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Hi All,
With reference to the 1108 Hz tune up tone at ENC Woofferton.
May I confess to being the constructor of this unit in 2007!
With the arrival of the RIZ 250 kW transmitters was a new control system which resulted in the 1981 BBC designed and supplied "WATCH" system being decommissioned. Within the WATCH was a BBC Tone source unit with an 1100 Hz output.
This could no longer be used but we still needed a source of "Local Tone", hence the local construction of a new unit .
It uses a Wein bridge transistor circuit and a Philips TDA7052 BTL audio amplifier in the output stage to 600R for 0 dB output. there is a simple 12V power supply on board as well.
The frequency is fixed by means of Philips orange polyester 0.068 uF capacitors in the bridge with associated 1% resistors.
Thank you for checking both the actual freq and the harmonics! I never did check; I just worked out the theory so I was not too far off!
Regards,
Dave G4OYX
On Wednesday, 22 June 2022, 16:13:23 BST, Wolfgang Bueschel <dg1sbn@t-online.de> wrote:
Richard you are right,
KIWI server graphic display on Chrome browser
is a amateurish matter compared to Italy's Perseus V4.1 ,
used to use exact Perseus or Elad display gear in past decade,
which shows the latest Hertz measurement. Unfortunatelly at Tuesday I had a 600 Ohm call during the BBC transmission,
so I was not able to measure the exact test tone procedure frequency. Remember on Tuesday it was as approx. 1108.8 Hertz
display on Kiwi server at Sao Paulo Brazil. ... in this life i will not become a friend of the KIWI server display
anymore . 73 wolfy df5sx JN48OR
----- Original Message -----
From: Richard Langley
To: WOR@groups.io
Sent: Wednesday, June 22, 2022 2:06 PM
Subject: Re: [WOR] [HCDX] Glenn Hauser logs June 21, 2022
On Tue, Jun 21, 2022 at 05:07 PM, Wolfgang Bueschel wrote:
21.29:05 UT June 21
switch on at ENC Woofferton bcast center on 12065 kHz,
heard some 1010 Hertz test tone procedure crash start.
Typo? I measured the main tone frequency to be 1108 kHz accompanied by
several harmonics. -- Richard Langley
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