(Google translate)
Vielen Dank für die Ergebnisse, der Isolator ist derselbe wie in der PA von Bisonelectronics.
Der Verlust ist nicht so schlimm und sie bieten immer noch einen gewissen Schutz für VSWR, aber Sie können sehen, wo sie eingesetzt werden sollen.
Adrian
The un-modified PA on the Speccy An display same as before no changes to settings so it is a few dB down on the modified one.
Adrian
It's scary seeing 12 Amps draw, I had visions of smoke being released everywhere.
At present I still have in the input and output circulator's as standard, I read in the notes about the heat-sink being both DC and RF ground for the transistors, and thought the layer of heat-sink compound may be having an effect. I hope it works for you in stopping the instability, as it did for me.
Adrian
p.s. I have not tested the un-moddified PA unit so no idea how it would perform. Time to put it away and try to get the odd contact on NB.
I think I need some assistance!
I have had a near panic today. The power supply came in, I made up a few more connectors, I modified one unit and mounted it on the heat-sink and tried to do a few tests. Powered it up and the current through my meter was 4.5 Amps instantly, nothing seen on the Speccy An so I keyed a signal on the input to the amp and instantly saw an output at 2.4GHz current at 12 Amps!!!!
To say that the dummy load and heat-sink got hot very quickly was an understatement, It turned out the unit was spurious with no input and taking 300 watts from the PSU.
I sat down and had a rethink on things as one does. I removed the board from the heat-sink and removed all the heat-sink compound between the PA devices and the aluminium, the surfaces are smooth and I probably stuck a bit to much in there. Any way after cleaning it all off and reassembling it all back together, another attempt.
This time quiescent current of 0.86 Amps and transmit current of 4.6 Amps with 2 Watts drive and clean output into the Speccy An.
The set up is above, the picture shows the BU500 going through a 30dB directional coupler, it should be just under 2 Watts, and the -30 dB output to the spectrum analyser. Then the BU500 would drive the PA and the output from the PA to the 30dB coupler etc.
Now this is the bit I do not believe of my test gear.
I offset the display slightly between the two screen saves. The smaller peak is the BU500 direct at just under 2 Watts which is say 32.7 dBm, the vertical divisions are meant to be 10 dB so that puts the upper trace at some 15 dB higher so that would be 47.7dBm or 58 watts. OK it is just a single carrier, but with a input power of 129 Watts it seems high output. No tests done on linearity yet or anything as I have spent enough time on this for today and I would need to sort out cooling fans before I start to push the amps more.
The plan over the coming days is to test using my Hackrf and MHL21336 Amp to drive it where I can do stepped dB settings, but I need a way to confirm power readings more accurately.
Suggestions on how I could test them better appreciated?
Cheers
Adrian
Hello Viliam; I do run it at 1MHz, I have tried a few others with no noticable difference to my ears. I just wish to get away from scribbles of callsigns and locations on bits of paper as I go and then constantly correcting things as I realise I heard wrong. I will get there, eventually.
Adrian
I would guess that the information on what may damage the transponder is not going to be released as I am sure some will then try!
This was my home made POTY and I cut the LNB just before it started to flare and carefully used a file and emery until it would just slide into the copper tube. The leading edge of the LNB still had a taper on it so in effect there was a good transition from the tube to the slightly smaller diameter of the LNB. The joint was later sealed on the outside to stop water ingress with some enamel paint.
I hope this is what you are looking for, if not let me know and I will delete it to stop any confusion, I am sure others will help.
Adrian
Thank you all for your comments.
At the moment I am trying to focus a bit more on the NB section, age is sometimes getting the best of my hearing and I seem to be struggling with some signals on the satellite when either very week signals or sometimes with what seems high audio processing.
Perhaps better headphones are required, or, perhaps better understanding of SDR console. I was running the software with minimal gain on the RTL thinking it would help reduce noise. Last night I ran it with auto gain and found not only did the signal meter give 59 + signals but with some signals the audio was clearer as it reduced the background noise, a bit like FM quieting.
I think as mentioned I need some other headphones rather than Hi-fi ones, some with a shaped audio response for communications.
The down side to running auto gain was the changing spectral colours when two stations where close to each other.
But I will build a filter and give it a try see if it helps reduce any noise especially for the WB section.
Again many thanks, keep playing and learning.
Adrian
Thank you. I will have a look for the article.
At present I am using an single output unmodified LNB. I use it with 13 Volts for narrow band and 18 Volts for DATV. So my question is, if I built a Interdigital filter based at 744 MHz with a bandwidth of +/- 6Mhz to cover NB and WB would it actually make a difference with respect to SNR to me listening on NB?
I do not know if typically sampling at 1Mhz in SDR console sets the bandwidth or the total noise hitting the sdr receiver.
Any enlightenment appreciated.
Adrian
I thought the modified boards were circa 40 watts with a single carrier (CW). I will be very happy to be told that they will do 40 watts Average with a DATV signal?
Ahh, but the norm is wanting a 59+ signal with lots of processed audio and wide band signals as mentioned by M0EYT some time ago.
I have not heard/seen a Leila signal on the narrow band section, but why would it need to be at the same time as a large carrier, and not as the carrier drops as say a short 800Hz tone at end of transmissions. The ones wishing to cause issues with the satellite would not be bothered, but respectful operators would then know they are hitting the limit and should reduce power.
How it can be accomplished in software I admit to ignorance, but there are software people out there that I am sure can do it. The wideband visual system appears to work well and operators do take notice of the system, but I appreciate on NB a visual only system may not be noticed if we run spectral views on our own PC's.
Anyway, I hope a solution is found soon.
Adrian
Honestly, I believe most of the so-called pirates are just legal radio amateurs playing around or are ignorant.
I also believe this statement to be true.
Some time ago I posted a question Is there a Too Much power warning on the NB transponder, would it be an overlay in Spectrum or waterfall? as I was seeing signals well in access of the CW beacon. I heard Pirate Hunter talking on the very large signals outside the digital beacon when we had the Russian sounding voices playing. I was very surprised there was not an alarm raised at the time.
@all and also please avoid tuning with a carrier better using your microphon..
I hope the comment gets through.
A quick question on power, I am sure I read that the power should not exceed the level of the CW beacon when sending a single carrier, so in effect speech would always be below the CW beacon level, although I can not remember where I found this, is this correct?
I do hope the transponder does not get muted, or if it does it is only for a limited time frame.
Adrian
I will not get my power supply until probably late next week, depends on the slow boat from China. So unfortunately I can not give any comparisons, but I would also struggle to give definitive readings as I have no accurate power meter at 2.4 GHz all i could do is a comparative level from say two watts with the spectrum analyzer.
Adrian
OK thanks for the quick answers there are some on Ebay but once I saw what is required, I checked the local garden/DIY centre and they have "Copper slug & snail tape (L)4m (W)40mm" for UKP £4.50 so I will get a roll of that.
Thanks again.
I need to ask something simple, the copper pads used for snow flaking what are people using? I do not have any thin copper so will need to get something and wondering what I should be looking for or ideas as to what may be suitable.
Adrian
Thank you Chris for responding. I was wondering if it was similar to the wideband spectral monitor for the DATV section where it adds the words to the signal information.
I believe that guidelines say that no single carrier should be above the CW beacon (some say the digital beacon?) so that speech is below. But one day monitoring for a while some of the levels where hitting 40+dB over noise. Hence I was looking at the spectrum display for the narrow band without seeing anything and wondering what I was missing.
No problems it was just out of curiosity.
Adrian
Hi Enzo, I really would not like to choose which way you wish to go, it is a personal choice for you to make, you have to consider what radio gear you have, 2m or 70cm etc, if you have any DATV gear, what budget you have and how much you want to spend over what time period. I have more time than money.
Lets see if anyone else come up with ideas and pro's cons of various set-ups.
Many of the converters need to have inputs attenuated. You can get the BU500 with some attenuation built in and that is what you have looked at so it requires 100mW drive. To go from 5 watts you would simply stick another attenuator in line from the TS-200 output and if my maths is correct you would need 17 dB of attenuation, so I would suggest a 5 watt 10 dB bought attenuator and then probably make a simple pi one made from resistors. Two 120 Ohm and one 47 Ohm resistor will give 7.3 dB so you can drive it with that, or, for a bit of safety margin use a 20 dB attenuator.
I actually got the BU500 with out any internal attenuation, so from my 1 Watts output from a Standard C58 I actually added 36 dB attenuation. The reason I chose my BU500 is to be able to drive it from a hackrf One SDR transceiver directly as it's output is typically around -10 dBm to 0 dBm so 1 mW at max.
A popular up-converter is the Kuhne up-converter. That will allow you to drive it directly with 5 watts and will give up to 20 Watts output from looking at the specs, but the unit was well out of my price range. But if you want a very simple to operate system and have the money, I would suspect this will be the easiest way to get on phone. As to DATV I am not sure about using the Kuhne, but again I am sure a user of the unit will chip in.
There are also converters from Bulgaria, SG labs and one from the amsat shop the S-Band Transmitter Mixer for QO-100 (P4-A) is worth a good read up on.
I would sit down with pen and paper and work out all your choices, include a few extra option you may not be considering yet such as portable operation or always fixed operation, i.e. use of batteries or mains etc. Phone is easy, I have managed to get that far even though it is still spread over my desk it works, DATV is taking me a lot longer as I rework cellular PA's for 2400Mhz, sort out required 28 Volt power 10 Amp supplies etc.
Adrian
Just to add, all this is from my perspective and budget and the fact I like to build things up rather than just buy in the goods, mainly because money is limited.
Phone will be easier to start out with. I have what I consider to be a simple system, as yet on receive side it is very simple. 1 metre dish unmodified LNB and a SDR receiver from Ebay (Auzener) this is going to my laptop running SDR Console and I use the Digital beacon to lock the receive display and keep it steady.
On Transmit I am using an old 2m multimode driving a BU500 up-converter, the converter is capable of 2 watts output and even with 7 metres of RG213 to the dish is enough to put a reasonable signal to the satellite. A bit of extra heat-sinking on the converter is really needed, I use a small fan to blow air across the fitted heatsink.
You can drive the converter (as you can with many other up converters with a multitude of frequencies, either 28, 50 144, 435,MHz etc. You can reprogram the local oscillator of the up-converter to match your input frequency to come out on 2400MHz. I would always recommend a Band pass filter on the output of the converter no matter which one you use.
To actually put your transmit signal into the same dish as you receive from I would recommend you build/buy a dual feed, typically a POTY (Patch of the Year). If you wish use a separate dish then it is also possible to use a helix antenna feed just for transmit, or build one around a satellite LNB for dual feed. That choice will be down to you either way will require some building skills or modifying skills for the receive LNB.
If you can already do DATV, on another band the up-converter is capable of passing DATV signals from a lower band, and putting out on 2400, again the same as many of the converters available. If you can not generate DATV you will also need is a system to generate it such as software driving a lime mini, or Pluto SDR transmitter.
Also a decent power amplifier will be required, probably one capable of at least 30 to 40 watts, or more at 2400 MHz. The reason is the extra power levels required for the bandwidth used in DATV, this is dependent on the SR rate used, the higher the SR rate the higher power amplifier is required.
There is a big difference between peak power and average power used on DATV so a typical PA that can output 50 watts of pure carrier will only be around 12.5 watts on DATV. The amplifiers have to be highly linear for the modulation system and are normally used at levels of -6dB or -7dB from the 1 dB compression point of the amplifier.
I hope this information has helped initially and I am sure other members will be along to offer other information soon.
Adrian
