Antenna cable length

[scottb]

Hi there,

We already have some antennas installed with some old Cisco 802.11b APs hanging off them, so we're looking at replacing those old slow APs - probably with some Bullet5 units.

The cables leading to the antenna are quite long (probably 30m+ at a guess), so my question is can I just replace the Cisco APs with Bullets and expect a decent performance boost, or will that cable length deteriorate the signal too much?

I don't really want to run Cat5 and install the unit.

Should we be considering a set of PowerStations instead of bullet?

There's a few different links that we're looking to do this on
- 100m
- 300m
- 1km
- 2km

Cheers,
Scott

[UBNT-Mike.Ford]

What type of cable is it, and what is the output power of those Cisco units?

Thanks,

Mike

[scottb]

I may have answered my own question.. The Cisco units have a specified output power of 20db and the bullet is from 17-22db

[six]

Hi there,

We already have some antennas installed with some old Cisco 802.11b APs
[...] replacing those old slow APs - probably with some Bullet5 units
[...]
I don't really want to run Cat5 and install the unit.


Those antennas will be a bigger problem than the length of the cable. If I'm reading you right, you intend to use Bullet5s (5.8 ghz radios) with your existing antennas from your 2.4 ghz Ciscos.

I'd pull down one of those antennas and do a few tests before assuming it will perform very well or even at all on a different band. Worry about your cable loss after you find out if your antennas will work. Personally, I'll bet your SWR is through the roof due to the impedance.

It may be a whole lot of no-fun to reinstall your gear, but I also think you should really consider just running the CAT5 to eliminate the cable loss, too.

[WHT]

Thats unbelievable anyone would run 30 meters of coax instead of mounting the radios closer to the antenna. The SWR would easily be within limits, but the cable loss would be very high.

Apples to apples, the Bullet TWO has similar power output of the Cisco 802.11b radios, but I don't know what your regulations are concerning type certified radios (the Bullet 2 is only certified for a 6 dBi antenna in the U.S.).

Those antenna should also be replaced due to age, even if you used replacement 2.4 Gig radios. And would have to be replaced if you went to 5.8 Gig.

For the distances you are needing, the Nanostation 5 at 5.8 Gig would certainly work and less problems with 2.4 Gig interference.

[rconaway]

Didn't Cisco do a Poe on some of those older units over the coax meaning the radio is inthe antenna. I pulled some down last year that were like that.

[kijoma]

they may have a LNA/PA in the antenna and bias tee to power it. else no point powering over the coax! as you wouldn't use coax if the router was up there :roll: