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Re: LF: Better picture of the 807 based 500kHz TX

To: <[email protected]>
Subject: Re: LF: Better picture of the 807 based 500kHz TX
From: "Graham" <[email protected]>
Date: Wed, 19 Dec 2012 22:29:27 -0000
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Now  there is  a  idea  , could  use  a  music  synth  to  make a wobbly note  , and  send it  via the  ssb exciter , for  a  real  retro vintage cw sound ?
 
just had a long  retro  data  qso  with  Chris  xiz , on 502 , must be  2  years at  least  since used  rtty  ,   beacon  still  running  now  , not  sure  if anyone is  still  monitoring  , all  this  web linking  has  spoiled  things !  
 
73 -G..

From: M0FMT
Sent: Wednesday, December 19, 2012 6:53 PM
Subject: Re: LF: Better picture of the 807 based 500kHz TX

OK Graham
 
Good point! But it doesn't jump it chirps quite pleasently Louis PA0LCE runs one on 500kc/s and tells me ops like the Retro sound.
 
73 es GL Pete M0FMT IO91UX
From: Graham <[email protected]>
To: [email protected]
Sent: Wednesday, 19 December 2012, 17:52
Subject: Re: LF: Better picture of the 807 based 500kHz TX

Probably   a  early  form  of  Spread Spectrum  , hard to  JAM   if is its  jumping   about the  band  and  difficult  to  make a  fake  transmission if the  Tx has a  wobbly  bob  signature  : )
 
G..

From: M0FMT
Sent: Wednesday, December 19, 2012 5:42 PM
Subject: Re: LF: Better picture of the 807 based 500kHz TX

OK Mal
 
Point taken. I was referring to a "Power" oscillator like a single 6L6 used as an Xtal oscillator running at 15 / 20Watts which means normally there is insufficient current (really) from a VR tube for the Anode(plate) so all that is necessary is to stab the screen. Otherwise I totally agree.
I do know the standard T1154 chirps well. There is a PA0 who runs one on 500 and I am sure you have worked him it is like a signature signal HI. 
I think there was some kind unpleasantness going on at the time of the T1154 manufacture so the fine points of frequency control was probably a low priority.
73 es GL Pete M0FMT IO91UX
From: mal hamilton <[email protected]>
To: [email protected]
Sent: Wednesday, 19 December 2012, 11:55
Subject: Re: LF: Better picture of the 807 based 500kHz TX

Hi Pete
Stabilise both Plate es Screen on an Oscillator, followed by a Cathode follower to avoid chirp and osc pulling.
The T1154 was very unstable with a bad chirp, surprised it ever passed Quality Control
G3KEV
 
----- Original Message -----
From: M0FMT
Sent: Wednesday, December 19, 2012 10:08 AM
Subject: Fw: LF: Better picture of the 807 based 500kHz TX

 Try again minus cct too big I think.

73 es GL Pete M0FMT IO91UX
----- Forwarded Message -----
From: M0FMT <[email protected]>
To: "[email protected]" <[email protected]>
Sent: Wednesday, 19 December 2012, 9:52
Subject: Re: LF: Better picture of the 807 based 500kHz TX

Hi Dimitris and group
 
I have not seen the schematic but it is usual to stabilise the screen of a power oscillator to reduce chirp on key down.
Now you have shown us yours I will show you mine. I usually sketch the schamatic after the event so foregive the presentation on the back of an envelope.
I now get at least 4Watts after adjusting the ant link coupling away from the chasis. Best audible DX Kent 80miles best Opera DX PA0 land.
73 es GL Pete M0FMT IO91UX
From: Dimitrios Tsifakis <[email protected]>
To: [email protected]
Sent: Tuesday, 18 December 2012, 23:46
Subject: Re: LF: Better picture of the 807 based 500kHz TX

2012/12/19 Graham <[email protected]>:
> Why the  stabilised  screen  supply ?
> G..

It's embarassing. I like the glow of VR tubes! :-)

73, Dimitris VK1SV



 




 


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