Yes, fully agree David; if we bifurcate the S.S. amp design and build endeavour to less than 600 Watt PEP, and no time limit 1.5 kW, then it's an entirely different ballgame whereby things become ver
Indeed Alek. And when the DX path is open and the antenna pattern take-off angle optimum for the path then a mere few watts is perfectly satisfactory :-) Contesting and pileup breaking is an endeavou
You have to build it Cathy... :-) There's a sad demise of homebrewing and RF skills nowadays as more and more out of the box appliance operators dominate the ham airwaves. A good respectable IMD 600
Gentlemen, The real issue here in respect of this excellent discussion about diplexer termination of harmonic energy is the profound impact on IMD and linearity. These MOSFET and LDMOS RF power devic
Yes indeed Jim. This can be seen in NEC modelling when perfect ground is chosen or a metal sheet groundplane is deployed... Leigh VK5KLT Yes, but that's not the point. What better ground does is 1) b
I heartily agree Charly. Sadly there has been an insidious creep in the commercialization of ham radio markets for profit and financial gain that coincides with the rise of technically unskilled appl
Hi David, Well at least the surplus military gear commonly adapted and used by hams was build to decent performance specs. Re your "The FCC needs to catch up with noise floor challenges & modern tech
Ah perhaps the real underlying issue here David is the modest degree of technical knowledge and understanding required nowadays for folk to obtain a ham ticket. The qualification requirements have be
Well said Mark; I concur with your pragmatic sentiment here. One of my favourite television anthology programs is a "Thousand Ways to Die"...it's pure entertainment all about dumb-ass people's stupid
I agree Jay and Joe; tube amps and replacement tubes will be around for quite a while to come; longer than most of us old geezers on this amps forum! They produce excellent bang for buck and operatio
I concur with your more conservative design strategy here Jim. The latest MRFX1K80H devices are certainly a step in the right direction for high-power RF amplifier devices; but limitations remain par
Roger there on the comments below Jim. For adventurous homebrewers here's an interesting article on an alternative novel approach to SSB generation and its efficient switched-mode amplification by K1
Excellent advice here Ian! Cement-cased power resistors are an abomination... 73 Leigh VK5KLT I The main problem with the Quadra PS is its tendency to blow the step-start resistors (R2A, B, C) that l
Good point Peter; not an appealing scenario for your average punter...where pragmatism and practicality rule the day. Perhaps limiting the Class-A PEP to 10 Watts and having a PA bias mode switch wou
Yeah Peter's Class-A amp is likely run with considerable back-off so the expected efficiency figures seem worse. Nevertheless I'm sure it runs squeaky-clean with very low IMD at 25 Watts PEP. The "av
Precisely correct Peter! If the HF antenna lobe take-off angle is fortuitously optimal for enabling a given DX hop path then QRP Tx power will wing it! No amount of Tx power or Rx sensitivity / SNR w
Hi Jim, If folk want to learn how to work the world on 160m top band DX from a suburban block and cleverly work-around any perceived antenna height and size restrictions then I recommend a careful re
Rob, I concur with your succinct sentiments here about transmitting tubes. The only proviso I would make is the inclusion of a soft-start mechanism on the filaments to bring them up slowly in a contr
Herb, My advice here is throw the damn 87A anachronism thing into the trash can and don't throw good money after bad with these thieving clowns. Clearly and sadly Alpha is now nothing like it was in
Yes Dick, I concur that Brad is THE man to best sought out the problematic 87A amp with its poorly conceived abomination of microprocessor controlled architecture and further plagued by its now obsol