I don't disagree at all with this. The point I was trying - however ineptly - to make is that solid state technology requires a different approach to traditional tube design. work of to Again, I don
** The main difference being that combiners are the norm with solid-state due to the practical limit of a few hundred watts per module. Also, for the same number of watts of RF out, due to more wast
Is it all that different? Whatever the technology, different devices offer benefits/disadvantages. The feedback systems are most easily applied round a transmitter rather than an amplifier, and I'm n
I don't know what designs you are familiar with, but combiner losses don't usually impact significantly on efficiency. That's why they are used in high-efficiency AM BC transmitters... The use of mod
**High-efficiency BC-type designs are not suitable for applications where linear operation over a range of frequencies is required. _______________________________________________ Amps mailing list
don't In terms of fractional bandwidth BC transmitters covering 500 - 1650kHz aren't narrow-band! Of course BC transmitters are designed for AM, and aren't linear, but there are people using class-D
** Dr. Schmidt. Please explain why high-efficiency BC-type designs are suitable for applications where linear operation over a range of frequencies is required. Tnx _________________________________
Author: Steven Grant W4IIV <stevengrant98@yahoo.com>
Date: Tue, 16 Dec 2003 08:32:24 -0800 (PST)
http://hawkins.pair.com/wabcnow.shtml should give you a heads up on the operation of these broadcasting beasts. they are totally digital, and uses square waves for RF genoration...they are not linear
** Not linear is OK for SSB? The difference in S-units between an amplifier that 60% efficient and an amplifier that is 90% efficient - for the same power input - is 0.3 S-units, or 1.76db. _________
Author: Steven Grant W4IIV <stevengrant98@yahoo.com>
Date: Tue, 16 Dec 2003 16:49:20 -0800 (PST)
no rich..not ok for SSB nor for shortwave...something to do with switching speeds. i assume when i say not linear, i also mean not good for SSB also a question not related to this thread......what wo
** So why would a Ham want a not-linear amplifier? ** The bandswitch in a SB-220 is not very ok with a 3800vdc anode supply. 3000v is close to the limit for a SB-220. If one needs more output it tak
** I have yet to hear a Ham station on SSB who is getting 90% efficiency from his/her linear amplifier. My SB-220 linear amplifier probably uses c. $1.20 worth of electricity per month. Going to 90%
The 90% efficiency thing actually make some sense from a weight standpoint if you consider amps intended for DXpedition style operation. Of course this assumes that all of the circuitry needed to lin