Hi Louie, I prefer the AL-1200 of this group, assuming the 3CX1200 has continued availability (no problems thus far). Reason: Instant warmup just like AL-82, but a single, very rugged metal-ceramic t
That was certainly interesting. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
Joe, In many Mirage 6m amps, including a model A1015 that I have at home, the circuitry for RF sensing is actually mostly in place, on the circuit board; it's just not connected! This makes it reason
I surely agree with Rich's comments, below. RF-activated T-R switching, especially in amplifiers using two or three relatively slow relays as the Mirage amps do, is very much not great. However, at l
Or, of course, anyone who really doesn't care about noise but wants to move a lot of air in the equivalent space could use a Nidec TA500 wide body B34607-16, like I do....190 cfm, about double the ai
What terrible news for the worldwide amateur radio community. Bill was a great operator and a tireless contributor to our hobby in more ways than I can count. Tom, if you get a chance, maybe you can
Thomas, in my 4-1000 grid driven amps I faced a similar dilemma 20 years ago. Using the HV to drive the screen supply seems like a great idea, since if the B+ goes down, then the screen does too, pre
4CX250Bs require a regulated screen supply, making the PSU design more complex. They have enormous gain (about 20 dB), so drive requirements are very low, requiring either a low power exciter or an i
The pair of 4CX250s can't draw more than about 600mA peak plate current, with a much lower average than that. 25uF should be sufficient. My homebrew 2 x 4CX250 amps for 2m and 135cm have 28uF/2500V f
Manuel, is nobody answering you on this? I don't know what conversions you've seen, but I've converted three SB-220s to six meters over the years, and each the same way. In all cases, I got rid of th
Manuel, I'd suggest you go ahead and try that, but in my experience, that's a lousy modification. It assumes you're sacrificing only the 10m band for 6m, and leaving the other bands intact, including
Oops, forgot to mention, my plate tank for 6m (SB-220 mod) is 3-1/2 turns of 1/4" copper tubing on a 1-1/2" diameter form (inside diameter of the tank coil); plate TUNE cap is 2-30 pF Jennings vacuum
You have it correct. The 2002 uses a pair of 8874s (GG) at 2500V to produce about 1 kW PEP output power with ~50W PEP drive at 144 MHz. It's a single band amp, made for many years; the more recent re
25W or so is probably about right; but when tuning up, the amp should be tuned up at full power, not at "carrier" power for an AM signal! So, you must be prepared to provide it with sufficient drive
Isn't this supposed to be about amplifiers or contesting? I just wish we could get *some* contesters to turn their mike gains down and speak clearly into microphones very close to their lips, so thei