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From: "Ken Wright" <ken.h.wright@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
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Date: Fri, 29 Feb 2008 21:07:06 -0000
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Subject: LF: RE: G3LDO 500kHz rig
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Hi Peter.
How many watts is the PL519 running?, I have some 807s I was thinking of
using, but they like 750 volts on the anode.

Regards.

Ken M0KHW

-----Original Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Peter Dodd
Sent: 29 February 2008 16:11
To: rsgb_lf_group@blacksheep.org
Subject: LF: G3LDO 500kHz rig

Hello LFers,

This is a short description of my 500kHz transmitter and antenna.
The driver comprises a DDS3 Hands direct digital synthesiser, which came 
in the form of a kit. I bought this some time ago as a driver for 73 and 
136kHz and has now been reprogrammed for the 500kHz band.
The transmitter uses a PL519 TV sweep tube (valve) with 380v on the 
plate (anode). This is driven by a metal 1632, which is a 12v  heater 
version of a 6L6. The design of the transmitter is derived from my junk 
box and provided me with some nostalgic pleasure.
The antenna comprises a HF quad. The quad and its feeder is used as a 
short vertical with a capacity hat and is resonated with a variometer 
and matched with a ferrite multi tapped transformer located in the 
garden shed at the bottom of the garden.
The antenna has a calculated gain of around -20dBi.

The DDS3 is programmed using DOS via the printer port. In the meantime 
all my computers have moved on and the only DOS computer I have left is 
an AcerNote 760iC laptop, which I still use for QRSS keying. 
Unfortunately it doesn't seem to want to talk the DDS3 via the printer 
port. Did some old laptops use different pinouts compared with standard 
printer ports?

regards

Peter G3LDO