Sidebar Sidebar
  • You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

High level modulation

D

dxhound

Active Member
Nov 17, 2006
778
58
38
Lately I have been really interested in the "Boat Anchors" For those of you who dont know what Im talking about, boat anchors are old tube style transceivers or even transmitters and receivers separately working in conjunction using what is known as a duplexer.

I find you cant beat the audio quality of these older rigs in both receive and transmit. My question is this, Are there any solid state hf rigs using a solid state amplifier section that employ high level modulation to get that classic cb AM audio?? I have done alot of research and come up with nothing.
 

My guess is you won't find "high level" audio in modern day solid state hf rigs simply because "low level" audio is a better choice to help prevent distortion. However that doesn't mean today's hf rigs won't have good AM audio.
 
GRTS said:
My guess is you won't find "high level" audio in modern day solid state hf rigs simply because "low level" audio is a better choice to help prevent distortion. However that doesn't mean today's hf rigs won't have good AM audio.
Click to expand...

Preventing distortion has nothing to do with it.Size and the requirement for separate RF and high powered audio amps does.High level modulation simply means that the final RF amp has the modulation applied to it. In the case of a 100 watt RF amp.running class C (which is fine as a high level modulated stage) it requires approximatly 70 watts of audio to modulate it to 100 %. That means that the radio must contain a good quality audio amp capable of at least that much clean power and have the power supply to handle it as well.It is much easier and cheaper to modulate a low level RF stage with a watt or two of audio and then amplify the signal to 100 watts using a class AB stage. the big reason why most modern radios have less than stellar performance on AM is that they almost never transmit a full carrier and BOTH sidebands for a true double sideband AM signal Most transmit a carrier and ONLY the upper sideband which while this technically all that is needed,tends to limit the sound quality when heard on a regular AM receiver. :thumbdown:

Long live class C plate modulated double sideband full carrier AM! (y)
 
It seems some folks are getting High fidelity and High level audio confused. The website above about the audio monsters is Hifi. Basically they are widening the bandwidth of there ssb audio. Wich personnaly I feel defeats the purpose of ssb. It bad enough with the bands as crowded as they are on 3khz bandwidth let alone some people running 6-7khz. Diff. strokes for diff. folks I guess.
 
Dxhound,what you say about high level versus high fidelity is true. The thing I laugh at about these ESSB guys is that a lot of them bitch and moan about the "old buzzards" running the wide AM signals and thenwhat do they do? They take a narrow band SSB signal and widen it out to at least as wide as a double sideband AM signal just so they can have better audio quality.All they had to do in the first place was flip the mode switch to AM. I prefer SSB for voice hands down but I will not run ESSB.Perhaps a slight tweaking of the microphone EQ or the radio's processor and filters but that is all. For truely great sounding conversations I fire up the tube type Heath DX-60B and run a little grid modulated AM.When set properly it sounds just as good as a plate modulated rig.
 
QRN, sounds like were on the same page. Thats why I have been lookin at buying one of the older ft101x rigs or kenwood rigs. I enjoy the occasional AM ragchew on 160 and 11 meter, but mostly im a sidebander. The distance and clarity achieved over other modes just impresses me. The only thing better if your into it is CW. But anyway, I guess Ill just have to snag one of the older tube rigs for the AM audio, I just was trying to limit the rigs in the shack down to one neat package. But for now the boat anchor will do!!
 
I agree, and of course they must have a handle on the side........


73
Jeff
 

Attachments

  • 4935.jpg
    4935.jpg
    30.6 KB · Views: 156

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ BJ radionut:
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.
  • dxBot:
    kennyjames 0151 has left the room.


      Top Bottom
      Back