W6IWI, Tucson AZ

Operating Position

• Teletype model 15 for Heavy Metal RTTY
• Top Shelf
  • Dentron Clipperton-L HF power amplifier
  • Daiwa CN-501H RF power meter between the output of the Clipperton-L and the line to the antenna. Behind the CN-501H is an MFJ 4117 power injector to put 12VDC on the outgoing coax to drive the MFJ 998RT remote antenna tuner.
  • Above the CN-501H is a Wouxon KG-UV6X VHF/UHF handheld transceiver. It is driving an external VHF/UHF vertical antenna
• Middle Shelf
  • Seacomm SEA245 HF transceiver control head. The transceiver itself is on a shelf under the table
  • Daiwa CN-501H RF power meter on top of the Seacomm SEA245 HF transceiver control head. This wattmeter is on the input to the Dentron Clipperton-L and after the SEA 1630 antenna tuner as shown in the block diagram above.
  • Battery operated digital clock set to UTC. Line operated clocks are often reset by RF.
  • EM63 TX Android tablet running DroidRTTY and Morse Code Reader. Driven by the Seacomm SEA245 unbalanced low level receive audio output (on the transceiver itself). This output is run through a voltage divider with a series 100k and 2.2k to ground to reduce the level down to microphone level suitable for the audio input of the tablet. See here for information on the TRRS audio connector used on tablet computers. An adapter cable similar to this adapts the tablet audio input to an unbalanced shielded line to the transceiver audio output.
• Bottom Shelf
  • USL CM-8E cinema booth monitor. The CM-8E is across the SEA245 audio bus. The DSP in the CM-8E is configured to act as a narrow CW filter. The headphone output of the CM-8E is used to listen to the filtered audio.
• In front of shelves
  • Vibroplex Blue Racer Deluxe bug with Round Arm Vari-Speed Accessory to slow the bug down to about 15 wpm.
  • MFJ 557 straight key with code practice oscillator. The code practice oscillator provides CW sidetone since the SEA245 does not provide sidetone. A pair of diodes prevent interaction between the code practice oscillator and the SEA245 PTT circuit.
• Netgear WN2000RPT WiFi Extender used to bridge WiFi to Ethernet equipment in shack.
• CZUR ET18PRO scanner. Used to scan manuals for Saving History From The Dumpster.
• Samsung 55 inch TV used as computer monitor.
• Tecsun PL-310ET DSP-based portable multiband radio. Covers LW, MW, SW, and FM broadcast bands. Uses the SI4734 single chip receiver. Very impressive!
• Shure 522 PTT microphone used on Zoom and similar calls.

RTTY Corner

• Teletype model 14 Transmitter Distributor (punched paper tape reader). On top of the TD, there are a couple patch boxes. Each of these has four 1/4 inch TRS connectors in series (tip and ring connections in series, shell grounded). Each jack has a shorting switch shorting tip to ring when no plug is inserted. The back patch box is connected to the Flesher TU-170 terminal unit. The front patch box is connected to a Teletype 152950 loop supply with a series 2.2k resistor, setting the loop current at 60 mA. Each piece of Teletype equipment (TD, reperf, 15KSR) has a cable with a 1/4 inch TRS plug on it. These can be plugged into either loop (that sourced by the TU-170 or that sourced by the Teletype 152950). Each piece of equipment with the TRS plug has floating circuitry (selector magnet, keyboard, distributor, etc.) with no internal voltage source. There is no voltage on the unplugged TRS connectors.
• Teletype model 14 Typing Reperforator. This punches "chadless" tape to be read by the TD. It also types on the tape so tapes can be read by humans.
• Flesher TU-170 Terminal Unit (modem) with WAVE2 oscilloscope used as a tuning indicator. The TU-170 receives audio from the SEA245 transceiver audio bus. When transmitting, it drives the audio bus with Audio Frequency Shift Keyed tones (2.125 kHz mark, 2.295 kHz space) and pulls the PTT line low. The TU-170 also has an autostart switched AC outlet. The model 15 printer is plugged into this outlet so the printer motor starts when RTTY tones are received.
• Teletype model 15KSR page printer.

Test Equipment and Parts!

More Stuff!