Boston WLVI and WHDH

[koralis]

Any idea what is going on with WLVI and WHDH in boston? WLVI went out a couple of days ago (signal strength down to 60 and lower) and WHDH dropped out last night. WFXT, WSBK, WBZ, and WCVB are all fine. Did NBC move towers? It doesn't seem reflected on the antennaweb web site if so.

[koralis]

I got an email back from WHDH. One of their HPA tubes blew out, so they've been running at reduced power. They hope to have it back up to full strength soon.

I guess I don't need to reorient towarsd providence after all.

[oldschoolecw]

Thanks for the info

[n3ntj]

I got an email back from WHDH. One of their HPA tubes blew out, so they've been running at reduced power. They hope to have it back up to full strength soon.

I guess I don't need to reorient towarsd providence after all.

What? These stations don't have parts on standby? :lol:

[Tower Guy]

What? These stations don't have parts on standby? :lol:
The HPA tube is 40ish grand. They go gassy if they sit around as spares.

Half a transmitter shouldn't matter unless the home antenna is undersized.

[dsanbo]

[QUOTE=Tower Guy;815648]The HPA tube is 40ish grand. They go gassy if they sit around as spares.

Half a transmitter shouldn't matter unless the home antenna is undersized.[/QUOTEH
High-power RF tubes like those in TV and FM transmitters are USUALLY "burned in" when they first arrive....either as new units or replacement "spares".....I used to put new 4CX15000A's (for a Rockwell/Collins 831G2C) in a homebrew filament supply/socket "jig" and "cook" the tube(s) for a couple of hours at varying voltage (ie., 1/2 hr. at 3.75V, 1/2 hr. at 3.9V, 1/2 hr. at 4.0V).....then put them back in their box(es) and MARK the date I performed the "burn-in"...Of course....if the tube(s) THEN are allowed to set for another extended period....they COULD get "gassy" again....!:(
BTW....the 4CX15000As I last worked with were on the order of $7500 each (1979 dollars....).
Some of the EIMAC klystrons for UHF transmitters are 3-4' tall and weigh several hundred pounds; they're installed with the aid of an electric winch assembly similar to what's used for auto engine removal......just in case anyone might be wondering how "a tube" can run into $40,000...!!

[koralis]

The HPA tube is 40ish grand. They go gassy if they sit around as spares.

Half a transmitter shouldn't matter unless the home antenna is undersized.

Or you're 25 miles from the tower. What was a very good signal turned into a signal that couldn't be locked on. I'm sure everyone within 10 miles was fine.