Advertisement
Alignment:
Turn on whatever reference signal source you plan to use. This can be a
regular transceiver keying a few milliwatts into a dummy load, a crystal
oscillator or a signal generator. Or, you can look for a known signal that you
have tuned in on another receiver.
If you are without any reference signal whatsoever but have a reasonable
antenna , you can use your familiarity with the 20m band to make a rough
alignment of the receiver. If Ham radio and 20 meters are new to you, here's a
rough idea of what you can expect to hear on this busy band:
14.00 - 14.08 MHz - CW, most of it is fairly fast
14.08 - 14.15 MHz - Teletype (RTTY) and digital operation
14.10 - 14.20 MHz - SSB voice, many different languages
14.20 - 14.35 MHz - general SSB voice operation
NOTE: A miniature transformer alignment tool is used to turn the slugs in L1
and L2. If you do not have one, make one by gently sanding the tip of a
wooden match stick, a kabob skewer or other piece of wood or plastic. While it
seems that a small jeweler's screwdriver could be used, be aware that its
metallic construction will make adjustment of L2 very erratic and could
damage the powdered iron slug. Any kind of metal tip will affect the coil's true
value, so that the oscillator will run at one frequency with the metal instrument
in the coil can, and a completely different frequency by itself.
For now, set the tuning control to its mid-point. Use the insulated alignment
tool to gently rotate the slug in the top of L2. If it starts to get tight , DO NOT
FORCE IT! Instead gently rock it back and forth until it loosens up. You should
find your 14Mhz reference over a range of approximately 12 to 15 MHz. The
varactor tuning control can cover any 300 KHz range chosen within the 12 to
15MHz limits.
Adjust L1 for maximum received signal strength. Now you're ready to
receive on-the-air signals! After you get used to its tuning and
performance, you can adjust the tuning control, L1 and L2 to get the exact
tuning range you want.
ALIGNMENT HINT FOR ALL DIRECT CONVERSION RECEIVERS:
You will clearly hear the oscillator of your kit - very close to its receiving
frequency, if you tune around for it on ANY shortwave radio covering the same
frequency range. Even if your shortwave set does not have a BFO (beat
frequency oscillator) for CW-SSB, you'll still hear a powerful 'hiss or quieting'
when your shortwave receiver is tuned near the frequency of the HR20. Your
shortwave receiver is actually picking up the oscillator signal within the HR20!
HR20• 15
Advertisement
