LMR-400 Coax & Base Antenna installation questions!

[ebayguy]

I am awaiting a Solarcon Base antenna,:headbang so I can get my base up and running on 11M band. I am setting up in my basement, and planning on putting the Solarcon on the peak, via a DirecTV/DishNetwork J-Arm(with the support struts), and 4ft fiberglass masts. Not sure how many masts yet, as I am afraid of heights.(I ordered 12, for a total of 45.5' fully assembled) I am pretty sure that the connector end of the masts will fit inside the J-Arm. I am new to the base setup, so please forgive my ignorance. Here are my questions;

#1, Is it acceptable(without raising my SWR's), to install the LMR-400 coax thru the steel J-Arm, and up thru the fiberglass masts? I am pretty sure that going thru the fiberglass isn't a problem, but the metal!!! I don't know.

#2, If so, do I loop the coax out of the top of the mast, to the bottom of the antenna?


#3, Should I use stand-offs to run the coax up the side of the house, or am I being paranoid? The J-Arm came with the support struts to hold most of the weight!

#4 How high is high enough, to use guy wire?

Any, and all help is appreciated. Thanks....

 

[Mudfoot]

Can u post any pics of the mount?

Running the coax as you describe is fine, no stand offs needed unless you want to dress things up.

I just worry about torsion and lateral forces affecting the dish mount. Those verticals can really whip around.

I might not fully understand how you propose to mount everything.

 

[ebayguy]

I hope this helps. I haven't installed it yet, so I can't give you an installed shot.

 

[Robb]

I wouldn't mount the antenna mast to another existing mount. Might be more than the two together will handle in a strong wind. If you have 45 ft of mast; I would mount the mast at two points along the side of the building for strong lower support. Then use dacron guy ROPE to secure the mast just below the feedpoint of the antenna itself at three points mounted securely below. Using a non-conductive rope like dacron will keep CMC's from happenimg (read 'CMC' below). Dacron is preferred because it won't fall apart after years of UV radiation exposure as lesser rope will do.

45 feet from the ground surface to the feedpoint of your antenna is plenty high enough without trying to get another 10 or 20 ft more. Doing it the way I suggested will make the setup very strong indeed. Another thing: find some friends to help you set this up, as it can be very dangerous to do it all alone. Especially if the risk of nearby power wires are present and it should it slip out of your grip and land on them. Bribe some friends with a pizza dinner for helping; that will usually work.

If you don't have the ground plane kit for the Solarcon; then you might not be too popular with your neighbors. Your antenna system will give off a lot of TVI ('television interference') due to the fact that the antenna will end up using the coax as a ground plane (because you didn't install the ground plane kit) and this will be the cause of a lot of 'common mode current' which will cause a lot of the TVI and a neighbor that is less than pleased with your new hobby.

Even if you do get/use a ground plane kit, you may well want to make a common mode current choke just below the antenna. Five winds of coax wrapped closely together around a 2 liter soda bottle and taped together with waterproof tape.

Hope that helps some . . .

 

[ebayguy]

Please do not laugh! op: I am not an artist, and it was a rush job.

 

[BOOTY MONSTER]

i wouldn't do it . when the wind blows it's gonna be a lot more stress/leverage on that mount than it was intended for .

 

[ebayguy]

Thanks for the input ROBB. I only planned on using 2, maybe 3 of the masts. I was assuming that all of that vertical force was not intended on that DishNet J-Arm.
As far as electric wires, luckily I live in a neighborhood where the wires are ALL underground. Which makes it great for installing any antenna.
Now, if I am understanding you correctly, I am to loop the coax coming from my setup, to the antenna? Then before it gets to my antenna, loop it around a 2 liter bottle, tape it, and keep from contacting the mast? How in the world am I supposed to keep it from touching the mast? The coax has a very hard plastic coating, which makes it very difficult to bend around small/tight corners. Then I have the problem of not having it touch. Am I to use a non-conductive support, to keep it from coming into contact?
I am only asking because I don't think I totally understand. I am not trying to be sarcastic.

 

[Robb]

Thanks for the input ROBB. I only planned on using 2, maybe 3 of the masts. I was assuming that all of that vertical force was not intended on that DishNet J-Arm.
As far as electric wires, luckily I live in a neighborhood where the wires are ALL underground. Which makes it great for installing any antenna.
Now, if I am understanding you correctly, I am to loop the coax coming from my setup, to the antenna? Then before it gets to my antenna, loop it around a 2 liter bottle, tape it, and keep from contacting the mast? How in the world am I supposed to keep it from touching the mast? The coax has a very hard plastic coating, which makes it very difficult to bend around small/tight corners. Then I have the problem of not having it touch. Am I to use a non-conductive support, to keep it from coming into contact?
I am only asking because I don't think I totally understand. I am not trying to be sarcastic.

I wouldn't mount fiberglass mast - or anything - to that existing mount. AS Booty agreed that it wouldn't be wise. Too much stress on that point. Just use all of the 45 ft of fiberglass mast and secure it to the side of the building at two points; then guy rope it from the top.

The only 'looping' you will need is at the base of the antenna.
4 ft below the antenna feedpoint will be just fine.
You don't neet to loop it in the shack if it is looped below the antenna feedpoint.

Since you are using fiberglass mast; you will definitely need to get a ground plane kit for the Solarcon.

You only have to consider keeping the coax away from the mast if it is made of metal.
Fiberglass should work just fine because it won't conduct CMC's.

 

[hotrod]

i wouldnt do it. either. that other mount wasnt designed for that kinda stress .
id mount it along side your house.i use the poles on the porch to tie rope off
and a pipe clamp at the peak of roof.now mine isnt the best of setup either
but being im renting its best i can do.

 

[BOOTY MONSTER]

....... now mine isnt the best of setup either
but being im renting its best i can do.

im in the same situation here .

 

[ebayguy]

I too, am renting. But for what I pay, as long as when its removed I patch holes for leaks, he doesn't care. The only problem with using the mast all the way to the ground is, its the side of the house. Its all garden! Really soft dirt. What would you suggest I use to avoid the soft dirt? Something that is not permanent.....

 

[BOOTY MONSTER]

Easy Up EZ32 Telescopic Antenna Mast Ground Plate

Easy Up EZ32A Heavy Duty Telescopic Antenna Mast Ground Plate

using multiple sections of FG mast may allow a lot of bowing in the middle if it isn't bracketed multiple places along the way . how high is it to the peak of the roof from the ground ?

 

[ebayguy]

If you figure that each floor is 10ft, and then the peak, prob about 25-26ft.

 

[Robb]

If you figure that each floor is 10ft, and then the peak, prob about 25-26ft.

Soft ground isn't a real problem - lol! You can use a short length of pipe (1 ft or less) placed into the ground to act as a base. Just so long as the ID of the pipe is greater than the OD of the fiberglass mast.

If the peak of the building is 26 ft and the the overall length of the mast is 45; then you are still ~20 ft above the building. I would go with that in a heartbeat - no problem here. The only thing you need to do is secure the mast at the point of the building before it goes above it. The using a level to attain the ground point with a bubble level to assure that it is perpendicular.

You might also strap the side of the mast to the dish mount for an additional mount point. Just don't use it as the main support is all!

 

[BOOTY MONSTER]

i wouldn't have 20 ft of mast above the bracket point , especially fiberglass mast without at least 1 set of guy wires . id use 2 for FG . id also want more than a foot of pipe/mast in the ground to secure it at the bottom , especially if it's soft ground .

just my opinion .......