29 October 2007

Multiband beam (70 MHz)

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I have no experience on this matter, so this is a purely theoretical post . If looking for a directional antenna that covers 50 MHz, 70 MHz ...
22 October 2007

Antenna tuners are reversible

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I'm back on posting after a few weeks without any shack or lab activity. I had few minutes to spare, so I wanted to do a measurement on ...
28 September 2007

Closed for holidays

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About to take a short vacation, with lots of open projects: FT-817 hands free adapter Finishing 4m TX #1 Rebuilding 4m TX #2 (it has a short...
25 September 2007

Controlling canned oscillators

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For a number of projects it might be interesting to control the frequency of a canned oscillator. Some of them have a control pin, others an...
17 September 2007

Tektronix 7A13: broken relays

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Relays sit on sockets, so it's very easy to test them outside the original location. Pinout is printed on one side and, before you worry...
14 September 2007

Tektronix 7A13, debugging

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I have a Tek 7A13 amplifier plug-in that shows a problem. The 1V:100mV:10mV/div ranges work fine, but others don't. With both inputs at ...
07 September 2007

4m TX - foto

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Ecco come si presentava il TX il 6 settembre 2007: Da sinistra a destra: filtro C-L-C, BNC e rele', 74AC08, moltiplicatore x5 e, in alto...

Comb Generator - measured

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I built the circuit in about one hour. With an accurate selection of NOR gates usage, the signal can be routed through the 74HC02 simply ben...