertical for DX. Obviously I would need to make sure that it was insulated from the ground, guy wires & whatever antenna it is supporting (not sure if there may be some undesirable coupling/interaction there)?

As I said, in an ideal world I would absolutely love to just put up a massive tower with beams on the top & be done with it.

Although there is technically space to do that, planning constraints would prevent that. It would also be like putting up a massive advertising sign saying “expensive radio equipment here, come & nick it”.

As I said, I need to be a little bit sensible with what I do as I’m trying to keep it low key & under the radar!

Other amateurs that I have spoken to are trying to convince me to go for a dipole arrangement. What do you folks think?

So fellow chasers, what works best for you? Working within the constraints above, what would you put up if you were in my position?


#2

OK let’s kick this off - firstly I do not know your name - you’ll get lots of ideas from “those who know” - the wise and those who think they are wise!

How high is the tree and can you climb it? Pity the drawing is not done in pen then we could see it properly!

Some of us are getting old and our eyes aren’t brilliant. Don’t worry about NVIS, I never do and I’ve worked 100s of activators on 80m. A lot of DXers let alone SOTA chasers would give their eye teeth for a plot like you describe, as far as I can tell from the faint drawing. You don’t need anything special, but in my experience a resonant or near resonant (under 3:1 before matching) and you should work 100s of station on HF SSB. If you learn CW well you should work 2 or 3 times as many as you can on SSB! If you want a long wire to work well and tune it on various bands due to the mismatch you’ll need lots of wire on or under the ground to reduce earth losses - or wire in the hedgerow. The farmers tractor or hedge cutter will not like it I expect.

The challenge will not be the aerials it will be getting the remote side to work reliably.

I think I have the quals to know - 132000 Chaser points as of today and I am an activator as well and No. 1 DXCC Honour Roll. I am allowed to crow like this as its new year and I have been drinking pink fizz!

PS Which part of the country is this in?

73 Phil G4OBK


#3

Hi James,

Full wave 80m (or 160m if it will fit) sky-loop - supported by probably 6 x 10 metre fishing poles possibly just strapped (cable ties) to the fence posts - no guy ropes needed. Black wire and although the masts are visible, they’re hardly as objectionable as steel masts or towers and have the added advantage that they bend in any storms. Cost is relatively low and I know for a fact that the 80m loop works remarkedly well on 60m, as well as 80, 40, 20m - not so good on 30m though. as I have used one here. I was surprised that it even worked on 60 metres but it did - really well.

Checkout my general notes here (more about my 40m loops than the 80m one but the principals are the same): https://vk2ji.com/equipment/antennas/40-metre-horizontal-loop-antenna/

I have tried various feeds and while feeding with ladder line allows the antenna to be switch to a capitively loaded vertical on 160m, I would stick with the far simpler (and cheaper) Q-section option to math the loops 170 Ohms down to 50 ohms.I would not use a Balun. Those who say adding a Balun make the antenna multi-band have not tried a Q-section cut for the antennas lowest frequency, the antenna is a multi-band antenna no matter how you feed it.

Low maintenance. There is 2-3dbd gain on all but the resonant frequency in the direction AWAY from the feed point corner. Maximum gain is obtained when the area within the loop (no matter what shape it is) is maximised.MORE IMPORTANT than gain is that the loop is a quieter antenna than either the dipole or end-fed and much quieter than any vertical. With the lower noise level of (in my experience up to 1.5 S-points) you’ll be hearing stations that others cannot. Being so close to that power line, low noise is probably the most important point. The Sky-lopp (aka DX-Buster) is a good compromise between a low radiation DX antenna and a more local NVIS antenna (when the propagation is there).
No radials or counterpoise needed for a loop (these would be needed for an end-fed or a vertical antenna.

73 Ed.

P.S. I played with the graphic a little - is this more legible now Phil?


#4

OT: just hover your mouse pointer over the person’s avatar and their name will popup.

Capture


#5

I would recommend putting up whichever is the easiest and see how well it works. You can always change it later if it doesn’t perform as well as you had hoped.

I moved into a new home about a year and a half ago and to get on the air quickly I put up my SOTA activation antenna, which is an end fed wire. It worked so well that I haven’t yet bothered to put up a dipole or anything else. Storms have taken it down several times and a couple of those times I added more wire to it before pulling it back up.

The current configuration is vertical 60 feet, horizontal 140 feet, then a 90 degree bend with another 100 feet horizontal for a total of 300 feet. At some point in time I inserted a 4:1 unun and still use it, though I’m not really sure if it’s needed now. There are a few radials (need to add more) on the ground and I use a tuner.

It seems to work fine, though I don’t have another antenna to compare it to. I’m located in North Carolina and have successfully chased summits throughout the US, Europe and even Hawaii. I’d rather have a beam on a big tower, but my wires seem to get the job done.

Most likely your rural location will have a much lower noise level than your current location, which will allow you to hear many summits that would have been buried in the noise. If you can’t hear them, you can’t work them.

Good Luck!

Paul - KB9ILT


#6

Hi James

I can’t add anything to the antenna suggestions; if it were my project, I’d probably go with Ed DD5LP’s idea.

There is a (non SOTA) hill near me with a small commercial installation at the top, where the equipment is underground in a manhole. I just thought that might be useful to you - if the field is not prone to flooding, of course.

Advantages: Relatively easy to secure with just a lockable heavy steel lid; not easily visible from a distance; cool in summer (if you insulate the lid). Perhaps relatively cheap, if you can provide the manpower!

Please keep us informed, it sounds like an interesting project…

73 and HNY,
Adrian G4AZS


#7

I have a suggestion based on your Option 1, the use of a trapped dipole. The suggestion comes from a number of WSPR experiments that VE6AGR and I made in Calgary to help a club member install first a 20m dipole, then to upgrade it to a 2-element wire Yagi. Our contribution was compare the WSPR results of his antenna with a portable SOTA antenna, an inverted-V dipole.

We were surprised at the results. If your criterion for success was to contact as many stations as possible (and surely this must be of interest to a SOTA participant) then the inverted-V was better than the dipole and often as good as the 2-element Yagi.
The reason for the result was that the inverted-V (centre height about 25’) is essentially omni-directional and was spotted all around, whereas the dipole had deep nulls off the ends of the wires which was not adequately compensated for by the slight increase in range broadside to the wire.

So my suggestion is a modified Option 1, to try a trapped dipole rigged as an inverted-V. It’s simple, you have a number of the components already, and you have experience with trapped antennas.

And a second suggestion is to characterize your antennas as you try different designs, using WSPR. It’s interesting and useful.

Ian VE6IXD


#8

Much clearer now Ed, thanks. Having the antenna mounting point in the corner of the plot reduces the aerial options somewhat James. I’ll have another look at it after I finish off the bottle of chilled fizz, which is getting warm but my view is that the ideas from Paul, are easy, practical and would serve as a good starting point if the pole is to stay in the top corner of the field. As the aerial field will be left unattended for weeks or months at a time KISS I would say is best.

Thanks to Andy for the tip regarding names!

73 Phil


#9

PS As well as the question about the tree - how tall is the mast James and how many radials have you put down and how long are they on average - 100s of feet of wire or 1000s of feet?

Phil


#10

Ian,

I think the problem James has with erecting an inverted vee of some type (which would likely also be my suggestion), is that the mast is almost in the corner of the field and not at a mid point so an inverted vee could not be fanned out either side, if you get my drift.

Phil


#11

Hi Phil,

Name is James.

Thanks Ed, that should help a few people out.

Probably around 20ft or so (6 meters in new money). I was going to use around a 6-10 meter mast at the equipment end.

I’ve yet to try climbing it but could be a little hairy (as it overhangs a small stream. Having said that, it does have quite a thick trunk so I reckon that I could lean a ladder against it. Obviously I would need to brace the bottom of the ladder to stop it sliding out (put the legs against the bull bars on the jeep maybe, I very much doubt that the ladder will push a 2 ton Jeep out of the way)!

I don’t think that getting a rope into the tree to hold the wire is an insurmountable obstacle.

I’m in the process of learning CW but it is a long & frustrating process (especially when other work, family & domestic commitments take over).

I am getting there slowly, but it is taking a while.

I started off with just a couple of letters and have been adding them 1-2 letters at a time as my decode gets more reliable.

I’ve got around half of the alphabet sussed at around 15-18 wpm with approximately 75% accuracy at the moment.

Figured I could put in a radial field (plenty of space for that) around the mast at the equipment end (towards the north-east of the field). As long as that (aluminium) mast is insulated from the ground, the antenna that it is supporting and the guy wires, I should be able to use it as a vertical (on either 20m or 40m)?

I’m not too worried about this. The only tractor that goes in there is my own. It’s only used to cut the grass, so as long as the radials are buried under the surface it won’t be a problem.

I was planning to put in a vertical with a buried radial field sooner or later, so could use the same radial field for both antennas maybe?

Sounds like you’ve got the same idea as me, I like your style!!!

One of the thoughts that came to mind as I have a full wave 40m loop at my home QTH. It seems to get out ok, but the S7-S9 noise absolutely kills my receive. I can’t hear anything but the strongest stations (hence setting up the remote station).

Unlike you I feed it with a 4:1 balun. Will look into the Q-section though.

I have tried operating from there before (albeit only on 20m with a 1/4 wave vertical). The noise floor was extremely low. Between S0 & S1. Not tried it on any other band but hoping that given the low noise on 20m it won’t bee too much of an issue.

You’re telling me!!!

I’ve wasted days (literally) trying to get the 4G link to work. The carriers “CG-NAT” caused us the most problems.

We tried all sorts, including a VPN to try to get around it. Even with the help of a computer engineer we struggled.

I tried to get a fixed public IP SIM for the router, but the mobile networks in the UK don’t seem to want to let you have one of them unless you are a business user requiring it for M2M use.

The solution was actually fairly simple in the end. I run a small event radio communications hire company and we needed it to run equipment at our remote transmitter site!!!

There is some truth to this as we do need a 4g link there for business use, so I was able to get a fixed public IP on a 4g SIM card under the guise of my business.

Problem solved. Works like a charm!!!

The biggest challenge will likely be making sure that we have enough power to keep the router alive as there is no grid power despite the overhead power lines, so will have to run on solar (not great on the UK).

For obvious security reasons I don’t want too many people knowing where it is. To give you a very rough idea of location, it’s in Wiltshire, very roughly 10-15 miles SE from Bath.


#12

I’m surprised to hear that, but I guess that makes sense.

I like Ed’s suggestion for a full wave loop (several other amateurs have almost wet themselves when I’ve uttered the words “full size 160m sky loop”!!! I might go with your suggestion to stick up the dipole (in an inverted V configuration) to begin with with, then possibly try a loop later.


#13

OH power lines that,s buggered it straight away

Full wave loop on 160m for sure
karl


#14

Absolutely. Precisely what I’m aiming for. A simple solution that is effective & just works!

Undecided & I’ve yet to put the radials down. We are very early in the planning stage.

I have aluminium mast sections which slot together, so realistically around 10 meters or so is probably the limit for this type of mast without it bending in the middle when I try to put it up?

I guess that I could get a bigger mast (up to around 20m telescopic masts on eBay for a reasonable price) but I don’t really want to spend the money if I can manage with what I already have. As Paul said “put up whichever is easiest” “I can always change it later”.

I’m led to believe that around 16-20 radials is a good starting point, but more are required if you can’t fit full sized quarter wave radials in. Thinking maybe around 30 radials around 10-20 meters or so long?

I’ve read that the optimum for broadcast stations is 120 at a quarter wavelength. That said, there seems to be plenty of literature opn the internet that says that you are into diminishing returns if you go above around 20-30?

I put the mast there as it gave me the longest length of horizontal wire if I went for the long wire (or inverted L) option.

I’ve not actually started any groundwork for the mast or radials yet, so there is flexibility in where the mast & guy wires go. The radio box must be located somewhere against the hedge/fence on the eastern boundary to the north of the gate (to keep it out of site of the road).

The antenna itself can be moved around.

Only real considerations are:-

  • The length of the feeder cable (I’d guess the shorter the better to reduce the amount of loss).

  • The power lines as I obviously don’t want to kill myself when setting it up, or have it arch when it rains and blow my kit. From what I’ve managed to figure out on line, the wooden masts (which this is) only carry in the order of a few hundred to a couple of thousand volts), in comparison to the big metal pylons which can carry significantly higher voltages.


#15

Nice idea, I’m not sure how easy or practical it will be to dig a large hole in the ground and then re-enforce it to prevent it from collapsing.

The ground also gets very soggy in the winter, with me becoming the proud owner of several small ponds last year! Putting equipment underground may not be the best plan!

My current plan is a couple of old military ammunition cans (reasonably water-tight) with all the equipment in:-

  • One will hose the radio, control box & tuner (if required for the antenna)

  • The second will house the router, solar chargers, maybe later I might add a Raspberry Pi to run WSPR/FT8 etc

  • Both of these ammunition boxes will then be housed in a locked metal storage box (similar to what you see on the street corner for phone lines/internet service providers etc) which will be hidden next to the hedge against the fence line by the gate.


#16

Your biggest average power requirement will likely be the heaters you will need to keep the contents of your boxes from getting damp over winter.


#17

Most definitely! That is the biggest motivation for me wanting to set up a station at a remote location.

I ran a 1/4 wave vertical on 20m from the location a while ago.

I initially thought that I had a problem with the antenna/radio as the noise was so low (between S0 & S1).

I could hear stations that I would never of heard over the racket at my home QTH (which as I type has an S6-S7 noise level on 20m & S9 on 40m, using my Diamond CP5H vertical).

Working from home is nearly impossible for me unless they are an S9 (which SOTA stations rarely are due to the fact that they are QRP and running less than ideal portable antennas).

To be completely honest, if I had a lower noise level at home then I would probably not have bothered with the hassle of trying to get a remote station up & running. I would have made do with what I have.

Unfortunately I live on the edge of a fairly big estate. After trying to DF the source of the noise, I found that it was coming from almost every direction. In other words, it’s coming from multiple sources.

It’s far easier to install a remote station on land which I already own at an alternative/remote location than to try to fix dozens of sources of noise across a large estate. Especially when I have plans to be moving house within the next couple of years.


#18

Just to say, thanks to everybody for all of the suggestions so far.

If anything, it appears to confirm what I already suspected and what other people have suggested.

So far I draw the following conclusions from the comments made so far:-

  1. Long wires need a really good ground (which I guess that I do have the space to install) and can be a little tricky and probably not the best way to go.

  2. Either a dipole or a full wave loop is going to be the way to go with this.


#19

That is a concern.

I’m hoping that the sealed ammunition boxes will keep most of the moisture out, especially if I pack it with silica gel.

Given that it will be packed into a fairly small box, I’m hoping that the heat generated from the solar chargers & router will provide a little bit of warmth inside the boxes.

I’m still waiting for the solar kit to show up, but this is something I will need to figure out.

I had considered a small generator with remote start to power a small heater, but this seems to be adding complexity, and is more to go wrong.

Something that I need to think about.


#20

James - What is the maximum distance you can mount the guyed pole away from the north east (as we see it) corner of the field without it becoming too prominent? If you are considering an inverted vee for mulitband use with a single coaxial feeder, then the further you can get that away from the north east corner the better I would suggest. I am looking at an Off Centre Fed Dipole as a possibility - either in an 80m sized version (around 120 feet top or a 160m version with 240 feet top - approx). Very easy to make yourself, easier still to make if you purchase the balun and choke from a reputable source.