Warning: Creating default object from empty value in /homepages/11/d132647312/htdocs/Amfone/mkportal/include/SMF/smf_out.php on line 47
BIFET Compressor Mic and IC-718 by WA7JHZ




 
The AM Forum
December 12, 2018, 09:23:15 PM *
Welcome, Guest. Please login or register.

Login with username, password and session length
 
   Home   Help Calendar Links Staff List Gallery Login Register  
Pages: [1]   Go Down
  Print  
Author Topic: BIFET Compressor Mic and IC-718 by WA7JHZ  (Read 860 times)
0 Members and 1 Guest are viewing this topic.
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2428



« on: October 30, 2018, 02:24:25 PM »

The attached JPG shows what I've been doing with my BIFET compressor mic and Icom IC-718. Followed by a decent linear amplifier, it is hard to tell the difference between it and a modified broadcast AM transmitter.

Logged
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2428



« Reply #1 on: October 30, 2018, 02:26:18 PM »

The attached JPG shows a reversed order between the 4 kHz LPF and AGC/peak-limiter on my proposed compressor mic circuit. The complex phase shift of the LPF occurs before the AGC/peak-limiter, and its noise and distortion are low enough to allow this. Note that I've also added a positive modulation control circuit (U12).

Logged
ab3al
Member

Offline Offline

Posts: 13


« Reply #2 on: October 30, 2018, 05:48:00 PM »

does this improve the audio bandwidth of the transmitter or just controll the agressive agc. looking at it from my phone cant see to well
Logged
Steve - K4HX
Administrator
Member

Offline Offline

Posts: 2428



« Reply #3 on: October 31, 2018, 11:07:51 AM »

This circuit is to control modulation levels. There is a 4 kHz lowpass filter to limit higher frequencies.

In general, the only way to improve the audio bandwidth of a transmitter is to modify the transmitter, not with external boxes. Yes, an equalizer can overcome some inadequacies but there are limits to this approach.
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands
 AMfone 2001-2015
Powered by SMF 1.1.21 | SMF © 2015, Simple Machines
Page created in 0.07 seconds with 18 queries.