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Organization: Alexa Crawls
Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period.
Collection: Alexa Crawls
Starting in 1996, Alexa Internet has been donating their crawl data to the Internet Archive. Flowing in every day, these data are added to the Wayback Machine after an embargo period.
TIMESTAMPS
I
picked up many valves on the broken TV-sets on the street about 30 years
ago. I got many 12BH7A on them. In these days (in the end of 1990's) I
made a radio to receive 7MHz SSB and CW signal with these valves stocked.
12BH7A can make his job with only 12V on it's plate. See fig2! Half side
of 12BH7 oscillates the 6.9 to 7.2MHz CW with ECO oscilator. It is injected
to RF port of a single balanced mixer. On the other hand, 7MHz signal is
injected on the RF port of the mixer. Therefore an audio signal comes on
the IF port of the mixer. This signal is amplified by the other side of
12BH7A. Single balanced mixer convertor has 10dB loss. An audio amplifier
has 38dB gain. Total gain of this radio is 28dB. I could receive the domestic
SSB and CW signals clearly with dipole antenna.
