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NSTREME 2 on Single Rootenna?

Posted: Sun Apr 08, 2007 3:37 am
by jo2jo
since some of the rootenna's can support BOTH 5.8 and 2.4, but only come with 1 connector, could you just solder another connector on and use one pigtail on a radio @ 5ghz and one radio on an antenna @ 2.4? at the same time? or use a diplexer inside the case with a few custom pigtails and cables

If not does anyone have any ONE antenna solutions to running two frequences at one time (for either a backup radio, or for nstreme 2 / bonding)


Posted: Sun Apr 08, 2007 6:25 am
by warwick09
Its funny you say that... but what you really need is a diplexer.

Here is a decent one.

Posted: Sun Apr 08, 2007 9:58 am
by jo2jo
ive read about those, they would work i assume if you have a:

2.4 / 5ghz anteanna with only one antenna port.

it would be much cheaper to use a rootenna, any ideas as to if the solder ing would work?

Posted: Sun Apr 08, 2007 12:24 pm
by mipland
it would be much cheaper to use a rootenna, any ideas as to if the solder ing would work?
You can't simply "solder" another connector on the antenna, it will result on a unbalanced antenna impedance.
If you want to use a dual-band antenna, you have to use a diplexer.

Posted: Mon Apr 09, 2007 12:09 am
by voip4life
Try a 'dual polarity' antenna. Radiowaves and several other antenna manufacturers make dual polarity lnb's (dipoles) that you can add to their dishes that have two connectors, one vertical and one horizontal. Plug two radios into it and run them simultaneously with only one dish per side. The dishes are more costly, but in my opinion worth it. Make sure the antennas have two connectors on it, many manufacturers claim their antennas are dual polarity but you have to choose one or the other or rotate the antenna 90 degrees for the other polarity. Expect to pay at least $700 per link on the low end, our radio waves were $1800 per link.

Posted: Mon Apr 09, 2007 5:03 am
by jo2jo

the costs are high on the dual band antennas / dishes.

thats why i dont see why a single 2.4/5ghz rootenna with diplexer in the box, would not work with one radio at 2.4 and one radio at 5.X ghz.

any objections before i order all the custom pigtales and diplexer?

this would be great as a VERY VERY CHEAP nstreme2 box or what i plan on doing, and doing voip over 5ghz else 2.4ghz OR

use one radio, with 2 u.fl's like the R52 and then set a fail over script that will set it to use the 2nd connector and set it to 5ghz, set the 1st connector to 2.4ghz...if someone wipes out your spectrum on one freq, auto switch to the other

Posted: Mon Apr 09, 2007 7:25 am
by 0ldman
What you asked before is different. You can use a 2.4/5.8GHz Rootenna as long as you are not using both at the same time.

If you are relying on failover, you're in good shape.

For bonding, its another boat.

Posted: Mon Apr 09, 2007 8:13 am
by jo2jo
why can they not be used simultaneously?

Posted: Tue Apr 10, 2007 3:08 pm
by aaronm
My guess is you probably could run both freqs at the same time on one antenna. The diplexer is cheap so would be a cool experiment to try. Now I just have to figure out how to convince my boss to let me order more parts...

Posted: Tue Apr 10, 2007 6:24 pm
by ekran
Diplexer is a nice solution, but I don't think it will fit in a rootenna.

You can use both frequencies on the new rootennas, and you will need some sort of a combiner. My recommendation, if you want to get your hands dirty and need it in quantity, is to build your own using just a few pieces of coax. I had a blueprint somewhere, but a few minutes on Google should return similar results.

Posted: Tue Apr 10, 2007 8:29 pm
by aaronm
Good point, it may not fit inside the rootenna along with your other hardware.

I dont see the need for a combiner though as the diplexer will take inputs from two different radios and pass them through to the antenna on one coax cable, unless I am missing something.

Posted: Tue Apr 10, 2007 11:53 pm
by jo2jo
aaron, what are you thinking? solder another pigtail?

as soon as i get a 2.4 / 5 roo in i will test this..but in the full size, 2.4 ghz one, i certinly think one of those hyperlink diplexers would fit.

Posted: Wed Apr 11, 2007 3:08 pm
by ccrum
I've tried combining signals onto a single antenna( albeit in the same band at 5 GHZ) using what is called a circulator. A ciculator is sort of like a diplexor, but only allows energy to flow in one direction. They have three ports, an input or transmitter port, an antenna port, and an output or receiver port. The TX signals go into the tx port and energy would only flow OUT to the antenna port. Signals coming IN on the antenna port would only flow to the output or receiver port. In theory it sounds great and I bought some high dollar circulators to try it out. I was getting great received signal levels on both ends of the link, but virtually no throughput (was getting 20+Mbps with seperate antennas on different polarities and the same boards/radios, but only about 300kbps with the circulator and a single antenna). I put the cirulator on the spectrum analyzer and found that I was only getting about 18 dB of isolation between ports. Obviously, more is needed, but I can't find a ciculator that has more. The other theory I have is that since enrgy only flows in 1 direction, I wasn't getting the reponse from the other side on both radios. Even though one radio is TX and one is RX, I'm assuming there is still some messaging going on between the TX-RX individual links. It's possible that the combiner was functioning too well and not allowing the return messages to arrive. For example if you just consider one half of the link, the two radios must handshake and acknolege eachother. It's possible that once the TX radio sent out handshake signal to the RX on the other side, the combiner sent all the incoming signal coming back from that receiver to the RX card instead of back to the TX card. This seems a more likely explanation. Any ideas?

Posted: Wed Apr 11, 2007 8:02 pm
by odie
ccrum - did you try "nstream dual" on your installation or just e simple link ?

Posted: Wed Apr 11, 2007 9:05 pm
by aaronm
jo2jo - This picture is from the website linked above: ... iagram.gif

I have no experience with this diplexer, or any diplexer for that matter, but from the above picture it would seem that one could use two radios transmitting at different frequencies on one dual-band antenna. Thats the theory anyway, in acutal practice it may not work very well.

ccrum - The RF equipment I worked on in the USAF used circulators and they worked quite well, but the transmitters and receivers were only designed to do just that. In other words the transmitters only transmitted and the receivers only received. Why did you try using a circulator anyway?

Posted: Wed Apr 11, 2007 11:23 pm
by ccrum
To answer the questions above...yes I was using Nstreme2 hence the two radios on each board. To the second question, I used circulators so I could stay in the same band. Diplexers typically take two different frequency bands, combine them, then you need another diplexer at the other end to split the signals apart again. The diplexer sold by Hyperlink takes 2.4 and 5 GHz. I wanted to use two different frequecies from the 5 GHz band. So, I need a circulator. But it appears that the circulator might have been working too well and not allowing the handshake to occur between the TX-RX pairs on the dual Nstremem link. Circulators are commonly used in Cellular equipment where one freq is TX only and one freq is RX only and all signalling goes on the appropriate channels. I'm guessing that with Nstreme2, each link has to establish some kind of acknolegement between cards since these are essentially 802.11 links. So, if ALL the signal coming in is redirected to only the RX card on either side, the TX card will never be able to establish the handshake, right? Keep in mind, it is not necessary to combine signals, only to provide enough isolation between them. That is why a circulator would be good. The receivers on each side never see signal that is not intended for them (i.e from the transmitters on their same sides) becasue all energy coming from those transmitters is going out the antenna port of the circulator.

Posted: Thu Apr 12, 2007 5:34 am
by ccrum
Just FYI...I did a cursory search and found it surprisingly hard to locate a decent 5 GHz combiner/splitter. Hyperlink has one, but the specs on it aren't particularly good. It only has about 15 db of isolation, and a 2:1 VSWR isn't great. You'll lose about 6 dB per channel using this. A circulator still would be the best option if you wanted to keep both frequencies in the same band...if you could overcome the handshake issue. BTW, Hyperlink's diplexer has worse stats at 2:1 up to 2.5:1 VSWR, 0.75 dB insertion loss, and the 3 dB hit you take going through the combiner/splitter, it looks like your total loss is even higher. Make sure you upsize your antenna if you use one of these.

Posted: Thu Apr 12, 2007 8:51 am
by rickard
Hi ccrum,

Intresting about your test with circulators, in a few weeks i will try my new manufactured Combiner for the band 5.4 -5.8 Ghz with 4 input/output to one antenna :-) its a another company that will build this for me .
it have 25 db isolation betwen the inputs. and i hope it will work.
I dont have all the specs yet .


Posted: Thu Apr 12, 2007 10:05 am
by warwick09
... Thought this might be of some aid.

Apparantly tranzeo has some pretty good 5.8 combiners ... decent specs.

Only downfall is they dont seem to offer 40mhz bandwidth spacing, but nonetheless still perfect for a nstreme dual setup.

Description: Channel Shield 5765/5805


Posted: Thu Apr 12, 2007 1:31 pm
by ekran
aaron, what are you thinking? solder another pigtail?

as soon as i get a 2.4 / 5 roo in i will test this..but in the full size, 2.4 ghz one, i certinly think one of those hyperlink diplexers would fit.
As far as I know, the dual freq rootennas come only in the slim line version, which is 1" deep. The smallest side of the diplexer is 1.75".

Why would you want to put a dual freq diplexer in a 2.4 only Rootenna?

Posted: Thu Apr 12, 2007 3:17 pm
by aaronm
Oh I get it now ccrum you wanted to use each of the radio links in half-duplex mode so that together using nstreme you have full-duplex operation over one antenna. It must be like you were saying then that the radios have some handshaking to do with eachother.

For the best nstreme performance using one antenna I think one of these would be your best bet, as voip4life posted earlier.