Posts by pe1chl

  • TX: legal considerations

    It of course varies by country and by current situation. Here the regulations changed on 1-1-2019 so now, like in the past before the EU trade liberalization changed that, it is again illegal to possess or sell transmitter equipment without license or registration, not only to use it. And there is special attention to items like Jammers and amplifiers.

    So I guess it would not hurt to make some note about "for registered radio amateur" on the label... ("licensed" instead of "registered" in countries where that still applies)

  • AMPLEON 250W PA module for 2.4 GHz

    120W PEP here in the Netherlands.

    But we have only 2320-2400 on 13cm, plus 2400-2450 "only for satellite use".


    Of course Es'hail-2 is the first satellite where this is going to realistically matter, so we have to see what happens. When the authority gets overwhelmed by interference reports due to all those amateurs uplinking on 2.4 GHz, the regulations could change...

  • WB TRANSPONDER TESTS

    Frankly I am not so afraid of "alligators" in the original meaning (big mouth, small ears) as they were known on Phase3 satellites. There was a real reason for them - poor receiver and not hearing themselves back, increasing power until they did.

    On Es'hail-2 it will be very difficult to make a bad receiver setup so everyone should essentially hear the same thing (the transponder noise floor).

    So everyone should be able to hear themselves and judge the level well.

    Also, the advent of SDR technology and panoramic receive display with waterfall should enable everyone to see what is happening.


    Of course there is still room for "antisocial" stations but maybe we should attach another animal name to them?

  • 20W WiFi Booster module for 2.4 GHz

    That is another design, it is bi-directional (also includes a preamp) and a version exists that has power supply over coax so you can mount it in the mast (with an indoor bias tee included).

    Ofcourse it has to be checked if that performs as well.. the construction looks more wimpy.

  • WB TRANSPONDER TESTS

    Quote from DH2VA

    On the other hand, I would be thrilled to see the transponder filling up.. which means microwave activity and the ultimate proof that microwaves are easy. Something James Miller G3RUH postulated long ago..

    Well, in the old days when the use of microwaves was first coming up for satellites, it was not so easy. I remember the designs (never built one) for linear amps with tubes like the 2C39 and others. Lots of mechanical work that either took a long time or was expensive. I also still have a klystron for 10 GHz in the junkbox. And experimented with gunn-diode modules intended for automatic door opening (doppler radar movement sensors).

    But a lot has changed since then. Of course due to the same developments that at the same time are a hazard to our microwave bands: large deployments of consumer-oriented devices that stimulated the development of devices and brought down the cost.

  • What TX amplifier do you plan to use?

    gain = 10*log((4*pi*A)/labda^2) = 10 * log((4 * 3.14 * .6 * .997) / (300 / 2400)^2) =

    26.8dBi.

    Of course a little less in practice due to imperfect illumination.


    Well, at least it does not seem to be a ridiculous advertisement spec...

  • 2,4GHz transmission check

    Ah yes I of course have my G0MRF converter for P3d... didn't even think of that!

    But I only tested on 2320.2 until now so that is not so practical for now.

    Of course once we are on 2400 it can be used...

  • 2,4GHz transmission check

    I have a local WebSDR on 2320 MHz which I used to check my SG LAB transverter set to this frequency.

    When Es'hail-2 is opened I can change it to 2400 with a jumper setting.

    By the time I build this thing in an extra enclosure (with a PA of suitable size, to be determined after opening of the transponder) I will probably make that controllable with an external switch so I can use the same thing for 13cm DX when desired.

  • Captures of PLL LNB drifts over time. WIth & without mods.

    Quote from YO9HZN

    I will try to send a e-mail to ConnorWinfield to get the whole picture.....

    It would be very interesting to know if these modules are only a TCXO (with a crystal operating at the specified frequency) or if they indeed are some kind of synthesizer that generates the frequency printed on the package from some other crystal frequency.

    Of course it would be attractive for the manufacturer to do that, as they could manufacture a single device and then one-time-program it to the desired frequency, but frankly I find it hard to believe that manufacturers would do that without mentioning any of it in the datasheet or even the specsheet.

    They should know that not all users of the product can live with the disadvantages of having a synthesizer.

    A fixed divider, that would be another thing. But you would expect that mostly with low-frequency blocks specified for digital clock usage. E.g. a 1 MHz block could contain an 8 or 16 MHz crystal and a divider.

  • 3cm Kuhne transverter

    It is likely that sensitivity will not be an issue at all.

    With my low-end setup (80cm "transparent dish" of questionable geometry, 7-euro LNB from China, and SDRplay RSP1a (or RTL-2832 stick) I get the noise floor of the transponder at 12dB above the noise floor of the receiver equipment.

    So there is no reason to try to get the most out of the converter, pre-amps etc. Especially not on narrowband. Maybe on wideband, when you want to use a dish smaller than what is envisioned.

  • NB passband monitoring

    On my 80cm dish with unmodified SR-3602 LNB and SDRplay RSP1a I have the transponder noise at least 12dB above the noise floor, so I think you will have some performance to gain there...