Posts by pe1chl

    Where can i find more Infomation using an ADALM PLUTO for TX ing to QO-100 ?



    These stations are usually using the newest version of SDR-RADIO which has support for the ADALM PLUTO.

    It generates about 0dBm at 2400 MHz so you first need to amplify this a bit (say 10-15dB) with one of those generic amplifiers, probably insert a simple filter centered on 2400 MHz, then a 5W or 10W WiFi booster. Those items are available from our Chinese friends for bargain prices.

    The frequency stability of the ADALM PLUTO is not great, it is better to replace the 40 MHz TCXO with a better one or a GPS-stabilized source e.g. the Leo Bodnar Mini GPS clock or some home-made thing.

    But frankly it would be best to replace the ADALM PLUTO with something that is specially designed for this purpose (better TCXO, 2400 MHz filter included, a bit more output so it can drive a WiFi booster or even with integrated PA).

    Such a box will undoubtedly appear on the market.

    To be able to use a HF transceiver that has no 144 or 432 MHz capability I am looking for a tTransverter to 2,4 GHz with 28MHz input, does such a product or kit exist?

    Probably not. The problem with upconversion by mixing is that the output of the mixer does not only contain the wanted product Fosc+Finput but also the Fosc-Finput (the mirror) and the Fosc itself.

    When the ratio of mixing is too large, like when going from 28 to 2400 MHz, these products are relatively close to the wanted frequency and more difficult to filter.

    Remember the entire 13cm band is from 2320 to 2450 and so a single fixed filter would not do anything at all, it would have to be a tunable filter.

    Even when you restrict the use to only Es'hail-2 there would still have to be a filter that passes 2400 MHz and strongly rejects 2400-28 and 2400-(2*28) MHz.

    While that of course is possible, it makes such a transverter harder to construct than one with an IF of 432 MHz, where the unwanted products are 2400-432 and 2400-(2*432).

    (even using 144 MHz as a first IF is something I would rather avoid when starting with zero requirements)

    When you really want to start with small budget it may be better to look at SDR solutions. While an SDR suffers the same limitations, the unwanted frequencies are so close (the IF is normally near zero) that it is okay when they are down by at least the S/N ratio of the signals on the transponder plus some margin, say 30dB total. That is achievable with an I/Q system as used in such SDRs.

    Ready made SSB transmitters for the Es'hail-2 uplink will likely be developed and become available, but right now there already are stations that use something like the ADALM PLUTO with a small 13cm pre-amp and a WiFi booster as a final amp, requiring at most some filter for really clean signals.

    Such a construct would cost ~300 euro in total, plus of course a computer to run the software.

    Already working... unbelievable!

    Well I have been on the WebSDR at work too, last week. Especially when the transponder was suddenly opened sooner. And that first night will never be forgotten (unfortunately I was not ready, put up the antenna only next day).

    Our group is also working on TV stuff. We have the ATV relay PI6ATV that transmits a multiplex of 17 channels in DVB-S2 on 3cm already (some of the HD), and we are arranging for reception and relay of the QO-100 wideband TV (one-way of course), received on a 2.7m dish using MiniTiouner and relayed from the receive location to the repeater via HAMNET link. Testing is going on right now, I saw parts of the beacon video coming by.

    Hi Peter - I presume you have been sleeping all day, what a week :-)

    Paul M0EYT ( has been requesting pictures to make a gallery on his site, but I have not seen it yet. I have put my station info on my QRZ.COM page.

    I have 11-12dB transponder noise above LNB noise here.

    I have heard a couple of Brazilian stations but nothing from Thailand and India yet.

    Of course, people with less money to spend may have chosen to wait until the whole thing actually works before constructing a station.

    But I heard other exotic stations like Western Sahara.

    The majority of the stations is English, German, Dutch, French etc, but I am sure that is going to change.

    At first I did that too, but of course "only if RX frequency changes" is quite a lot when you are tuning around the band, and it is kind of useless to make the TX track all that.

    Yaesu CAT is a dumb protocol and when timing works out incorrect all kinds of things can happen. There exist simple commands that say things like "erase all memories" and "return to factory initial settings" that you do not want the radio to execute, yet they are just 5-byte sequences of which only the last byte is significant, no checksumming whatsoever.

    So I prefer to limit the transmission a bit and hitting a key before transmitting is not much effort for me. For you with the touchscreen solution it may be different.

    Found some renamed chinese lnbs on market.. ordered some models and i will open them up to see if they have pll or dro..

    I got one of those SR-3602's and on the box and LNB there is NOWHERE the mention of PLL so I complained at the store and the assured me it was PLL.

    So I opened one and indeed it is true!

    (this LNB cost me only 7.50 euro including shipping... what times are we living in?)

    DL3DCW the frequency stability of my system is by far not good enough to observe that kind of behaviour...

    I normally tune by rolling the mousewheel while in the waterfall or spectrum (not in the frequency bar of course) and it works smoothly.

    Initially I was re-adjusting the LNB LO frequency manually via the "configure I/O devices" dialog when it had drifted too far, and when doing that it would forget the settings of the panoramic display.

    But now I am controiling it via the TCP port and this is no longer happening...

    I have one of those "special CAT cables" which comes with a USB serial converter and the mini-din plug for the FT-817. It is an FTDI chip which was programmed to look like special for some software package but using an FTDI tool I have re-programmed it to look like an ordinary USB serial and it shows as /dev/ttyUSB0.

    At first I had the trx constantly tracking the tuning, but then I remembered that Yaesu transceivers sometimes crash or even corrupt their settings when sent many many CAT commands so I changed it to only set the frequency when hitting a key.

    This is better anyway, as now I can tune the receiver while transmitting without risking to re-tune the transmitter. I even can do a re-calibrate while talking.

    I have started to build some program to do this type of stabilization, and what I already have now is a big improvement in handling of the station already.

    It is a program that I use in a small window alongside GQRX on Linux, it displays the current LNB LO and Rx frequency and when I hit a key it switches to either beacon, I can tune that to a predefined audio frequency (in the audio spectrum/waterfall subwindow) and hit another key. It then re-calculates the LNB LO according to the tuning done and switches back to the frequency where I was tuned.

    During listening I can also keep the frequency of the received station OK using left/right arrows and it will tweak the LNB LO setting so the indicated station frequency remains the same.

    The next step will be some automated tuning. The problem is that GQRX has only a single virtual receiver, so I cannot keep a receiver tuned to the beacon. However, that should be possible to add as it is built on GNU Radio.

    I also have a key that instantly transfers the tuned receive frequency to the corresponding Tx frequency on the FT-817 used for uplink via CAT. Much more convenient than whistling and watching the sweeping carrier on the waterfall!

    PS: To get class A, class B need to collect 1000 QSOs (recommended format .ADIF) to get to class A licence.

    Well, here in PA (Netherlands) a Novice license is not allowed to transmit on 13cm either, but at least you can get a full license by passing an exam, no QSOs required (and it is even not required to get a Novice license first, I never had one and immediately passed the exam for full license).

    However, we are only allowed to transmit in the 2400-2450 band when it is to a satellite. It is of couse advisable to make a directed beam as much as possible to avoid interference with WiFi.

    I am using a lot of WiFi/Router equipment from Latvia :-)

    I told DB2OS about the problem at A71A and they immediately went to investigate that. It was clearly visible when they tuned around with constant carrier.

    This is likely unrelated to the beacon issue. Remember the A71A clubstation and the Es'hail teleport are two different stations.

    On the beacons I occasionally heard interference that resembles RFI from someone standing nearby while using a GSM phone. That is why I suggested the ferrite beads.

    The transponder is made by the manufacturer of the satellite, MELCO.


    It is based on their standard transponders but with changes because of the different type of usage.

    There are block diagrams in the presentations that were given by DB2OS during AMSAT-UK satellite colloquium and others, you can find them on Youtube in the AMSAT-UK channel:

    The antennas are horn antennas (without dish) I think. Exact details are a bit difficult to get "because of NDA" :-)