[BC] Are there AM stations still using Tube Rigs?

[Ronald J. Dot'o Sr.]

I've followed this thread with interest as I maintain four BE AM-1A's 
and a Gates 1.

Only one station (a directional) has the BE output network.

The output network is like adding tuning and loading controls to the 
AM-1A and is NOT a substitute for an ATU.

I have a simple method for adjusting the ATU used with an AM-1A.  I 
start out at low power, say 50 watts with no modulation and adjust the 
coil taps one turn at a time for the lowest reflected power.

It's important to do the adjustments without modulation so that the 
tuning is centered on the carrier frequency.
When you add modulation the sidebands will raise the reflected power 
slightly.  So far the sidebands seem centered during our annual proof 
for occupied bandwidth with this method.

In the past I've adjusted the ATU with a bridge to a 50 ohm, 0J match 
but the TX didn't like it when I applied power, as I guess things 
change under full power, so I adopted this method which doesn't 
require the test equipment and works for me.

After I get a good match I raise power in increments and do any fine 
tuning required.

One station has an AM-1A main and a Gates 1 as the backup.

I adjusted the ATU for the best match for the AM-1A and then switched 
to the Gates 1 and adjusted the tuning and loading for the best match 
into the ATU according to the tuning instructions in the Gates manual.

The SS TX's do NOT tune and load the same way as the tube rigs so read 
the tuning procedure in the manual and stick to it.

Ron D

----- Original Message ----- >

> If you have a system with a constant load, there's not much point to 
> having
> tuning and loading. Remember that SS is not forgiving like tubes. 
> Tubes will
> tolerate a short term piss-poor load that generates more heat than 
> RF.
> Transistors cannot tolerate that, whichis why I'm glad in a way 
> there's no longer
> tuning and loading. The BE 1 kW is a nice little transmitter. The 
> ones near me are
> like Energizer Bunnies; they keep going and going, or whatever that
> commercial says. You get my point :-)
>
> Jeff Glass
> Northern Illinois University
> Dell 2650 Win2000 AOL 7.0
>