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Re: Topband: DX-100 adventure contiunued

To: 'topband' <topband@contesting.com>
Subject: Re: Topband: DX-100 adventure contiunued
From: "Keith Jillings (G3OIT)" <g3oit.keith@jillings.org.uk>
Date: Wed, 08 Jan 2014 22:33:16 +0000
List-post: <topband@contesting.com">mailto:topband@contesting.com>

The DX-100 High voltage is choke input by design. I changed the low
voltage supply to choke input as well and the rf stages are behaving
very nicely with that. I already think my line is "high" and I'll take
readings various times as you have suggested. Light bulbs don't seem to
last very long here, either.

Tom asked about bleeder current. I didn't try to measure it but I
watched the high voltage decay to zero in a very few seconds when I
switched it off with no 6146s in the sockets.


In my (very distant) youth I came by a DX-100 that had been built from kit by a local, who could never get it to work. I spent a few interesting weekends studying the circuit and the construction, and then set to with a hot soldering iron and got it working. I used it as my one and only TX for a fair few years, modifying it to do this and that as I went along.

Mine was fed from 230 volt mains, and as I recall the HV was in the region of 900 volts off-load, sagging quite a bit on-load. I never worried about it, and the PA valves remained happy throughout. The electrolytics didn't go bang either, but they were very much younger in those days.

I eventually sold it to a local dealer and put my pocket money to it to buy an FT101E which I still have and use with my VHF and UHF transverters.


73

Keith
G3OIT


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