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Remember, software upgrades are freel WEFAX and SSTV demodulators Commercial inquiries are welcomed. We offer rapid prototyping of custom commercial, civil, and government applications including intelligent radio, wireline, and telephone modems. DSP-12 Multi-mode Communications Controller 695.00 One Megabyte RAM Expansion Option Date Time Clock Backup Option 8-Channel A-To-D Telemetry Experimentation Option Wall-Mount Power Supply for DSP-12 110 We accept MasterCard amp VISA and can ship C O...

By Ulrich L Rohde KAWEU

Ulrich Rohde

This last of three parts presents verification examples for the nonlinear mathematical approach of calculating phase noise in oscillators. Example 1 A 10-MHz Crystal Oscillator Fig 18 shows the abbreviated circuit of a 10-MHz crystal oscillator. It uses Fig 18 Abbreviated circuit of a 10-MHz crystal oscillator. TYPICAL NOISE CURVE FOR R 10 MHZ FREQUENCY' STANDARD Chp 3 304SR Carman 10.E- G Hz 12 Jan 1987 13 37 04 - 13 12 33 0 -10 -20 -30 0 -50 -SB -70 -80 -90 -100 -I 10 -120 -130 -140 -150 -160...

Harold E Price NKK

I had planned to make the source for the FEC system discussed in the previous column available in this column. Events have conspired to keep that from happening the first Christmas where my daughter was old enough to get into it recommended , a kidney stone not recommended , and work made for an interesting December. Not to worry, though, the mailbag brought some interesting comments on the subject of FEC. In the December column, I said Tests made by Jon Bloom at the ARRL lab show that coding...

By Bob Bruninga WBAPR

The marriage of global positioning satellite GPS technology to amateur packet radio is the new frontier. By its very nature, the most important aspect of any radio communication network is the knowledge of the location of all of its participants. With the price of GPS receivers set to fall under 300 this year, and with new units being the size of a matchbox, there is no reason why all mobile units, whether voice or packet, should not periodically transmit their location. This article begins...

By Nick Ciarallo VEHOT

Some time ago, I built a 220-MHz repeater. Since this was to be a low-budget project, the more home-brew equipment the better. One of the circuits necessary for the repeater was a Morse code ID circuit. Searching through amateur radio publications turned up many interesting articles, but none that I really liked. I consulted with other hams and came up with a nice circuit that, as it turned out, provided more functions than just a Morse code ID for the repeater This article describes the...

By Bill de Carle VEIQ

Coherent CW CCW is an old technique for digging weak CW signals out of the noise. The system synchronizes the receiver to the sender s keying. Thereafter, due to the rules of Morse code each dah equals exactly three dit-times, and spaces between marking elements are always an integral multiple of one dit time the receiver knows precisely when the carrier is allowed to turn on or off. This is useful information that would otherwise have to be transmitted at the expense of additional power and or...