[Amps] trouble with TT centurion

[ka1xo at juno.com]

Hi John,

Crank up your full kit with a good dummy load. First, crank up the exciter with the NYE going to the Load resistor, full tilt, and check for RFI/TVI. Borrow a rcvr and check your audio after you get a good match on the NYE. (In other words, put the DL on the antenna jack on the NYE, not the DIRECT jack.)

All good? Then only after that passes well hook up the amplifier and do the same test, on all bands, using the tuner to adjust to the 50 ohm load.

This will eliminate and identify some basic areas of concern, such as an intermittant connection in the NYE, or a cold solder joint in the amp or tuner. 

The presence, all of a sudden of increased RFI sounds like something is rectifying and shooting spurs. You could rent a Wiltron and graph your emission spectrum: Use the Cantenna's sampling port. When it's doing it's bad thing and you're monitoring it, give the pieces of equipment a slight shot on the side, same way you'd straighten out an old telvision turret tuner glitch and see if it makes a presence in your signal.

If you're not afraid of heights and fairly skilfull, put the rig in AM and use the amp at around 1/3 power, key it up and gently hit the sides of the transmit deck with a dry wooden chopstick handle and listen for microphonics. There's another source of spurious nastiness. If the PA
is unstable it'll be slightly microphonic. If you hear more than "clunk," meaning you hear "crunch," then there's definitely a bad
connection and everything should be resoldered.

Does this give you a good start?

Hal
KA1XO/2