Posts by SV1BDS

Hi,

Active GPS 4 way splitter with bias tee for active antenna MMIC preamplifier and active GPS antenna.

Hi,

My 1st block for gnuradio is built successfully emulating the existing FFT process in order to try to solve the problem of finding both delay and offset.

Hi,

50 MHz - 900 MHz & GPS preamplifier is connected to a satellite splitter drived by a discone with a notch filter and a GPS active antenna. At shack drives another amplifier and a passive 4 output splitter with a 5 dB increase in GPS SNR.

Hi,

A progress report for the echo cancellation project on QO100.

The frequency offset was coarse founded using 750 BPSK beacon. Also the delay was manually coarse founded. After that the delay can be fine tuned. The frequency can then fine measured within about 0.2 Hz.

Also knowing the delay the frequency offset can be coarse founded.

The goal now is to coarse find both frequency offset and delay without knowing one of them.

The results when signals are within 1Hz is that the audio practically desapears in the nulls of 1sec period. The suppression is not below 10 dB as the audio SNR in not above 10 dB without cancellation.

It is important to mention that normal voice is used to determine frequency and time offset. Tests are on 950 by default.

The 'bird' is a nice place for expirements and not just a repeater in the sky.

Hi,

About 120 boxes in GNURadio are used now...

Hi,

FYI the algorithm for finding the delay - phase gives now pretty good results. Tests are in 950.

Hi,

Mounting POTY feeder to bracket of a 80 cm dish for portable station.

Hi,

Portable station is completed. Fan added. A LC filter was added in series with FAN to prevent interference to LNB. A series diode and a parell diode eliminate the sparc produced by L when switched on/off by the thermal switch, that will destroy it in the near future.

Hi,

A GNURADIO flowchart is under development for echo cancellation. When I have results that are of general interest I will be post them.

Hi,

There is no reason for talking in different sidebands, you can use any different frequency you want. The only reason I find is to listen both stations in DSB. Also it is suitable for only 2 stations. Is these modes are permitted on QO100?

Hi Andreas,

One use LSB and the other USB?

My idea is that they use the same 2.7 bandwidth, not double.

Hi,

Yes is real FDX, but without more bandwidth.

Hi Peter,

My consept is to use FDX as a future not as a bug. The QO100 users can see this way as a new ham radio way of communication, similar to a telephone one, without more resources. It is our responsibility all the time to respect the other ones. QO100 is a great opportunity to discover new ways of communications. My goal is to use the FDX capability of QO100 as a way to have a more user friendly ham radio communication, comparing to the others. There is a negative approach of using QO100, saying that it is nothing more than a repeater in the sky. My view is that is a great area of new expirements.

Hi,

There are 3 parameters that have to be trimmed:

- time & phase

- amplitude

- offset of frequency

May be SDR console author can implement this as have the whole package ready.

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 HB9SKA

Can you explain better or are there more details somewhere ?

What section you need to clarify?

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.

OE3GBB Hi Gerhard,

Can we arrange a sched to test the new mode?

dm4im or any other is interesting?

Hi,

The obvious question is if this "mode" is permitted in QO100 and if yes if it must be any rules for it. This "mode" maybe can be very useful in an emergency where time is critical.

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.