Posts by DD1US

Hello Jean,

thanks and regards

Matthias

http://www.dd1us.de

Quote from DJ0VL

Hello Matthias,

I did some bias-adjustment tests on the PA that was sold as „ …4x BLF8G27LS-140V – STEREO ..:)“, assuming this is the PA we are talking about.

This PA uses a programmable 8bit potentiometer for the bias adjustment of the main and the peak transistors (as part of an analogue temperature compensated bias network). Unfortunately, the programmable bias voltage range of the peak transistor is limited to 0.4-0.6V.

As the PA uses the same transistor type for main and for peak channel, I simply connected the bias of the peak transistor in parallel to the main transistor and set the bias current to 1A per transistor.

73 Jean DJ0VL

PS: the other PA (2x BLC9G22XS-400AVT-2) that use the LMP92066 for the bias generation can be programmed to set the peak transistor to mode AB without any hardware modification.

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Hello Jean,

thank you for your answer.

No, I was referreing to the board with the BLC9G27XS-380AVT transistors.

Kind regards

Matthias

http://www.dd1us.de

Hello,

meanwhile I also built a DATV-PA based on such a 250W pallet from Ampleon. I am getting 230W output and the bias point is quite stable over temperature.

Here is a description (sorry it is still in German but you will probably understand based on the many pictures):

http://www.dd1us.de/Downloads/…0BPC2425M9X250%20v1.2.pdf

If there is enough interest I might translate it to English.

Kind regards

Matthias

http://www.dd1us.de

Hello Gerhard,

nevertheless thank you very much for your answers.

Kind regards

Matthias

http://www.dd1us.de

Hello Gerhard,

ok, no problem. I was just wonderingas this PCB looks promising.

Are you aware of any information with respect to the adjustment/programming of the board?

Kind regards

Matthias

http://www.dd1us.de

Hello Gerhard.

have there been meanwhile any results in the evaluation of these 2.6GHz PA boards?

Kind regards

Matthias

http://www.dd1us.de

Hallo DL8YF,

also meine Rechnung sieht anders aus:

Downconv 286 Euro

Upconverter 214 Euro

Gehäuse Surplus/Flohmarkt selbst angepasst 20 Euro

Kleinteile 40 Euro

Isolator 30 Euro (damit ist der Sendezug incl. Endstufe auch bei nicht angeschlossener Antenne oder Kurzschluss 100% geschützt)

Damit komme ich also dann auf Kosten von 590 Euro und wenn man gerne bastelt hat man viel Spass beim Aufbau.

Es gibt sehr viele OMs die über QO-100 mit den AMSAT-DL Komponenten qrv sind, incl. DP0GVN in der Antarktis
mit sehr guten Signalen. Ich selbst nutze sich auch in meinem Portabelsetup. Der Downconverter hat in der Tat
recht viel Verstärkung um auch längere Kabelstrecken überbrücken zu können. Wenn das jemnd zu viel ist dann
reicht ein kleines Dämpfungsglied aus 3 Widerständen und Du kannst das entsprechend an Deinen Transceiver
anpassen. Ein passendes kommerzielles Dämpfungsglied kostet gebraucht ca. 15 Euro.

Du hast es aber richtig gemacht, wenn Du mit den Kompoenten nicht klar kommst dann nicht ewig ärgern sondern
etwas fertiges kaufen und sich daran freuen.

... suum cuique ...

Viele Grüße

Matthias

http://www.dd1us.de

Hi Tom,

thank you very much for your great work.

Could you please issue a pull request in Github and we will include your changes in the next official version.

Kind regards

Matthias

http://www.dd1us.de

Henry,

I think it should be 9-10dB MER of the DATV-beacon if the wideband transponder is empty.

Regards

Matthias

http://www.dd1us.de

George,

there is no reason why this should be forbidden.

As long as you use SSB and stay within 2.7kHz transmit bandwidth it is ok.

Go ahead and try it. I wish you a lot of fun.

Kind regards

Matthias

http://www.dd1us.de

George,

well, we have to acknowledge that not all radio amateurs are able to actively contribute to science and society. This may be due to a lack of technical knowledge or a lack of free time besides the daytime job.

For such people there is still the option to support organizations like AMSAT by money (by membership fees or by donations) and thus enable those organizations to forster contributions to science and society.

But for sure there are also quite some, who do not contribute anything but only benefit from the knowhow, time and money others are spending. As long as they value what they are enjoying it is fine for me but those who are only complaining without contributing are a real PITA.

Kind regards

Matthias

http://www.dd1us.de

Quote from SV1BDS

Hi,

A SDR based system must use the capabilities of software based solutions in order to do things that can not be done or is very complicated to do with hardware. All of us try to replicate hardware solutions into the software solutions and not think what new features can be implemented.

Good point George, but you still have to be compliant with the regulations in your country and according to your license.

Regards

Matthias

http://www.dd1us.de

Hello Gerhard,ok.

I think if you transmit with low power then that might be feasible with a Pluto. I wish you good luck and make sure you are measuring your emissions at a dummy load before transmitting with an antenna.

Kind regards

Matthias

http://www.dd1us.de

Hello Gerhard,
what are the requirements in OE-country with respect to spurious emissions of such a repeater (in band, out of band, harmonics)?

Kind regards

Matthias

http://www.dd1us.de

Sehr schön Armin,

vielen Dank für die interessante Beschreibung!

Falls jemand der Leser die Anleitung als pdf Datei haben möchte, um sie zu speichern oder auszudrucken,

dann kann er mich gerne anschreiben. Ich habe die Webseite von Hand in ein Word- und dann pdf Dokument konvertiert
und werde sie euch gerne zusenden (es muss sich ja nicht jeder die gleiche Arbeit machen).

Viele Grüße

Matthias

http://www.dd1us.de

Hallo,

ja, vielleicht sind die 20dB auch zu konservativ. Hauptsache die Erklärung wird anerkannt.

Danke für Deine Daten.

Gruss

Matthias

http://www.dd1us.de

Hallo Robert,

wie bist Du auf die Winkeldämpfungswerte von 50dB gekommen?

In vielen Literaturstellen wird auf ca. 20dB verwiesen, selbst hinter dem Spiegel.

Gruss

Matthias

http://www.dd1us.de

Hi Detlef,

really, are you sure ?

I think everybody should think about whether he wants to buy from someone who is ignoring clear rules of the satellite operator and
even makes money selling such non compliant components.

For me I have made my decision.

Regards

Matthias

http://www.dd1us.de

Detlev,

your first link shows products supporting only semi duplex and I do not recommend to promote them here in our list.

Kind regards

Matthias

http://www.dd1us.de

As Mike pointed out operating the Pluto via the LAN is no difficult.

Here is a decription:

Connecting the ADALM Pluto to the Local Area Network

Kind regards

Matthias

http://www.dd1us.de