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Lmr 400 inside mast ?

W5LZ said:
Think about that for a minute. It isn't the antenna it's self that's lossy, it's the matching network used to end-feed it. Any impedance matching network used to match an end fed 1/2 wave antenna isn't going to be 'super efficient'. But, that also certainly doesn't mean that that particular matching network is so terrible. The antenna typically gets a 'bad-rap' because too much is expected of it to start with. So why do they use that sort of matching system/network? Cuz' it's less expensive than others, is fairly simple, and is easy to adjust. Want a more efficient method of feeding the thing? Easy, feed it in the center... But you just made it more difficult to errect, not as simple mechanically. See where that's going?
'Doc
Click to expand...

'Doc, I know this issue about lossy matching devices has come up about the Imax, and for the most part I tend to agree with what you're saying above.

In my experience, with trying to figure out "what is going on issues" with CB antennas, I have repeatedly found that claims for such differences are generally far less than touted...when we are just using our radios to compare. Can high dollar test equipment test such differences and see some difference...of course.

So, I ask again...when we say an EFHW or a matching setup is more lossy, how much difference are we really talking about?
 
The coax is going in the mast then.

My old ,but new to me coax is 20-30 year old rg8 that I bought from a business band radio shop they had laying in the attic .best I could find around here
I live on the dark side of the moon,its either amazon or go with out.
I would like a 4 eliment beam that isnt to long to hit my roof.the I max is up 28 ft and talking well,but would like more gain,I have some rf feedback going on and WIFE not happy,I thought the lmr 400 would help.
Money is not the big issue but want to only do this once.its cheaper in the long run..
 
Last man standing said:
My old ,but new to me coax is 20-30 year old rg8 that I bought from a business band radio shop they had laying in the attic .best I could find around here
I live on the dark side of the moon,its either amazon or go with out.
I would like a 4 eliment beam that isnt to long to hit my roof.the I max is up 28 ft and talking well,but would like more gain,I have some rf feedback going on and WIFE not happy,I thought the lmr 400 would help.
Money is not the big issue but want to only do this once.its cheaper in the long run..
Click to expand...

been there done that. sadly lmr 400 wont cure it. however it may help lower it some
it did in my case.if thats rf is your issue id reccommend getting the sirio gain master
yes more money than just coax ,however i think your rf issues will be resolved or
mostly be gone.ya can upgrade ya coax due to age of ya old coax but dont expect
what your asking
 
The DB said:
Hey doc, good job addressing half of it, but you missed the big picture of what I am curious about... It wasn't just the higher than necessary quality coax to minimize losses, but that in combination with an antenna that is known to be more lossy than most... Care to take a stab at the whole thing?


The DB
Click to expand...

Money would be wiser invested in a good 5/8 wave with at least 1/8 wave radials or vector 4000, and then if you want add lmr 400, at least that way you'll get the benefit of the lmr400's lower loss. running it down the tube protects cable from weather and if right length tube could act as a sleeve balun/rf choke as well.

an antenna that's known to be noisy, has lossy matching system,no radials to decouple, notorious for common mode current and rfi, adding low loss coax could actually make it worse, I think that may be what THE DB is getting at in his bigger picture, i ain't read the pages after this post so not sure, but just about too.

thats my take on it before i do. :)
 
W5LZ said:
Think about that for a minute. It isn't the antenna it's self that's lossy, it's the matching network used to end-feed it. Any impedance matching network used to match an end fed 1/2 wave antenna isn't going to be 'super efficient'. But, that also certainly doesn't mean that that particular matching network is so terrible. The antenna typically gets a 'bad-rap' because too much is expected of it to start with. So why do they use that sort of matching system/network? Cuz' it's less expensive than others, is fairly simple, and is easy to adjust. Want a more efficient method of feeding the thing? Easy, feed it in the center... But you just made it more difficult to errect, not as simple mechanically. See where that's going?
'Doc
Click to expand...

I max 2000 isn't a 1/2 wave.

not sure about that, Sirio did ok centre feeding and getting gainmaster erect, not to mention balancing and choking it as well so it doesn't need radials. they also isolated it from mast too.

but hey, what do us Europeans know about antennas?

Small note, matching system is invaluable part of antenna, especially an I Max 2000, you can't blame one part for a complete design disaster ;)
 
Did that

I put on the new LMR400 ,in the mast this weekend,it helped a lot ,my noise level nothing showing on meter just junk in background
Went down by about 2/3s swr went from 1.8-1 to 1.4-1 less RF in other stuff to
Big change for me !
 
Last man standing said:
I put on the new LMR400 ,in the mast this weekend,it helped a lot ,my noise level nothing showing on meter just junk in background
Went down by about 2/3s swr went from 1.8-1 to 1.4-1 less RF in other stuff to
Big change for me !
Click to expand...

That is what I've seen for years working my Starduster's...a real quite working antenna with no TVI. The only difference is I used a mast in the antenna that was only 8' - 9' long. This is what I told you in my first post to you. <gotproof>

The guy that made that design knew what he was doing placing the coax inside the mast of the antenna.

So, the mast is more than just a cable conduit afterall.

Way to go and good luck...that SD will work about as good as any other CB vertical you can put up...if the tip of the SD'r is even close (3'-6') to the tip height of the other antenna.
 

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