A general question - why do we choose to run the two different polarities - ie vertical on FM and horizontal on SSB?
The reason I ask this is that over the past couple of years I have been running 2m from my mobile - FT817 - 5w into a helical wound vertical 5/8th wave.
One thing has become very apparent - FM is fantastic for repeater work BUT I find the 5w limits my range for being able to have reliable access - often I can hear the repeater several miles further away than I can access it.
Ok - I understand this and I fully appreciate the limititaions.
BUT - I have found that my range using SSB is around three times greater than it is running the same power on FM - and the cross polarisation of the two stations should have some effect - ie reduce the efficiency of the smaller mobile station.
Virtually all mobile stations will run vertical antenna - but home base stations usually run vertical for FM and horizontal for SSB.
It appears to me from the practical on air results that it would be beneficial for all uhf/vhf stations to run vertically polarised in both modes.
This would then increase the communications potential on the uhf/vhf bands - certainly the segregation of the wide and narrow modes needs to be observed - but there was something else that I noticed.
Running a bit of grunt from my home station using SSB horizontal creates some pretty obvious TVI - but when I run SSB with the same grunt vertical the TVI almost completely disappears. Of course I did note that every tv antenna that I can see is horizontally polarised so cross polarisation must have some marked effect in that regard.
So why do we run vertical and flat top? SSB is a fantastic mode for mobile uhf/vhf - with everyone running the same polarity we must surely double our potential user base across the whole band range rather than having the sort of "FM" only and "SSB" only divisions.
To be perfectly honest I have been amazed at just how good 2m SSB is for mobile use - and I could only see it get even better if the base stations were running the same big beams vertical - once the distance reduces to the point where it would need to rotate the beam at the home base then the home base would be well within range of the mobile and both stations could then switch to an omni directional antenna.
It just seems to be more practical to run everything on the one polarity.
From my home QTH I can run my beam vertical and open repeaters and talk simplex on FM to stations a long way away SIMPLY BECAUSE THAT IS WHERE I FIND THEM - some of those stations have been running all mode rigs and when we changed to SSB and stayed vertical the signals were stronger than the FM signals with the same power level - but when I changed to my horizontal antenna the other station would virtually fade out to barely readable.
Why do we run the two different polarities when obviously the one polarity would suti all modes - if we all run vertical in all modes mobiles would have far better coverage to base stations on SSB. The base stations being able to run large high gain beams have massive range both on tx and receive. The removal of cross polarisation from the equation just seems logical.
Any thoughts??
uhf/vhf antenna polarity
-
VK4TZL
Antenna Polarity
G'Day Kev,
An interesting post...here are a few thoughts for you to ponder.
Firstly, from what I have read and experienced, most man made noise at VHF is vertically polarised, so horizontal polarisation at least gives you a head start on trying to overcome noise.
Secondly, the mechanics of mounting long boom, vertically polarised yagis on a vertical metal mast/tower is a nightmare. I run a 17 element M Squared on 144, and around 37 elements on 432. Both antennas have the mast running through the antenna, but at right angles to it. The Mast diameter is about 60mm ( thick wall ally tubing ). Actually , the 432 Antenna is at the very top of the mast, in an effort to keep the mast away from the elements. A 60mm diameter piece of metal passing in the same plane as the elements, through the antenna would make a real mess of the pattern, especially as you go above 144 and the diameter of your mast becomes a significant part of a wavelength at 432/1296 etc.
You could of course, go to non metallic masts or use outriggers of fiberglass, but Oh, what an expensive exercise. You really want to keep ANY metal that is near the antenna at right angles to it, and of as small a diameter as you can get away with, safety and strength being considered of course. Sure, I've seen plenty of 144/432 Mhz Antennas, vertically polarised, with a great lump of mast between two elements, around the center of the antenna...it will still work, but you are really giving away gain and generally stuffing the whole thing
Some time ago I did source some 2 inch fiberglass tube when I was chasing the Holy Grail of antenna installations, but it was very heavy, and very expensive.
Thirdly...History...yep, it has been a given for so long that SSB is horizontal and FM is vertical..fullstop. I have read in various theory texts that horizontal WILL beat vertical on a side by side, weak signal path...and honestly, the reason/s given are long forgotten...but I may go and refresh the brain cells now that you have posed the question.
Long path ( say Hervey Bay to Gladstone/Rocky ) cross polarisation is a waste of time...I have tried it numerous times with Guys who have listened/called on vertical with the primarily FM Rig that had SSB capability, and it certainly proved the theory books correct. Having said that, I worked VK4KAY driving around Mackay last summer on 432 Mhz with 5/9 ++++ , Signals from my horizontal setup to his vertical whip...but very enhanced conditions.
I also imagine that most man made and geographical objects that attenuate and absorb RF are usually vertically polarised ( buildings, hills, trees and undergrowth etc..).
Trevor, 4AFL and myself have worked Linear ( Horizontal ) to Circular on 1296 ( 3dB down ) quite sucessfully on 1296 from here to Bris, but I would not even bother trying Horizontal to Vertical unless it was a spectacular opening.
And so endeth the sermon...
73
Glenn
VK4TZL
P S Someone get brave and ask Gordon, VK3ACC ( ex 2ZAB ). Have a chair handy.
An interesting post...here are a few thoughts for you to ponder.
Firstly, from what I have read and experienced, most man made noise at VHF is vertically polarised, so horizontal polarisation at least gives you a head start on trying to overcome noise.
Secondly, the mechanics of mounting long boom, vertically polarised yagis on a vertical metal mast/tower is a nightmare. I run a 17 element M Squared on 144, and around 37 elements on 432. Both antennas have the mast running through the antenna, but at right angles to it. The Mast diameter is about 60mm ( thick wall ally tubing ). Actually , the 432 Antenna is at the very top of the mast, in an effort to keep the mast away from the elements. A 60mm diameter piece of metal passing in the same plane as the elements, through the antenna would make a real mess of the pattern, especially as you go above 144 and the diameter of your mast becomes a significant part of a wavelength at 432/1296 etc.
You could of course, go to non metallic masts or use outriggers of fiberglass, but Oh, what an expensive exercise. You really want to keep ANY metal that is near the antenna at right angles to it, and of as small a diameter as you can get away with, safety and strength being considered of course. Sure, I've seen plenty of 144/432 Mhz Antennas, vertically polarised, with a great lump of mast between two elements, around the center of the antenna...it will still work, but you are really giving away gain and generally stuffing the whole thing
Some time ago I did source some 2 inch fiberglass tube when I was chasing the Holy Grail of antenna installations, but it was very heavy, and very expensive.
Thirdly...History...yep, it has been a given for so long that SSB is horizontal and FM is vertical..fullstop. I have read in various theory texts that horizontal WILL beat vertical on a side by side, weak signal path...and honestly, the reason/s given are long forgotten...but I may go and refresh the brain cells now that you have posed the question.
Long path ( say Hervey Bay to Gladstone/Rocky ) cross polarisation is a waste of time...I have tried it numerous times with Guys who have listened/called on vertical with the primarily FM Rig that had SSB capability, and it certainly proved the theory books correct. Having said that, I worked VK4KAY driving around Mackay last summer on 432 Mhz with 5/9 ++++ , Signals from my horizontal setup to his vertical whip...but very enhanced conditions.
I also imagine that most man made and geographical objects that attenuate and absorb RF are usually vertically polarised ( buildings, hills, trees and undergrowth etc..).
Trevor, 4AFL and myself have worked Linear ( Horizontal ) to Circular on 1296 ( 3dB down ) quite sucessfully on 1296 from here to Bris, but I would not even bother trying Horizontal to Vertical unless it was a spectacular opening.
And so endeth the sermon...
73
Glenn
VK4TZL
P S Someone get brave and ask Gordon, VK3ACC ( ex 2ZAB ). Have a chair handy.
-
VK4KKD
Re: Antenna Polarity
VK4TZL wrote: Firstly, from what I have read and experienced, most man made noise at VHF is vertically polarised, so horizontal polarisation at least gives you a head start on trying to overcome noise.
To be honest Glenn I find the noise levels to be exactly the same when switching polarities at any given moment - S5 of noise horizontal is S5 of noise vertical. At times the noise is such that neither polarity is usable. But the advantage of being able to work mobiles with really solid signals from the QTH-H with the vertical is the bonus.
Secondly, the mechanics of mounting long boom, vertically polarised yagis on a vertical metal mast/tower is a nightmare. I run a 17 element M Squared on 144, and around 37 elements on 432. Both antennas have the mast running through the antenna, but at right angles to it. The Mast diameter is about 60mm ( thick wall ally tubing ). Actually , the 432 Antenna is at the very top of the mast, in an effort to keep the mast away from the elements. A 60mm diameter piece of metal passing in the same plane as the elements, through the antenna would make a real mess of the pattern, especially as you go above 144 and the diameter of your mast becomes a significant part of a wavelength at 432/1296 etc.
I think this is more the crux of the issue - the "magic bullet" long boom yagi - but of course nowadays there are super plastics available very cheaply - for example I went to a plastics manufacturer looking for strong cheap formers for wire wound verticals - asked all the usual questions and received all the usual answers - I was just about to leave when the bloke had a lightbulb flash on top of his head. "I wonder if this stuff we make for the main roads people would be any good?" he mused "they cut the end of it to a point and are able to drive it through bitumen with a sledge hammer - they use it for temporary signs and stuff"
"Let me have a look at it" I said and he led me out into the factory to a pile of odds and sods near a big industrial bin - he dug around a bit and stood up with two 3.5m lengths of plastic pipe - just the perfect size for what I needed. He gave them to me for free.
I raced home and cut a thin slice of one and put it in the microwave - no melting or distortion. It is perfect for sliding into the end of a piece of 40NB blue end galvanised pipe and attaching vertically polarised yagis to. And he was right you can drive it into rock hard ground with a sledge hammer.
Being a quad user though I don't find any difference having the antenna vertical or horizontal as far as the interaction from metal objects goes - but I do make certain that the object is precisely half spaced between elements. On air I certainly can't see any difference except I save a bundle by not having to worry about the masting etc.
You could of course, go to non metallic masts or use outriggers of fiberglass, but Oh, what an expensive exercise. You really want to keep ANY metal that is near the antenna at right angles to it, and of as small a diameter as you can get away with, safety and strength being considered of course. Sure, I've seen plenty of 144/432 Mhz Antennas, vertically polarised, with a great lump of mast between two elements, around the center of the antenna...it will still work, but you are really giving away gain and generally stuffing the whole thing
Some time ago I did source some 2 inch fiberglass tube when I was chasing the Holy Grail of antenna installations, but it was very heavy, and very expensive.
Thirdly...History...yep, it has been a given for so long that SSB is horizontal and FM is vertical..fullstop. I have read in various theory texts that horizontal WILL beat vertical on a side by side, weak signal path...and honestly, the reason/s given are long forgotten...but I may go and refresh the brain cells now that you have posed the question.
Hmmmmmmmm - the magical mysteries of radio - for so long I have seen folded dipoles of up to 100mm used for 2m yagis - and read goodness knows how many articles that point out that the distance between the conductors is not critical so long as the distance remains constant - now it seems that was all wrong and yagis can't work if the folded dipole is not reduced to a small bend at the ends. I think a lot of commercial antenna manufacturers must have red faces to find out they have been selling antennas that can't work hi hi.
I think for every subject we can raise in amateur radio there will always be different voices extoling the +/- of this or that. About the only thing that seems to be consistent is the inconsistency LOL!
I just spent the whole day today bending and trying folded dipoles of various sizes - the correct tip to tip length - just different size bends.
I did a simple test with a signal strength meter mounted on a fiberglass pole that spun around a 360 degree circle centered on the center of the boom of the antenna - on the same plane of course. With the same power input there was zero difference in the signal on the meter from dipoles down as small as 12mm between the conductors right up to 90mm between them. Why is it so? According to Hoyle the wider spacing should not work anywhere near as well as the small spaced dipoles. But of course there was a flaw in my method and that's how it is all made magical. Really though - who gives a rats black a**e if the antenna works.
Long path ( say Hervey Bay to Gladstone/Rocky ) cross polarisation is a waste of time...I have tried it numerous times with Guys who have listened/called on vertical with the primarily FM Rig that had SSB capability, and it certainly proved the theory books correct. Having said that, I worked VK4KAY driving around Mackay last summer on 432 Mhz with 5/9 ++++ , Signals from my horizontal setup to his vertical whip...but very enhanced conditions.
I also imagine that most man made and geographical objects that attenuate and absorb RF are usually vertically polarised ( buildings, hills, trees and undergrowth etc..).
Trevor, 4AFL and myself have worked Linear ( Horizontal ) to Circular on 1296 ( 3dB down ) quite sucessfully on 1296 from here to Bris, but I would not even bother trying Horizontal to Vertical unless it was a spectacular opening.
I am currently going through every article I can find on parabolic dishes. I was not going to bother too much with 1296 from the home QTH and was mainly going to concentrate on working it portable - but after reading a bit on the parabolic dish I have an idea for a dish that I will be able to fold away - sort of like the shutter on a SLR camera - or an umbrella - using my new hydraulic tower in a short version - only 6m high when up - but with a 4800mm dish - using the fine woven mesh from Melwire. I think the perfect way to get the form correct is to do it with either steam explosion or compressed air - once the formers are shaped the mesh would be attached and the whole thing made so it will fold into the space of one segment. I am still drawing up the design and working through the mechanics of it. Wind loading is the killer though and I doubt it could be deployed at much over 60kph - even then deflection could be a problem. But the only other option is to go with a smaller dish which can't fold away. Or mutiple beam antennae and run with the reduced gain.
And so endeth the sermon...
73
Glenn
VK4TZL
P S Someone get brave and ask Gordon, VK3ACC ( ex 2ZAB ). Have a chair handy.
-
VK2YDD
"Virtually all mobile stations will run vertical antenna - but home base stations usually run vertical for FM and horizontal for SSB."
Why don't you use a halo antenna when mobile. Have a vertical on one side and the halo on the other. Then you will have the best of boths worlds. I think there is a picture on Davids VK2BA's website with his halo mounted on his car many years ago..
Cheers Dom VK2YDD
Why don't you use a halo antenna when mobile. Have a vertical on one side and the halo on the other. Then you will have the best of boths worlds. I think there is a picture on Davids VK2BA's website with his halo mounted on his car many years ago..
Cheers Dom VK2YDD
-
VK4TZL
Antenna Polarisation
G'Day again Chaps,
You make some interesting points Kev, and I was dredging around the Web last night and found Cubex..who make and sell Quads for HF/VHF. I noticed that they use F/Glass Mast supports for their VHF/UHF Antennas. A Hint perhaps that having metal poking up "inside" the Quad is not a good idea.
Likewise as for a Yagi, but tolerated if the Metallic support is at right angles to the plane of the antenna, and is not significantly large.
Having watched what Fluidmotion ( SteppIR ) went through when desinging their range of Antennas, we are all assuming a lot. They used a purpose built Antenna Test Range, with large supports to get the Antenna away from the earth, calibrated Test Antennas and calibrated receivers.
The rest of use...unless you have a very large area free of any obstructions, and some pretty fancy test gear...are really guessing with a lot of our constructions. I have made all my antennas over the years on VHF/UHF ( All Yagis ) until 2004 when I erected some M Squared Yagis. My homebuilts all worked, and I managed low SWR's and made contacts. I did have some missgivings about the method of construction, as I pop rivetted the elements to a square boom...great when the thing is new, but I could see corrosion slowly turning the thing into an air cooled Dummy Load over time, so the M Squared's, that use insulated elements, appeared to be the way to go.
I never had the opportunity, or the room for that matter, to run my homebuilts against the M Squared...and this really is the crux of all antenna home construction...it works, but is it working as well as designed ?
Likewise, I do not really have the room to try Vertical 17 elements against horizontal in a comparison for signal strength and noise, and success over known weak signal long paths...and I would need a Buddy at the other end to do likewise to achieve any meaningful results. Interstingly, being behind all the Brissy Stations when they are Txing South in the Mornings on the A/E Net, I can hear some of you " off the back " much better than others...does this mean, some have poorer F/B Ratios, better Sites ( i.e F/B is OK but my Antennas can see their's better than another QTH ) or does the path change that much from Site to Site ?
Kev, you are always reasonably weak at this QTH, compared to John or Greg...are those Quads better F/Back performers than the other Guys Yagis, or is your QTH a poorer shot from here than the other QTH's ????
There is a lot of guess work going on here...I don't think any of us really knows if our current aluminium collection is working as well as it can !
Going from 10 elements to 17 elements did not, in my imagination, make that much difference when I try to work Neil, 2EI. I have seriously been considering going back to 4 stacked 9 element Yagis, to reduce my turning radius and backlash on my rotator on windy days with the 17 element monster. I priced M Sqaured, but nearly fainted...so it will be DL6WU home construction...or maybe I should try 4 stacked 9 element Quads from you...an interesting thought and maybe you would like to give me a price...seriously !
I have spent some time ( lots of time ) agonising over if I have "the best" antenna farm I can construct, given my situation...no doubt you have to.
If we could get some other interested party at a fair distance who would be prepared to go with vertical for a while , it would be an interesting exercise...but I then come up against the Mast problem, with it intruding into the antennas apeture. It would be a waste of time turning the 17 element antenna to vertical...the Mast would bugger the thing totally.
You really need an H Frame of non metallic design ( that plastic you came across ) mounted to your mast, and then you can go either way without fear of screwing things up.
These Antennas are great time wasters Kev !
73
Glenn
VK4TZL
You make some interesting points Kev, and I was dredging around the Web last night and found Cubex..who make and sell Quads for HF/VHF. I noticed that they use F/Glass Mast supports for their VHF/UHF Antennas. A Hint perhaps that having metal poking up "inside" the Quad is not a good idea.
Likewise as for a Yagi, but tolerated if the Metallic support is at right angles to the plane of the antenna, and is not significantly large.
Having watched what Fluidmotion ( SteppIR ) went through when desinging their range of Antennas, we are all assuming a lot. They used a purpose built Antenna Test Range, with large supports to get the Antenna away from the earth, calibrated Test Antennas and calibrated receivers.
The rest of use...unless you have a very large area free of any obstructions, and some pretty fancy test gear...are really guessing with a lot of our constructions. I have made all my antennas over the years on VHF/UHF ( All Yagis ) until 2004 when I erected some M Squared Yagis. My homebuilts all worked, and I managed low SWR's and made contacts. I did have some missgivings about the method of construction, as I pop rivetted the elements to a square boom...great when the thing is new, but I could see corrosion slowly turning the thing into an air cooled Dummy Load over time, so the M Squared's, that use insulated elements, appeared to be the way to go.
I never had the opportunity, or the room for that matter, to run my homebuilts against the M Squared...and this really is the crux of all antenna home construction...it works, but is it working as well as designed ?
Likewise, I do not really have the room to try Vertical 17 elements against horizontal in a comparison for signal strength and noise, and success over known weak signal long paths...and I would need a Buddy at the other end to do likewise to achieve any meaningful results. Interstingly, being behind all the Brissy Stations when they are Txing South in the Mornings on the A/E Net, I can hear some of you " off the back " much better than others...does this mean, some have poorer F/B Ratios, better Sites ( i.e F/B is OK but my Antennas can see their's better than another QTH ) or does the path change that much from Site to Site ?
Kev, you are always reasonably weak at this QTH, compared to John or Greg...are those Quads better F/Back performers than the other Guys Yagis, or is your QTH a poorer shot from here than the other QTH's ????
There is a lot of guess work going on here...I don't think any of us really knows if our current aluminium collection is working as well as it can !
Going from 10 elements to 17 elements did not, in my imagination, make that much difference when I try to work Neil, 2EI. I have seriously been considering going back to 4 stacked 9 element Yagis, to reduce my turning radius and backlash on my rotator on windy days with the 17 element monster. I priced M Sqaured, but nearly fainted...so it will be DL6WU home construction...or maybe I should try 4 stacked 9 element Quads from you...an interesting thought and maybe you would like to give me a price...seriously !
I have spent some time ( lots of time ) agonising over if I have "the best" antenna farm I can construct, given my situation...no doubt you have to.
If we could get some other interested party at a fair distance who would be prepared to go with vertical for a while , it would be an interesting exercise...but I then come up against the Mast problem, with it intruding into the antennas apeture. It would be a waste of time turning the 17 element antenna to vertical...the Mast would bugger the thing totally.
You really need an H Frame of non metallic design ( that plastic you came across ) mounted to your mast, and then you can go either way without fear of screwing things up.
These Antennas are great time wasters Kev !
73
Glenn
VK4TZL
-
VK4KKD
Dom, have considered the option - problems arise with the mounting on my vehicle as I do not want to roof mount (I have a van which is already a drama at some undercover parking lots) and mounting on the nudge bar would mean fitting some sort of elevated mount and that's not an option.VK2YDD wrote:"Virtually all mobile stations will run vertical antenna - but home base stations usually run vertical for FM and horizontal for SSB."
Why don't you use a halo antenna when mobile. Have a vertical on one side and the halo on the other. Then you will have the best of boths worlds. I think there is a picture on Davids VK2BA's website with his halo mounted on his car many years ago..
Cheers Dom VK2YDD
About the only good reason I can see for horizontal mounting at the home QTH is the problems associated with mounting long boom yagi arrays vertical polarised - on air testing of both options have shown marginal differences in manmade noise levels between the two polarities at any given moment (except when someone drives by in a VW - then the vertical registers a better pick up of the hash from the electrics of the old banger). Power line noise levels are the same.
-
VK4KKD
Re: Antenna Polarisation
Glenn - time wasters for sure mate hi hi!
I have tried non conductive masting and found that providing the metallic masting was precisely mid way between elements there was no change in the polar plot. Moving off the mid point did produce unwanted lobes.
Apart from feedline losses, which can be overcome, the stacking/baying of shorter antenna arrays certainly has its place. The getting rid of guys and trusses for one thing.
F/B may be the cause - but conditions and topography more than likely play a big role. I have a rise immediately to my North which is close enough to but a damper on my signals to the North - but your signal to me can be S5 when I am looking South and then it rises to 40 over 9 when I turn the antenna around to the north - so I suppose during certain propagation conditions the F/B does play a big role. More so of course when I was running the two phased 10el quads - but I cut three elements off them so I could get them into the van and now only run a single 7el - and I must say it is far from an optimum condition as it was built for satellite work and a 50ohm feedpoint. I am in the process of building my SSB array which will consist of a pair of matched Delta Loop beams which will only have 6el each but they will be 100ohm feedpoints and optimised to give a lot more forward gain than the 50ohm ones. F/B will still be reasonable and in a sparse ham populated place like Australia the F/B is not such a major issue.
If you wish to home brew some yagi with insulated elements Glenn just get Stauff blocks - VK4JMC set us onto them as an ideal way of mounting insulated elements.
Some people frown on me for using full wave loops - but on air I can't really see any vast improvement of those using long boom stacks over my little short boom quad - I hear people at exactly the same S indication as other stations and get similar reports back from far field stations. I have a manageable antenna that is just over 2m long - mind you the 100ohm deltas loops will be 3.1m long so I won't be able to stick them in the back of the van for taking portable - so I will probably build a couple of 5el jobs for portable - they give plenty of gain and no problems.
To me it seems like common sense to use the full wave loops - after all doing more with less is what is all about and the KISS principle never had a better home than ham radio
[/b]
I have tried non conductive masting and found that providing the metallic masting was precisely mid way between elements there was no change in the polar plot. Moving off the mid point did produce unwanted lobes.
Apart from feedline losses, which can be overcome, the stacking/baying of shorter antenna arrays certainly has its place. The getting rid of guys and trusses for one thing.
F/B may be the cause - but conditions and topography more than likely play a big role. I have a rise immediately to my North which is close enough to but a damper on my signals to the North - but your signal to me can be S5 when I am looking South and then it rises to 40 over 9 when I turn the antenna around to the north - so I suppose during certain propagation conditions the F/B does play a big role. More so of course when I was running the two phased 10el quads - but I cut three elements off them so I could get them into the van and now only run a single 7el - and I must say it is far from an optimum condition as it was built for satellite work and a 50ohm feedpoint. I am in the process of building my SSB array which will consist of a pair of matched Delta Loop beams which will only have 6el each but they will be 100ohm feedpoints and optimised to give a lot more forward gain than the 50ohm ones. F/B will still be reasonable and in a sparse ham populated place like Australia the F/B is not such a major issue.
If you wish to home brew some yagi with insulated elements Glenn just get Stauff blocks - VK4JMC set us onto them as an ideal way of mounting insulated elements.
Some people frown on me for using full wave loops - but on air I can't really see any vast improvement of those using long boom stacks over my little short boom quad - I hear people at exactly the same S indication as other stations and get similar reports back from far field stations. I have a manageable antenna that is just over 2m long - mind you the 100ohm deltas loops will be 3.1m long so I won't be able to stick them in the back of the van for taking portable - so I will probably build a couple of 5el jobs for portable - they give plenty of gain and no problems.
To me it seems like common sense to use the full wave loops - after all doing more with less is what is all about and the KISS principle never had a better home than ham radio
[/b]
Re: Antenna Polarisation
Hmmmmm..what a good idea...strange it never even crossed my mind. Have seen and used Stauff pipe clamps/supports in industry for a long time and never gave it a thought.VK4KKD wrote:
If you wish to home brew some yagi with insulated elements Glenn just get Stauff blocks - VK4JMC set us onto them as an ideal way of mounting insulated elements.
The gems of useful idea's obtained from these forums..great.
73 Phil...VK6ADF
-
VK4KKD
Re: Antenna Polarisation
VK6ADF wrote:Hmmmmm..what a good idea...strange it never even crossed my mind. Have seen and used Stauff pipe clamps/supports in industry for a long time and never gave it a thought.VK4KKD wrote:
If you wish to home brew some yagi with insulated elements Glenn just get Stauff blocks - VK4JMC set us onto them as an ideal way of mounting insulated elements.
The gems of useful idea's obtained from these forums..great.
73 Phil...VK6ADF
Phil,
They do make for a very neat job - various ways to fit them - but to me it seems neat and tidy to drill the boom and tap it to 5mm to begin with - use stainless machine threads - then if wear and tear comes into play and a thread is stripped you can then go to a 6mm thread - finally if needs be you can drill right through the boom and use nylocs. Simple easy and cheap - and they do make for a neat yagi if that is your desire. The DE can easily be mounted using 4 of the Stauff blocks and fitting a short piece of fiberglass into the ends of the DE then drill to suit some 4mm stainless hardware to attach the balun and coax - a bit of silastic to waterproof the feeder and bingo. The KISS principle in action!
-
VK4TZL
Antenna Polarity
Excuse my ignorance...but what exactly is a " Stauff B;ock " and where do you get them ?
73
Glenn
VK4TZL
73
Glenn
VK4TZL
Re: Antenna Polarity
Hi Glenn...have a look at this link for a PDF on them...VK4TZL wrote:Excuse my ignorance...but what exactly is a " Stauff B;ock " and where do you get them ?
73
Glenn
VK4TZL
http://www.miningandhydraulics.com.au/p ... Clamps.pdf
As to where to get them....Perhaps Kev can fill you in seeing he is in the same state and there may be a local supplier...I have never bought any myself just used them in industry.
73 Phil...VK6ADF
-
VK4TZL
Antenna Polarity
Ahh...Thanks Phil...I'll go find a Hydraulics place and see what they have.
73
Glenn
VK4TZL
73
Glenn
VK4TZL
-
VK2KRR
I did pose this same question a long time ago, but now have both vertical and horizontal arrays on 2m from home.
I dont find much difference in realtion to noise either and at times horizontal is worse.
I find it easier to mount multiple vertical yagis, but to have a very long boom in vertical would be difficult with element interference and boom supports. Single verticals need to be spaced away from the vertical mast.
I've worked a repeater over 2800 Km away on 2m vertical, so polarity dont make a difference for distance as long as each end is the same (with tropo).
I dont find much difference in realtion to noise either and at times horizontal is worse.
I find it easier to mount multiple vertical yagis, but to have a very long boom in vertical would be difficult with element interference and boom supports. Single verticals need to be spaced away from the vertical mast.
I've worked a repeater over 2800 Km away on 2m vertical, so polarity dont make a difference for distance as long as each end is the same (with tropo).
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VK4KKD
G'day Leigh,VK2KRR wrote:I did pose this same question a long time ago, but now have both vertical and horizontal arrays on 2m from home.
I dont find much difference in realtion to noise either and at times horizontal is worse.
I find it easier to mount multiple vertical yagis, but to have a very long boom in vertical would be difficult with element interference and boom supports. Single verticals need to be spaced away from the vertical mast.
I've worked a repeater over 2800 Km away on 2m vertical, so polarity dont make a difference for distance as long as each end is the same (with tropo).
I have been gobsmacked at just how good 2m SSB is from the mobile running 5w into a vertical whip - it just seems we are really wasting a terrific potential by not using SSB more in the vertical polarisation for mobile to home base comms. The contacts I have had have been from me vertical to home base horizontal - if we elliminated the cross polarisation attenuation those contacts could have gone from just plain terrific to supercaliphragilistic expialidotious!
And yes long distance FM vertical is no problem - so why the heck are we not making full use of the stations that are mobile with SSB by using a vertical for SSB from home - seems like a good way to expand the air time - rather than trying to cope with the pills and ointment brigade on the repeaters.
Hope to get some serious distance 23cm soon - 2.3m dish will be set up on one of my trailer mounts for hilltopping - if possible I will try to organise a trip during the spring/summer to activate some gridsquares.
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VK4CZ
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A alternative to Stauff can be found at DX Engineering - see http://www.dxengineering.com/Sections.a ... tID=33#Top
Yeah very similar and probably cheaper than Stauff (not knowing exactly how much Stauff are). Off the subject of Stauff and it's clones, last time I looked at a ATN Antenna's catalog they sold the plastic antenna insulators like they use on their antenna's so I guess for a neat job thats another possibility. (if they still do..not seen a catalog of ATN for about 5 years but I presume they do.)VK4CZ wrote:A alternative to Stauff can be found at DX Engineering - see http://www.dxengineering.com/Sections.a ... tID=33#Top
73 Phil...