Thread: FET Questions
View Single Post
Old 28th Jan 2014, 9:57 am   #78
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,909
Default Re: FET Questions

Lots of RF gain in a supertuner is OK just so long as you have a supermixer to handle it.

Very few of these firms were into careful design at the system level. A standard failing was that there were hundreds of articles and books written on planning the frequency conversions of a receiver and combatting VFO drift, and getting noise figure of a stage down, BUT there was a general lack of info on how to design a system for good dynamic range.

Consequently there are tuners, receivers etc where the gain/loss distribution and the distribution of selectivity aren't poorly thought out, they weren't thought out at all. A lot of choices were done by copying someone else's and maybe tweaking something a bit.

For planning such systems, there was a lot of tedious arithmetic needed, so it was fertile ground for what to do with that new computer the department had bought.
Later on, spreadsheets were great for the task. Here's the one I built and used.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is offline