New operational mode

1st Official Post

    Hi,

    I have a proposal for a "new" operational mode for NB.

    The traditional QSO using USB in all frequencies is half duplex. This is due to the fact that is impossible to Rx during Tx. Using USB is possible two stations or more to talk at the same time without interfering each other.

    The proposal is that two or more stations talk together like a telephone conversation. Of course callsigns must told every few minutes according to ham radio laws.

    This will provide a more "natural" mode of communication that is impossible to implement with out QO100.

    Many years ago we had a relay running abt. 30km from my qth. Uplink was a 3khz wide "channel" on 2m SSB and downlink was regular 70cm analog FM. Fullduplex conversations were possible as long as you used a carrierless mode on the uplink , like ssb or cw. Two or more users could transmit simultaneously without interference other than what you would see when two or more people in one room talk at the same time. It was a lot of fun as long as none of the participants was significantly louder than the others. But here is the rub. Some stations do not run duplex gear - aka DXP groundstation - , others turn down rx volume while they transmit (for a good reason, you hear the feedback if they don't) and some sdr users expirience huge audio delays when their computers are slow or when they listen to web-sdr. We see that many times on qo-100, when stations talk over each other without noticing for some seconds. For a conversation like George has in mind, fully analog stations will work best. So go ahead , ask your qso-partner if he/she is capable of or wants to run a duplex conversation. I don't think Amsat-DL will establish a special range for duplex-qso's on the satellite. Or will they?

    73, Martin

    • Official Post
    Quote from SV1BDS

    Hi,

    I have a proposal for a "new" operational mode for NB.

    The traditional QSO using USB in all frequencies is half duplex. This is due to the fact that is impossible to Rx during Tx. Using USB is possible two stations or more to talk at the same time without interfering each other.

    The proposal is that two or more stations talk together like a telephone conversation. Of course callsigns must told every few minutes according to ham radio laws.

    This will provide a more "natural" mode of communication that is impossible to implement with out QO100.

    Hello George


    I understand your "new" mode as Fullduplex. It's possible that both operators can talk at the same time, but if they are understanding each other is another question. As you know, a good operating practice and discipline is important in a roundtable.


    Well George, I think this is an old hat for you and it is possible, I understand you wrong ?

    Hi,

    We have the first QSO with dm4im to test it. A new way of ham radio communication exists.

    The difference from a traditional full duplex communication is that many users transmit at the same frequency the same time.

    The conclusions from QSO was that we have to be at the same frequency and have the same level of Tx audio. Headphones is mandatory. We tend to talk as in half duplex and it needs practice. It is nice that the other participant can acknowledge or interrupt if can not understand something. We said that it will be interesting to test it with more people. I have to adjust my headphones not to confuse me my own voice. Technically is not so easy to eliminate your own voice as it comes with delay as it performed in telephone headset's. We have a very nice QSO fast exchanging information between us.

    Hi George,

    I am ready for a test also. It is very eays to change Pluto frequencies. Switch off SyncRX and adjust the Rx and Tx Frequencies where ever you want. It is a kind of split mode which is very easy also. Just look which station is accepted from the DX and turn your transmitter to this
    frequency. There is a very big advantage having a spectrum.

    73
    Andreas

    Let me chime in.

    I'd not call it a new mode, i'd rather call it a technique and we do it all the time when we use our telephones.

    Me and George had a qso on a single passband of abt. 2.7kHz, no split or offset. We adjusted our transmitters so we were roughly the same level. George interrupted me and I interrupted him when we had a question or needed clarification.

    QSK?

    Because we were same level and had only the delay of the roundtrip time, interrupts were heard nearly instantly and the talker could pause for a moment to listen to his counterpart , then resume speak, completing his thoughts and reply to the insertion. We are used to listen ( uh... :/ well.. many of us ;) ) until a transmission is finished, so it feels a bit odd to say "yes" , "right" or "say that again" while it's not your turn. But after a while it feels natural and gives the conversation a flow. It will be interresting to see how many people can attend such a qso at once whithout chaos.

    No time for crocodiles.

    73, Martin

    Dear All ,


    Hello ,

    As far as I understood is to use split operation. and there for full dublex
    So
    station A constantly RX (Freq A-20khz) and TXs (FREQ. A) on a split frequency (constantly)

    and station B does the same inverse split and also RX (FREQ A) and Tx's (FREQ A-20KHz) at the same time. (constantly)

    So both stations allegedly will talk full duplex at the same time BUT occupying double the bandwidth aka 2 TX stations on 2 channels of 2.6KHz for 1 QSO !

    This is not a mayor problem as its done in situations where crazy pileups happen. So its possible but Whether or not It is worth to be implemented because you will have half the bandwidth to operate ( in regards to, other stations IF everyone employs this very "mode" / "type" of operation ) the bandwidth of the SAT is finite and not infine.

    This is my understating of what everyone is trying to do I suppose if my understating is wrong feel free to correct me :D

    Thank you in advance


    73 DE 5B4AKV

    Alex

    Quote from 5B4AKV

    So station A constantly RX (Freq A-20khz) and TXs (FREQ. A) on a split frequency (constantly)
    and station B does the same inverse split and also RX (FREQ A) and Tx's (FREQ A-20KHz) at the same time. (constantly)

    That is not what we did, we both operated on a single "channel". Sure, split operation like you propose simplifies everything, but you are right, each qso will take twice the bandwidth.

    73,

    Martin

    Okay so in esence is mostly operator practice and keeping the TX ON all the time , and since both stations use Full dublex ( aka monitor their own TX signal) you can just make it much faster and harmonized .. and just talk right after the other person ?
    Right ?
    well its an interesting mentality given that most of the times the conversation between 2 stations its almost crystal clear audio it could be done :D
    thanks


    Alex

    Hi,

    Some notes:

    - it is not a new modulation mode, it uses existing modes, it is an new operation mode.

    - headphones is mandatory!!!

    - all stations must have the same audio level. So the strongests ones must QRP to the lowest one.

    - all users use the same frequency.


    I will try to implement in gnuradio self audio cancellation, in order not to hear your own voice.

    Quote from SV1BDS

    I will try to implement in gnuradio self audio cancellation, in order not to hear your own voice.

    Now THAT is what you're after... What a 8) idea. You had my attention before , but now i'm really thrilled.

    You buffer TX audio for the roundtrip time and have a DSP process RX audio . Just substract the buffered TX audio from RX audio. As simple as that.... :whistling:

    So all my blah blah about analog radios will work best is for the birds, :) .

    73, Martin