KFI transmitter off the air
 

"Dave" wrote in message
...
David Eduardo wrote:

"Telamon" wrote in message
...
The 640 KFI transmitter just dropped out. Just before it dropped out
started sounding a little funny.

It's only been on a few weeks now.


They are using the old Harris DX series, I believe. The new transmitter
had a catastrophic failure, and a new Nautel is apparently on rush order.

I thought they had an old Continental 317 (best damn AM transmitter ever).

The Harris was the main, and the floor furnace the aux. I am told that the
new BE selfdestructed, and will be replaced with a Nautel (all into the new
tower) and the DX is the temporary main.

KFI transmitter off the air
 

On Oct 30, 6:37*am, Dave wrote:
Wingdingaling6 wrote:
On Oct 29, 11:29 pm, Telamon
wrote:
The 640 KFI transmitter just dropped out. Just before it dropped out
started sounding a little funny.

It's only been on a few weeks now.

--
Telamon
Ventura, California

My cousin is an bcst engineer out there on the West coast. KFI had a
major transmitter failure
and is running on a backup xmiter with half power.

25 KW into an 8th wave antenna is more like 20% power.

Dead Air here for KFI on 640 kHz; but most of
the 'other' LA and SD AM-MW Radio Stations
were coming in very well.

~ RHF
Twain Harte, CA

KFI transmitter off the air
 

Telamon wrote:


KFI is having a lot of bad luck with transmitters and antennas.

So now that they have had two transmitters burn up anyone know why that
happened?


No excuse that I can think of. Broadcast engineering doesn't attract
the best and brightest any more. Other specialties pay a lot better.
People used to do it for love of the medium, but that's out the window
as the medium generally sucks.

KFI transmitter off the air
 

Telamon wrote:
In article ,
"Bob Campbell" wrote:

"Telamon" wrote in message
...
KFI is having a lot of bad luck with transmitters and antennas.

So now that they have had two transmitters burn up anyone know why that
happened?
Because they were broadcasting in HD?

rimshot

I suppose that is possible.

I was thinking more along the lines of the cooling system failed or a
HV component failed shorting out the final stage.


There are protections for both of those. However I must point out that
solid state transmitters have no B+.

KFI transmitter off the air
 

"Dave" wrote in message
...
Telamon wrote:


KFI is having a lot of bad luck with transmitters and antennas.

So now that they have had two transmitters burn up anyone know why that
happened?


No excuse that I can think of. Broadcast engineering doesn't attract the
best and brightest any more. Other specialties pay a lot better. People
used to do it for love of the medium, but that's out the window as the
medium generally sucks.

One transmitter burnt, and it has been commented that this is due to a
design issue since 2 others (there are not that many 50 kw installs in the
whole US) have gone the same way. The engineering at KFI is superb... but
it's the same thing as giving a lemon car to an Indy 500 driver... it will
still break down.

KFI transmitter off the air
 

"Telamon" wrote in message
...
In article ,

So what is the voltage out the finals on a solid state transmitter?


There are no finals. Just a bunch of combined modules. The Nautel 50 has 8
RF and 4 modulator power modules. There is no final stage.

KFI transmitter off the air
 

"David Eduardo" wrote in message
...

"Telamon" wrote in message
...
In article ,

So what is the voltage out the finals on a solid state transmitter?


There are no finals. Just a bunch of combined modules. The Nautel 50 has 8
RF and 4 modulator power modules. There is no final stage.

Ain't power MOSfet's a wunnerful thing?

KFI transmitter off the air
 

In article ,
"David Eduardo" wrote:

"Telamon" wrote in message
...
In article ,

So what is the voltage out the finals on a solid state transmitter?


There are no finals. Just a bunch of combined modules. The Nautel 50 has 8
RF and 4 modulator power modules. There is no final stage.

Ok, Don't call the modules "finals" then but what is the output voltage
to the antenna? I would like to know what the RF current is as the
output is supposed to be 50KW.

You know the skin effect will concentrate all the current into the
conductor skin. I wanted to calculate the current density.

I wonder what the power loss is in the hardline from transmitter to
antenna?

I expect the parallel solid state design will have much lower voltage
and higher current than older tube designs. It would then follow that
transmitter destruction is more likely to result from connector problems
in a solid state transmitter where the higher voltage tube designs would
result from insulator breakdown or flashover.

--
Telamon
Ventura, California

KFI transmitter off the air
 

"Telamon" wrote in message
...


Ok, Don't call the modules "finals" then but what is the output voltage
to the antenna? I would like to know what the RF current is as the
output is supposed to be 50KW.

Almost all phasors or lines are50 or 52 ohms today.

You know the skin effect will concentrate all the current into the
conductor skin. I wanted to calculate the current density.

I wonder what the power loss is in the hardline from transmitter to
antenna?

The line manufacturers all have specs on loss as a function of frequency.

I expect the parallel solid state design will have much lower voltage
and higher current than older tube designs. It would then follow that
transmitter destruction is more likely to result from connector problems
in a solid state transmitter where the higher voltage tube designs would
result from insulator breakdown or flashover.

It all ends with a match to 50 ohm line at the output fitting on top of the
box.

KFI transmitter off the air
 

David Eduardo wrote:

"Dave" wrote in message
...
Telamon wrote:


KFI is having a lot of bad luck with transmitters and antennas.

So now that they have had two transmitters burn up anyone know why
that happened?


No excuse that I can think of. Broadcast engineering doesn't attract
the best and brightest any more. Other specialties pay a lot better.
People used to do it for love of the medium, but that's out the window
as the medium generally sucks.

One transmitter burnt, and it has been commented that this is due to a
design issue since 2 others (there are not that many 50 kw installs in
the whole US) have gone the same way. The engineering at KFI is
superb... but it's the same thing as giving a lemon car to an Indy 500
driver... it will still break down.

There's obviously a dumbass factor at work somewhere is this chain of
events. Somebody designed a HPA stage prone to catastrophic failure,
didn't they?