Create Log Periodic feed line

[JackTV]

Hey Everybody,
I have a create log periodic antenna (50-13000mhz) I am changing the feed line that came with the antenna because the one that came with it has gone bad.Do i need to install a feed line the same length or can i just install a connector (type "N") inplace of the feed line?If i have to install another feed line i plan on using a low insertion loss coax(lmr 400 or something better)Let me know what you all think.

Thanx,
Jack

 

[N_Jay]

Hey Everybody,
I have a create log periodic antenna (50-13000mhz) I am changing the feed line that came with the antenna because the one that came with it has gone bad.Do i need to install a feed line the same length or can i just install a connector (type "N") inplace of the feed line?If i have to install another feed line i plan on using a low insertion loss coax(lmr 400 or something better)Let me know what you all think.

Thanx,
Jack

Hmm, if the antenna you "created" is designed properly for the bands and impeadence desired, then teh transmission line can be of any length.

(You may want to check the source of your antenna design for more information)

Assuming you meant 50 MHz to 1300 MHz, that is quite a spread for a log periodic.

10X is typical, but you can build more then one set of elements sharing the boom. i.e a 30 to 300 set and a 150 to 1500 set.

 

[JackTV]

Create is the name of the company that made the antenna.

 

[N_Jay]

Hey Everybody,
I have a create log periodic antenna (50-13000mhz) I am changing the feed line that came with the antenna because the one that came with it has gone bad.Do i need to install a feed line the same length or can i just install a connector (type "N") inplace of the feed line?If i have to install another feed line i plan on using a low insertion loss coax(lmr 400 or something better)Let me know what you all think.

Thanx,
Jack

When you say feed line you are tralking about the line from teh factory N-connector to the connection point on the elements?

If that is the case, you have to make sure that that piece of line is not part of a matching circuit. I seem to recal that LPDA antennas are usually 200 to 300 ohm feed.
Since your is 50 ohms, it is probabaly match some how.

Take a close look at what you are replacing and try to duplicat it.

Or call the company and get a new part.

Or get some information on LPDA design and figure out what needs to go there.

 

[LarrySC]

Short answer: If its 75ohm coax then replace with same. Same for 50ohm.

 

[fivestarr]

Create Designs log periodic

I have a Create log periodic. I may be able to help if all you need is the length of the feedline. Let me know and I will get up there and measure it.
Fivestarr

 

[JackTV]

Thanx for offering but I already have the piece of feedline off of the antenna.I will most likely use a piece of LMR 400 the same length of the original feedline.Who knows maybe performance will be better with a lower loss coax.

Thanx again,
Jack