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RF cable length

Posted: Thu May 21, 2009 4:58 pm
by jpjust
Hello, folks.

I see some people talking about cutting the RF cable at correct lengths, to avoid standing waves (just as amateur radios do). What do you say about it? Should we really care? Or it doesn't has strong effects in microwaves links?

Re: RF cable length

Posted: Sun May 24, 2009 2:31 pm
by Egate
Think your cable should not even be as long as to have to be cut.

Re: RF cable length

Posted: Mon May 25, 2009 12:40 am
by doush
mine are 3m each

Re: RF cable length

Posted: Mon May 25, 2009 7:37 am
by angboontiong
..........................

Re: RF cable length

Posted: Mon May 25, 2009 8:52 am
by ste
You have to tell us the detail as...

1) Distance between radio and antenna.
2) Each end with what type of RF connector.
3) How many RF surge arrester will use.
4) What's type of the RF cable you plan for it.
5) What type of the antenna connector.
6) The antenna gain and distance to other end.

With that, then only we can advice you.
jpjust asks if there are some coax lenght constraints other than the
total signal loss. So something like keep cable at a multiple of wavelength.
I dont feel your questions are correlated with this ;-)

Stefan

Re: RF cable length

Posted: Mon May 25, 2009 8:54 am
by RK
You have to tell us the detail as...

1) Distance between radio and antenna.
2) Each end with what type of RF connector.
3) How many RF surge arrester will use.
4) What's type of the RF cable you plan for it.
5) What type of the antenna connector.
6) The antenna gain and distance to other end.

With that, then only we can advice you.
Did you even read jpjust's question?
None of what you asked is relevant.

Re: RF cable length

Posted: Mon May 25, 2009 8:57 am
by RK
Hello, folks.

I see some people talking about cutting the RF cable at correct lengths, to avoid standing waves (just as amateur radios do). What do you say about it? Should we really care? Or it doesn't has strong effects in microwaves links?
I don't know. But what I do know is that wavelength at 5.8 GHz is 5.2 cm.
Cutting cable that exact is difficult.

Re: RF cable length

Posted: Mon May 25, 2009 1:50 pm
by jpjust
ste:that's what I meant.

This weekend I learned that cable length does matter. Sometimes, a long cable is better than a short one (but not so long). We have to consider the wavelength and other cable's attributes to determine the best size :)

I'm still learning how to calculate the correct size. I can post it here as soon as I have learned everything correctly.

Re: RF cable length

Posted: Mon May 25, 2009 3:06 pm
by titius
Please do so, I cant wait to see results. This is interesting thing if its true.