The guys also made a 1: 9 transformer from 61 materials. Of course, I did not achieve such power, but the amplifier turned out with amazing linearity! And YO6PMX rights are not heated at all! Thank you YO6PMX!
Hi. I am glad that you have built one too. The amplifier works fine with that 9:1 transformer, as it can be seen on the pa0fri's site. I said from the beginning and I am repeating it, it is not my schematic, I built the amplifier using a schematic from PA0FRI's site. I never said it is linear at 1.7 KW, in the matter of act, I guess it is working in class C at that power... Probably 1 Kw, maybe 1.2 Kw is a decent power where it is working linear.
Hi Perian! I built an amplifier - concept - model with water cooling by R3KR. See pls ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-_DWhgO9t5Eo.html Chinese transistors mrfe6vp61k25h were used
Good information on the ferrite output transformer. Just be aware that those transistors will not be linear at 1.7kW O/P. They are rated for 300W each.
Bonjour Marc. Comme je discutais avec Eric hier soir, le schema se trouve sur la page de PA0FRI qu'on peut trouver ici: pa0fri.home.xs4all.nl/Lineairs/BLF188%20HF%20amplifier/BLF188%20HF%20versterker.htm. J'ai utilise la version de 23 decembre 2015 sauf la resistance de 33 ohms entre les grilles. Si vous voulez, je pourrais envoyer des photos detaillees par mail. 73 et bonne journee!
Very nice show of your SS amp! Yes, they can easily make the power, especially with today's LDMOS. Of course, the secret to the high power is with the I/O transformers. Indeed KF8OD has made some beautiful amps, both SS and tube. Even tho the SS amps are great, I still like tubes. I hope you don't get too enamored with SS. ;-) Also, nice commentary on the accuracy of your CN-801wattmeter at 2:54. I will get one. 73!
Very interesting, thanks for sharing, as you know it is not very hard to get a lot of power, question is how linear is it? what is your bandwidth? Can you put it on a spectrum analyzer ?
Hello Michael! It is a pleasure and a honor to have this comment on my video. I watched your videos several times, visited your site and got a lot of ideas there. Thank you also for your help with the output filters. Wish you all the best from YO!
Hello Marcel, Utilisez-vous le symétriseur T4 du schéma de PAOFRI dans votre montage ou simplement T3 en filtrage ? Bravo pour votre réalisation. Gérard / F6EHJ
Very nice amplifier, I am thinking of building something similar, really glad to see that it is possible to make such a robust solid state amp. How does it perform?
MUltumesc! In ceea ce priveste senzorul, conductibilitatea termica a ansamblului e foarte buna, nu am reusit sa il supraincalzesc niciodata pana acum si nici diferente majore de temperatura nu am sesizat. E mai usor de ingropat in aluminiu decat in cupru... Am facut intre timp inca vreo 3 exemplare, pentru prieteni, si nici acelea nu se incalzesc semnificativ, chiar pleaca ok regulatorul de temperatura...
sa mai faci te rog un test: pune ansamblul amplificatorului la frigider, la 4 grade, cateva ore. Dupa aia, alimenteaza ampliful, cu sarcina artificiala la iesire, si verifica curentul de repaus al MOSurilor. Tine ampliful alimentat, fara excitatie, si vezi cat creste curentul de repaus, si daca se stabilizeaza la o anumita valoare, si daca valoarea e cea recomandata pentru VRF2933. E un proces de durata, dar te scapa de cheltuieli neprevazute. Timpul alocat testului sa nu fie mai mic de 4-5 ore.
Hello. I like the unit you have buit. Can you give me a schematic and material list so I can build one . Also can i build one using 8 or 12 of the 2933 Transistors?
Looks great thanks for sharing! By any chance did you connect it to a spectrum analyzer to see what the signal looked like? I am just curious to know how much of that power is staying on frequency, I want to build one of these as well. Thanks again.
Hello. No, I never connected the amp to the analyzer, but I have built some output filters using PA0FRi's design. The attenuation of second and third harmonic was ok for those filters. After connecting the filters I have lost between 100 and 200W, so I assume that those were harmonics. Approx 1.5 KW remained on all bands. so i think is ok. As I said before, I do not claim that the amplifier i working in linear mode at those frequencies. I would recommend to use such amplifier for powers around 1Kw - 1.2KW. At 1.7 it is certainly pushed to it's maximum.
@@perianmarcel2059 Thank you for your reply. I find this extremely interesting and I hope to build one of my own. I really appreciate you taking the time to make this video and sharing.
Hello. The power supplies are salvaged from old mobile telecommunication equipment replaced for upgrade. They can be found on Ebay or on local ham internet sites sometimes. Any 50 - 54V 50A will do it.
Hello. Yes, this is correct. I chose this method knowing that there are different commands for the linear from different transceivers (simple relays in older transceivers, low level logic commands from newer transceivers) so the "rf vox" is somehow "universal" command mode. The same can be seen in most of the RM Italy ham amplifiers (HLA 300 by ex.).
The transistor is rated at 150 MHz in its datasheet. My amplifier has been tested between 3,5MHZ and 29 MHz. The power supply is 50V 50A built by a romanian company (Antrice). Those power supplies are widely used in mobile telecommunication companies.
Nothing for now. The amplifier is not on the antenna in a full functional assembly yet. I am intending to use a set of filters described by KF8OD (thanks again). In this moment I am using the amplifier in 20m only with only one filter, described by PA0FRI here: pa0fri.home.xs4all.nl/Lineairs/BLF188%20HF%20amplifier/BLF188%20HF%20versterker.htm The 20m filter has 2 coils of 560 nH each, on T130-2 toroid core and 3 silver mica capacitors (150pF-330pF-150pF). It has been tested on spectrum analyser and it is suppressing very efficiently the 3-rd harmonic and quite ok the second.
Hello Perian , do you make amplifier board like this complete for sale minus vrf 2933 for sale? I would like 2 complete boards. Also how many amps does this unit draw? I can give you email if you like.
Hello and thank you for your interest, but these projects are not for sale, I have no time to build for sale. They are just for educational and experimental purpose and they are under continuous improvement :) . Have a nice day! Marcel
Hello. I don't understand what "fast" means. The switching is done using an old russian hardware method. The output relay (antenna relay) has two contacts. One is used to switch the RF and the other one is commanding the input relay (12V DC), so, there is impossible to start the amplifier before the antenna is coupled...
michaelscoofield I mean QSK switching in between TX and RX. If there is relay then its too slow to listenning in between own dots and dashes on CW. Anycase its great job. Congrats. Petr
Hello Perian I fallow all your amplifier congrulations! I learning lot of things and pratic ideas your amplifier material61 amazing idea but I did not found this ferrite if its possible write here company code please 73
The VRF2933 is a 50 volt VDMOS device that is capable of 300W per FET up to 150MHz. According to the datasheet, you can push them much harder. I'm sure the linearity will suffer, but I've heard of people running 4 of these at 1.2-1.5KW all day long with no issues. They also make a VRF2944 that does 400W per FET. Both handle up to a 70:1 SWR also. Microsemi has made some seriously impressive devices using the VDMOS technology.
FYI: These are VDMOS parts, not LDMOS parts. See Dick Frey's (K4XU) video from Microsemi... fun watch. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-bMEsEATudgM.html Disclaimer: I am a Microsemi employee.
@@perianmarcel2059 Buna Marcel multumesc pentru raspunsul rapid dat. La rindul meu sint in construirea unui linear amplifier cu 4xSD2943 dar sint intr-un impas si nu stiu cumm sa il setez pot sa trimit mai multe informatii daca ai timpul necesar. Mutumesc anticipat 73! VA7ZAR
@ , why do you assume an efficiency below 50%? The total dissipated power of an VRF2933 is 648 W www.microsemi.com/document-portal/doc_download/77339-vrf2933-mp-datasheet . If we assume a 50% efficiency (which is the worst i've ever seen!) , 1300 W is an acceptable power for 4 pills. Ok, the 2nd and third harmonic is about 200W (measured that). Can I have 52% efficiency? :) Some says one can acheive even 60% efficiency in class AB... www.electronics-tutorials.ws/amplifier/amplifier-classes.html Of course that the amplifier cannot be putted on the air without output low-pass filters, as i said, after filtering I have lost about 200W at the output.
@@perianmarcel2059 ...just because you use a specific rf class it doesn't mean you have that efficiency. for that output power of VRF2933 your IMD will be much worst for SSB use. in push-pull topology, the even harmonics are canceled, only odd will be present and strong (cause no LPF filter), which will count in fake watt output. 50V, 1.7Kw will give an impedance of 2.8 ohm, how a 1:9 transformer would work???.
Not an accurate power output as it is rich in harmonics. Let’s see the power output at the fundamental on a spectrum analyzer or after a proper LP filter.
