RE: LF: Re: RE: MORE VALVES

["Ken" <ken.h.wright@btinternet.com>]

Hi Graham.

I have about 60uF smoothing, did the ripple calculation from an old ARRL Handbook.

 

Ken

 

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Graham
Sent: 19 December 2012 22:40
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: Re: RE: MORE VALVES

 

Talking  of  wobbles  , no  wobbly  bob  before  operating  as  well  !!

 

It would  be  funny if  the  NOV  stated  100 mW  max  erp  or  some  other qrp level  ....

 

650-0-650  400 mA , too  small , core will  saturate with  FW  bridge , the  centre tap   indicates the  core  is  'small'  as  designed   for  half  wave  .. will  need  over 40 mF  smoothing  at those  rates  , if its single phase 50 hz  , that's  4Kw  pk 

 

will  need   1500-0-1500  1 amp  oil filled , choke  smoothing ? .. time to  dig   out the  1950 handbooks

 

G

 

From: mal hamilton

Sent: Wednesday, December 19, 2012 10:24 PM

To: rsgb_lf_group@blacksheep.org

Subject: LF: Re: RE: MORE VALVES

 

Ken

The valve and base in the picture is a 4CX1500B  that was intended for 137 Khz not 500 Khz.

At present both on 137 es 500 I am using solid state Transmitters, which are probably safer. I do have a selection of Dentron Amplifiers for the HF Bands with 8875 valves.

Watch those High Voltages, no margin for mistakes, one Wobble and you Vaporise !!

73 es GL de Mal/G3KEV

 

 

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

From: Ken

To: rsgb_lf_group@blacksheep.org

Sent: Wednesday, December 19, 2012 8:20 PM

Subject: LF: RE: MORE VALVES

 

Hi Mal.

What valve are you using? I am currently building a TX with a 6293 Beam Tetrode in the PA. the building of the two power units has slowed the construction down with the inter-linking control cables etc. The PA xformer is 650 – 0 - 650 volts @ 400mA with a bridge rectifier, the valve max anode voltage is 3Kv and anode current 1.5A. I am hoping for Class C, 500 watts output cw on 472kHz (if we ever get the NoV).

 

73.

 

Ken

 

M0KHW

 

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From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of mal Hamilton-Sent: 19 December 2012 09:39
To: rsgb
Subject: LF: MORE VALVES

 

This is a 137 Class C amp project, but since CW activity  has dropped to virtually NIL I am not rushing to complete.

de G3KEV