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

[dynotherm at earthlink.net]

There a few here and there but support and the cost of tubes
and power is killing them off. The "warmer" sound is an audio thing
that IMO comes from coloration of the distortion by the addition of
some rounding. The BE is one of the best sounding small boxes I've
heard, tube or SS.

There are three principal 1 kW's on the market and none of them has
a tunable network. AFAIK BE is the only one that offers one as an
add-on, and I've heard they sell very few.

All modern SS boxes have a very low PA output impedance and a network
matching that UP to 50 ohms. In the old days we matched the more or 
less 3000 ohms PA output impedance DOWN to anything from 30 to 230
ohms.

There is a reason for all this. If you are matching DOWN it is not
expensive to make the matching network variable with a simple Pi
network. Not so in a SS box where the match is UPWARD. There are
also more strict emission requirements to meet today. Another fact
is nearly all stations have a 50 ohm line and an ATU.

If the ATU matches the tower to the line, driving the line directly
will work. From a maintenance viewpoint it leaves a lot to be desired,
but it is cheaper and it works well. If every station insisted on
tuning and was willing to pay the $1000 - $1500 it would raise the
price, you would be able to buy a box with an unnecessary (for most)
tuner built-in.

The real solution to this problem is correctly matching your tower
to your line with an ATU. If the tower is not stable that is a sign
you have other, more serious problems. These probably involve 
instability in your skirt - if that is still what you are using.
Fix that, and you won't need a tuning unit at the transmitter.

Scott, this is the 21st century. Things change. Tubes died over
25 years ago. Fix the skirt, get ATU tuned and the BE will live
happily ever after.

Phil Alexander, CSRE, AMD

-----Original Message-----
>From: wmroradio at bellsouth.net
>
>The reason why I ask is because the tube transmitters can tune into loads that a solid state, like my BE can not. I called be BE and they wanted nearly $2,500.00 for a output network to go with my AM1A. I contemplating on finding me a latter model tube transmitter that is solid state up to to the finals, that has an output network.