vertical and horizontal transmission at same time

[Shockwave]

no,... it is NOT "ALL" polarizations when fed 90 out and Xpolarization.

this is basic turnstile antenna theory.

when 2 antennas are @ 90 degrees to each other and are fed 90 degrees out of phase and mounted horizontally the antenna is nearly omnidirectional on the horizontal plane.

When mounted vertically the antenna is directional to a right angle to its plane and is circularly polarized.

these antennas are normally used when working the FM sats, but, they can be used on HF with some success, go here: Circular Polarization on HF

We will have to disagree on this one then. Try various angles with a dipole when receiving a circular polarized FM broadcast signal. As long as the dipole remains broadside to the received signal, you can move the antenna from vertical to horizontal and not see any change in signal at any angle. There is not a peak at the vertical and horizontal points when the signal is truly CP.

You'll notice no where in the links you give does it suggest that a CP signal is only polarized at 90 and 180 degrees. In fact it explains that this system sets up a rotating electromagnetic field. This rotating field is present in all polarizations in TX and remains responsive to all polarities in RX. Depending on the orientation of the two elements, it's also possible to have a nearly omni directional CP signal. It's done every day on the FM band in designs like the ERI Rototiller.

 

[W5LZ]

And what you may not be accounting for is that is both transmitting and receiving stations are not using the same polarization there will still be losses. How much loss? I don't have the slightest idea, but it's noticeable. Circular polarization at HF is a waste of time and money. Play with it, see for yourself.
- 'Doc

 

[Shockwave]

And what you may not be accounting for is that is both transmitting and receiving stations are not using the same polarization there will still be losses. How much loss? I don't have the slightest idea, but it's noticeable. Circular polarization at HF is a waste of time and money. Play with it, see for yourself.
- 'Doc

The maximum loss would be 3 db compared to a matching linearly polarized signal. The gain could be as much as 20 db compared to a cross polarized linear signal. CP is not common on HF because of antenna size. However, many people already have the perfect dual polarity beams to for the CP array. The advantages of CP when working DX on HF are noticeable because the signal is always changing polarity while often suffering from multipath distortion and heavy attenuation from cross polarization.

 

[Henry HPSD]

Something to contribute to the discussion:

Horizontal antennas have a additional 6 dB from the groundgain (if it is up high enough).
Vertical antennas lack that additional gain.

Something i have been told by a propagation guy:
If the HF signal penetrates the inosphere the signal gets broken up in 3 parts:
1 the ordinary 2 the extraordianry en the Z component.
Due to the influence of the earth magneticfield each part gets a circulair polarisation.

The stronger the magnetic field (near south/north pole) the stronger the signal will rotate.

It has absolutly no advantage to place your antenna either vertical or horizontal from that perspective.
Any advantege that will be seen comes through the different take-off angles produced by the different polarisation.
(the same advantage one can have using different antenna heights).

The biggest loss is (as always) between the angle of propagation and the angle of radiation of the antenna.

So near the equator the rotation of the signal isnt that bad, near the magnetic poles it is not.

We cant "predict" which way the prop will go, but on the other hand im not so sure if we can actually "switch" that fast and keep up with the rotation of the signal.

So, im saying..it migth not be the polarisation which gives people the advantage..
Its the change in take-off angle for those who "claim" good results with theyre duo/quatro or what ever polarisation

Kind regards,

henry 19sd348
All about antennas

 

[Needle Bender]

I'm under the impression that it is always beneficial to transmit on horizontal but be able to shift between horizontal and vertical on receive.
What would happen if two opposing circularly polarized beams were co-phased? Would it just cause cancellation, or be beneficial in covering all possible angles and rotations?

 

[W5LZ]

Needle Bender,
Why would it be beneficial to always transmit horizontally and have the ability to change between vertical/horizontal polarization when receiving? That would be true only if the signal made a 'skip' change, polarization change... in both directions. Having the ability to make a polarization change when receiving is certainly nice, but without the ability to also make a polarization change when transmitting it would be a "one-way" benefit. Not always being a benefit to the person hearing/not hearing you. Unfortunately, propagation is not always reciprocal. Or, I'm simply not understanding what you're trying to say...
- 'Doc

 

[slateblue]

Hiya

Interesting conversation, I run a single quad, and use it on the CB band, 11 m and then 10 and 12 meters too. This antenna is vertically polarised to pull in the local vertical FM signals in the UK. Additionally, I use the same antenna on the 11 and 12 meter ham bands for DX. My results speak for them selves and this is a really good cheap and easy antenna with directional performance.

With regards to polarization, before the vertical quad, I ran a H delta-loop which was similarly very good for DX but possibly not as receptive to local signals. Indeed, the reason for changing antenna is to get more mass/wire in the air and to change the polarisation!

Circular polarised rf, will come from left-hand or right-handed helixes, whether or where the loop is fed does not matter. I have two HF mag loops here, one was bought the other constructed at home! The difference between L-Handed and R-handed circular polarisation may be compared to the difference between V or H polarisation, it's just symmetry in action! In fact, as mentioned by another peeps, if the signal is ground wave propagated then generally the V-polarised is used above 17 meters. For example, put up a H-dipole and you will not hear all the local V signals but you will hear the further sky wave propagated signal! Because, as previously mentioned, once the signal has been through the ionosphere the signal rotates and bends due to the charged particles and effects of the geomagnetic field.

Therefore, usually use V-polarised for local and mobile via ground wave, range will depend on propagation and location. But, for use H-polarisation when using sky wave propagation for DX and signals bounced through the ionosphere. However, H-polarised antennas give a better low angle radiation which will thus move through the ionosphere and be bent much easier than the same V-polarised signal! Lastly V-polarised signal still move through the ionosphere at the higher frequencies but, the angle of incidence is not as effective as H-polarisation because of the shape of the ionosphere, it like a flat layer!

 

[Needle Bender]

Doc, slateblue answered that better than I could

 

[Captain Kilowatt]

Hiya

Interesting conversation, I run a single quad, and use it on the CB band, 11 m and then 10 and 12 meters too. This antenna is vertically polarised to pull in the local vertical FM signals in the UK. Additionally, I use the same antenna on the 11 and 12 meter ham bands for DX. My results speak for them selves and this is a really good cheap and easy antenna with directional performance.

With regards to polarization, before the vertical quad, I ran a H delta-loop which was similarly very good for DX but possibly not as receptive to local signals. Indeed, the reason for changing antenna is to get more mass/wire in the air and to change the polarisation!

Circular polarised rf, will come from left-hand or right-handed helixes, whether or where the loop is fed does not matter. I have two HF mag loops here, one was bought the other constructed at home! The difference between L-Handed and R-handed circular polarisation may be compared to the difference between V or H polarisation, it's just symmetry in action! In fact, as mentioned by another peeps, if the signal is ground wave propagated then generally the V-polarised is used above 17 meters. For example, put up a H-dipole and you will not hear all the local V signals but you will hear the further sky wave propagated signal! Because, as previously mentioned, once the signal has been through the ionosphere the signal rotates and bends due to the charged particles and effects of the geomagnetic field.

Therefore, usually use V-polarised for local and mobile via ground wave, range will depend on propagation and location. But, for use H-polarisation when using sky wave propagation for DX and signals bounced through the ionosphere. However, H-polarised antennas give a better low angle radiation which will thus move through the ionosphere and be bent much easier than the same V-polarised signal! Lastly V-polarised signal still move through the ionosphere at the higher frequencies but, the angle of incidence is not as effective as H-polarisation because of the shape of the ionosphere, it like a flat layer!

Doc, slateblue answered that better than I could

Food for thought.

If the above is true then why is it that a simple ground mounted vertical can and often does beat a horizontal yagi at height on long haul DX? This has been noticed and repeated many times on the amateur bands? There are exceptions to almost every rule and simply stating that horizontal is better for TX'ing than vertical is one of those blanket statements that has many exceptions.

 

[slateblue]

Food for thought.

If the above is true then why is it that a simple ground mounted vertical can and often does beat a horizontal yagi at height on long haul DX? This has been noticed and repeated many times on the amateur bands? There are exceptions to almost every rule and simply stating that horizontal is better for TX'ing than vertical is one of those blanket statements that has many exceptions.

Hiya

It's simples, yes a plain vertical can beat a yagi which is 20 meters high. However, I think we need to consider spooky action at a distance......everything is possible but not always probable......that mobile vertical would not beat a high positioned yagi more that 1 time in a 100 or maybe a 1000. Remember, propagation through the ionosphere is chaotic in nature and, the electromagnetic spectrum, RF functions through quantum mechanics so everything is possible especially the in-probable but not all the time.......

Einstein called quatum mechanics spooky action at a distance......think maybe I can use that as my signature

 

[Captain Kilowatt]

Hiya

It's simples, yes a plain vertical can beat a yagi which is 20 meters high. However, I think we need to consider spooky action at a distance......everything is possible but not always probable......that mobile vertical would not beat a high positioned yagi more that 1 time in a 100 or maybe a 1000. Remember, propagation through the ionosphere is chaotic in nature and, the electromagnetic spectrum, RF functions through quantum mechanics so everything is possible especially the in-probable but not all the time.......

Einstein called quatum mechanics spooky action at a distance......think maybe I can use that as my signature

Nobody said anything about a mobile antenna. I said a ground mounted vertical. Think GAP Challenger DX, Butternut HF6V etc. A properly installed vertical has a VERY low take off angle allowing good DX performance.

 

[Needle Bender]

A properly installed vertical has a VERY low take off angle allowing good DX performance.

news to me. Read #6 "The severe aperture interference also causes the antenna to exhibit a high angle of radiation. It would be easier (and cheaper) to elevate the antenna far enough so that the aperture does not touch the ground. "

 

[Robb]

Isn't the definition of a vertical antenna as 'poorly radiating in all directions'?

Of course, receive/hearing in all directions has its advantages - and disadvantages too. It can be advantageous to hear in all directions with a omni-directional vertical; and then flip to a horizontal beam antenna to focus on the station that you want, as well as to reduce receive noise and get some usable gain in RX and TX.

I know that a 5/8 wl vertical will have a low angle of radiation; but I don't think that applies to a 1/2 wl vertical.

I originally thought this thread was concerned with a "V" quad and its 45 degree radiation phase. That is why I thought it would have receive and transmission loss due to the 45 degree phasing. My mistake.

Let the comments fly.

Picture below depicts 1/2 vertical radiator (dotted lines) as opposed to a 5/8 vertical radiator (solid lines):

 

[slateblue]

Hiya

Yeah, the mobile bit came from the fact, because antennas used in a mobile situation, mostly on higher frequency bands are thus vertical polarised so that it becomes easier to use the antennas with ground wave or local communications.

Please forgive me, if I painted a slightly confusing picture.:blush:

Recently, I used a FT-817 on battery with a Diamond 10 m antenna whilst using a mag mount to do some amazing DX so this has coloured my thoughts on the subject.

All though, the theory still applies to a 5/8 vertical on 12 to 10 mhz and a quad, but it would not matter because in the case of f2 propagation, this layer is upto 70 miles thick so the signal has many degrees of freedom to bend and thus change direction depending on local ionization values.

Anyway, unless your QTH has severe space constraints, if you are that keen then, why not just have two antennas? End of problem!

 

[wavrider]

Isn't the definition of a vertical antenna as 'poorly radiating in all directions'?

Of course, receive/hearing in all directions has its advantages - and disadvantages too. It can be advantageous to hear in all directions with a omni-directional vertical; and then flip to a horizontal beam antenna to focus on the station that you want, as well as to reduce receive noise and get some usable gain in RX and TX.

I:

Robb I did an antenna comparision yesterday with ZL1BI,

I have the IMAX 60" to the feed piint on top of the tower, The fan dipole 20/40/80 meters is at 56' to feed point.

The Imax RS was a 5-3 to Col using 100 watts.

The Fan dipole using the 3rd harmonic on the 40 meter leg was also an RS of 5-3 with the same 100 watts. The dipole is oriented so the major lobe works into EU and S. Pacific.

Verticals, If installed correctly, radiate rather well in all directions.

Try a 40 meter vertical for dx, ground mount it with say around 24 to 36 ground radials.

More times than I care to count the ground mounted vertical had a better RS report than the two element 40 meter yagi.

The yagi was at 70 ft up the tower, the vertical was 8 inches off the ground at the feed point. The vert was the go to antenna for working DX in EU.

A good vert is hard to beat especially on the lower HF bands.