I am exploring options for a cheap amp for CW contesting, choices are new AL-811 with 572 tubes (about 700 watts out) or an old SB-220 that I have to re-tube and provide the "standard mods" to (about
Paul Don't even think about using 572Bs in contest duty, they are just not up to it. I had an FL2100Z( pair of 572Bs), and the anodes would go cherry red in no time with repeated CQs, even at ouir 40
Gosh, the original fan in my 30-year-old SB-220 is about the quietest fan I've ever heard in a KW amplifier. Bud, W2RU _______________________________________________ CQ-Contest mailing list CQ-Conte
Paul, We took an AL-811H (the four-tube model) to the Bahamas as one rig of a multi-two station for ARRL DX CW. We hammered it on 80/20/10 with no problems for 48 hours. Now, we did not run it at it'
I use the AL-572... 4 572's runs a cool kw out with no problems for a whole weekend. Takes only about 70 watts from my 920 to run it to full output and it is one of the easiest to tune that I have ev
Paul, SB-220. Clean it up, do the mods, invest in a good, new pair of 3-500s. Stiffen up the power supply as best you can. I have one here that's my radio number two standby...still crankin' out the
-- You should be able to find a nice SB-220 with good tubes for $600 or less. Add Electronic Bias Switching to reduce plate current to zero between dits and dahs (Ameritron will sell you a circuit bo
We used an 811H down at J3A for many years on the 80M station without any problems. Changing to 572B's will increase the headroom of the tubes, but the power supply is the weakest link. It won't take
Paul: I recommend the AL811H over the SB220. The ability to use it on 160 meters makes all the difference. My SB220 (with an external fan added) runs too hot on 10 meters in a contest and will shut d
I have been using a loaner AL811H from K4BAI since about last Fall. Unfortunately it's down for some repairs right now. If you use this amp for contesting make sure you use some type of external fan.
Hi All Used to have a FL-2100B here, and now use a SB-200-both with a pair of 572-B's. I've found that putting a couple of muffin fans on top of the amp sure helps to keep things cool. Did a CW conte