today we built the full PA equipped with all boards,
the board in the middle is the (already released) 10W-PA. Right of it is the prototype 30W booster and at the left is a small universal board with an attenuator to fit the input to the 50mW of the Amsat TX mixer.
All boards can simply be screwed to a cooler, but we did an aluminium box, just for fun. The red plug is the 24V supply (2A max) and the black plug is the PTT input.
The 10W-PA followed by the booster has these data:
Output: 26 watts Peak
Input: 10mW (for full output, nice to be used with an SDR)
Gain: 34 dB
in my case I have put an 10dB attenuator in front of the PA, so I need 100mW for full output.
This small board (in the picture on the left) has pads for up to 5 SMD components (0603 or 0805). It can be used as attenuator, filter or whatever is needed.
The RF lines of all boards are at the same position, so all boards can be easly stacked together with a solder bridge. Alternatively SMA connectors can be soldered to each board's input and output.
I have ordered a couple of these filter boards and also the booster, should arrive end of this week, as usual you may contact Ernst (email@example.com) if you need empty boards.
Great job. I try MRF21030 and MFR21045
it took some time to get the new PCBs, but they arrived this week.
The first board which is finally released is the 10W amplifier.
10W means, compression begins at 10W output. In SSB we can expect an average power of 2,5 watts and if a speech compressor is used up to 4 watts, which works well with many QO-100 antennas. Gain is 17 dBm. We built a couple of board and no additional tuning was required, all worked immediately, so you usually don't need any measurement equipment except a DC voltage/current meter.
The board has a PTT circuit now. The quiescent current is only ON during TX. The requirements for a cooler are very low (in SSB only), a piece of aluminium or any other cooler is usually sufficient.
The complete development documents are available for everybody for free. Please see here: www.dj0abr.de .
A member of our local club, Ernst, firstname.lastname@example.org, has empty boards available. If you want to get a board, please write an email to Ernst and ask for board number: 10821.
The next step is a 30 watt booster which can be connected between the 10W PA and the antenna. The prototype is already working, currently I wait for the final boards.
Great ! Nice job !!!
as promised I give you an overview on the progress for building a low cost PA for es'hail-2 NB transponder.
We have the prototype finished and tested. It is running fine.
The total cost of material of the amplifier is about 20 Eur only.
The performance data are:
output power is 5 watts
with 100mW input (nice fit to the Amsat TX mixer board)
output power is 10 watts
with 200mW at the input.
You can read more detailed information here:
since this prototype works so well, we will continue with a second version including a PTT circiut and a few other parts. But we keep it simple so everybody can build it easily.
If more gain is required (i.e. for SDR transmitter), simply two of these boards can be chained, giving a total gain of up to 34 dB. I have used two boards in series for the power tests because my generator has only 10mW max output.
All parts are available worldwide from digikey or mouser.
I have 4 PCBs left, if anyone wants to build it, just write me a forum-message.
The part list, circuit and gerber data will be published on above web pages during the next days.
Last month i tested two PA without sucess ( Counterfeit parts and re tuning 2100 mhz LDMOS) . I will try to buy MHT1008N for test.
My arduino is 5v. The ADF4351 is 3v3.
I used some resistors the pins Clock, Le and Data.
Nice duoband-solution. The RX seems to work very well.
Did you test the Helix feed (of course NOT in direction to 26E ;-)) ) - is there interference of the TX-signal on 2,4 GHZ with the reception of the LNB ? What about the loss in gain because of the helix-feed is "to close" to the dish and not really in the focus ?
Any information and data would be appreciated.
73 de Johannes, DL5RDI
P.s. thanks to Heiner for posting the Youtube-Video !!
Thanks for your comment. Probably i will test TX this week (with dish other direction). I don't have some basics equipments to measurement 2400mhz. However i also believe that i will have an big desense or saturate my LNB.
I will test with 5 watts.
Rio de Janeiro.