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 Probably only ever buy 1/2 waves for 10m and 11m

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Probably only ever buy 1/2 waves for 10m and 11m Empty
PostSubject: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSat Apr 20, 2024 8:56 pm

I modeled this for 28.5MHz - 4.9M for the half wave no radials, 6.25M for 5/8 wave with 4 radials and 2 x 3.125M elements for the 5/8 wave dipole. The same applies for 11m band of course. Specific to 5 degrees take of which a lot DX comes in at for 10m and 11 m bands and over a "real ground" model.

The reasoning is as follows, the following are plots at a feed point of 10meters which would be average 2 storey house height. i.e. a Chimney.

1/2 wave end fed vertical = SILVER ROD 1/2 wave Gain at 5 degrees = 1.6dBi

Probably only ever buy 1/2 waves for 10m and 11m 10m-half-wave-at-10m-feed-1-7d-B

5/8 wave end fed vertical = SILVER ROD 5/8 wave with 4 radials Gain at 5 degrees = 2.0dBi

Probably only ever buy 1/2 waves for 10m and 11m 10m-58-10m-feed-2-0d-Bi

5/8 wave dipole with choke = like the Gain Master Gain at 5 degrees = 2.1dBi


Probably only ever buy 1/2 waves for 10m and 11m 10m-58-Dipole-10m-feed


I compensated for the feed point of the coaxial dipole by approx 3.29M so the height below antenna was 10M. i.e 1 dipole legs length, so feed point (for end fed 5/8 wave dipole) becomes the bottom of the bottom leg of said dipole.

This suggests you should save your money and install a 1/2 wave silver rod. Even more so if you can get said 1/2 wave at the same tip height as a 5/8 wave would sit. Then the differences really will be virtually nothing.

You gain a mere 0.4dBi (0.5dBi for the 5/8 dipole) and that is if you install 4 radials on the 5/8 wave. The Gain Master type antenna would likely become a little unbalanced (electrically speaking) on a chimney with roof materials close by. Though with a built in choke would suffer less from CMC issues.

But you can make an ugly balan for a 1/2 wave Silver Rod for next to nothing.

These are of course only models, but they make you wonder if it is worth spending more than £55.00 on 10/11m antenna. It says nothing of durability etc.

You are less likely to have significant CMC on your coax with a 1/2 wave end fed than a normal 5/8 wave end fed. (especially if it is a no radials 5/8 wave) Sirio's 1/2 waves are the best, thicker aluminum more heavy duty copper wire coil.

Probably imperceptible gain for significantly more money than £55.00.

Models are not perfect and they are not the real world so we should take that into account. Any of these antennas working as the models suggest would be fine DX antennas. CMC and not having radials are likely the thorns in your side for any install, though can be resolved through likely installing the 4 radials on the 5/8 wave and/or putting the ugly balun on the "normal" 1/2 and 5/8 waves close to the feed point.

Happy to see if others come up with different results.


Last edited by FreqFreak on Sun Apr 21, 2024 11:06 am; edited 1 time in total

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSat Apr 20, 2024 10:02 pm

You must have something wrong in your modelling, Solarcon show their half wave length A99 antenna as having 9.9dBi gain and they can't be wrong, can they? Wink ...I'm just jesting of course. But I don't know how companies get away with such misleading advertising.

There is such as small theoretical difference as you've found our between 1/2 and 5/8 wave types of verticals. One might work better over the other for one person, but at another persons QTH the other one might work better. Only way to really find out is try both in the real world.

If I was to buy one now the Sirio 1/2 wave would be my choice too. But I won't buy a base antenna when I know I can make better performing ones for almost nothing. And when I say better performing, I mean in the real world.. as you noted already that models are not perfect. My delta loop, which I am just about to do an update on my thread on here, modelling shows a much poorer gain than the 1/2 and 5/8 models above at 5 degrees, but it performs like a beast for DX, especially into south America. In the end theoretical figures are interesting and can help guide decisions but trying for yourself is the only real way to find out.

I hope your great posting helps others on here if they are undecided on what to buy and if they should save their money and stick with the 1/2 wave.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 21, 2024 7:59 am

Back in the CB days I wasted a lot of money buying various ludicrous verticals Sad

Until a proper silver rod became available then we never looked back.
Had it on a 17foot piece of steel water pipe in the garden, my mum used the homebased
and she was known all over.

It was up for years even survived 1987.

That was the best vertical that fitted this location.

I use a ground mounted Hustler 6BTV, mainly for lowbands but it does catch the
odd dx on higher bands now and again, especially when I forget to swap ants.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 21, 2024 8:31 am

SangueG wrote:
You must have something wrong in your modelling, Solarcon show their half wave length A99 antenna as having 9.9dBi gain and they can't be wrong, can they? Wink ...I'm just jesting of course. But I don't know how companies get away with such misleading advertising.

There is such as small theoretical difference as you've found our between 1/2 and 5/8 wave types of verticals. One might work better over the other for one person, but at another persons QTH the other one might work better. Only way to really find out is try both in the real world.

If I was to buy one now the Sirio 1/2 wave would be my choice too. But I won't buy a base antenna when I know I can make better performing ones for almost nothing. And when I say better performing, I mean in the real world.. as you noted already that models are not perfect. My delta loop, which I am just about to do an update on my thread on here, modelling shows a much poorer gain than the 1/2 and 5/8 models above at 5 degrees, but it performs like a beast for DX, especially into south America. In the end theoretical figures are interesting and can help guide decisions but trying for yourself is the only real way to find out.

I hope your great posting helps others on here if they are undecided on what to buy and if they should save their money and stick with the 1/2 wave.

Thanks, 1/2 waves are fairly practical for most and many do not wish to DIY so it offers a very easy and affordable route into CB or Ham radio.

£55.00 is a good price for the materials used in the Sirio 1/2 GPS. It's good quality, steel bracket, good aluminum, easy to tune, good quality copper coil and good quality SO-239 and highly practical for most as it has no radials.

You may wish to just add a jubilee clips on top of the screws to be sure.

I would go as far as to say if a "normal" end fed 5/8 wave (or coaxial 5/8 dipole) works better for someone in any significant capacity than a 1/2 wave or it would likely be because it is absent of CMC on the coax (common mode currents on the coax) or that they have a decent set of radials on the normal 5/8, either many shortened or 4 long.

If you are on a tight budget a radial-less 1/2 wave IS NOT in any way a poor performing relative.

It's 99pct as good and close to up to 3 times lower in price.

Gain Master style has its own problems. You really must get them high and in the open otherwise the pattern is very negatively affected. That lower leg of the dipole is the issue. If that is near roof line, walls, even trees etc. that lower leg will interact with any local objects and throw the pattern out and any of that 0.5dBi extra gain will never be present. They are very sensitive. I know as I have one and have used it in many situation. They are a complete DX disaster ground mounted as one example and do not really start working as they should until 6 meters off the ground and in the open.

I have personally used all of the above and own all the above and my basic findings..

Normal 5/8's and MAX2000 - difficult to tune, radials a pain, never in reality performed better than a 1/2 wave over many years.

1/2 wave - just work well and not fussy - gain figures virtually imperceptible different from the longer 5/8 (even with tip in naturally lower position).

Gain Master - very fussy needs to be 20 feet high and in the clear. It can be argued that the same can be said of all antennas but for a 5/8 wave coaxial dipole it is especially so.

So you can save money without any concerns at all. And if you really want your 0.5dB gain back upgrade and use high quality coax. (and you get your 0.5dB back at all angles TX and RX.)

This is very good for a good price per meter.

https://www.hamradiostore.co.uk/f-zero-coax-cable-various-lenghts

It is very stiff though, so is not for installs that need sharp bends as it has a solid copper core.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 21, 2024 10:13 am

Sirio 1/2 gpe was using the Swedish repeater at EU ch20 & had good results (21KM10 mentioned to me at one of my youtube post) ... perhaps is my next one because down here in Greece with out license allow us to use only 0dBd antennas (according to manufacture sirio for this antenna is 0dBd / 2.15 dbi at sirio papers) ... when was searching about it i have seen users talked to other side of the world (with high power) ... but a Negative was reading some had issue with high wind, it broke at the plastic where you can see the inductor coil ...

A99 seems good option but for me is over priced for 1/2 wave, how ever i did spoke with one from Paris using this antenna & was strong signal

As FreqFreak mentioned some do not wish to DIY, example my self  not have time to make my own (now summer time down in Greece  most of times busy) a ready one is easy option

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 21, 2024 10:58 am

The somewhat difficult to accept truth, and I have been there myself and own all of the above antennas is that for DX, conditions rule everything, given 3 virtually identically performing vertical antennas.

The only actual performance criteria you have available above another station's performance to tweak is height above earth which naturally lowers your radiation angle and reduces your ground losses.

If you can get any of these antennas to a feed point 12M and above they are the same.

To all intents and purposes these 3 antennas are identical for use on 10 and 11m in all but price.

It's an odd one to have to swallow as we all want to think we have a little advantage cause we paid more or simply like to feel we have a slightly better station.

We don't. It is pure fantasy. Sooner or later  and typically over many years and a couple of sunspot cycles you find this out.

£55.00 and you have a high performance DX antenna if you can mount it up nice and high. Cool Just make sure you make an ugly balun which costs about £4.00

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeMon Apr 22, 2024 8:33 am

5 degrees is possibly probable if you live on a boat out at sea or maybe on top of the highest hill around but for the majority of us its only a dream
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeMon Apr 22, 2024 10:44 am

3-10 degrees is where a significant amount of intercontinental DX comes in on 10 and 11m band. These angles especially for 27-29MHz are important and a worthy angle to base potential performance.

This is why 11M Dxers elevate. Most serious DX'ers elevate because this increases the performance of any antenna for DX. It sounds incredibly obvious but there is good technical reason behind it.

Obstacles in the way of that will of course attenuate incoming signals to various degrees and from various compass points related to geography and local buildings etc. and for the most part people can do nothing about that. And where they can you elevate the antenna as far as is practical/safe.

Every antenna is capable of TX and RX some energy at these angles even a ground mounted 1/4 wave but it is not a high performance antenna on 10m compared to a elevated 1/2 wave. It'll DX in good conditions like everything, but won't help you out on the difficult DX, the difficult paths, the rare opportunities where you have 1 chance every now and then, in poorer conditions. Here it will put you on the back foot.

The following is in the interests of learning, propagation and possibilities... not trumpet blowing:

I am in a fortunate position, and put the effort in, to be able to make contacts when a band is dead to many. i.e. there was a short Atlantic ocean opening on 15m the other day but it was marginal the 2 contacts in the East of the USA were 20mins apart both to the same state, both mainly S0 R3 to R5 and fading in and out. Max peak signal was S1. My antenna was fed at 11m. I can never know for sure as we never can, but when these marginal contacts happen and I largely hear an extremely empty band (to me in my QTH that is) I strongly suspect that this is an extremely low angle path.

Notwithstanding, low noise RX on both ends, 2 people who happen to come across each other, a beam user on one end always helps, persistent calling on my behalf, a critical mass of ops using or not using any given band. We are like sheep, if we hear hiss we assume band is dead. If we all only listened and never called we would be in serious trouble in this hobby !

I made my first ever contact with Samoa on the same day SSB phone - 100W on a 1/2 wave DIY at S0 R4 2 hours earlier, I was very pleased.

To balance that success with significant failures.. I have had many very poor days where I get run of the mill DX or very little. That is just the way it goes. If I had a lesser set up than I did, I would not have heard or QSO'd with that Samoan station on that day at that moment. There is a good chance I may not hear Samoa again for years.

To balance the success that's actually a fairly easy path to Samoa with mostly salt water hops, efficient compared to land hops. And as always there IS luck involved, however good your set up is given your situation and effort level.

DX is mainly luck, until it's not. Holding S0 QSO's is about what you bothered to put in.

Here is a little visual exercise. Many CB DXers using 100W have had Australians coming in at S7-S9 when conditions are good on 11m. That signal has traveled relatively unimpeded for 9,000 or 14,000 miles (long way round). It comes out of the horizon at 5-10 degrees at 10dB over S9 as there has been very little to attenuate it, just the hops themselves, the interaction with the ionosphere and land/water hops.

A few houses or buildings in the way is not going to make much difference to that signal ! It'll pass straight through them and if you get an S7 it's lost approx 22dB by the time it hits your antenna. 

It seems possible to me and statistically likely to be a below 10 degrees QSO.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeMon Apr 22, 2024 10:19 pm

Newbie question ... what means 5-10 degree? the signal transmitting from the antenna at specific degree example a 5/8 can do that ... or the angle of the antenna needs to be at this position for DX, example a monopole vertical (single long radial) slightly bend it at 5-10 degree ... or both will work ... or this is the angle of getting the signal receiving a signal ... thanks
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeTue Apr 23, 2024 3:07 am

I'll leave this here...in short no matter what you get there's little difference in any of them and usually when someone says they replaced X for Y antenna and it was way better it is often because of what else was also altered in the installation than just the antenna.

Probably only ever buy 1/2 waves for 10m and 11m IllAB9ql

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeTue Apr 23, 2024 9:14 am

I think I have seen that overlay one, what is interesting is the 1/4 wave types (with matching for Astroplane) do as well if you can get them up to 10M high.

And as they are like a cage or have 4 radials few people favour the 1/4 wave, they stick out a bit to the eye. They end up being almost as long almost. Lets face it, it's a dipole with 4 legs instead of one and just spread for a good match. (and much wider from the radials)

One thing not considered is matching losses and they all have them, albeit likely small (except 1/4 wave, unless we include angling radials at 45 degrees, essentially lossless). 

Between the 3 designs we have, coil alone for 1/2 wave, coil and possibly the radials influence on impedance for a 5/8 traditional. And a stub match plus its coaxial choke coil for the 5/8 wave 'end fed' dipole.

I cannot calculate them as it is beyond my mathematic knowledge, but likely similar.

I will add to this, all losses add up (and that is the very opposite of what you want) and they should be minimized but at what point does cost per 1/2dB become a factor ? 

The low angle antenna pattern gain or loss (depending on how you view it), seems to provide the least value per 0.5dB lost compared with for example buying a 1/2 wave and spending on lower loss coax.

For me the take away is that the humble, basic 1/2 wave is a virtual equal and much lower in cost. Has the benefits of being relatively less fussy to install and is less obtrusive to the eye.
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeTue Apr 23, 2024 11:35 am

babis3g wrote:
Newbie question ... what means 5-10 degree? the signal transmitting from the antenna at specific degree example a 5/8 can do that ... or the angle of the antenna needs to be at this position for DX, example a monopole vertical (single long radial) slightly bend it at 5-10 degree ... or both will work ... or this is the angle of getting the signal receiving a signal ... thanks

Generally antennas are either vertical or horizontal by user choice.

The easiest way to understand this is to enlarge any of the images of my first post.

The red dot at the end of the thin black line line is positioned at 5 degrees in each image and the "gain" at that angle is at the top of the image.

It is written : Elevation angle = 5 degrees

5 degrees is chosen as a nominal value which represents a useful angle to compare antennas for likely DX performance.

A good antenna system will have good RF output pattern from ideally an arc like shape from say 3 degrees up to around 30 degrees. DX can come from any angle between 3 and 30 degrees approx (and occasionally slightly higher)

On 10 and 11m much DX comes in below 10 degrees from the horizon.

The image at the bottom of this post has 3 dots on the horizon at approx 5, 10 and 15 degrees, most DX on 10m and 11m comes in from below 10 degrees out of the sky/horizon.

The higher your antenna is, up to about 15m above earth (relative to 10/11m band) the more RF energy your antenna will radiate at these important low angles. (and crucially, also have more receive "gain")

Any piece of matched wire will DX, potentially with good conditions but it is not a credible or useful benchmark. In fact a relatively poor antenna is NOT a benchmark for performance even if it can DX.

A poor performance antenna can work in strong conditions, but do we want to use poor antennas that only work in strong conditions ? Mostly no, we want high performance that work in weaker conditions (which is most of the sunspot cycle!). Some of the best DX I have done has been in weak conditions with or on the edge of what is possible with VERY low signal levels.

If we choose to be without a beam for whatever reason and you want to be a serious DXer and get the difficult stuff (not the run of the mill over and over) you must take care of details. Otherwise you cannot even hear it, never mind have a chance of working it.

If you are fine with very long wait's, that is also an option. i.e. waiting for perfect conditions at your QTH, waiting for a pile up you can break (ham term for many stations calling from around the world all at exactly the same time to try and contact a rare country.) with a bad antenna, being incredibly lucky on using grey line efficiencies (sunset/sunrise DX). A lot needs to come together for any given contact. That may happen very rarely in 1 lifetime for a ham/cb user with just a piece of wire (which is all these antennas are, a self supporting piece of wire in the guise of aluminium tube or wire in a fibre glass radome).

Choose your bits of wire carefully.

We all want different things so details are not for all. There are different levels of input and effort for any cb'er or ham, some more relaxed and casual.

Do it the way that makes you happiest.


Probably only ever buy 1/2 waves for 10m and 11m Degree10

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeTue Apr 23, 2024 9:03 pm

Great post.  My 2p worth is that there are two (or maybe three) camps on antennas

Live on a farm 'in the outback', put up whatever towers you like, 50m height for a dipole - why not ?

     (Make friends with a farmer and operate at weekends/remotely)   

Not enough height, not enough garden,  neighbours would complain the antenna was upsetting the Birds/Fish/Gnomes so whatever goes up easily and near invisibly is your choice.
In the latter case its useful to ask what length will fit the space then turn to how to feed it. 
- Bottom fed vertical wire is  often possible if there's a tree or it slopes to the chimney
- End fed horizontal is considered not a good as a vertical in some directions /distances but out-performs the vertical in others
- Quarter waves are really only good if you can bury or 'hide' a load of radials around the base 

In the real world and real life buying a load of cheap wire and cheap cord that you won't cry over throwing away is a great way to start experimenting

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeTue Apr 23, 2024 10:21 pm

@ FreqFreak Great explanation ... can not find the Thanks button, only the Like button
Thanks for detailed answer, even some one with not good English will get the point ... i understand now how works the 5-30 degree ... 



Quote :
A good antenna system will have good RF output pattern from ideally an arc like shape from say 3 degrees up to around 30 degrees. DX can come from any angle between 3 and 30 degrees approx (and occasionally slightly higher)

On 10 and 11m much DX comes in below 10 degrees from the horizon.

Now my question (Not you You in general) once i guess no one have seen the electromagnetic waves, how do they know at 10/11m DX comes below 10 degree ... 5-10 degree is like waves following the shape of Earth like with Medium Waves ...
i say this because from part of West & all North i have mountains (towards Europe) & from there i have the most DX contacts (yes ok Europe using way more CB's) ... & i have tried VHF dipole (yes at CB Band) car CB antenna & Boomerang, just the Boomernag is way better because is at the correct freqs to my eyes)

If they are correct i guess i am only DXing when the waves comes occasionally from about 20 degree & upper due to the mountains ... unless waves following the Earth shape at these Freqs like Medium Waves ... 
So i guess If i was by the sea level would have way more contacts at 10/11m, while VHF & upper Freqs will be the opposite (the higher Freqs more optical contacts so higher ground level for DX)

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Probably only ever buy 1/2 waves for 10m and 11m Empty
PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeWed Apr 24, 2024 8:49 am

There are a little +/- button on top right of everyone's posts I think this is thanks, maybe ?

This information is in black and white print. Lots of scientific research is done all the time, often military based. There are books solely about ionospheric interactions with RF. All info on likely radiation angles for each band 10m/15m/20m/40m is in the ARRL Antenna book :

https://home.arrl.org/action/Store/Product-Details/productId/2012451048

The higher the frequency on HF the more chances the signal will arrive below 10 degrees.Though for all bands there are many contacts made below 10 degrees.

To support this I like to think like this.. if we considered higher angles say 40 degrees it would require so many hops to DX 10,000 miles there would be no signal left by the time it reached your antenna.

Every time a signal refracts in ionosphere it loses something around 7-10dB as it interacts with the charged layer, energy is lost as a minuscule amount of heat, particle interaction friction/dissipation. (VERY loosely estimated it depends on frequency and angle and ionization levels). And of course same when it comes back down to earth hits land / salt water / objects. Every hop attenuates the signal and I read the lower the angle the more the losses in the ionosphere but with the benefit of greater distances jumped)

We can also consider this. Imagine being in a glider 270miles up inside the F2 layer between you and your antenna there is empty air. There is nothing at all to attenuation your signal so in that balloon your 20 Watt signal on earth gives 30dB over 9 signal ! (an estimation) each time it comes down and goes back up it loses estimated 10dB. This is why signals can be so strong over thousands of miles. And yet you friend 20miles away cannot hardly hear you as you signal is lost as heat through buildings/ground/metal objects.

If I recall correctly the maximum distance from 1 very low angle hop is approx 2,700 miles - it varies as the F2 layer charges change height a little each day and with season. So you need maybe 4 hops to get 10,000 miles to other side of planet. Or maybe it is chordal hop it gets trapped in 1 layer up high and has a super efficient path.

https://www.hamradioschool.com/post/chordal-hop-propagation

This suggests when you make a QSO in the same continent (let's say Europe) it is likely more higher angle hops, if the QSO's are 350-1,000 miles for example.

"Quarter waves are really only good if you can bury or 'hide' a load of radials around the base "

The only thing I would say about that is that a 1/4 wave on the ground for 10m/11m is never good unless you are on ground as flat as a pancake or a beach. It is merely ok, it will DX ok but will be totally and utterly destroyed in terms of performance by a £55.00 silver rod at 10m elevation. In poor conditions you will make DX on the elevated Silver rod that the 1/4 wave may not even know is there 

Take my S0 R3 Samoa QSO, with a ground mount 1/4 wave you would be hearing hiss !



Ignorance can be bliss, in this case, it's just a lost rare DX.


Off the top of my head the difference at some low angles can be 6dB !

Ground mounted 1/4 waves can be good antennas, just not on 10/11m. Local obstacles, significantly reduce low angle output compared to elevated antennas. If they were any good CB operators would use them and they don't !

Here are 3 plots 1/4 wave ground mount, 1/2 wave at 10m and 1/2 wave at 13m

There is 6.4dB and 7.6dB less loss at 5 degrees than a ground mounted 1/4 wave.

It is why no CB station ever uses a 1/4 wave on the ground.

1/4 wave ground mounted with 32 radials -4.8dBi (that's a minus/negative 4.8dB)


Probably only ever buy 1/2 waves for 10m and 11m Quarte10

Silver Rod 1/2 fed at wave 10m +1.6dBi (this is positive)


Probably only ever buy 1/2 waves for 10m and 11m Half_w10

Silver Rod 1/2 wave fed at 13m +2.8dBi (this is positive)



Probably only ever buy 1/2 waves for 10m and 11m Half_w11
Just buy Silver Rod and get it as high as you can, job done.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeWed Apr 24, 2024 12:45 pm

babis3g wrote:
@ FreqFreak Great explanation ... can not find the Thanks button, only the Like button
Thanks for detailed answer, even some one with not good English will get the point ... i understand now how works the 5-30 degree ... 



Quote :
A good antenna system will have good RF output pattern from ideally an arc like shape from say 3 degrees up to around 30 degrees. DX can come from any angle between 3 and 30 degrees approx (and occasionally slightly higher)

On 10 and 11m much DX comes in below 10 degrees from the horizon.

Now my question (Not you You in general) once i guess no one have seen the electromagnetic waves, how do they know at 10/11m DX comes below 10 degree ... 5-10 degree is like waves following the shape of Earth like with Medium Waves ...
i say this because from part of West & all North i have mountains (towards Europe) & from there i have the most DX contacts (yes ok Europe using way more CB's) ... & i have tried VHF dipole (yes at CB Band) car CB antenna & Boomerang, just the Boomernag is way better because is at the correct freqs to my eyes)

If they are correct i guess i am only DXing when the waves comes occasionally from about 20 degree & upper due to the mountains ... unless waves following the Earth shape at these Freqs like Medium Waves ... 
So i guess If i was by the sea level would have way more contacts at 10/11m, while VHF & upper Freqs will be the opposite (the higher Freqs more optical contacts so higher ground level for DX)

It is likely your European contacts are fairly high angle, in view of a restricted horizon. You may get some mountain diffusion effects from the edges of mountains but mainly not and much more rarely.

I do have some good news for you babis3g, after all you live on an island, if you go to the coastal road or on a beach with your boomerang or any vertical antenna (even the mag mount whip), and in this case a beach mounted 1/4 wave can work very well you will have a very good DX situation.

Look around you coast line and go to somewhere like

Angelokastro Paleokastrtites 490 83 This is high up and near sea. Look around coast for a good place that works for you, practical place. Maybe Ag. Georgios 490 83 nice beach. Like a radio heaven place. Set up with safety in mind first and foremost for you and others. Take very good care to not be near electrical cables etc. Or just find empty place in wilderness near the sea.

Only thing is sometimes you can get local/domestic QRM problem so sometimes it takes time to find a place that is good.

If you are close to a salt water body (the sea/ocean) you will achieve a free gain to your signal of about 9dB on TX and RX.

This is a little complex to explain but in short, salt water is to RF a type of "ground". Not just good or very good ground but exceptionally good ground because the surface skin of the water is partly conductive.

And you have an open horizon with no attenuation down to 1 degree.

And there is a phenomena on such a conducting sea water that pulls down your lowest angle of radiation significantly, this relates to the sum of 'in phase' reflections from the sea surface for radio signals coming in and going out from your antenna.

So if your antenna receives 10 Watts from your TX it will be similar to operating a transmitter at around 80 Watts approx. And it is also giving you 9dB gain on your RX.

If you get to the coast on a good day (you still need good conditions in the sky) you will have a DX day to remember.
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Probably only ever buy 1/2 waves for 10m and 11m Empty
PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeWed Apr 24, 2024 8:46 pm

thanks again for the deep explanation ...

will start regarding Silver Rod, is at my plan later to update to Silver or Sirio GPE 1/2 ... but  mentioned at an other post will need stronger mast .. personal i do believe ( & all know) will be better because antennas matches better CB Band Freqs (are longer)

Regarding the angle at 10/11m bands, will accept the tests done by the experts & the military etc ... 
BUT i have a small doubt because no matter what super miracles or phenomenon if want to call it happening to atmosphere is difficult for me to believe i am reaching ionosphere passing few layers D / F etc especially with 4 watts & vertical antenna (if was horizontal maybe & even that with 4W still have doubt is reaching that distance) & with mountains around me ... but is possible

The ones trying to reach the ISS all have beam antennas pointing to the satellite & perhaps way more than 4-7 watts & some they may not even reach it under normal conditions

Like under the sea there are few paths (a not detailed but huge example from Corfu going to Crete & from there to Gibraltar out of Mediterranean sea) must be same with atmosphere but with different conditions as electromagnetic waves traveling straight line, with out reaching top or deep atmosphere layers ... but that is my thinking, can not test ... maybe a silly idea of me ... so i do accept the test by the experts as they have a good back up/explanation on it

I did take a handheld last year at the top of mountain near Troumpetas mountain (middle of the island, not by the sea) & had no success perhaps the stock portable antenna was way too small (eurosonic es2000) even far can see the sea from so high ... but will try again later sometime when will have more free time at sea level (right next of it) as you saying, i know a few safe places away from electrics & people ... boomerang is hard to carry, i do not have car, but a car antenna is easy to deploy


Quote :
It is likely your European contacts are fairly high angle, in view of a restricted horizon. You may get some mountain diffusion effects from the edges of mountains but mainly not and much more rarely.

today managed to be heard at Russia (not mountains from that site) & nothing from EU (a head mountains), so what you have said regarding my EU contacts are at high angle seems correct as nothing came from there

Again Thanks for your detailed support & valuable time ... i appreciate for your help
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeThu Apr 25, 2024 8:18 am

Many contacts are made above 5-10 otherwise all the short dx would never be heard or worked
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeThu Apr 25, 2024 9:31 am

Not having a car is a bit of a problem for beach/mountain radio as is having a mountain range surrounding your QTH in some areas. Exact paths of any QSO can never be known with certainty. We can get some idea of broad direction from beam users headings. However even those may be misleading as the waves can bend/refract not only up/down but inside the F2 layer and exit at a new angle (and over multiple hops).

It is not quite a mirror reflection situation up there.. it is multiple interactions with ever less dense atmosphere with differing layers of charge maybe 10miles thick and eventually the waves are bent enough that the waves come back out of those layers back down to earth, this is why it is a lossy process.

Most of what hits mountains at below 10 degrees is dissipated/absorbed and goes nowhere, though I have of possible reflections from some hams. There is a possibility (rare conditions) where there can be enhanced tropo/sea paths but this does not happen often (not to be confused with just tropo). Those contacts will not have the audio profile (fading / phasing) of "skip" contacts so are easier to identify they happen rarely and would likely happen to just 1 or 2 countries local, maybe Italy east coast is most likely for yourself.

Think it all out, make it work for yourself. And maybe a Silver rod in your exact and unusual situation would not actually be better for you than the Boomerang (just a little more efficient as less coil losses) as you need a high angle take off to get into the sky before the mountains.

You now have the basic knowledge to test it, in the end it is a practical hobby with significant theory behind it. And propagation is still not very well understood, but we have some broad understanding that makes scientific sense.


I will add as an extended thought there is no certainty that if your signal goes in at say 30 degrees that it comes out at 30 degrees. This is really rather difficult to know and beyond my knowledge, it could possibly come out at 30-20 or 10 degrees ? My knowledge of those immensely complex interactions in the F2 layer is at its end at this point.

I do know that at times (typically summer) a long DX QSO may use both E and F layers and then we have very little clue what is happening. I find it one of the most fascinating aspects of the hobby.

In any event all these 1/2 wave vertical antennas will TX/RX signals 5-30 degrees quite nicely but there is no need to spend a load of money.


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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeThu Apr 25, 2024 9:45 am

chazwozza wrote:
Many contacts are made above 5-10 otherwise all the short dx would never be heard or worked

Sure and even a relatively poor antenna will work those angles but only high performance antennas will make and hold a contact at very low angles / low signal levels.

And those stations are often some of the most interesting, rarer, challenging, and distant.

So are a very worthy aim.

And you do not need to spend more than £55.00 for an antenna that can potentially do it very effectively and conveniently.
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeThu Apr 25, 2024 1:39 pm

Take a look at the page 33, graph bottom right of a DX path percentage of time vs elevation angle:

"Figure 2 — Composite probability of arrival angles."

https://www.arrl.org/files/file/QEX_Next_Issue/May-Jun_2011/QEX_5_11_Siwiak.pdf

It's pure physics and maths but unpredictable and changing every moment.

And to quote a pertinent paragraph:

"For example, the combined 80 m to 10 m arrival angle statistics between Florida
(FL) or Massachusetts (MA) and all regions of the World are shown
in Figure 2. Those statistics show that half the arrival angles are less than 6°,and that 90% of the arrival angles are smaller than 16°. So for HF cases, we will confine our interest to arrival angles between 2 to 16°"

That says a great deal in very few words.
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 28, 2024 8:39 am

To be fair modeling software is all well and good for working out antenna dimensions etc but it no way represents real world working conditions good luck with the 1/2 wave.
The way i see it any tiny gain is worth having it all adds up


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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeSun Apr 28, 2024 12:15 pm

I agree.

Modelling is only an idealized reference point. Nothing more than that it only serves a very basic purpose. It is not a real world antenna, but based on some real world inputs. None of that shown is a guarantee. It is only a broad starting point. Put a massive house, car, shed, different ground type, another antenna, fence, tower, any metal object within 10 meters etc. nearby and it has already changed the idealized suggestions.

We can come full circle and come back to the high likelyhood that a 1/2 wave is by no means second best, it is least fussy and likely to perform as good in the real world if not even better than the normal 5/8 end fed with substantial radials and 5/8 end fed dipole type in the absolute clear away from any objects (Gain Master style).

The extra 0.6dB 'gain' is only pattern gain, i.e. re-focus of the RF dispersion, but only if it can be achieved in a real world installation.

I reckon that gain will never be realized with a Gain Master unless you happen to have a pole in your garden 30 feet high with nothing closer than 10m to the antenna.

Anything in the so called "reactive nearfield" of an antenna means a model which includes 'pattern gain' is pie in the sky.

Here is further thought..

We have probably all seen huge 20dB over signals from DX every now and then.

That is a 74dB signal ! (notwithstanding the discussion between an S point being 6dB vs 3dB, it's a big signal let's agree on that.) compared to no skip at all at lower than S0 = close to a 0dB signal.

The only time you notice what a really good wire antenna is at the bottom end of the scale and on the very low angle contacts. So 7dB less pattern loss 'gain' at 5 degrees falls into insignificance with high signal levels but could be the difference between interesting DX or the sound of hiss at the other end.

Are we worried about the 20dB over 9 signals being only 13dB over 9 or are we worried about the S0 contact that will be the difference between a contact or hearing hiss ? Probably only ever buy 1/2 waves for 10m and 11m 1f44d
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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitimeYesterday at 9:41 am

I took my own advice and put a 1/2 GPS up, temporary on push up poles to 8 meters. Working good. 1.5:1 27 through 28MHz. I could probably improve that, nicely made classic antenna. I have had it here a while but only put it it together to test it out, now it can be put into service for some home DX whenever I wish.

I like that it does not have radials and not as tricky as a Gain Master type to set up in a temporary 'fancy a bit of DX this morning' situation.

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PostSubject: Re: Probably only ever buy 1/2 waves for 10m and 11m   Probably only ever buy 1/2 waves for 10m and 11m Icon_minitime

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