tag:blogger.com,1999:blog-7590176649168185428.post1039030030063974020..comments2024-03-29T07:34:28.586-04:00Comments on SolderSmoke Daily News: Circular Polarity and The Water Wheel in Dale's Moonbounce AmplifierBill Mearahttp://www.blogger.com/profile/07662500663603350847noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-7590176649168185428.post-70333857387512861532013-12-16T15:44:40.097-05:002013-12-16T15:44:40.097-05:00"noise figure of under 0.24dB".
I don&#..."noise figure of under 0.24dB".<br /><br />I don't know if that reflects how much things can change, or how slowly it takes to improve things.<br /><br />There was some review for a Nuvistor converter back when the Nuvsitor was new, and the writer compared it with a converter with a 417 in the front end, and the Nuvistor beat the 417 converter. The writer added "I guess it's time to tune up the 417 preamp.<br /><br />I think it was a 417, which were regular tubes but uncommon and I think relatively expensive. I don't think it was a 416 was was an even fancier tube.<br /><br />The point was that without any real effort, the Nuvistor gave a noise figure that was better than the 417, unless one put in extra effort to tune up the 417. The same could be said about the parametric amplifier, unheard of noise figure, especially at the higher frequencies where few active devices worked at all, but endless effort needed to tame it and adjust it.<br /><br />I think even 20 years ago one could get GasFets that had about 2dB noise figure, though I can't remember if that was with lots of effort or not.<br /><br />0.24dB noise figure at 1296 I think would be seen as impossible fifty years ago, certainly impossible without a lot of effort to choose a specific device and endless tuning, and maybe even supercooling things.<br /><br />And then the transmitter is equally shocking. Back then you would have had to put a lot of effort into getting a high power transmitter at 1296, and likely it was horribly inefficient. Now it can be done with transistors?<br /><br /> Michael<br />Michael Blacknoreply@blogger.com