Posts by DL5CN

Hallo Stef,

wenn das so ist, dann wünsche ich mir an allen Plutos einen gescheiten PTT-Ausgang.
Bisher leider gar nicht oder nur mit F5OEO-FW.
Das wäre mal was, mit dem Wunsch bin ich sicher nicht allein.

Danke
73
Andreas

Hallo M0MDS (name?),

there is something basicly wrong with your receiver.
What is the current consumption of the LNB? There must be much more signal even if the polarisation is false. If you switch on LNBs supply, the noise floor in the SDR Console gets up. Don't care about the skew angle, this is a further step. All the settings for the Console are correct?
Did you ever try to receive terrestic signales with the Pluto, VHF-, UHF Relays for example.

73

Andreas

Hallo,

no idea what happens inside the Pluto. Especially when playing around on different frequencies, it happens some times, the output was very low. The "repair technology" was to start transmitting at VHF with increasing frequency. May be, it could be a miracle, it helped. Never checked the results with different firmwares. Of course, first step is to use the actual one or try a DFU setup.

73
Andreas

Hi Pat,

with a normal constellation of Pluto and CN0417 you can expect a level around +20 dBm. The Pluto itself should be used with 0 dBm and a good linearity. In case of low level output try to transmit on another (lower) frequencies and increase stepwise for example 100 Mhz. Not sure if this will help, I had this situation also and could solve it.

73

Andreas

Hallo Ulrich,
den Effekt hatte ich auch. Mehr zufällig hatte ich zur Fehlersuche begonnen, bei niedrigen Frequenzen (100 MHz) zu senden, was überraschenderweise wieder einen Ausgangspegel ergab. Eine Steigerung der Frequenz (100MHz-Schritte) führte zum Erfolg. Den Grund für den Effekt kenn ich nicht, inwieweit das in Deinem Fall zutrifft bleibt leider Spekulation.
Viel Erfolg.
73

Andreas

Hallo,

don't send direct mails to Simon. This is the wrongest way ever. There is a forum where such things can be discussed. By the way, transmit power is adjusted once. No need to move the slider.

73
Andreas

Sehr schön,

aber weiß Jemand wo das stattfinden wird? Genauere Daten mit einer Ortsangabe wären hilfreich.
Auch unter dem angegebenen Link finden sich keine Details...

73
Andreas

Hallo,

I received the surprising information, the actual Adalm Pluto Firmware 0.38 supports the GPO-Port. It is possible than to use it as PTT. As far as I know, GPO is supported by DATV-Firmware only, for example F5OEO?

Can anyone confirm this, please.

At present I use POE-Adapter to bring a PTT-Signal to the PA. It works but the plugs of these adapters are not very reliable.
Beside all this , with a PTT-Signal direct out of the Pluto it is possible to use it in normal network. This is an advantage.

Thanks in advance

73
Andreas

Hallo,

a combination of a patch-antenna with reflector disk and "looking through" LNB is successful used by so many stations. The dimensions of the patch are available in the net. All other compromises go in the wrong direction. Adjusting the distance between the patch and the reflector at some points, the correct matching diagram can be achieved with the help of small network analyzer. My recommendation is a SAA-2N. It has N-connectors, a calibration kit for SOLT and a case. The dynamic range is remarkably.

A lathe can be helpful to assemble a patch. If the reflector is made of brass 1mm and the patch itself of copper 0,5 it's easy to adjust. Even LNBs with a horn can be used. Remove the horn and drill a little brass tube to carry the patch with reflector. Add a plastic lense from an

useless LNB.

Soldering is easy with hot air. Between reflector and patch there is a 3mm gap. Fix it while soldering with some pieces of 3mm thickness.

By the way, a clear difference with this patches and normal helix antennas with 3,5 windings couldn't be found. If a helix is mounted on a similar reflector disk with brass tube, antennas are easy to change for performance compare.

Have fun, 73
Andreas

Hallo,

bei dem Verstärker kann man nicht viel falsch machen, ich würde allerdings zwei in der Leistung abgestufte MMICs verwenden. Z.B als ersten MMIC RFGA2054 und danach einen TQP7M9103. Das dürfte insgesamt eine bessere Linarität ergeben. Die möglichweise anzupassende Dimensionierung der Beschaltung steht im Datenblatt.
Es gibt sehr gute Erfahrungen mit einem Asien-Verstärker mit dem QORVO-Chip SZA2044 (1W). Das ergibt nach dem Pluto locker 200mW PEP mit ausgezeichneter Linearität. Allerdings sind offenbar auch Fake-Chips unterwegs, Verstärker mit dem SZM2166 (2W) erwiesen sich als unbrauchbar.

73

Andres

Hallo George,

Probably this is not a good news but this S-Meter readings don't show the real situation. All user signals, the beacons also are referred to the transponders ground noise. How much noise you will see depends from the overall gain in your receiving chain. And all the user signals are not more than 20 dB above the basic nose. This is a graphic out of an official AMSAT-Information edited by DH2VA.

Believe or not, the max. SNR reaches 20 dB even with big dishes . Don't worry about your S-Meter, you are not alone. Most of commercial radios have this problem. The worst is ICOM, in some ICOMs below S9 one S-Unit is 3 dB only. Don't know who did this but it is total unacceptable. From my point of view it is more than respectiveless against the radio amateurs. Who is ICOM that they define their own S-Units? Hope, I am not the only one who is going to critisize this.

(I own a HERMES with PowerSDR-Software. I can show a straight line from -130dBm to -14 dBm (overdrive of the AD-Converter). And one S-Unit is 6 dB at all levels. And this is not a commercial radio. PowerSDR was done from a handful of highly qualified radio amateurs. Sorry, but I am excited about this always).

SDR-Console is a wonderful program too. I and all my friends are very lucky about it. I did many recommendations to them.
Simons work has to be highly appreciated, no question. The advantages while satellite operation is unreached from other solutions. But the level measurement is a bit to optimistic. We know this and all is fine.

73
Andreas

Hallo,

the Level-Information from the Console for any signal exceeds the real values. It depends from the the zoom of the spectrum and modulation. Both WebSDRs give realistic SNR of the Beacons. It is less then 20 dB.

There is an AMSAT-Document with a graphic that shows possible SNR is going into a saturation of approx. 20 dB with increasing dish size. By the way any SNR-information has to be completed with the receiving bandwith. In a CW-Channel ist less noise so the SNR of a single carrier goes up with lower bandwith. Usual is SSB with 2,4 KHz.

In this thread the improving of receiving is discussed.

Post

RE: Antenna size for edge of footprint reception (3.9 degrees)

Hi Simon,
the QO-100 with its narrow band transponder will show a characteristic picture, two beacons at the edges and one in the middle. My recommendation is to use a wide spectrum for searching with more than 500 KHz. Do not look at a specific signal but at the peaks of the beacons. Don't care about the exact frequency of signals but try to optimize the levels first.
My "search equipment" is a bias tee, a little battery and a RTL-Stick, I prefer SDR#. It is completed with a small laptop. This…

DL5CN

Apr 27th 2024

73
Andreas

Hi Simon,

the QO-100 with its narrow band transponder will show a characteristic picture, two beacons at the edges and one in the middle. My recommendation is to use a wide spectrum for searching with more than 500 KHz. Do not look at a specific signal but at the peaks of the beacons. Don't care about the exact frequency of signals but try to optimize the levels first.
My "search equipment" is a bias tee, a little battery and a RTL-Stick, I prefer SDR#. It is completed with a small laptop. This all is independent from the radio and can be used even if the dish is outside. I am not sure if you will "see" the transponders basic noise floor? With high angle elevation like here in Europe the noise is a very good indicator for fine adjusting a dish. It is totally independent from any frequency.

When will you start with your activity? Probably this will give a heavy pile up.

73s
Andreas

Hallo,

it is good to define phrases, why not. In addition, my comment is, in some cases the prenounciation could be clearer. Especially some weak signals are hard to copy even if the audio has low frequency parts only.
No harm meant but some final amplifiers generate a lot of distortion and intermodulation products. It is easy to check the correct driving power and audio gain looking at one of the two webreceivers. At least the transponder itself is a flying spectrum analyzer and shows the own signal. Another question is how to hit the correct frequency if calling someone.
As often repeated, for this reason the AMSAT always refers to duplex radios. No need to talk about the advantages of software defined stations. The daily signals show it.
Don't mind me and I am far away from critisizing but a clear and linear SSB-Signal should be the goal of every amateur radio station.
And guys, don't hesitate to mention it.

73

Andreas

Hi Mark,

all looks great. Here is a picture of my "radio", mounted closed to the LNB.

It is a good weather unit. Don't care about the plastic cup which mechanical protects the helix. It was filled with beer once.

Your PSU seems to be a little bit oversized .

Before portable operation you often have to adjust the dish, I recommend to use the transponders basic noise as an indicator.

It can be seen cearly using 2 MHz bandwith. The software is SDR# with RTL-Stick V4. The rising of the noise while optimizing the dish is independent from any signal and frequency. Behind my dish, there is a little board to carry a small laptop. Moving the tripod and the dish and seeing the maximum noise at the display takes some seconds only. Especially outside of the motor home it seems to be useful using the RTL-Stick, a little battery with a current limiter, a bias tee and a laptop, independent from the radio and the Computer inside. I call it the "setup kit".

In the last days I made some bad experiences with heavy wind. The radio acts as like a sail. More stability is needed.

What is about a PTT-Circuit in your setup?

Regards
73
Andreas

Hi Mark,
all the components you have are necessary. For portabel acitivies I recommend an outdoor unit very closed to the dish, probably fixed at the LNB carrier, as I do. That means for transmit the Pluto as the central part, CN0417, power amplifier. For receive the LNB and the Pluto are used. Both frequencies can be handled by the Pluto, no further mixing. A network cable goes into the motor home. The receiver is locked with the SDR console. If you expect different temperatures, a stabilized external 40 MHz-clock for the Pluto gives more fun, even when it is mounted outside. Leo Bodnar is my tip. No matter what type of dish you will use. The radiation pattern of the transmit antenna should match with the f/D of the dish. Mounting of a normal LNB with a feed horn behind the reflector plate of a helix cannot be the optimum. Some friends and I use slim line LNBs with a plastic lense instead of a Horn. The wave Guide with the lense can be placed in between the Helix. Both antennas are closed to the focus point. If you like, I send pictures. Another advantage is the easy change of transmit antenna type.
73
Andreas

Hi,

some additional ideas. I agree with Sandro fully. If you like to use LimeSDR or Pluto on the same band, with the same frequency, a good isolation of the receiver input is nessecary to avoid overdriving when amplified transmit power can reach the receiver. Probably a direct short cut at the boards input is required. With separate connectors for transmit and receive only an antenna relay is used. But it's isolation must be perfect. It is funny to play around with SDRs on VHF and UHF. But using it for QO-100 it is a complete different story.

73
Andreas

...das liegt daran, daß die meisten Journalisten nicht zuhören, wenn man mit Ihnen spricht und dann "irgendwas" schreiben.
In den seltensten Fällen bekommt man einen Artikel vor dem Druck nochmal zu Gesicht, leider.
Natürlich herrscht meistens Zeitdruck...

Hallo,

die Frage lauetet, ist die von der Pluto-Firmware erzeugte PTT immer noch 800ms verzögert?
Ich hatte das mit dem Evariste mal besprochen, er hatte das bestätigt und auch Änderungen zugesagt, ich benutze mittlerweile POE-Adapter. Kann also sein, die Verzögerung ist jetzt geringer? Für SSB sind jedenfalls 800ms zu viel. Für den Pluto-Betrieb in einem Netzwerk
wäre die vom Pluto selbst erzeugte PTT günstiger.

Hat schon mal Jemand den Pluto-Spike angeschaut? Wie hoch ist der tatsächlich und wie lang?

73

Andreas

Hallo,

the Pluto boards are multilayer and have higher thermal capacity. With two solder irons and some low melting tin it will be possible. With hot air soldering a mask of aluminium foil around the oscillator is recommended to avoid blowing other nearby components away.

73
Andreas