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Re: LF: Fw: LOST TRACK

To: <[email protected]>
Subject: Re: LF: Fw: LOST TRACK
From: "Graham" <[email protected]>
Date: Thu, 13 Sep 2012 00:03:28 +0100
Importance: Normal
In-reply-to: <7BC98E57810B4E9DBE3F6FF425538CFE@inspiron>
References: <7BC98E57810B4E9DBE3F6FF425538CFE@inspiron>
Reply-to: [email protected]
Sender: [email protected]
Yes Lee,   I remember  the  project  , looks  very well  made , bit of a  tom-tit  over the  500 to 477   migration  , will  the  filters  re-tune ?
 
 I  have  seen   7 MHz  AM   stations  in the  usa using  eer  as  high  level  modulation , with  e/d amps  ,  I think  most  high power  broadcast     sw  use this  system as  well  now ? ...mobile phones  use it  for envelope  shaping ...... there  was a  page of links  on the  uk500khz  group 
 
IMD / s/n levels   -35 dB   maximum ? which is  not  bad ....ssb .. may  be  IMD rises  as the  power o/p  decreases  ?
 
G.

From: Lee Hudson
Sent: Wednesday, September 12, 2012 11:40 PM
Subject: RE: LF: Fw: LOST TRACK

Hi Graham, All,

 

I made an EER PA and Transverter to 3.5MHz for use on 500kHz based on Jim?s first design.

And I?m sure there are a few others about.

 

First prototype of Class D PA

https://dl.dropbox.com/u/15400416/IMGP0336.JPG

 

3.5MHz to 500kHz Transverter with Phase and Envelope outputs to PA

https://dl.dropbox.com/u/15400416/IMGP0371.JPG

 

Switchable 50 or 200W EER PA with automatic protection

https://dl.dropbox.com/u/15400416/IMGP0415.JPG

 

LPF and TX/RX Relay

https://dl.dropbox.com/u/15400416/IMGP0414.JPG

 

Final Trio

https://dl.dropbox.com/u/15400416/IMGP0385.JPG

 

Works a treat on all the usual modes and is even quite respectable on SSB.

90% efficient on full output.

 

Stefan?s attempt at a switched mode envelope supply sounds interesting, and a nice way to get mid power efficiency up.

 

73, Lee M0LMH.

 

 

 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Graham
Sent: 12 September 2012 17:45
To: [email protected]
Subject: Re: LF: Fw: LOST TRACK

 

Jim M0BMU  

 

Published  a  design  and  made a working  system  ........  he  also  eliminated the  need  for  a complicated   drive  by using  complimentary   out put  devices  ... I don't know  who else  made such a thing .... ?

 

G.. 

 

PS ::  I vote  for  Jims  design   ! 

 

From: Clemens Paul

Sent: Wednesday, September 12, 2012 5:31 PM

Subject: Re: LF: Fw: LOST TRACK

 

>You  can  use a  class  E/D    amp  in linear , with  envelope  restoration  , that  maintains  the  efficiency  , s/n   >imd   is  about   35 dB .

 

To my knowledge the first description in amateur literature of an

EER (envelope elimination and restauration) PA (400W) was by DJ7AW in CQ-DL 4/2001.

It's still in service.

I have the article as pdf  (in German) and can send it to anyone interested in building such

a PA which is not an easy task.Therefore,as far as I know, only two such PAs have been built.

One by DJ7AW and one in South America (Joe?). 

 

 

73
Clemens
DL4RAJ

----- Original Message -----

From: Graham

Sent: Wednesday, September 12, 2012 5:17 PM

Subject: Re: LF: Fw: LOST TRACK

 

Mal,

 

Things  have  moved on a bit

 

You  can  use a  class  E/D    amp  in linear , with  envelope  restoration  , that  maintains  the  efficiency  , s/n   imd   is  about   35 dB .

 

The  Op structure allows for  up to  50% loss  of  signal   randomly  along the  time  line , ie  first 50% , last  50% or  randomly  distributed

 

Problem with  short burst is the  'average energy' level  , like a  radar  , huge KW peak  powers  but  only  watts  average power .....and  yes  , wide  bandwidth .

 

Detecting  a carrier  is one thing  .. to  recover  data is a much  more difficult  thing and requires  a higher  level of energy

 

G..

 


 

 Virendatenbank: 2437/5264 - Ausgabedatum: 12.09.2012

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