Hi Graham,
Only modification required is to the rig!
To allow TX on 3.472-478 or whatever it’s
going to be here.
Lee.
-----Original
Message-----
From:
[email protected] [mailto:[email protected]] On Behalf Of Graham
Sent: 13 September 2012 00:03
To: [email protected]
Subject: Re: LF: Fw: LOST TRACK
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 ?
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
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 .... ?
PS :: I vote
for Jims design !
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.
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?).
----- Original Message -----
Sent: Wednesday,
September 12, 2012 5:17 PM
Subject: Re: LF: Fw:
LOST TRACK
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
Virendatenbank:
2437/5264 - Ausgabedatum: 12.09.2012
