January 25 2001
I found an August 2000 e-mail from you in my Cumbre notes
about Ecos del Torbes and have enjoyed finally seeing
photos of the
station. Many, many thanks for documenting such a fine station. We listen to it regularly and prefer it to our understaffed satellite-glut local
stations.
Except for the 9640 one-kilowatt unit, the Ecos del Torbes
780 kHz 50 kW transmitter was instantly recognised as a Harris MW-50A,
which is a pulse to amplitude design run by many of the US clear channel
stations. The 4980 kHz 10 kW transmitter is a Harris BC-10H broadcast
transmitter, which uses solid state low power stages and 3X2500 tubes in
the modulator and final stage. The BC-10H also has resonators and traps
at the third harmonic to square up the final stage plate current and
this raises efficiency to about 87%!
Ivan Escobar is an engineer after my own heart, as I also
ran a Harris AM transmitter when I was a station owner. If you ever confer
again with Senor Escobar, tell him his transmitter building interior
is cleaner than many US stations and I am very pleased with the excellent
fidelity of YVOC! It sounds great on our Watkins-Johnson precision HF
receiver in our office, which has a bandpass of better than 8 kHz within
1 dB. You can also tell him by now I have been a listener
to Lo Ques de Noche Recuerda for 31 years.
Thanks again, Don, for your fine reporting in Latin America
and especially for such informative photos.
January 26 2001
Harris moved on from the BC-10H and MW-50A to the DX -10 and DX-50 digitally synthesized AM (and shortwave) transmitters, but still include the SX-1 through SX-5 and Gates One through Gates Five solid state 1 kW through 5 kW
transmitters. These solid state transmitters have final stage efficiency in
excess of 90% and sound as clean as FM. Nonetheless, there are still many
superb sounding MW-50A's and BC-10H's still in service and hence Ecos del
Torbes is among excellent company.
Regarding Ecos del Torbes, our database lists YVSC (9640)
as authorised for 10 kW. Does Ivan Escobar have any plans to increase its
power from 1 kW? Also, the photo showing the multi-element shortwave
antenna, presumably for YVOC based on my received signal strength,
suggests it has a reflector behind it and a shorter director element in
front. That should give about 3 to 5 dB gain. The effective power in
our direction from YVOC may be close to 30 kW. Again, just a conjecture
from the photo.
Best regards,
Bill Sitzman
This website is maintained by Don Moore,
Venezuela Menu
Main Menu
What's New
Best of this Site
Radio History
Clandestine Radio
Technical Aspects of Ecos del Torbes
Consulting Engineer
Association of North American Radio Clubs
DXer of the Year for 1995.