THE DARK ART OF GROUND PLANES

Hello All,

I have a problem with a Solarcon A99.. It seems to work ok but I seem to drag in a lot hash. Now ive been told that fitting the ground plane kit will help with this, however having read the destructions it tells me I need 9ft of clearance on the radials, now we get to the problem. I have it mounted on a side wall of the house which has a slopping roof not a gable end,, I have 9ft of clearance on what would be 2 of the radials but the remaining 2 would need to be cut to no more than 4ft in length,,, not a good idea I think.... So could I use aluminium radials and curve them to get the size I need but keep the electrical and mechanical length,,,, in short does the shape of the radials have much effect.

Thanky kindly Tom 73s

I wouldn't waste time, money and effort on a ground plane. If there was one thing that may be of help, it would be a coax choke (so-called ugly balun) just underneath the A99. This consists of 5 turns of coax cable tightly wound with a diameter of about 4 to 5 inches. This can help to reduce interference and RF on the outer sheild of the coax (common mode current). If that doesn't work, the interference may be from your house or neighbours. This is where you have to focus your efforts in trancing the source of the interference.

Ok Cheers ill give it a try.

73s Tom

You could also ground the pole as well to see if that helps.

Now that I can do,, I did try a ballan but made it of the wrong dimensions didn't work (my fault). Question for you ,,, would it make any difference if I ground the pl259 ( the screen side ) to the pole too.

Best 70thirds from Tom 26CZ455

No, I doubt it would make any difference unless there was a fault.

Ok Dave,
Thanky kindly

Tom

The A99 is prone to bringing in noise/hash but when i used mine homebase it was no noisier than any other vertical antenna but position is everything. My A99 was approx 30ft away from anything else that could cause interference and approx 25ft from the floor to base of antenna and i always had a zero noise floor and still do using my Vector 4k.I do use HF radios with very good filtering unlike my CB rigs which do pull in more noise,still zero on the meter but just a harsher noise.

I now use my A99 portable and again get a zero noise floor across 11m and again keep it well away from possible causes of interference..

I wonder if a all ally type antenna would suit you better as some have found the A99 just is too noisy for them.

Hello Cozzmik.

Well my antenna is oooow whats the height of a house, well its base is level with the roof apex, im mounted to a side wall between two semi's.
I did have an aluminium Sliver Rod up until the high winds bent it somewhat, but I still had the same or there abouts noise level. I think my biggest problem is being very close (3 to 4 miles ) from the land of the channel 19 muppets, on a bad day they wipe out 80% of the bands I can access, most days I have a hash level of 7 to 8.....
Having said that I have tried putting the radio on battery power and turning of the house supply, made no difference , I really think my problem is the muppets using 100w to talk 3 miles and most of them have had the magic screwdriver out..... well that's just me having a moan,,, but what can I do to improve things other than nukeing the black country.

Tom, 26CZ455

Sometimes it's hard to give advice on a forum as there can be so many variables to a radio set up. Now you have given additional information Tom, if you are getting a lot of over load from nearby stations and I assume localised electrical/digital interference that can't be readily sorted out, then may be you have to think of using a horizontally polarised (flatside) antenna, whether a dipole or beam of some kind. Unless you are talking to other stations locally with a horizontal antenna, it would really be for skip work only, but you may get a drop in noise and less overload by your vertically polarised ch19 good buddies

Cheers Dave,

I know what you mean, I used to get people ask me if I knew what " this funny sound in my engine is ",,,,, I was wondering about going flat side, also wondered about a beam, would the front to back rejection help or is my root trouble too close for it to help. Im guessing there is still lots I can do to help myself, so the info from all you lads is a great help, just being pointed in the right direction is half the battle.

73s Tom

"Would the front to back rejection help..."

You may be able to null some of the noise, but only you can find that out. Meanwhile a horizontal 1/2w dipole is easy to make, either from aluminium or bamboo cane and wire or even wire suspended from two poles or structures and see if that helps. Any wire generally will do and you can see if there is any improvement or differences before shelling out more money. Delta loops are popular as well. There are videos on YouTube.

Had a butchers at the delta loops, if im honest at the size they are might just as well go for a pdl2,,,, the dipoles and wires may be a better option at the moment. many year ago I made an inverted V in my float, it seemed to work quite well. Now the delta loop had me thinking, what if I use the delta type arms to hold up a V,,,,, trying to imagine the radiated pattern of the inverted V if it was the other way up would I get a mirror image off the inverted pattern,, I idea being to keep both vertical and horizontal ,,,, would it work I don't know but I think im going to give it a try...

Its ok you can call me a numpty I wont get offended 73s Tom


Ps. Brain malfunction....... What if I build ( ill call it a quad) 4 element dipole, 2 vertical, 2 horizontal from a common base but give each its own feeder and use a switcher box at the shack end of things that way I could switch polarization.... lol I lost the plot

Lol, I would keep it simple Try horizontal first, you could change it for a V or inverted V afterwards. The SWR will slightly change in different configurations.

Same here also on my A99 , best place for it now is on this hills /P

Hello Matt,
Give my regards to Toot hill, haven't been down there in years, got a friend lives there. As you can see from the profile picture my mobile station is off air due to police action lol lol had it nicked and they stopped it with a stinger.

73s Tom

! OMFG ! And then some.

I just rough cut 9ft 6 of twin and earth 2 screw connector blocks and some parra cord and threw it out the bedroom window and tied one end to the shed,,,,,,,,,,,,,,,, QRM ,,,, GONE,,,,,,, France 9* Italy 8-9 ,,,,,,,
rofl you can keep ya A99 my bit of wire works better.......

Seriously, it was just to test or try and fine what my mexico was coming from,, the cheapest nastiest components you can imagine and its head and shoulders above the A99 and the silver rod. Im now going to perfect it,, set the swr ( which is 2-3 all round without trimming) would you believe im having to squelch out the frogs.... Im going to build 2 wires one north /south and one east /west and a switcher box,,,,,, lol "flatside rules ok"

Big grinning 73s to All.............. must get the swr sorted I got frogs to blitz lol lol lol

Excellent!! Glad you have solved your problems.

A common theme on forums and social media is my antenna is the best, and that antenna is crap, blah blah blah, but they don't realise different situations require different solutions!

Very true Dave.


I was shocked this morning with the difference, years ago played around with "V"s in the loft, yes they worked but that's all I could say about them,,, but after this mornings experiment im going on with the wires. I even tried it vertical,, about a 1/3 was coiled up on the floor but it was still working as good and better than the A99....
so the quest now is to learn more about wires and how to use them, yep I got a thousand questions but I wont bend your ear today.

something I did like was the wire is a lot less visible from the road and less likely up upset the locals.

Tom

I was never a great fan of the A99 but the last big storm it wrecked the antenna and been disabled so I got the A99 antenna, put it up and the noise level is the same as the silver rod no increase in the noise got the joints typed and new good coax swr is very good 25mhz to 30 MHz a little high at 25mhz and a little high at 30mhz like 1.6 and 1.5 top end so all the bits I use swr is very good, its on a 10ft pole in my garden we are not allowed to have an antenna on the house but happy in the garden so it in the garden we live in a bungalow and I get out well I live in a north south valley , but I am 300ft asl so I get out well and I am happy at that but the antenna some like it some hate, but I like it its good for me as been disabled its ok for me but I am back on the air as for a little while, we could not go out but will be back in the hills again.

Well I put one up as the Silver rod I had looked more like a silver corkscrew... To be fair the A99 can thump it out but it does seem to drag lots of c*ap back in... However my little bits of wire are showing great promise, so for a few days im going to play long wires and dipoles lol,,, I was amazed just how good the wire was. I had it horizontal and all I lost was the interference, local stuff was coming in just the same,, once ive set the swr I can really give it a go.

73s Tom

Cozzmik wrote:

The A99 is prone to bringing in noise/hash but when i used mine homebase it was no noisier than any other vertical antenna but position is everything.

If you don't give them a RF ground then that comes as little surprise. Google common mode RFI.

Back in the day, when i was heavily 11m active, first thing i did was knock up a dipole for 11m, elaborated to a discone targetted to over 24-30 Mhz, as i used to listen to 12 & 10m ham traffic as well.

By the time i got my ticket, i resurrected an unused 11m eight element co-linear i had built and tweaked it for 10m, and rebuilt the discone to further WB it.

But certainly a dipole is a good move, especially for Dxing, as it's easy to rig up to hoist a wire item up quite high without too many wind sheer issues, cost's tuppence ha'penny to build a simple rotator and and an motorised addon so you can shift the DP between vert/mixed/hori polarisation.

And whilst not the first choice for a quality build, a couple of quarter wave rods with long telescopics added (one per rod) gives you a cheap adjustable item along with a rudimentary mast of some sort for temporary pop-up use whilst experimenting or using as an Rx antenna.  Done right, a rod+tele construct dipole makes for heck of a load of multiband coverage paired to a good Rx.

As for GP's, and where applicable, that's a big old murky aquarium to look at.  Some very informative sources, way too many highly inaccurate 'chinese whisper' misinterpretations and as such a lot of stuff presented as fact that's very clearly not.

But as a very rudimentary basic starter :-

Anything 'Hertzian' antenna (i.e. balanced) doesn't need a ground or GP as it uses each 'arm' is part of a balanced pair which incorporates a ground anyway.  In fact, if you add a GP, electrically connected it destroys the balanced state and if not electrically connect and sits below (such as as submerged/buried water tank) it will distort the radiation pattern, but if it's separated enough it starts to positively act as a reflector.  A true vertical collinear, despite looking like a Marconi-type 'monopole' is actually a stack of end-fed dipoles, so is a Hertzian type.

Marconi-types, better known in monopole form such as many verticals and telescopic and most HH helicals, or anything without a balanced element, relies on a ground or GP.  As you get nearer to full wave (such as 5/8 verticals), you can get away without a ground or GP but a GP of sorts is really still necessary to avoid undue distortion of radiated pattern.  Anything less than 5/8th of a full wave length you definitely want a ground or GP.  On marconi-types, the GP or grounding acts to create a virtual mirror of the physical element, and its basically that which creates the known radiation patterns you expect.

A marconi-type often talked about, on the lower bands as a cheap long antenna, is the 80/160m variants of a mono pole.  You can easily put up a 1/2W or 5/8W wire vertical, and put a spike in the ground as a GP - but you'll get a sub-standard result, where a mesh is laid out it improves as a GP, as does a set of radials (at least a triangular arrangement of three).  As a baseline, whatever your driven vertical element lacks (proportion of a wavelength) is the idealised size your GP should provide.  However there are lots of wrinkles, gotchas and tweaks to consider as your GP arrangement also affects the overall termination impedance of the antenna.

Back in the the days when transmitters used full valve PA stages, or a valve PA final, getting close to the right impedence at termination wasn't a big deal as valve PA's could take a crap load of abuse (still the ideal choice of preference on linears even now) - but rest assured your transistorised discrete transistor or thick film PA module is no match for enduring such abuse of a severe mismatch.

So on many levels, where the antenna type is of a Marconi type design, you need a ground or better still a suitable GP arrangement.  Height above the ground is a big factor to any antenna, but some types work well at near or ground level, but not all and even when suited, it compromises the radiation pattern somewhat.

A Mag Loop is one of a select few that perform well at ground level and sometimes at their best.