×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Should I care about the antenna's length if the gain and antenna type are right?

Should I care about the antenna's length if the gain and antenna type are right?

Should I care about the antenna's length if the gain and antenna type are right?

(OP)
Hi all bigsmile,

Recently I bought a 2.4 GHz wireless Xbee PRO module with a RP-SMA connector. Previously I was using a 2.4 GHz Xbee PRO which had a small black antenna attached to it and I was receiving signals from an identical Xbee module. I had bought this Xbee from Sparkfun:

Link

My plan was to replace this module with the RP-SMA compatible module and attach an Omni-directional antenna with a higher gain to it so I can extend the range of signal reception (both Xbees were used for receiving signals). After attaching the antenna and testing the RP-SMA Xbee, I realised that the range had increased. When I was searching to buy an antenna I did not consider the length of the antenna at all, but mainly its gain was my focus.

Now, my question is if the length of the antenna is important, how important is it? Do I need to consider the length as long as the antenna is an RP-SMA antenna and has the gain I want?
My other question is if I want to use an SMA antenna extension cable like this one to put my antenna away from my Xbee module:

Link

Do the same length criteria or limitations apply to this cable length too or not? In other words for example if I have a 1/4 wave antenna, does adding this extension change that length?
I have calculated that I will only have around 1.5 dBi signal loss which is fine by me.

Many thanks in advance
Replies continue below

Recommended for you

RE: Should I care about the antenna's length if the gain and antenna type are right?

"...an Omni-directional antenna with a higher gain..." is probably a collinear antenna array.

Google up some images of 'collinear antenna' and you'll begin to see how the length (height) of the collinear antenna implies more elements, and thus more gain (while remaining omnidirectional in the azimuth).

RE: Should I care about the antenna's length if the gain and antenna type are right?

(OP)
Thanks a lot guys 2thumbsup. So just to clarify my doubts, is the length of the extension cable provided in the second link going to have any other effect on signal reception other than a bit of signal loss which I have calculated? Because I just want to use that cable to put the antenna away from the Xbee wireless module.

RE: Should I care about the antenna's length if the gain and antenna type are right?

(OP)

Quote (The length of cable is presumably shielded, and does not act like an antenna, unless something is wired wrong. )

Thanks. That makes sense.

RE: Should I care about the antenna's length if the gain and antenna type are right?

If you have a 1/4 wave antenna, this extension cable does not adding change that length. Cable is not an antenna.

AlexAntDesign.com

Alex,
alexantdesign.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close