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The Broadcast Archive

the one that looked like an ice maker or washing machine was

the original Vanguard.

The Vanguard was simply (really not so simply) a class A amplifier and was

picky about its load. Today, it would be simpler because we understand stuff

like "cusp rotation" for matching loads across a frequency span, but in 1 kW

stations of the mid-60's that would have gotten a lot of blank stares in

most places, especially from the typical Gates clientele who tended to be

small market stations on limited budgets.

Vanguard installations were either mostly trouble free or nothing but

trouble, and the difference was the personnel running them. In short,

it was an idea both too far ahead and too far behind its time IMHO,

and marketed to the wrong audience. It was also one of the least efficient

boxes ever built - maxed out at just over 30% and that was not easy. I

often wondered how it might have done if marketed by Collins. Probably

much better, but the PDM/PWM idea would have killed it in the end.

When properly tuned for modulation, it was FLAT from 20 Hz to beyond 20 kHz

with under 1% THD. If the load was well matched it sounded better than FM.

The Vanguard was the original 1 kW single tube transmitter. It was

> essentially a linear amplifier, which had final amplifier efficiency of

> approximately 36-40%.

The II included all the fixes that developed for the

original design - minor stuff that made the exciter/driver more stable and

somewhat easier to tune correctly PLUS a built in dummy so you could tune

it on the dummy and KNOW the box was OK, and that the real problem was your

load. The frame was the same used for the contemporary BC-1G and later 1H.

Basically, the difference between a V and V-II was about the same as the

difference between a late model 1T and 1G, which is to say packaging and

marketing with typical first generation design clean-up.

With a good load, they could be made to sound better than anything else on

the band, but sadly, those were few. IMHO the efficiency advertising was

a mistake because it encouraged mis-tuning to try to get it. Secondly, the

guy who designed it didn't understand the realities of AM transmission

systems. BTW - He's also the same guy who gave us the TE-1 FM exciter and

the VP-100, so I'll make no further comment and let that speak for itself.

Stereo was simple, just plug in the exciter. Secondly, regardless of the

power level from 0 - 1100 watts, all you had to do was dial it up so it

made hitting multiple power levels of the early PSRA/PSSA days a breeze.

It would do anything you can do now with a PWM box except help with the

power bill. <g> However, you had to know how to talk to it. <ggg>

Properly installed and maintained by someone who understood it, there was

no better transmitter. The V-II was a better physical fit in most plants and

it included all the engineering fixes, but it was very complex in its

simplicity. <g>