Thread: 4NEC2?
View Single Post
  #89   Report Post  
Old October 16th 18, 10:03 AM posted to uk.radio.amateur,rec.radio.amateur.antenna
Spike[_3_] Spike[_3_] is offline
external usenet poster
 
First recorded activity by RadioBanter: Feb 2014
Posts: 180
Default 4NEC2?

On 16/10/2018 08:08, Jeff wrote:

I'm fairly sure the SSB was generated at 9MHz. Googling for a
reminder, I find a large number of 9MHz sideband crystal filters
available, while nothing for 5MHz. Presumably, the 9MHz sideband
crystal filter is use for both the receiver IF filter and in the
exciter SSB generator to strip off the unwanted sideband.


You are correct 9MHzwas a common IF for both tx & rx.


A common way of generating both usb and lsb was to have 2 switched
crystals with frequencies just above and below 9MHz in the oscillator,
feeding a balanced mixer, before the xtal filter, and switch depending
on which sideband you required.


Is there a mathematician on here that can explain the maths of sideband
inversion/retention?


--
Spike

"Nearly all men can stand adversity,
but if you want to test a man's character,
give him an internet group to manage"