My Lightning 6 Quad antenna

[Captain Kilowatt]

I also need to consider the feasibility of installing this on the tower. I plan it to put it above a which is above a 5 element 20 meter yagi all on an 88 foot Rohn 45g mounted on a Voyager hazer.

What do you think?

I think I would like to see an engineering report on your mast. Seriously? An iMax 2000 mounted about nine or ten feet above the quad boom (you said 3 feet above the tip of the diamond which is a little over 6-7 feet from the boom) which is mounted above a 19 element 2 meter yagi which is mounted above a 5 element 20 meter yagi? I also think you should study wind dynamics. Altering the pattern is by far the least of your worries.

 

[Road Squawker]

... the quad boom which is mounted above a 19 element 2 meter yagi which is mounted above a 5 element 20 meter yagi....

I was wondering if anyone else was gonna catch that

 

[jessejamesdallas]

Hello all, I pulled the trigger on a Lightning L4+ today. I'm looking for input as to whether it is worthwhile to try to put my iMax above the quad. I can probably get it a maximum of 3' above the top of the diamond but I don't want to take a chance of deforming the quads pattern if this is a questionable practice. Any input is appreciated. thanks, dennis

Wish I had seen this thread before you bought that L4...I had one...(There's pictures of mine on Lightnings web site, under "Quad Testimonials") and had it up for little over a year or so before Mother Nature turned it into a pretzel...

Don't get me wrong, they are great antenna's, but the problem is with the wires Lighting uses. On mine, the wire was constantly breaking at the little eyelet's on the ends where there's a screw that holds the wire to the spreaders...(due to high winds from thunderstorms) Think I had to lower mine at least a half dozen times to fix the wires...(usually it was the driving element wire, but the reflector wire also broke once)

Another problem with Lightnings Quads, is these set screws they send to mount the spreaders onto the spreader holders...They are "suppose" to go in at a angle in this pre-drilled hole and somehow magically put tension on the spreaders to keep them from moving...Good luck with that! After several calls to Lightning, I decided to ditch the set-screws that came with the antenna, and drill small holes threw the spreaders and use small bolts and nuts to secure...you'll see what I'm talking about when you start assembling the spreaders...

What did it in was a storm that broke a wire, then the wire got tangled up on the tower, and ended up snapping one of the spreaders...Instead of fixing it again I decided it was time to just replace it with something stronger, so I bought a MaCo Shooting Star since that was the closest thing to the L4...Haven't had to fix anything yet on the MaCo, and it's been up now going on 2 years...Can't tell any difference between the two as for as signal strength go's...The MaCo did tune a little better and easier than the L4.

One reason I bought the L4 was because it's light weight, and was not too big a problem to raise the tower with it. The MaCo weighs about 10 pounds more than the L4, and when raising the tower with it, that extra 10 pounds feels more like 50 pounds! lol

One other thing...I would ditch the idea of having another antenna above the L4...If you just want to have a ground plane antenna also, stick it on a different pole 30' (or farther) away from the L4

 

[Marconi]

Praying you will be able to keep your word not to be up and down over and over again trying to figure out what effects what, or if it is the antenna you got wrong or something else in the vertical antenna farm you tell us about.

My buddy that has as an L8+ has not responded to my email as yet and he has had time so I don't have answers for some of you questions.

I have no real experience with the SE L4+ Quad, but my model of a Horizontal polarized 5 element Quad shows little effects to match, angle, pattern, or gain...with an Imax added about 3' feet higher than the highest point on the model.

That said, however, my model also has a choke added, that was badly needed at 36' feet. I did not remove the choke from the model to check if the choke was enough to mitigate the CM currents after adding the Imax. My traditional Quad model is also a current fed design and if that makes any difference...I'm!

Let me know if the manual you get is not similar to one of the two I emailed you, OK? I would be interested to know the difference.

 

[Marconi]

1st file Quad model without the Imax added to the model, with and without choke added.

2nd file the same Quad with the Imax added to the model, with and without choke.

Take note of the magnitude of the red lines for currents on the mast for these models. Those lines suggest the common mode currents that may develop on this Quad model.

 

[dennis4040]

I think I would like to see an engineering report on your mast. Seriously? An iMax 2000 mounted about nine or ten feet above the quad boom (you said 3 feet above the tip of the diamond which is a little over 6-7 feet from the boom) which is mounted above a 19 element 2 meter yagi which is mounted above a 5 element 20 meter yagi? I also think you should study wind dynamics. Altering the pattern is by far the least of your worries.

Hi CK glad you asked this gives me a chance to double check the numbers.
First 10' out of the tower is where the 20m and 2m antennas are mounted. It is 2" with .25" wall. Don't know the exact specs because I bought it used but I'm guessing it is at least 95,000 yield because it was holding up a 40' 3" boom 7 element 7 band quad plus the 2m antenna for 7 years in west Dallas where I bought it. It is however the weak link as you can see from the images I will post. Total mast ~75 mph max wind speed. I'm hoping it might be 100,000 yield. I know,, hope is not a good plan.
The next section is 3"x6' .5" wall T6 aluminum 38,000 yield. Attached by reaming for good fit to 2" mast with 12" overlap and 8 - 7/16" stainless bolts cinched against the mast. This is the way my Alpha Spid rotator is attached and it works great.
The next 2 sections are 2"x6' .25" wall T6 reamed for tight fit and secured with a 2.5"x12" .25" wall coupler using 8 1/4" stainless bolts on four quadrants and epoxied. Mast calculator shows 90 mph rating on this 11.5' section.
I've dropped the idea of a vertical above the quad.
I plan to use 2.5' of 1.5" out the top and phillystran to prevent boom sag unless I can determine that is not a problem with the L4+.
I hate boom sag.

 

[dennis4040]

Wish I had seen this thread before you bought that L4...I had one...(There's pictures of mine on Lightnings web site, under "Quad Testimonials") and had it up for little over a year or so before Mother Nature turned it into a pretzel...

Don't get me wrong, they are great antenna's, but the problem is with the wires Lighting uses. On mine, the wire was constantly breaking at the little eyelet's on the ends where there's a screw that holds the wire to the spreaders...(due to high winds from thunderstorms) Think I had to lower mine at least a half dozen times to fix the wires...(usually it was the driving element wire, but the reflector wire also broke once)

Another problem with Lightnings Quads, is these set screws they send to mount the spreaders onto the spreader holders...They are "suppose" to go in at a angle in this pre-drilled hole and somehow magically put tension on the spreaders to keep them from moving...Good luck with that! After several calls to Lightning, I decided to ditch the set-screws that came with the antenna, and drill small holes threw the spreaders and use small bolts and nuts to secure...you'll see what I'm talking about when you start assembling the spreaders...

What did it in was a storm that broke a wire, then the wire got tangled up on the tower, and ended up snapping one of the spreaders...Instead of fixing it again I decided it was time to just replace it with something stronger, so I bought a MaCo Shooting Star since that was the closest thing to the L4...Haven't had to fix anything yet on the MaCo, and it's been up now going on 2 years...Can't tell any difference between the two as for as signal strength go's...The MaCo did tune a little better and easier than the L4.

One reason I bought the L4 was because it's light weight, and was not too big a problem to raise the tower with it. The MaCo weighs about 10 pounds more than the L4, and when raising the tower with it, that extra 10 pounds feels more like 50 pounds! lol

One other thing...I would ditch the idea of having another antenna above the L4...If you just want to have a ground plane antenna also, stick it on a different pole 30' (or farther) away from the L4

JJ thanks for the input, you make some excellent points.
I have also heard that the spreaders wear from movement in the mounts. I was thinking of using silicone of some sort to eliminate that as someone else posted somewhere. Did drilling through seem to weaken them?
Sounds like the spreaders are strong enough if they don't get tangled with a broken wire?
I have been conversing with someone in Canada that has an L2 that says his has held up to ice/snow combo very well so far and he has now ordered the L4+.
They are using 13 gauge wire now is that what yours had?

Yes I have a small tilt tower and every pound you add makes a big difference tilting it up. This is on an 88' 45g with a Voyager hazer. The total weight of antennas, rotor, and mast will be about 175 LB, which is still less than the Quad that used to be on it.
Thanks for the input, looking forward to further comments.

 

[Marconi]

Dennis I can't comment on your numbers, but I've played with my model that has the Imax, and in making the Imax the live element its pattern shows to be skewed badly with the antenna 3' feet above the tip or with the Imax mounted to the boom.

I think my buddy with the L8+ uses a 4 way type standoff boom support and I would assume it does not interfere with functions. In fact I think this support comes in the kit.

I don't know if the L4+ will need 4 way support but I would recommend up and down (sag) support. I don't like boom sag either, and I saw it when I ran a 4 element horizontal only using a Moonraker boom. Before going up with the antenna I thought the MR'r boom material looked pretty sturdy and it had a nice long heavy duty center support for the tips.

I took it down a fixed it with guyed support using wire and some lightweight stainless steel tensioning hardware.

 

[dennis4040]

1st file Quad model without the Imax added to the model, with and without choke added.

2nd file the same Quad with the Imax added to the model, with and without choke.

Take note of the magnitude of the red lines for currents on the mast for these models. Those lines suggest the common mode currents that may develop on this Quad model.

This is very interesting. It looks like the choke improves the gain both with and w/o the iMax, have I got that right? I really believe in chokes, the only reason I didn't use one on the iMax is because it is temporary and I wanted to see what it would do. I built a simple CMC meter this weekend and I do have CMC on the iMax at the shack end. Quite a bit more than my OCF wire which came with a current balun, and my 20m Yagi with a Balun Designs choke balun which has virtually none in the shack. I have not calibrated the meter but everything is relative. I also have not checked along the coax in other places yet.
Do you think I should use a couple of chokes on the L4? I really like the Balun Designs models and I could possibly locate 2 on the boom with short wires to the feed point. What do you think?

You are right about worrying about the tuning and interplay of the other antennas. Too many unknowns that can effect performance. I have dropped the idea of the iMax above the quad. After looking again, I think I can assemble and tune the L4 on the ground and fish it up between the 20m elements and the 2m. This will hopefully simplify things some. Still will need fine tuning on the tower.

Yes I will update you on any changes to the manual.
Thanks again, dennis

 

[dennis4040]

Dennis I can't comment on your numbers, but I've played with my model that has the Imax, and in making the Imax the live element its pattern shows to be skewed badly with the antenna 3' feet above the tip or with the Imax mounted to the boom.

I think my buddy with the L8+ uses a 4 way type standoff boom support and I would assume it does not interfere with functions. In fact I think this support comes in the kit.

I don't know if the L4+ will need 4 way support but I would recommend up and down (sag) support. I don't like boom sag either, and I saw it when I ran a 4 element horizontal only using a Moonraker boom. Before going up with the antenna I thought the MR'r boom material looked pretty sturdy and it had a nice long heavy duty center support for the tips.

I took it down a fixed it with guyed support using wire and some lightweight stainless steel tensioning hardware.

That seals it, I'm not putting anything above the L4, why put up what I consider a high performance Quad and then mess it up with another antenna. Thanks so much for the models!
The weight will be minimal and I agree the vertical support will be worthwhile especially if I add a couple of baluns.

 

[Captain Kilowatt]

Hi CK glad you asked this gives me a chance to double check the numbers.
First 10' out of the tower is where the 20m and 2m antennas are mounted. It is 2" with .25" wall. Don't know the exact specs because I bought it used but I'm guessing it is at least 95,000 yield because it was holding up a 40' 3" boom 7 element 7 band quad plus the 2m antenna for 7 years in west Dallas where I bought it. It is however the weak link as you can see from the images I will post. Total mast ~75 mph max wind speed. I'm hoping it might be 100,000 yield. I know,, hope is not a good plan.
The next section is 3"x6' .5" wall T6 aluminum 38,000 yield. Attached by reaming for good fit to 2" mast with 12" overlap and 8 - 7/16" stainless bolts cinched against the mast. This is the way my Alpha Spid rotator is attached and it works great.
The next 2 sections are 2"x6' .25" wall T6 reamed for tight fit and secured with a 2.5"x12" .25" wall coupler using 8 1/4" stainless bolts on four quadrants and epoxied. Mast calculator shows 90 mph rating on this 11.5' section.
I've dropped the idea of a vertical above the quad.
I plan to use 2.5' of 1.5" out the top and phillystran to prevent boom sag unless I can determine that is not a problem with the L4+.
I hate boom sag.

Am I reading this right You have 27 feet out the top of the tower? First section is 10 feet. Second section is 6 feet. Third and forth sections are each 6 feet. 10+6+6+6-1 overlap=27 feet. Where is the rotator mounted at? That is my concern......the rotating moments presented to the rotator and the tendency to bend the top of the tower over. that's a tremendous bending force presented to the top depending how far down the tower the rotator is mounted.

 

[jessejamesdallas]

Dennis, drilling holes in the spreaders where the set screws go should not weaken the spreaders since the pre-drilled hole in the mount is about half way down... where mine broke was at the end of the mount where the spreader comes out. Wire got snagged on the tower, then the wind turned the antenna which pulled the top spreader over like a bow...I guess flopping around it finally snapped.

Don't remember what size wire was on mine now, but like I said, that was my biggest problem, wire always breaking at the eyelets

 

[dennis4040]

Am I reading this right You have 27 feet out the top of the tower? First section is 10 feet. Second section is 6 feet. Third and forth sections are each 6 feet. 10+6+6+6-1 overlap=27 feet. Where is the rotator mounted at? That is my concern......the rotating moments presented to the rotator and the tendency to bend the top of the tower over. that's a tremendous bending force presented to the top depending how far down the tower the rotator is mounted.

Yes, you have it correct and I understand the concern regarding all the stress at the rotor/Voyager hazer. The rotor is inside the hazer so only about 2' or 3' of mast is below the top of the hazer. The top section of tower is 8' and I have 3 guys, steel cable at 30' 1/4" phillystran at 50' and also at 80'.
This is a possible weak point as you say but I don't think it could be more stress than it handled with the 40' quad. What do you think?

I have stiffened the hazer a bit with 2 steel cables tying the top and bottom plates together.
Leverage can be a bitch, do think I am over stressing the top of the tower?

 

[dennis4040]

Dennis, drilling holes in the spreaders where the set screws go should not weaken the spreaders since the pre-drilled hole in the mount is about half way down... where mine broke was at the end of the mount where the spreader comes out. Wire got snagged on the tower, then the wind turned the antenna which pulled the top spreader over like a bow...I guess flopping around it finally snapped.

Don't remember what size wire was on mine now, but like I said, that was my biggest problem, wire always breaking at the eyelets

Great info JJ, I think I will do mine the same way with the spreaders.
1st thing I'm going to do is measure the wires, if I have a problem with breakage (I hope not) I will replace them with something stronger if I can find something better in 13 gauge which is what it is designed for.
Thanks again, dennis

 

[dennis4040]

Am I reading this right You have 27 feet out the top of the tower? First section is 10 feet. Second section is 6 feet. Third and forth sections are each 6 feet. 10+6+6+6-1 overlap=27 feet. Where is the rotator mounted at? That is my concern......the rotating moments presented to the rotator and the tendency to bend the top of the tower over. that's a tremendous bending force presented to the top depending how far down the tower the rotator is mounted.

I have attached an attempt to model the mast stress with the 30' quad, 2m yagi, and 2m vertical.
40' quad max wind 93.39mph
My current proposed array with L4+ 75.33mph
Might need to bring it down a bit. Is ~80 mph a reasonable goal.
You can't plan for everything, we just had a tornado hit about 8 miles from me last month. What about the tower stress, I assumed if the mast/hazer would hold up the tower would be ok?