Posts by DL5CN

    Hallo Ömer,
    kann Eure Lösung bei einer abgesetzten Station am Spiegel (PA - PTT) samt Pluto (Daten) beide über ein LAN-Kabel steuern? Das wäre interessant, dann könnte man auf die im Pluto erzeugte PTT verzichten. In den Blockschaltbilder ist immer noch eine PTT eingezeichnet.
    Noch interessanter wird das dann mit einer 5GHZ Bridge, da ist nämlich derzeit das PTT-Signal zur PA noch nicht geklärt.
    Ich habe mehrfach schon Spiegel samt Radio draußen und Laptop am Beamer drinnen gehabt. Da wäre eine solche Lösung sehr wünschenswert.
    Danke
    73

    Andreas

    Hallo,
    ok, tut mir leid, das war eine nicht ganz korrekte Bezeichnung. Auf die Ubiquiti Nanos bin ich auch schon gestoßen. Die TRXe bekommen im Gegensatz zu anderen recht gute Bewertungen.
    Aber, das wird ja noch nicht alles gewesen sein? Für eine vergleichsweise kurze Strecke zu einem abgesetzten Spiegel samt Funkgerät tut es vielleicht auch ein reduzierter Aufwand.

    73
    Andreas

    Hallo,

    ich war erneut in einer Situation, wo ich gern eine drahtlose Kopplung zwischen Pluto und Laptop gehabt hätte.
    Welche Hardware für 5,8 GHz ist empfehlenswert?
    24 Volt am Spiegel wäre nicht optimal aber machbar.
    Sogenannte Wireless Bridges gibt es, die bekommen aber unterschiedliche, herstellerabhängige Kritiken. Mir ist auch nicht klar ob die im Laptop vorhandene 5,8 GHz Mimik benutzbar ist oder die Reichweite zu sehr einschränkt.
    Durch eine Mauer bzw. Fenster sollte es schon gehen. Meist ist ja der Spiegel bei Vorführungen im Freien und der Laptop hängt an einem
    Beamer indoor. Der mögliche Datendurchsatz spielt gewiß eine Rolle?

    Sachdienliche Hinweise sind willkommen, danke.
    73, Andreas

    Hallo,

    please don't compare levels shown by the Console without looking to the zoom of the spectrum. The level is changing dramatically while zooming. The IS0GRB receiver shows approx. 18dB SNR of the beacons. It seems to be realistic. To compare dishes or receiving situations it's more useful to look to the basic noise floor of the transponder. If this is above the LNB noise all is ok. No further improvement is possible. It is good for dish adjustment also. Because of the unknown LNB gain, S-Units as absolute levels say nothing. Very often discussed but hard to do.... I've forgotten to talk about the bandwith of the receiver. 2,4 KHz is a kind of standard.
    73
    Andreas

    Hi,

    my recommendation are chinese boards with SZA2044 or SZM 2166 Chips from Sirenza. These boards work well between the Pluto and the SG-LAB Amplifier. All this is available on ebay. The french offers seem to expensive to me.
    In addition a PC, a USB to Ethernet Converter and Power over Ethernet Adapters are useful. Please use the search function in the forum.
    All this was discussed and written down so many times.
    It would be nice to know your name.
    73
    Andreas

    Hi,
    yet another wish. If you talk about amplifers and power don't forget the intermodulation distortion. Single tone values are useless.

    The Console in combination with Pluto gives an excellent two tone signal.

    The screen shot is an AMSAT-PA (with preamp) with good linearity. Please note, two carriers with 30 dBm give 36 dBm, that are 4 Watts.

    With the preamp, the amplifier does not need any driver and can be used direct after the Pluto.
    The intermodlation distortion products can be related to the carrier level or to the PEP-level, which is 6 db more. This looks much better in the datasheets.



    Not only a "dB world" but a linear world too :-).

    73
    Andreas

    Hi Guys,
    which unit do you use for return loss? What shoes your network analyzer for S21?

    With modern concepts like network and spectrum analyzers and SDR-Technology we have to get used to logarithmic systems. There is a little software from Rohde & Schwarz for Android and PCs also. It is called "dBm Calculator". You can transform linear and logarithmic units to each other. It helps, to get familiar with all this.

    73
    Andreas

    Oh Boys,

    did you ever heard, with logarithmic values, gains and attenuations can be added easily instead of multiplying and dividing. We should follow the professionals.

    Look forward, please.

    73
    Andreas

    Hallo Frank,

    tut mir leid, ich habe was verwechselt, sri. Kühlung oder nicht hängt davon ab, wie die 40 MHz-Taktversorgung beschaffen ist. Mit einem besseren als dem originalen 40 MHz TCXO und dessen thermischer Isolierung gegenüber der Platine (Drahtstücke) ist die Stabilität ausreichend. Bei starken Temerpaturschwankungen im Freien kommt man um einen GPSDO nicht herum. Die Console zeigt die Chip- Temperaturen an.
    73

    Andreas

    Hallo Josh,

    ok, all is fine. And if you take care, the radio function ist satisfied.
    It is a pity that ICOM didn't go one step further to bring the 705 to duplex operation.
    A simple approach to a portable Radio is a Pluto followed by the AMSAT-6W-Amp.



    The rest is power supply and - if wanted - a GPS-RX. The rig is mounted with two clamps closed to the LNB holder.


    The only Connection is a Ethernet cable. And Power. 12V from a battery or from mains. With a short wiring to the Helix, 4 linear watts out of the amp are enough. As you see in the first picture with my dirty setup it can be done smaller still. A WEBSDR requires a PC. This is good to operate a Pluto too. In the field it is nessecary to have a sunshield. This is a disadvantage of modern displays not working in a bright environment.

    73
    Andreas

    ...."there is no radio that can work duplex"....

    Hey Guys, don't know if I should laugh or cry.
    Is it nessecary to talk about the Pluto again and again really? From my point of view full duplex means listening exact on the same frequency. One can see and hear stations transmitting very closed to or direct on used channels. Or finding their own transmit frequencies, scratching across the full transponder with full power. This is modern technique, horrible. I am sure, they have no spectrum displays and no duplex radios. I don't like to repeat all the other advantages of SDRs.
    But I like to repeat offering help and support if needed and or wanted. Radio Hams were always seen as open to future technologies. SDR is not future is present. I don't see any reason not to use it.

    Give you a kick and start....it is easy.

    73
    Andreas

    Hi George,

    I'll try to post a picture.



    The Controller on the board is an ATMEL TINY 45. There are Boards with a - well known - C340 Chip. There were not recognized by the Console. I don't know, why Simon uses so hard restrictions.
    I use a PTT-Chain, starting with a button (USB to TTL Converter) which pulls a status input to GND. This triggers the Console and the above shown relay. The PTT-Signal is send to the amplifier with two Power-Over-Ethernet-Adapters in combination with the ethernet cable. With this configuration, the Console itself can control PTT when transmit call sign or voice keyer.
    73
    Andreas

    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

    Hallo Ernst,

    at least I agree with you :-). The Console levels do not show the real SNR but are rather comparable under the discussed circumstances. May be, Simon will find the motivation to implement another DSP-routines one day. Probably just like PowerSDR. It's level measurement works perfect.
    In summary we are more than satisfied to have a program like the Console. All properties together give excellent satellite operation possibilities. Not to forget the Pluto. Who watched - as i did - over the last two years the deveplopment of this program has to bring a highly estimation to Simon.

    By the way, a friend, DL4JAL, desinged an USB-Control-Unit with Audio in- and output, PTT-Switch and a generator for CW. More details can be found on his website. All the functions are summarized to one USB-Port, controlled by a PIC.

    73
    Andreas

    Hallo Ernst,

    thanks for your informations. Unfortunately the Console ist not the best instruments to do such tests. To compare SNRs of a specific station between stations at different locations, there are some more parameters which has to be kept comparable. The zoom value for example has an enormous influence on the level meter. When I do the test, you described, I find 35 dB peak of the idle carrier of the CW beacon. But we know, this is much to much. To get reliable results other level meters with other instruments have to be used.
    The Console Level Meter is good for optimizing the own dish or LNB position. From former threads we know, the transponder signals will not override 20 dB SNR, also with larger dishes. If you can see the transponder noise floor clearly, your receiving system is ok. There is nothing left to do. SNRs of the stations you receive, depends on their transmit power only.
    From my unimportant point of view, when turning a dish to the sat, the increase of the noise floor is a valid criteria to optimize position and checking the own receiver. And, this absolutely independent from other parameters. We talk about 3 KHz bandwith.
    Please don't mind me, discussing it a bit controversly.

    73
    Andreas