Battle of the Ground plane #2

[211inthamag]

Little something got left at my front door yesterday afternoon, will have it up by the weekend for testing and hope it meets my expectations ! My first impression of the antenna so far for a fiberglass antenna is that it is made very well.. the one thing that I didnt like is the instructions were somewhat in italian and not very informative !

 

[bob85]

bobby make sure you assemble it correctly with the correct overlap of joints and don't overtighten the hose clamps crushing the tube, you will hear the tube creak as the hose clamps get tight, stop when it creaks,
pull the top section out until the wire is fairly tight then shove it back in 3/4 inch or so before nipping the final hose clamp,

a couple of locals had them snap in moderate 60mph winds because they assembled them wrong.

 

[211inthamag]

"THANK YOU" bob for the advise...I will make sure that it is perfectly put together at the specs given and will def not over do it on the clamps, would hate to end up using it for a fishing rod :blush:

 

[211inthamag]

Im assuming that the 2nd and 3rd section is about 70 1/2 inchs each since it tells me its about 1800MM per section...I am horrible with MM measurements , please correct me if im wrong! :headbang

 

[bob85]

divide the millimeters by 25.4 to convert to inches = 70 55⁄64in , or a little over 70 3/4 inch.

 

[211inthamag]

Ok well I wasnt far off so thats good, 70 1/2 or 70 3/4..either way it should be fine..so im going to set both at exactly 70 3/4 inch

Crazy thing is when I put 1800 mm into a converter it tells me it is 70.866 inchs....arg

 

[Marconi]

211, if them guys at Sirio had given us 6" inches more material in all of their tubing lengths...the point Bob is making wouldn't likely make any difference. Personally I think sections 2 & 3 should be 70.875" inches each, and that would give just a little bit more overlap for #4.

But your little error noted earlier...might just be the difference in success and failure like Bob suggested. As you make sections 2 & 3, a little shorter that they should be, you will be inadvertently be making section #4, sit inside of #3, with less overlap by the amount of your error x 2.

I wish I had checked and recorded this top element overlap. Maybe you could mark you antenna when you get the wire stretched out like Bob suggested, and tell us how much overlap you get for #4 element.

I figure the overlap should be about 4" inches when the antenna is properly setup.

Good luck.

 

[211inthamag]

Well 70.866 is very close to 70 1/2 correct? or would you suggest it be at 70 3/4?

 

[Marconi]

Well 70.866 is very close to 70 1/2 correct? or would you suggest it be at 70 3/4?

Of course I agree with you 211, your 70.5" is very close, and I can't be sure such a little difference could be a problem, but I thought it was worth noting.

I set my GM at 70.875". I don't know if mine is split at the junctions where the hose clamps go, but something is different about my GM.

So, I'm planning to take it down when it gets a little cooler, and I'll measure everything that I failed to do in the beginning. I'll also post if I see any splitting of the plastic too.

I was just trying to clarify what Bob was telling you. I realize that was totally unnecessary.

 

[211inthamag]

I put it together and here is my lengths im getting! This is with the 2nd and 3rd measured at 70 3/4 each and the 4th being stretched out and me pushing it back in 3/4 a inch for slack inside antenna.

From end to the tip measured out at 287 inchs
From where the coax goes to the tip is 273 inchs
From top of coil to tip is 267 inchs

correct me if im way off with my measurements

 

[Marconi]

I put it together and here is my lengths im getting! This is with the 2nd and 3rd measured at 70 3/4 each and the 4th being stretched out and me pushing it back in 3/4 a inch for slack inside antenna.

From end to the tip measured out at 287 inchs
From where the coax goes to the tip is 273 inchs
From top of coil to tip is 267 inchs

correct me if im way off with my measurements

Very good 211, my coil to tip notes show 267.5" inches.

If you still have it down, give us the exposed length for #4. That might help some guys figure their install out easier.

I think you're right on the mark.


Good luck,

Thanks

 

[211inthamag]

I have it down and will go measure it !! Yeah I adjusted the top element back 3/4 a inch...I wonder if your problem with your antenna is the 4th element not being retracted back enough and still have or had a bind on the coax....very possible!!

UPDATE JUST A SECOND AGO!!! Here is the TOTAL LENGTHS AGAIN!! This is from the top of coil reading!!

1st Element (set base) is 56 Inch
2nd Element 70 3/4 inch
3rd Element 70 3/4 inch
4th Element 69 1/2 inch (this is with me pushing 3/4 inch back in after the coax gets to the tight mark when pulling it)
TOTAL : 267 inchs

Also I want to note that a inch to 1/2 inch difference could be from the last element adjustment to the black nipple being pushed in all the way or not being pushed in hardly at all

 

[Marconi]

I have it down and will go measure it !! Yeah I adjusted the top element back 3/4 a inch...I wonder if your problem with your antenna is the 4th element not being retracted back enough and still have or had a bind on the coax....very possible!!

Sure it could 211. I didn't make a note of how much I pushed section #4, back into #3, but I remember I had the thought that I made mine too loose.

I have wondered what would happen if the wire came loose from the brass hub it is secured in at the tip, would the wire slide down and make the antenna loose its match or not work at all?

The problem I see is just a minor change in the SWR readings on my inline meter, and a seeming increase in noise. Nothing else has changed with my setup over time, and I can't figure out what the problem really is.

I've have another thought too. Recalling that the top wire is pretty stiff, and if during a big wind the antenna bent over and stressed the hub connection, the wire broke or came loose at the top what would happen? The thought is...if the wire would slide down a little, and maybe that is what I'm experiencing.

My Daiwa CN801H meter use to show 1.0:1 for a big range around the CB band, but now I see about 1.3, and I can't explain that.

 

[211inthamag]

I edited my previous post!! Please read !!

 

[Marconi]

I edited my previous post!! Please read !!

Thanks for the added info.

I'll be sure and measure mine too...in case mine is breaking up and I did something wrong. I'll aslo get the amount of overlap I ended up with...for each section as I break it down.