Here in Dallas, KERA (90.1 FM) carries the BBC feed from local midnight
until morning when "All Things Considered" comes on.

Even if the "Beeb" has a somewhat liberal slant, its much better
listening than Art Bell's show, which seems to be carried by nearly
every AM station in the country trying to find something to drive its
tubes with during the middle of the night.

Paul

On 19 Mar 2006 06:09:50 -0800, "Paul_K5RT" wrote:

Here in Dallas, KERA (90.1 FM) carries the BBC feed from local midnight
until morning when "All Things Considered" comes on.

Even if the "Beeb" has a somewhat liberal slant, its much better
listening than Art Bell's show, which seems to be carried by nearly
every AM station in the country trying to find something to drive its
tubes with during the middle of the night.

Paul

Tubes?

David wrote:

On 19 Mar 2006 06:09:50 -0800, "Paul_K5RT" wrote:

Here in Dallas, KERA (90.1 FM) carries the BBC feed from local midnight
until morning when "All Things Considered" comes on.

Even if the "Beeb" has a somewhat liberal slant, its much better
listening than Art Bell's show, which seems to be carried by nearly
every AM station in the country trying to find something to drive its
tubes with during the middle of the night.

Paul

Tubes?


I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.


mike

m II wrote:
I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.

AFAIK there are solid state high-power transmitters out there.

--
All relevant people are pertinent.
All rude people are impertinent.
Therefore, no rude people are relevant.
-- Solomon W. Golomb

On Mon, 20 Mar 2006 03:41:16 GMT, m II wrote:

David wrote:

On 19 Mar 2006 06:09:50 -0800, "Paul_K5RT" wrote:

Here in Dallas, KERA (90.1 FM) carries the BBC feed from local midnight
until morning when "All Things Considered" comes on.

Even if the "Beeb" has a somewhat liberal slant, its much better
listening than Art Bell's show, which seems to be carried by nearly
every AM station in the country trying to find something to drive its
tubes with during the middle of the night.

Paul

Tubes?


I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.


mike
The only stations that still use tubes for AM are the poorer ones.

http://www.broadcast.harris.com/prod...u=WWWDX25U50AM

http://www.nautel.com/xr50.aspx

m II wrote:
I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.

Nobody makes a 50kw transistor, but 200 250-watt transistors in
push-pull-parallel will do the trick. Solid-state 50kw transmitters are
by no means unusual. They're also a lot more reliable than tube rigs.

We have a solid-state 6kw digital TV transmitter at work. It's amusing
to pull out two or three power amp modules and see *absolutely nothing*
happen -- the power meter doesn't even drop -- all that happens is you
get an alarm on the control panel warning of the missing modules...
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com

Doug Smith W9WI wrote:
m II wrote:
I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.

Nobody makes a 50kw transistor, but 200 250-watt transistors in
push-pull-parallel will do the trick. Solid-state 50kw transmitters are
by no means unusual. They're also a lot more reliable than tube rigs.

We have a solid-state 6kw digital TV transmitter at work. It's amusing
to pull out two or three power amp modules and see *absolutely nothing*
happen -- the power meter doesn't even drop -- all that happens is you
get an alarm on the control panel warning of the missing modules...


Neat. It's like a redundant array setup for hard drives.




mike

On Tue, 21 Mar 2006 02:31:24 GMT, m II wrote:

Doug Smith W9WI wrote:
m II wrote:
I was under the impression that most commercial transmitters used tubes.
I don't think a couple of 2n2222 transistors could handle a 50 KW output.

Nobody makes a 50kw transistor, but 200 250-watt transistors in
push-pull-parallel will do the trick. Solid-state 50kw transmitters are
by no means unusual. They're also a lot more reliable than tube rigs.

We have a solid-state 6kw digital TV transmitter at work. It's amusing
to pull out two or three power amp modules and see *absolutely nothing*
happen -- the power meter doesn't even drop -- all that happens is you
get an alarm on the control panel warning of the missing modules...


Neat. It's like a redundant array setup for hard drives.




mike
Sort of. The distortion goes up and the remaining devices are put
under extra strain.