you may have started a year or so ago....but you are doing really well.... I know you haven't ventured into making stuff for the public ... but I am really digging the way you have your setup...looks pretty solid and I think you are going to go further down this path and I really appreciate the time and effort you are putting into this project and videos...Thank you and can't wait to see the next
Love the pallet. Them tuning caps get hot ! great job with heatsink . I had xforce newer gray label with either blue or orange disk caps on PP 100 box with caps going bad. I use metal clad replacement . with the input resistors getting hot. try double the ohms and use 2 like feedback resistors .or find 5watt . with making 6Meter box going to use coils . just have to find board. found for FM broadcast band. looking for upper part of the old TV CH1 . that was re assigned that's why TV was 2 threw 13. VHF . I have old repeater heatsink that I will re use. its big ! I step at a time. My girlfriend comes first ! she a health care worker on the front line of what going on! working many 12Hr shifts . 73's
really like your videos i always learn something from them. great work. I have also been watch radiomedic111 build tube amps from scrach and like you he take the time to explane everything. great job. when you get ready to put them out in kit form let me know
ayeeee what up mudDuckSharky!!!!! stoked to see another video in the ldmos progress. i seen that 12 unit davemade joint on facebook aint that something uh? well Im watching the video now hope you and your family had a great christmas man!
I love what you have been doing with ldmos amps. I believe thee old transistor amps are to fade away fast once more people catch on to these amps and with improvements coming daily . I would love to build one , but i am a poor boy . So it may take me 6 months or more just to round up parts. Then pray i do not blow it up.
I am trying to find the reference circuit as I am particularly interested in the bias circuit. But all I see is the PCB layout that comes with their data sheet. I am building a 20-40m amp and would really wanna use these pills.
Your wattmeter reading includes the power from the harmonics. How much power do you get after running the RF through a low pass filter? A small cooling fan will keep your hot passive components from nuking, and maybe taking the LDMOS with it. Good insurance. Power supply might be happier with some extra airflow too. Nice work! Any way to pm you?
the input splitter is easy, the output combiner will be trickily to handle the power for a long Keyon ! when it's done the dummy load will heat the room real good!
That's very cool! Especially parts of theory.About thermal imaging: I suspect that wires inside the output transformer is hotter than those are outside. Also I mentioned, that a consumption current is being slightly decreasing (maybe I've missed the reasoning). Can you please provide me with the exact values of the harmonics? Or with just a sharp image of the specrtum analyser screen? As I understand, this is the one of four pallets with MRFX1K80? And 2 kW output? It's sum of all harmonics, and main harmonic is less than 1.8 kW?
I saw the table on the spectrum analyser's screen a table, if I'd got right, 1816W of 1st harmonic, 2,2W of 3rd harmonic, am I right? Also, about thermal imaging: bright and shiny metallic surfaces will show significally decreased temperatures due to low emmissivity (and therefore high reflectivity of ambient cold IR radiation). Painted radiator of waterblock gives correct results.
2kw continuous for an hour. Through what coax? It sounds impressive. Or am i asking a dumb question? What kind of cable will take that? Would make a good jumper into a big box.
@@MudDuckSharky thanks for the reply. Im considering running 3,500 to 4,500 through rg400. If you watched bbi's stress test video on a 16 pill. He said his rg400 was getting "sticky" on the outside.. so he changed to 393 for the rest of the test. You didn't comment on that particular aspect of your test. But actually why would you. It wasn't really the reason for that vid. But, that kind of info would be very valuable to me. As its the only hocus pocus in this game. What power can you really put through what coax. With your continuous testing. Your settup seems to be ideal for that. Your transistors can take the coax to its failure point and survive. 👍bonus. Lol. At least thats what ive heard about the "extremely ruggedized" version of the ldmos. But. Kudos on this series youve put together. Im really enjoying following this build. Thanks again, and happy new year.
If you notice that the power supply has dropped from 40.4 amps down to 37.3 now too so the output power is down a little as well, mathematically due to the heat of the power supply heating up and dropping power on the amperage side. So is the device drawing less or is the power supply heating up and not sustaining the power draw from the device being tested?
The voltage seems to be stable. So I suppose, the amplifier consumes less current due to heating (but what happens to output power?) ( But I'm just an observer, not author )
Why aren't you using SM mica caps?... instead of those ceramics with your heat sinks. The mica caps have a lower dissipation factor than the ceramics... and therefor will run cooler.
I will start by saying this most amplifier builders do not know the limit of what they build they know the power output peak and average on a almost perfect antenna being dummy load but in the real world where a man swr is 1.5 to just under 2 what he sees in his workshop and what happens at the station with such conditions maybe vastly different
