hamilton Rangemaster Final RF Stage Efficiency

There was one comment on the radio discussion forums that was a good suggestion, call the company(Keith Hamilton) or email and ask about the final amp.

@mark Yeah, I agree. but I thought it was a good conversation that provided some good technical insights without speaking greek. Some one  had said:

"A class C high level modulated RF state typically has an efficiency of 70 - 80%, if I remember correctly."

I don't think I knew that, it's an interesting piece of information (if true)). I know class C aren't as efficient than class E, and I know the first part 15 manufactured whip and mast transmitters were class E.. Their claimed efficiency was stated in the pantent but cant recall what it was.

Someone (I think it was Ermi) thouroghly explained how to test the Rangemaster for efficiency on the bench. Others pointed out things he didn't consider. Someone else made this point/question:

"If range/coverage is the goal here, isn't that controlled at least as much by antenna-matching as by output power?"

And the conversation goes on with all kinds of insights on the matter and that's just the thread here, there's more in the other..

Although the Rangemasters efficiency never was stated in either thread, it doesn't make them any less worthy a read.

I guess what had most struck me was the original question.. "looking for info on the output section of the hamiltons. are they class "E", "C"?"

They are class C like all the other transmitters - correct? There's actually no question about that, right? Otherwise that would of been a major talking point.

Which brings up the question (that I asked before without getting tesponse): Why have there been no Class E part 15 transmitters manufactured since the 1970s? (or have there).

Why, if class E is so much more efficient, do they always seem to gravitate to building the less efficient class C?

The SSTran AMT5000 kit was Class E.

One of the problems with Class E, as exemplified with the AM Transmitter Challenge, is that they can be difficult to tune, particularly with iffy RF grounds.  That's why that particular transmitter showed relatively poorly in the test.  And rather than attempt to find out why, and correct the issue, or at least explain it, the testing team just blamed the transmitter and moved on.  Well, no, it was a lack of understanding on the part of the user(s).

It's too bad, because anecdotal evidence from AMT5000 users showed that it could perform at least equal to if not much better than other transmitters available.

But I can see why the 'big guys' in the field use Class C.  Ease of use, and therefore you're going to get consistent results.  But Class E still has the greatest potential if you know what you're doing.

@artisan-radio So it because it's simpler to build and easier to install that class C is predominant for part 15. That's what I figured.

So far as I know there have been no part 15 AM transmitters manufactured as class E since 1974 when Digital Technologies Inc (who had manufactured for Info-Sytems Inc) had went out of business. 

Even though class E are more complicated for both the builder and installer, I find it surprising that if manufacturer where to go through all the trouble and expense of putting a such a nince device on the market today, they would aim for a class E...  but not even the abandoned "Parking Lot Radio" manufacturing venture opted for class E.

There must be another caveat in regard to Class E then just expense and simplicity. I can see why class C were the predominate choice 40 years ago, but not today or in the last 20 years.

I guess Phil thought the same thing which is why he came out with the AMT5000 kit.