MikroTik

Is there a way to use separate radios for send and receive in AP mode? We are thinking of building an antenna combiner/duplexer where this could be very useful.

it's called nstreme2

Nstreme2 is for P2P links and not for Point-Multipoint AP configs. We would like to combine several radios into one or two antennas. Being able to separate send and receive would be helpful in this endeavor. This could be done with a dual port radio such as an 8602 but need the performance of R5H (if they would stop burning up) or XR5 but those radios only offer one antenna port.

I am also looking for the WiFi can do that way...

you have the various antenna modes - rx a tx b or rx b tx a, however, only on radios with 2 antenna ports.

I think he talk about full duplex system with AP/station mode. All existing wireless card work only in half duplex mode.

I believe full duplex in multipoint mode does not have sense.

I post this link a few times every week.
http://wiki.mikrotik.com/wiki/OSPF_to_s ... redundancy

I believe full duplex in multipoint mode does not have sense.

It certainly does, Alvarion VL systems are full dup. They run nicely.

One radio can never send and listen at the same time.
Only radio combinations (in one box, or like minipci card, one card) that have two circuits, one for sending (transmitter) and one for receiving (receiver) with separate antenna connectors and connected to separate antenna's can do that.
Basically we talk about two radio's here. And they have to have a frequency shift and very precise filter to avoid that the transmitter (very powerful signal) is blowing away the receiver circuits (very sensitive circuits).
Good full duplex systems therefore always consist of two fully separate circuits and two different freq's.

Some MT cards have two connectors and in the software the option TX for one and RX for the other can be selected.
The cards therefore probably have two separate radio circuits. But in the OS you can only set one radio frequency so basically the risk is high the transmitter is damaging the receiver circuits over time. You need very high quality filters to stop that happening together with physical separation of the path the actuall radio signals travel. You have to use different polarized antennas for both chains to avoid to much interferences.
I have never seen any topic in the forum from users using this option. Probably not a very fashionable one. Too many problems?

Anybody talking about full duplex in one box talks about two radio circuits.
What Wifi radio's do is semi duplex, radio switches between send and receive mode all the time at such high rate for us humans it looks like both happens at the same time. But in reality is doesn't.

R.

One radio can never send and listen at the same time.
Only radio combinations (in one box, or like minipci card, one card) that have two circuits, one for sending (transmitter) and one for receiving (receiver) with separate antenna connectors and connected to separate antenna's can do that.
Basically we talk about two radio's here. And they have to have a frequency shift and very precise filter to avoid that the transmitter (very powerful signal) is blowing away the receiver circuits (very sensitive circuits).
Good full duplex systems therefore always consist of two fully separate circuits and two different freq's.

Yes. But this can be done with one Antenna. Licensed gear operates this way.
It would be of great benefit for latencies when this could be done with normal
APs/CPe Operation.
Never seen APs doing this.

One unit can, one antenna can never...

Compare it with speech and listen

Your head, is the unit.
Your ear (ok we have two, but lets say we have one) is one antenna, that can only listen. (Rx) Never make sound. Your mouth on the other end only makes sound (Tx), it can never listen,.

In radio technology the ´ears´ are very sensitive to pick up even the lowest signals (=sound) while the biggest shouters with highest volume is heard longest distance away.
In real radio world the ´sound´ (radio wave) produced by the mouth (transmitter) can be so loud that the eardrum (receiver) gets damaged.

Now, our head has so much cpe power (brain) that even if we shout out load we probably still are able to pick up signals coming from our ears. And when listening we can at the same time speak.
But this is only because we actually have two sound (radio) circuits. One for listening and one for producing sound. Our very powerfull brain (compared to a cpu) can handle both.

In radio tech the same happens. Some dual circuit radio's have the option to do both Rx and Tx at the same time but if the internal oscillator that produces the radio wave (and need the same to ´hear´ the incoming radio wave) has to serve both circuits basically this can only be done in a switching process. One time slot the oscillator produces a wave to send, the next it oscillates with the incoming signal.
This is simple or near-duplex.

Only units that have two oscillators in separate circuits can do a full duplex job. But actually we talk already two radio's now. It might be both are controlled by one CPU, but the technical characters of the radio which makes something ´a radio´ is double. Thus two radios.

But actually we are discussing the meaning of words here. What you refer to is a dual radio unit called ´a radio´.
I have a TV satellite receiver, called "a satellite receiver" but actually is has two receivers in it, to pick up the signal from two satellites at the same time. But if I order the same unit in the shop I will not order two receivers, I order one.

One unit can, one antenna can never...

Compare it with speech and listen

Your head, is the unit.
Your ear (ok we have two, but lets say we have one) is one antenna, that can only listen. (Rx) Never make sound. Your mouth on the other end only makes sound (Tx), it can never listen,.

In radio technology the ´ears´ are very sensitive to pick up even the lowest signals (=sound) while the biggest shouters with highest volume is heard longest distance away.
In real radio world the ´sound´ (radio wave) produced by the mouth (transmitter) can be so loud that the eardrum (receiver) gets damaged.

Now, our head has so much cpe power (brain) that even if we shout out load we probably still are able to pick up signals coming from our ears. And when listening we can at the same time speak.
But this is only because we actually have two sound (radio) circuits. One for listening and one for producing sound. Our very powerfull brain (compared to a cpu) can handle both.

In radio tech the same happens. Some dual circuit radio's have the option to do both Rx and Tx at the same time but if the internal oscillator that produces the radio wave (and need the same to ´hear´ the incoming radio wave) has to serve both circuits basically this can only be done in a switching process. One time slot the oscillator produces a wave to send, the next it oscillates with the incoming signal.
This is simple or near-duplex.

Only units that have two oscillators in separate circuits can do a full duplex job. But actually we talk already two radio's now. It might be both are controlled by one CPU, but the technical characters of the radio which makes something ´a radio´ is double. Thus two radios.

But actually we are discussing the meaning of words here. What you refer to is a dual radio unit called ´a radio´.
I have a TV satellite receiver, called "a satellite receiver" but actually is has two receivers in it, to pick up the signal from two satellites at the same time. But if I order the same unit in the shop I will not order two receivers, I order one.

Yes. One unit with 2 radios using one Antenna. Each radio is half duplex. Together
they operate fullduplex.