[Boatanchors] Modern AM Modulation techniques

[Gary Peterson]

“I heard that getting an old Gates MW1 on 160 would be hard to do.
for this reason I have avoided the broadcast solid state rigs. (Not
that I have offers to take free transmitters coming in every day.)”

The MW-1A would be a challenge to move to the ham bands.  Each module would have to be separately modified.  And, then the combining network.  Certainly not as easy as a tube rig.  I have sold two BC-1Ts and a Collins 20V to hams for $1 each.  I was glad to see them avoid the landfill.  We had to replace them as a steady supply of good, reliable tubes became steadily more expensive and difficult to obtain.  Running 24 hours/day, a Chinese tube would fail in as soon as 90 days.  The prices on NIB USA-made tubes tended to be outrageous.

On Mon, Oct 5, 2015 at 7:32 PM, Gary Peterson <kzerocx at rap.midco.net> wrote:
>
> One of the last great tube rigs was the Collins 828E-1 (later Continental 315R-1), both known as the ?Power Rock.?  Pulse width modulated.  Sounded absolutely super.  Extremely reliable.  I loved that transmitter.
>
”Those were rigs with a tube final and a single tube doing switching
right?  The last 1 KW tube rig Collins made (hybrid solid state) was a
PWM rig that ran a pair of 3-500Z in the final and had a single 3-500Z
switching the final.  I have no idea how that worked but I heard the
h.v. from the supply was around 8 KV!”

Yes, the Collins 828C-1 (can’t recall the later Continental model number) was the 1 kW version of their PWM rig.  We called it the “Power Pebble.”  8 kV is nothing.  The HV supply in the Power Rock was 14 kV !

Bob, a ham in Penn Yan PA (forget his callsign) has one on 160.  He is
a broadcast engineer and knows the rig.

> None of the solid state transmitters that I have dealt with are damaged by running into a funky load.  They just quietly fold back if a capacitor shorts out in the antenna coupler at the tower.
>

”Maybe this was a problem early on and eventually they made them fold
back.  I always heard that they'd dump off the air if the vswr on the
line got much above 1.2:1” “Rob K5UJ”


The Gates/Harris MW-1A would “rattle” or pulse when the load got too far off track.  It did that above about 1.5:1.  It was one of the earliest SS BC rigs.  They were pretty reliable, though.

Gary, KØCX