New DXpatrol "Groundstation" now Full-Duplex !

Dear OM,

Last week i purchased an DXpatrol ground station. I was curious to the inside of the unit. No single picture to find on the internet.

So I made some myself.

73's Rob, pa3eke

Under the mainboard you can find the amplifer.

Tnx for the pictures Rob !.

DXPatrol did not respond to my request for pictures :-/

• On the first pcicture - there is an unpopulated battery next to the GPS unit? How long will the GPS fix take?
• On the second picture - the board is mounted slanted in the case or is this an optical illusion?
• What are your experiences with the ground station? The VOX is working fine? Also with CW?

Thanks in advance Rob!

//Dietmar

Hello Martin,

looking at the manual of the QO-100 Groudstation of DX-Patrol indeed it shows that the transverter is working only simplex.

AMSAT-DL has made very clear for a long time than full duplex operations is requested by users who want to use QO-100.

DX-Patrol is making money by leveraging the investment others have made by implementing the QO-100 ham radio satellite
and they should respect the rules given by the operator of QO-100. Yet it looks like they are simply ignoring it.

I think this is very disappointing!

We can already today see the problems many people, who are using simplex operations, have to demonstrate proper operation.
They talk over each other frequently without noticing. In pileups it is quite easy to distinguish those with a proper full-duplex setup
and good operating skills from the others.

Hopefully many radio amateurs will understand that this transverter is not compliant to the requested operation mode on QO-100
and will thus choose one of the many other better solutions.

Kind regards

Matthias

http://www.dd1us.de

Hello Dieter,

• It seems indeed a upopulated place for a battery, see picture. GPS does take a looooong time to fix >5 min
• Optical illusion due distortion of the wide angle lens on the camera
• VOX working suberb in SSB, CW not tried. Overal i am pleased with the ground station. Its a grab and go for portabel use of the oscar 100. No build up heat in the unit. You have to use the enclosed LNB because the DX patrol goes straight to 70 cm.

73's Rob, pa3eke

Hello Martin,

Good point, indeed no duplex facility in the unit. You have to find a solution for your self. I have a second dish with RTL stick and raspberry PI and RTL_TCP server. I am synchronizing the Icom 705 with SDR console and Omni rig. In the field I can monitor by using the websdr and a phone. But for sure a duplex facility is missing. A build in downconverter to 2 meter can do the trick but it’s lacking

73 Rob

Hi Rb,

I am afraid that such a downconverter will not help. It looks like during

transmission the refrerence frequency for the LNB is not supplied to it.

Thus the LNB will not work. You really need a second setup which is

possible but not efficient at all.

Regards

Matthias

http://www.dd1us.de

Hi Guys,

use a modern SDR-Concept and all the trouble is gone. Full duplex, easy tuning, synchronize with the PSK_Beacon, only one oscillator for tx-stability, tx-equalizer, envelope compression, spectrum display, two tone signal for linearity tests, what else do we need? Don't be afraid in front of digital technologies. You are not alone. Don't hesitate to use it. If nessecary, you get help. The terminal program from G4ELI is free of charge. From my point of view this is very remarkable.
Have fun.
73
Andreas

Hello

I think the operator is more responsible for being simplex or duplex at the sat instead off people who sell the stuff. I use mostly my simplex station with a websdr on the background( on smartphone or pc) instead off my other setup and had never complains about being of freq.

When there is a dx station active, and not working split, why so much duplex working stations are to high or to low on his freq??? Their stations not calibrated correctly? +-30% stations are off freq! This is not the case when the dx station is working split because you can call wherever you want.

Allways complains about being simplex or duplex, why not complaining about all the stations being much stronger then the beacon? That's also a 'rule'.

Best 73's, Jerry

Hello, I got the new GS from DX-patrol monday.

A few remarks about the duplex, yes the unit is not duplex, so what.

advantage: if i turn on 70cm and hear a station in downlink, I know i am on the correct uplink.

I have been listening a few weeks on QO-100

Observations:

I see the tuning carrier from a lot of stations going over the band till they are plus minus on the situation they want to work, not good

I hear a lot of stations up to a few hundreds of Hz above and below the station they want to work, not good

I hear a large number of stations who are extremely loud (just above the beacon level), sound to me they want to see when Leila kicks off,, not good

There is nothing wrong with QO100 simplex groundstation, on the contrary, the whistling and hola is not necessary anymore....

Have I got full duplex, yes (otherwise i could not see the whistlers going across the band).

How was it done?

I split the RX signal coming from the LNB to a SDR stick (the splitter has a DC by pass on one port so that LNB works OK)

Using SDR consoles V3 get radio and stick nicely synchronised.

A few more things about the QO100-GS:

- it is vox operated, 2 VOX (one for PA and one for transvertor), both inside

-there is provision for a hard line PTT, (F6-1 F6-2 connector), short them out for PTT.

One thing is that you might need to connect the external PTT of the amplifier to the F6-1 line aswell

The lock (from the OCXO takes just abt a minute.

The lock from the satellite takes a few minutes.

Now let the flames come

Martin,

The RX setup (SDR-RTL stick) is used as wideband RX monitoring.

Advantage:

I see the whole band and where there is activity.

I see the tuners drifting over the band and see where they stop,.

And the unit does not violate any rules at all.

It all depends on how it is used, so down to operator.

(just like those transmissions that are stronger than the beacon)

If you use a nice sdr (with the added advantages) you play nice.

ps1: I have made ZERO QSO on the QO100 bird, playing just on RX for a long time.

ps2: when I saw the unit advertisement, it was clear to me that it was simplex unit.

I sold my seperate dx- patrol up down convertor (144/432) , which was full duplex, but to much cabling, GPSDO, seperate amp etc etc

Main reason for getting the DX-patrol GS, that it had all in a box, up/down/gpsdo, and its small, very small size to take in hand luggage.

I even got the dxpatrol helix antenna as the size compared to poty and LNB is smaller.

I considered DXTO from India (as that one has a 28MHz IF) which would have been cheaper on the IF rig , but price +taxes scared me off.

Now just need to get a small dish antenna that will fit the luggage as well (after the covid pandemic)

And to stay in the sat footprint when picking a location.

Johan

as time passes the 1st mods on the grounstation have been done.

My unit has external ptt control added already.

At the moment i'm looking to mod the rx circuit to have the rx splitter inside so that the sdr stick can be put inside the box.

The backplane of the box has room left for a usb receptable.

Would be less cabling .. and an answer to the duplex question.

And limit your power so that its not stronger than the beacon..