[Test-Equipment] Ekco noise source: the conclusion

[Dave Brown]

David
In typical noise source applications, the tube is not run as it is in 
a light fitting- Only ONE filament is energised (probably at a 'lower 
than usual' voltage)  and regulated DC is applied to the other end of 
the tube, using either one of the filament connections at that end.
The DC supply must be ripple free and probably around 200 volts - I 
suspect the actual voltage is not critical but it needs to be 
regulated to stabilise the noise output.

I have a number of spare tubes that were intended for noise source 
application in an X band calibration fixture used with a 600 MHz 
parametric amplifier made by Marconi. I still have most of the X band 
assembly as well, including the  noise source. The noise tubes are of 
course clear- they don't have a fluorescent coating on the inside of 
the tube.

 I looked in the handbook for the amp but find the one drawing that 
would clarify which of the two HT supplies was actually applied to the 
noise tube is missing!  It's the one that shows overall cabinet 
interconnections.
But it has to be either 300 or 150 volts-they were the only options.
 The drawing that shows the connection to the tube has the pin that 
goes to the positive supply labelled as +HT- but NO pin number-and on 
the related drawing that shows the connection block it goes to, there 
are both +300 and +150 supplies!   As I no longer have the cabinet 
this was in, I can't refer to the real thing to sort this out.

 Hope this helps,
 73
 Dave, ZL3FJ

----- Original Message ----- 
From: "Lecroy" <lecroy2607 at free.fr>
To: <Test-Equipment at mailman.qth.net>
Sent: Thursday, December 16, 2004 1:43 AM
Subject: [Test-Equipment] Ekco noise source: the conclusion


Thanks for your replies.
Finally I open this source and I found a standart fluoresecnt tube 6W 
21cm
length inside.
In some shops there are pocket lights with the same tube: I will buy 
one and
take the power supply.

Typical ENR value for such source seems to be around 15dB, I will 
check with
the new power supply.

73
David F1URI

> -----Original Message-----
> From: Bill Fuqua [mailto:wlfuqu00 at uky.edu]
> Sent: jeudi, 9. décembre 2004 19:55
> To: Lecroy; Test-Equipment at mailman.qth.net
> Subject: Re: [Test-Equipment] Ekco noise source
>
> It should use a low noise low ripple DC current source. But
> will take high voltage to get ionization started.
> HP made some a long time ago I think.
> 73
> Bill wa4lav
>
>
> At 12:52 PM 12/9/2004 +0100, Lecroy wrote:
> >Hi,
> >I'm looking for information about this equipement:
> >
> >Noise source (X band)  SA.2034
> >EKCO Electronics Ltd England
> >
> >It's a noise source with a fluorescent tube mounted in the
> waveguide. Does
> >anyone know what is the typical power supply voltage for this kind 
> >of
> >equipement ?
> >
> >David
> >
> >_______________________________________________
> >Test-Equipment mailing list
> >Test-Equipment at mailman.qth.net
> >http://mailman.qth.net/mailman/listinfo/test-equipment
>
>

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