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Last Update 7/19/12

Gates Vanguard

kW Transmitter


Phil Alexander says:
The one that looked like an ice maker or washing machine was the original Vanguard.
Vanguard I

Mike Monnier - W8BAC -converted this one to Ham use

Phil Alexander says: 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%.

Heh, heh, on a VERY good day with a dummy load.


Vanguard II


Phil Alexander:  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>



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