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I was laughing at the oscillating / Bias spike problem. Should never see such a thing from a production amplifier. Not funny for the end consumer, no, but funny as a tech to see that happening.

Yep seen this exact "wait, what? Really?" expression from anyone that I talk to about it that has never done anything but 11M. It's just because the only propagation they know is 11M propagation. Unless they study, or talk to people with more experience than they have (usually not, or they...

BTW: I love how the MRF300AN Datasheet from NXP give a 27Mhz Reference Circuit Layout and parts list. LMAO. It's like they know what's up.

Very interesting. Where have I been? A LDMOS in a TO-247 package. Now that's something else. Only issue I could see, after having spent 14 years replacing blown high power TO-247 (400-500V) Mosfets in audio amplifiers (for cars, KW+ size amps) is that you would want to make use of copper...

I'm sorry, I really mean no disrespect, the antenna you use is everything on any band. Most CB'ers that become hams I think initially bring a lot of the CB Snakeoil with them, but they'll lose that quick, usually. As far as needing an amplifier on Amateur bands, depends on what you are...

IDK he never really said, but he ended up with a IC-7300 and a AL-80B. Maybe he has license or is aspiring to get one because 10/11M DX is just dead. Sounds like they have a local group. We use to have one too, 39LSB really enjoyed it when solar minimum talking local. However now most of...

Ok I see here on the Youtube video description he adds this: The second issue is mainly when PP100 transistors are used in place of 2SC2879 transistors. The amplifier has a large current spike. The PP100's have a lower base bias threshold, typically I measure around .51 volts or so, and high...

That is funny LOL. What are the power transistors with more gain that they are using? Can't tell from the video, haven't researched it. Never worked on a ALS-500, only the 600 model.

Hmmm. Glad you went with a 80B and Icom 7300. As for all the whining about the 811A tubes, yeah they are fragile for carrier modes, and Toll Free is right they will happily produce the power you demand of them whilst burning a hole in the anode (thin, yes). Only thing I'd like to add is...

To get a quote from Richardson for 811A tubes go here. No idea what the price or minimum quantity is these days. https://www.relltubes.com/products/Electron-Tubes-Vacuum-Devices/Triode/811ANL.html

I have had an AL-811H for almost 10 years now, the original tubes where old Taylors junky, burned up, grid resistors had fell off the sockets in the amp blah blah the amp was in a really sad but complete state. After cleaning up and repairing the amplifier (grounding the grids directly too) the...

Rick, what drive power are you using? The full 5W or did you reduce it any?

I would like to play with one of these kits. If it's not against forum rules here, any recommended sellers? And approximate time to delivery? I see on eB ay at least they are only available from China shipping.

Just curious what you think. I seem to remember, years ago, reading about how if you do this sort of thing, specifically running a DC power transistor like the MRF9120 and many others intended for 28V or 48V etc systems, at 12-14VDC instead, you end up with the transistor producing a lot of...

Neat. This comes WITH the MRF9120 (from China) for like $48? (no heatsink)

Yeah the server I had it on is not same. I cannot edit the original post (or I couldn't figure out how) this is my schematic I posted a user had just added the part about adding in the 100 ohm resistors in the bottom right of the image: Sorry I hadn't been here since last year. I'm bad, I know.

To me it's crazy how things have changed. I've been around a while and just 20 years ago we had several options in the Houston area for good techs that would actually repair stuff, not just mic wiring, mods, and peaking. Now those guys are all gone, passed away, or retired. All that's left is...

LOL. Well I will totally make it, but I am old and fairly wise, and have a large skill set, raised on a farm, had to turn wrenches on my own junk to go anywhere, had to grow my own food, make my own money, and make my own deals. These kids these days skipped the part that I got from 5-18...

Yep. I know Justin, and the guy from Houston that built the Palomar amps (in this area Houston anyway, there are many other Palomar builders), I have been out of touch with him for a while, hope he is doing ok. I had the old 250Fet and 450Fet circa 2010-2011. Sold a couple to some friends...

My only experience with buying transistors from eBay that ship from China, was that I had a IC-706 non-MK that needed both the VHF PA and HF PA repaired. I bought a MRF255 (for the HF PA) for $50 from the most reputable seller I could find at the time (Polida? something like that), and a...