WB TRANSPONDER TESTS

Yes, WB Transponder is ON

Plots below show receiver spectrum with dish not pointed at the satellite to show reference noise level, and dish pointed at the satellite. Both NB and WB transponders visible. Dish is 3m, feed position possibly not optimised, and DU4BC preamp. HB downconverter. Polarisation is midway between V and H. WB transponder about 10dB above noise floor. Edges of spectrum have some intrinsic slope owing to SDR/software.

I always wondered about the limited bandwidth of the NB transponder. The designers have something in their minds that I don’t.

sv8qg : What is it that makes you wonder?

PA3FYM  I’m afraid that NB transponder will be like 20m at WPX contest in the near future…

I honestly have no idea what the activity will be in the future. It'll increase, for sure, when more commercially available equipment may become available for relative low prices. On the other hand, the whole transponder design lies in the 'microwave area' and (at least here in The Netherlands) activity on and above 23cm is very poor and not many HAMs are (primarily) interested. They prefer repeaters or short wave.

I reckon this is another issue of the category: "Let's wait and see" ?

Quote from sv8qg

I always wondered about the limited bandwidth of the NB transponder. The designers have something in their minds that I don’t.

Excellent question but rather simple answer: Power. If you do the whole math (which is easy.. antenna gains, path loss and so on) and add some secret sauce (aka values under NDA we cannot share) the completed dinner dish will be something like 250 kHz BW for the NB transponder if you ask for reasonable SSB capability with small size antennas. You only have so much power from the satellite transmitter. Bigger transponder BW = more QSOs = less power per QSO = less signal per QSO.

On the other hand, I would be thrilled to see the transponder filling up.. which means microwave activity and the ultimate proof that microwaves are easy. Something James Miller G3RUH postulated long ago..

Quote from DH2VA

On the other hand, I would be thrilled to see the transponder filling up.. which means microwave activity and the ultimate proof that microwaves are easy. Something James Miller G3RUH postulated long ago..

Well, in the old days when the use of microwaves was first coming up for satellites, it was not so easy. I remember the designs (never built one) for linear amps with tubes like the 2C39 and others. Lots of mechanical work that either took a long time or was expensive. I also still have a klystron for 10 GHz in the junkbox. And experimented with gunn-diode modules intended for automatic door opening (doppler radar movement sensors).

But a lot has changed since then. Of course due to the same developments that at the same time are a hazard to our microwave bands: large deployments of consumer-oriented devices that stimulated the development of devices and brought down the cost.

@DH2VA The majority of non technical minded hams want new countries, new bands for DXCC and new squares for VUCC. I’m sure that the next DXpeditions will be equipped with P4 earth stations. Not bad but alligators will grow rapidly...

SV8QG, please tell the community about your experiences via AO-40 - best woukd be about the L/S users on AO-40 especially the so called alligators.+

Frankly I am not so afraid of "alligators" in the original meaning (big mouth, small ears) as they were known on Phase3 satellites. There was a real reason for them - poor receiver and not hearing themselves back, increasing power until they did.

On Es'hail-2 it will be very difficult to make a bad receiver setup so everyone should essentially hear the same thing (the transponder noise floor).

So everyone should be able to hear themselves and judge the level well.

Also, the advent of SDR technology and panoramic receive display with waterfall should enable everyone to see what is happening.

Of course there is still room for "antisocial" stations but maybe we should attach another animal name to them?

dg0opk I will try this also today.. how to tweak streamreader.ini??

dg0opk Heiner

Can you tell us which commercial TV-Card do you use?

tnx

herbert

dl4sdr

dl4sdr Good morning Herbert I have here MiniTiounerExpress from DATV and TT-s2-1600 Cards from Technotrend inside a PC with PCI Slots. This I will try today with the EBSpro SW.

Jean-Pierre F6DZP had at the moment no support for TT-1600 card for DVB-S2 but I hope to convince him to do this..

I also wrote to Jean for TT-1600 and DVB S2, I hope he will satisfy us.

With EBSPro I can not reach the frequency of 10.492.

There is a limit to 10.7000.

I tried to edit the streamreader.ini configuration file without success.

I see that DG0OPK has been successful in this.

dl4sdr For using the commercial cards you need to modify the LO of your LNB to get the frequency range..