SIRIO SD 27 HEIGHT?

[Sonar]

I have my imax 2000 up in the air approximately 10' from feed point to ground.
It works surprisingly well.
My dx capabilities are excellent on SSB, but not so good on AM (unless conditions are very good.)
I recently decided to raise my 2000 to approximately 24 ft using a telescopic mast.
My reasons for wanting to raise it we're strictly to improve my DX capabilities on AM (which I've been enjoying more as of late). If the SD 27 will do what I'm hoping my 2000 will do (or better) at 24' I'd rather go with the SD 27.
With the help of a couple of site members I've decided to go with SD 27. I will be installing it in the horizontal position.
Instead of raising my 2000 to 24 ft it would be advisable for me to install the SD 27 exactly as I installed my 2000 and expected to do a better job while AM Dxing?
That would be on a non-penetrating roof mount with two 5ft masts.
In the opinion of those who know would the SD 27 do a better job dxing (especially on AM) at 10' then my imax 2000 at 24'? 100$ non penetrating roof mount, $150 120' of LMR 240 and $60 for the SD 27 is a an investment I don't mind making especially if the results for AM DX will improve. The 24' telescopic Mast is $160. I would have to purchase the lmr 240 anyway so the price difference between raising my 2000 or spending the money on the dipole, coax, and SD 27 is basically the same. I'd rather go with the SD 27 setup especially if it's going to do the DX job on AM that my Imax 2000 doesn't and or won't arrive 24'.
This is a clip of my my IMAX 2000 setup and the SD 27 would be put up exactly as the IMAX 2000 shown in the clip. Thanks for your input. 73 PS. Installing an antenna on my roof or anywhere on my homes structure is not possible.

 

[rabbiporkchop]

Hope this is useful.

 

[Sonar]

Hope this is useful.
View attachment 21361

 

[fourstringburn]

Raising the Imax higher will improve your antenna performance especially compared to being 10ft. above ground. If possible, it's best to get the feed-point of your antenna height 1 wavelength of it's intended frequency above ground. This would be 36ft. in your case. This makes it best for local work and still ideal for DX. However at 1/2 wavelength high, you can get a better take off angle which is better for DXing using vertical antennas.

If you are asking if the SD27 will work better at the current 10ft, I would say no.

If that Sirio antenna could be turned to be used as a horizontal antenna and you get it up to 36ft high, then you have an excellent Dx antenna but not so good for local. You would probably want to take advantage of using a rotor because horizontal antennas fire most of it's RF energy to the broadsides of the dipole. The cheap TV rotors would work fine.

 

[Sonar]

Raising the Imax higher will improve your antenna performance especially compared to being 10ft. above ground. If possible, it's best to get the feed-point of your antenna height 1 wavelength of it's intended frequency above ground. This would be 36ft. in your case. This makes it best for local work and still ideal for DX. However at 1/2 wavelength high, you can get a better take off angle which is better for DXing using vertical antennas.

If you are asking if the SD27 will work better at the current 10ft, I would say no.

If that Sirio antenna could be turned to be used as a horizontal antenna and you get it up to 36ft high, then you have an excellent Dx antenna but not so good for local. You would probably want to take advantage of using a rotor because horizontal antennas fire most of it's RF energy to the broadsides of the dipole. The cheap TV rotors would work fine.

A single 10-foot mast will put my iMax right at 18 ft give or take inches.
You're saying that the IMAX at 18 ft should give me better dxing capabilities then at its current 8 - 10 ft? I do understand a little about takeoff angle. Not much but enough to understand where you're going. So 18 ft should help me? This is definitely feasible.
I've heard about the dead points on horizontal dipoles and there's no possible way that I can actually spin an 18-foot horizontal antenna in such a small backyard. I'm not sure where I came up with the 18 ft.
What would be halfwave for my imax in height?.
The 18 foot horizontal is obviously not on the table any longer. There's no way I could get it anywhere near 36 ft.
If I could have I would have had the IMAX at the 36 feet and I won't be having these issues.
I take that back. They're not actually issues. My SWR is well within the acceptable range and the antenna gets out well. When I say gets out well I actually mean on SSb (while dxing.)
On AM I actually do well when the conditions are extremely good. LOL!
That's the problem. Whilst my locals with the same output and their antennas at the proper height or even higher are talking in the DX like they're talking to locals I'm struggling.
I may have mentioned it in a past post but I've been enjoying AM dxing a lot more as of late. I don't know if it's because I've actually never did any consistent AM dxing up until approximately two months ago, or I just preferred the talk style of single sideband. I guess since the cycle has disapated and conditions are really poor, i switched on my AM Set up and left it on for a couple of months. I would really like to avoid having to put up another antenna anyway and the fact that it's only going to be approximately the height of my IMAX it's going to basically be a waste of time and money (as members have convinced me this fact.) I'm not sure where I got that 18-foot number from. You only said half wave and I'm not exactly sure what half wave of my 5/8 IMAX is. I just assumed if a
full wave for a 5/8 was 36 feet halfwave would 18', but I'm not exactly sure of any of those numbers. If it's not 18 ft you're talking about when you mention half wave for my antenna what height will my IMAX do better at dxing besides the 36 feet it should be at? If it is 18-20ft then making that possible is a big
10-4! Any other advice on improving what I'm already using and the height that it's at (under 10ft) would be appreciated.Thanks 73 PS. As I mentioned I can get it to about a height of 20 ft. Anything above that is going to require guy wires. I have plenty of strong branches and bracing the tree using these heavy-duty bungees I have is doable. I can't draw anything into the trade self or wrap any type of metal strap around it either. The xyl gave that a big thumbs down. The tree belongs to her and an argument over an antenna is definitely not going to happen. She is cool with the bungee cord idea and after staring at the mast and picturing an added 10 ft I do believe the bungee cords and the pre-existing non-penetrating roof mount will do the job. I am enjoying the AMD Xing that I do do immensely, but I must say I'm still a stuttering fool when it comes to getting a qso going. The lingo on AM is definitely a different monster than that which is used on SSB.

 

[fourstringburn]

It's the height above ground at the antennas feed point(base of the antenna) that matters not the height to the antenna tip.

I mentioned horizontal antennas because they work best for long distances but they are mostly directional at both broadside ends so a rotor can really make use by aiming the signal where you want it.

It seems you are more interested in DX rather than local and it looks like that Sirio can be run horizontally which will give you a nice rotatable dipole using a rotor.

A dipole will work best at 1 wavelength above ground and your bi-directional.

AN omni-directional vertical for DX can work just as good at 1 or 1/2 wavelength above ground. Local groundwave is better at 1 wavelength.

If I was more interested in DX, I would consider going horizontal with a rotating dipole.

 

[fourstringburn]

I misread about you NOT being able to rotate a 18ft. dipole.

Before spending money on another antenna, get the base of your Imax up to 18ft at a minimum and with the locals, I'm sure you'll notice some difference.

 

[Sonar]

I misread about you NOT being able to rotate a 18ft. dipole.

Before spending money on another antenna, get the base of your Imax up to 18ft at a minimum and with the locals, I'm sure you'll notice some difference.

I will take your advice. It's definitely the easiest way to possibly improve my dxing capabilities especially on AM.
I have no problems with the locals as far as mean hearing them and then hearing me. The Palomar 300a Doug's help quite a bit. But obviously has nothing to do with my receive. if I can get an extra s unit on my receive side by increasing the height of my IMAX by 10ft that would be terrific. That would actually be worth it right there. If I were to gain an s unit on the other end that would be an added Plus. But the main point of raising it is definitely the DX end if it does better at 18ft than it does at 10 that will be the absolute icing on the cake. I actually heard a local who is using n a 99. He is also low to the ground from the feed point. I don't think as low as I am but definitely below the height and A99 should be. He added another 5' and now here's people that he either did not at all or had difficulty hearing before he added that extra 5 ft. Adding another 10 ft to my IMAX in definitely the easiest way for me to go and still feel confident that the occasional high wind storms we might have over here in New Jersey will not Bend what will essentially be two five foot masks and one 10ft mast. Maybe I should ditch the two five foot masks and go to 10 ft masts. I am not sure exactly how I will B fashioning the masts to the train but there will be some support holding it tightly against the strongest branch that exists on this particular tree. That branch is about 11 ft from the ground. Beside the non-penetrating penetrating roof mount that bracing to the tree at 11 ft will be the only support the antenna will have. Necessity is the mother of invention. We all know that. I will be doing some barbecuing over the weekend and while I'm back there I will look the train and the masks over and try to get an idea of the best way to brace the mast at least in one spot as there will be no guy wires. This non-penetrating roof mount with two 5ft maths and an IMAX on top of those did not move in 60 plus mile an hour winds. I'm sure I will figure out a way to brace the second masked to the strongest branch on the tree which is approximately 9 to 11 ft in the air. I would tend to believe that it being supported in that single spot at the height of about 11 ft will keep the masts from folding. Of course there's no guarantee. But I will do my best to have it stay exactly where I put it. I'm also lucky enough not to have any electrical wires above ground.

 

[fourstringburn]

Don't know if you'll pick up a full S unit, but you should get some noticeable gain on receive.

One thing to remember,
A simple dipole antenna at the right height and if fortunate to be over good conductive soil or salt water will be more effective than a 3 element beam at 10 ft over sandy soil.

So a better antenna doesn't always mean it'll be better if your still using the same height.

Good luck and let us know how you do!

 

[Sonar]

Don't know if you'll pick up a full S unit, but you should get some noticeable gain on receive.

One thing to remember,
A simple dipole antenna at the right height and if fortunate to be over good conductive soil or salt water will be more effective than a 3 element beam at 10 ft over sandy soil.

So a better antenna doesn't always mean it'll be better if your still using the same height.

Good luck and let us know how you do!

I'm glad I started this thread. I'm happy I asked the questions.
I never heard or read that a horizontal dipole actually had dead spots and works best when one is able to rotate it.
What I'm going to do is get two 10' masts. I'm going to leave the 5' mast that came with the non penetrating roof mount and is supported by it's quad pod, and using u-bolts attach the first 10' mast the leaghth of that 5' mast (from bottom to top)
With the imax 2000's mast attachment point will put at approximately 18'. Without guy wires anything over that height is not possible.
Even @ 18' I'm a bit concerned about high winds.
I will do my best to somehow support the second mast to the tree at about 12'.
The only (and better than nothing) is bracket or brace the mast directly to the tree.
I'm fairly confident the antenna and masts will stay put unless of course I get the rare 80 + mile an hour winds storm.
If that happens it might come down.
When I install the two 10' masts I'll see if there's more than one place where I can attach those masts directly to the tree.
Until then I'll enjoy the (AM) DX when the conditions are strong. Thanks to all who have helped.

 

[fourstringburn]

Dipoles are good antennas and many of us use them. I wouldn't say they have dead spots rather they have some weak sides. I run mine strung from north to south so the 2 broadsides are east and west. This gives me the strongest signal towards Europe to the east and Asia to the west and covers the most of the US well.

The weaker side is north to south but contacts are still possible and I have made many. This is why a rotable dipole or multiple dipoles facing different directions can be beneficial because you can direct the stronger part of your signal at will.

A vertical being omni-directional is nice for more complete coverage but a dipole ideally constructed and at the optimum height can be a bit more effective.

Your plans for your antenna sounds good. At 18ft with 12ft anchored like you said, it should be fine. Many people attach a 18ft mast to the eave of their house which can be around 14ft at the top of the A frame and stands year round without guy wires. After 18ft is when guy wires will most likely be needed if you want the antenna to stand up straight.

I did this once with an Imax before and it survived 60 mph winds.

Good luck with your project and let us know how it works for you!