Re: Project 9: 2M CW transmitter

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From: David Adams (dadams@cherry.cray.com)
Date: Mon Sep 27 1993 - 11:22:32 EDT


I have been thinking of doing something similar. A small tranceiver
or transmitter & receiver pair for 2M or 1.25M based on the
Motorola MC2833 for the transmitter and the MC3363 for the
receiver. I don't have any plans other than the fact sheets
that Motorola will give out with these parts, which will require
some modification. Has anyone tried anything like this? I think
it is one nice way to get a clean set up easy. (The boards came
with the chips.)

Do you still call it QRP when you are in VHF or UHF using < 5 watts?
(I will probably use 500 mw.) Low power is more of the norm here?

From the fact sheet:

        "The MC3363 is a single chip narrowband VHF FM radio receiver.
        It is a dual conversion receiver with RF amplifier transistor,
        oscillators, mixers, quadrature detector, meter drive/carrier
        detect and mute circuitry. The MC3363 also has a buffered
        first local oscillator output for use with frequency synthesizers,
        and a data slicing comparator for FSK detection.

        "*Wide Input Bandwidth -- 200 MHz Using Internal Local Oscillator
                                -- 450 MHz Using External Local Oscillator
        "*RF Amplifier Transistor
        "*Muting Operational Amplifier
        "*Complete Dual Conversion
        "*Low Voltage: Vcc = 2.0 V to 7.0 V
        "*Low Drain Current: Icc = 3.6 mA (Typ) at Vcc = 3.0 V,
          Excluding RF Amplifier Transistor
        "*Excellent Sensitivity: Input 0.3picoV (Typ) for 12 dB SINAD
          Using Internal RF Amplifier Transistor
        "*Data Shaping Comparator
        "*Received Signal Strength Indicator (RSSI) with 60 dB
          Dynamic Range
        "*Low Number of External Parts Required
        "*Manufactured in Motorola's MOSAIC Process Technology"

And of the MC2833 the fact sheet saith,

        "MC2833 is a one-chip FM transmitter subsystem designed for
        cordless telephone and FM communication equipment. It includes
        a microphone amplifier, voltage controlled oscillator and two
        auxilary transistors.

        "*Wide Range of Operating Supply Voltage (2.8-9.0 V)
        "*Low Drain Current (Icc = 2.9 mA Typ)
        "*Low Number of External Parts Required
        "* -30 dBm Power Output to 60 MHz Using Direct RF Output
        "* +10 dBm Power Output Attainable Using On-Chip Transistor
          Amplifiers"

My big fear is, "How the *&^%$! am I ever going to solder these delicate
little chips to these boards??! I have some disease that makes my hands
shake whenever I try to do delicate work like this. ;^)

One of the examples in the fact sheet (which uses the same board) is for
a transmitter at 144.6 MHz. (Also for 49.7 MHz and 76 MHz.) I heard the
rumor that they guys who develop these are hams and that the first test
applications are often set on the ham bands. For the receiver chip one
of the examples given is a "256 Channel Frequency Synthesized Two Meter
Amateur Band Receiver."

Has anybody done any homebrew with all in a chip parts like these? Do
you have any pros or cons to mention? What other chips should be
considered. (Heck! They are designing these so fast that before
I ever get to understanding what my options are, they have designed
and are producing another!)

I am wanting to try something on 1.25 M since Novices have privelidges
there and I hope (eventually) to drag my grade school sons' interest
into all this.

--David C. Adams Statistician Cray Research Inc. dadams@cray.com

                                "I have two poles tho' one is poor
                                   I have three cown & want five more,
                                I have not horse, But fifteen sheep;
                                   No more than these this year I keep,
                                Stears, that's two years old, one pair,
                                   Two calves I have, all over hair,
                                Three heffers two years old, I own,
                                   One heffer calf that's poorly grone,
                                My land is acres Eighty two,
                                   Which search the Record youle find true,
                                And this is all I have in Store,
                                   I'll thank you if youle Tax no more"

                                                --Asael Smith of Topsfield


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