(3) pc Low Power 20-Meter QRP HAM TRANSMITTER in Shielded Metal Can

Description

(3) General / Advanced / Extra Class 20 Meter QRP Transmitters - 14.318 MHz
1207
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Price is for (3)
miniature
QRP Oscillators
Go
CW
,
MCW
or even
AM
mode!
Amateur Radio HAMs, get a 20 Meter QRP NET on the air FAST and SIMPLE with these self contained low-power "transmitters". Price is for (3) shielded crystal controlled oscillators.
These are crystal controlled clock oscillators, in a shielded DIP-14 size metal can. The nominal 14.31818 MHz frequency falls nicely in the upper half of the 20 Meter Phone band available to all HAMs with HF privileges (14.225 to 14.350 MHz).
SIMPLE WIRING
Standard CW (carrier) Mode: Just ground pin 7, connect an LPF and/or antenna to pin 8, and key +5 VDC to pin 14 and you're on the air. This method works for receivers with a BFO or product detector. (If power leads are long, a 0.001µF bypass capacitor wired directly across pins 7 & 14 may improve oscillator stability.) You can identify different transmitters by the slight variations in crystal frequency. Can't get any simpler!
If you are using an AM-only receiver, just add a simple modulator, such as the example shown below, for MCW (Modulated CW). Change the resistor and capacitor values for different tones.
Note: The parts shown in the application schematics below are NOT
included. Auction is for the crystal controlled oscillator cans only.
LONG RANGE
Of course range is widely dependent on external factors and avid QRP'ers know the Antenna, Antenna and Antenna are the key elements of maximum performance. But as an example, I've taken 6M and 10M units on the road, using a short wire antenna draped over the car seat. They reached out over 1½ miles to a receiver connected to a roof level vertical. I expect these will perform similarly. But the real possibilities come from elevated, directional, gain antennas on both ends. Output power will vary depending on voltage, and especially with the antenna match, but it will be in the range of approximately 40~50 mW into a 50 Ohm resistive load.
AMPLITUDE MODULATION
AM operation is easy using a small audio transformer. (Transformers are available in our other auctions.) This example will work with any audio source intended to drive a speaker. Note the reversal of PRI and SEC windings. The impedances are not critical and almost anything close will work.
Suggested Low Pass Filter (LPF)
The harmonics are weak, but you can construct your own filter if you experience interference with nearby equipment.
The 16.5 MHz cutoff frequency for the example shown is well below the 2nd harmonic but with a wide buffer zone so loose part tolerances won't threaten clipping the fundamental frequency.
The 0.66 µH air core inductors can be handmade by close-winding 15T #22 on a ¼" form. For other wire sizes and/or coil dimensions there are Air Coil Inductance Calculators on the internet to 'roll your own'.
This plan is for informational purposes only. This listing does NOT include LPF parts.
Other possibilities:
Fox Hunt
Beacon
Telemetry
Model Rocket or Balloon Payload
Add a divide by 2 IC* circuit for a 40 Meter HAM band output.
Add a divide by 4 IC* circuit for a 80 Meter HAM band output.
Add an LPF and a small amp on your band of choice for a serious QRP transmitter.
* Note: a 74LS74 or equivalent binary divider is recommended.
160, 80, 40, 10, 6 and other 20 Meter versions available.
Check our other auctions or e-Mail us.
Note: Configurations and applications vary and performance varies. Please review FCC Part 15 and Part 97 if you are not certain your particular use is in compliance. The suggestions above are not intended to promote illegal or improper use. It is the amateur's responsibility to ensure the completed transmitter is in compliance and that it's operation does not interfere with other equipment.
Q20F-3
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Condition of Goods
Unless otherwise noted above:
NOS (New Old Stock) or better, clean, unused
30 day Non-DOA, Good-on-Arrival Guarantee
Untested, but NO JUNK or suspect parts
PCB parts are thru-hole, NO SMD/SMT
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IMPORTANT: The parts we sell are categorized as new because they are unused, but many of our parts are those rare, hard-to-find, discontinued, manufacturing surplus and
/
or old stock commonly known in the parts business as 'NOS' (New Old Stock). Some of our stock pictures show date codes which may vary from the actual product shipped.
Parts from a larger OEM package may be repacked for smaller lot size orders or for more practical handling and shipping.
We strive to give full and accurate descriptions to earn your 5-Star Feedback. Any known deficiencies are listed in the detailed description. Datasheets are provided when available. Some datasheets may be close but not a perfect match because of part revisions or because they may be from a different manufacturer. If you have any questions concerning our products please email us before purchasing. Your complete satisfaction is important to us before and after the sale. Thank you.