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

Updated on April 7, 2017 in ECE
0 on April 7, 2017

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:

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:

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.

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