** You been drinking the Cool Aide again Roger? Said phony was nowhere involved with Arpanet or the X.25 protocol. Or anything else for that matter except hot air. Carl KM1H _________________________
Interesting read but you missed a huge point. Antartica proper is still building up snow and ice. Yet the oceans are warming. Would you care to hazard a guess why? Carl KM1H _________________________
I worked in the cable TV industry for a short time a long while ago. I dug out my old CATV handbook and they give a pretty good explanation on intermod although they call it "cross modulation". I qui
Tube amps? You really must be ancient (-; The ones I worked with were SS, 5-450 mHz, and around the start of the broadband Class A brick output module typically driven by the highly linear 2N5109's.
ORIGINAL MESSAGE: REPLY: in·i·ti·a·tive: ?noun 1.an introductory act or step; leading action (sounds like first to me) and cre·ate: ?Synonyms 2. originate, invent. No reasonable person would doubt th
ORIGINAL MESSAGE: REPLY: What do they have to say about standing waves being necessary for an antenna to radiate? 73, Bill W6WRT _______________________________________________ Amps mailing list Amps
I am old but not quit that old. The amps we had were all solid state but the handbook that I was referring to was from 1968. I did see some of those old tube amps around but I don't remember much abo
I weighed in on this topic a few months back, my BIG point being that a transistor driver, when amplified by a grounded grid amp, that is cathode driven, would have a canceling effect on all the IM p
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sat, 17 Apr 2010 09:52:43 +0100
That's interesting. At first I thought this seemed silly, but then I thought about it, and I believe it may be semi-true in the case of CATV, but not true at all in the case of amateur radio. In the
Hi Dave, In further reading of the catv handbook it seems that what they mean by "well behaved amplifiers" is they provide a straight line relationship between output and IM contributions. A good on
Not quite right: Intermodulation products are extraneous signals generated by mixing two or more signals among themselves: they appear at very definite frequencies in the spectrum and are perfectly c
Not quite right: . Intermodulation products are multiplicative, not additive: if the first stage amplifier generates IM products of, say -6o dBc , a second identical amplifier will generate its own I
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sun, 18 Apr 2010 14:49:07 +0100
There are lots of claims, but I have not seen anybody post anything to substantiate these claims. I think it is a quite complex issue. I suspect an exact analysis is possible, which would put absolut
I consider the CATV amp analogy a good way to understand what is happening in a receiver. There is no need to cascade amps, simply add xx number of sources into a single amp which becomes the radios
My background in this topic is a bit weak, but as I see it: All we can deal with are analogies as the real world is dynamic and any testing such as the two tone is a bit outdated. OTOH how would we s
A simple way of looking at this problem is to consult an oracle and work out the combined third order intercept point (IP3) of the two (or more) stages. The equation for the ip3 of two cascaded stage
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Sun, 18 Apr 2010 21:50:31 +0100
I believe analytical techniques could be used to put absolute limits on this. Perhaps if I've got a bit of time, and inclination, I'll have a go at this. It can't be rocket science, though my maths i
IM and cross modulation are the same thing. With the catv amps there are many signals operating at nearly the same level that mix with each other to produce new products, some of which fall on the fr
I believe it's rare for any amp to have the output either in phase of 180 degrees out of phase with the input. BUT IIRC it's not all that complicated to set the phase to what every you desire in the
Author: "Dr. David Kirkby" <david.kirkby@onetel.net>
Date: Thu, 22 Apr 2010 11:52:21 +0100
To be more precise it is the *voltages* which add. The voltages must be added as vectors, not scalers, so it is not true to say the powers will add. They could cancel under some highly unlikely set o