Posts by OE3GBB

I thought it is a designed lambda/2 wire as any impedance of this "circuit" is not transforming anything.
73's

Quote from DB8TF

Just needed another "small" PA for a fellow OM to reach QO100 with a little bit stronger Signal than with the BU500 alone.

Remembered the Nokia PA i bought abt. 2 years ago on a ham fleamarket (15€).

Cut out the "small" amp (MRF21030 driving a MRF21045) from the PCB, snowflaked and put it in a old PC PSU case together with the BU500 and a fan.

Works good to about 30W pout, clean signal.

73s DB8TF

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Bridge of BPF beween the two stages by wire? is it lamda/2?
Ggerhard

Peter, thank your for the very informative reply.
73's Gerhard

Nice project! Why did you not use only 2 helix?
Did someone try 2 or 4 short yagi with H/V orientation and 90° phasing?
Gerhard

Hello All,
in the meantime I got a second Pluto and I also finished my 250W PA with BLC2425M9LS250.
But there is a new problem with OBS now. I have used UDP-recording to port 8282 of the Pluto before with success and had fine DATV transmissions in H265 over the satellite with my 100W SSB PA in RB modes.
But now, even I can see the stream working into the Pluto (Analyse mode), when receiving directly on 13cm with Minitioune I see H265 but no video, although I get the audio decoded.
I then changed the udp stream directly to VLC (32bit) on the same PC and got the same - no video but audio.
I also tried different resolutions, SR and FEC. I am using the basic - profile from BATC for OBS.
Any ideas I could try to get the video working again?
Gerhard

Using Scan&Tioune as of today I recognized a strange background noise on my WB receiver, when doing a very wide scan. I allways was disapointed because of low MER readings. What could be the reason for this strange periodic noise? I am using a 85cm offset dish pointing to QO-100 and I have a second LNB on the side for Astra in 18 degrees.

I have tried POTY and Helix feeds so far and would like to try a Septum feed on my offset dish with f/D=0,6.
Has anyone tried such a feed for QO-100 yet? Those are widely used for 13 cm EME.
Would like to know your experiences, before I start the project.
Yes, I know it is only for TX and I need a seperate dish for RX - I just would use it for DATV uplink if it is better then the others.
73's

Gerhard OE3GBB

I have put a strip of 12x3mm Teflon into the gap, oposite the connector, and tuned to resonace by the depth of the stripe into the gap.

Quote from ZS6AAG

73 from ZS6AAG,

Working for Doctors without Borders as a logistician, i thought to use the satellite for exploration mission where we dont have any network. The only problem is that we need 2 ham radios to supervise the communication process, one at the mission headquarter and one in the field. Very few are Ham radios in the Ngos.

Any ideas are welcome to resolve this problem. I have already dicussed it with my colleague working for MSF Swiss at our headquater. Normally we use the immarsat satellite, but prices per minute are very expensive and in case of a globale emergency the satellite can be overloaded by organisations and not perform well as it was in the earthquake in Haiti. The money that we will save by using the satellite will be used for the patient....

ZS6AAG, TT8JLH, C91MSF, 3DA0MF

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Hello, my daughter is working at MSF Barcelona and I know the situation there a little bit. I would propose, that a local radio club should agree on a cooperation with MSF and set up a clubstation on their building(s). The club could then operate that station in case of emergencies. When I am back to Barcelona (after the virus) I am willing to do some coordination if necessary.

Hi Michael, thank your for your excellent explanation. Is there a online data base of the Doppler shift measured for QO-100?

Quote from DD5ER

The Doppler deviation at 21:29:00 UTC was -11 Hz at QTH Düsseldorf for the frequency 10489.500 Mhz.

Regardless of the other things that still influence the frequency deviation, it fits

Is this Doppler deviation changeing slowly or jumping rapidly? When testing FreeDV mode2020 we have sometimes very good SYNC behavior, but sometimes not. If the Doppler deviation is changeing very fast, that could be seen as a phase jump and mess up the decoder. So I a curious to know.
73's Gerhard OE3GBB

Ich hatte den 24 MHz Referenztakt für meinen modifizerten LNB verwendet. Wenn ich die CW-Barke ansehe, dann ist die Frequenz nicht ganz stabil, sondern ändert sich immer leicht (trotz SDR-Console - Baken - Stabilisierung).
Vielleicht ist der Pegel zu gering? Wenn ich das Leo Bodnar GPSDO verwende, ist es optimal stabil.
Habe auch meinen Pluto mit einem 40 MHz OCXO versucht und ähnliche Variationen gesehen, mit GPSDO war es stabil, auch mit einem externen 40 MHz TCXO war es OK.

Daher fahre ich derzeit mit 2-Kanal GPSDO (40 MHz for Pluto und 25 MHz für LNB), aber ich wollte den V3D-Vonverter für meine portabel Station verwenden.
Werde die Tests daher nochmals überprüfen und den Converter in ein Gehäuse einbauen.

Nein, zur Zeit ist die Platine noch ohne Gehäuse. Ich sollte sie also erst mal in eine Metallgehäuse einbauen.

Ich habe die OCXO-Version des V3d-Converters, aber kann sie nicht für FreeDV verwenden. Ist leider zu unstabil. Brauche einen Umbau für GPSDO oder muss den Converter tauschen.

Is anyone using this amplifier of TELRAD, from their Breeze Compact 3000 equipment?

The boards have BLF6G27-10G as driver and BLF7G27-90L as final amplifer.

I have added new bias supply, a shield

and got ~20W output in DATV.

These amplifiers seem to have been used between 2,3 und 2,5 GHz so I didn't need to snowflake at all.

Would be interesting to know, if someone else is using these boards and their experiance.

Regards

Gerhard OE3GBB

@UA1CUU

Hello, I tested a second amplifier and the quiescent current was adjustable nicely. I tuned the amplifier to 2,4 GHz using a Z-shaped brass foil soldered to ground. Signal in DATV was 2,5W out with shoulders -30 dB. So it is a nice driver amplifier for DATV or a quite linear amplifier for NB modes. The efficiency of this amplifier is quite bad, for 2,5W out the input was about 1A at 28V.

ik4idy

I didn't read your message earlier, so I have meanwhile installed the official pluto.frm firmware and it is working with SDRC again. I think I will get a second Pluto to have one for WB and one for NB.

Next problem: Is it possible, that the Pluto with the beta firmware from F5OEO doesn't operate in TX with SDR-Console any more? RX is OK, but no output signal.

DM5RM

TNX, will try that.

Well, I could localize the problem.

It was my external 40 MHz TCXO into the Pluto. I changed to OCXO - the result was very very bad!!

Then I tried my Bednar GPSDO - beautiful signal with -50 dB shoulders. That's the way to go.

Unfortunatly I had used this GPSDO for my LNB and when I changed the LO for the LNB now to an external 24 MHz TCXO, the stability of the LNB went bad.

So next days will try another method or get a second GPSDO.

Has anyone changed the TCXO inside the Pluto and had similar problems regarding the shoulders?