Ramsey Electronics FR1 Assembly And Instruction Manual - page 15
FR-1 • 15
different adapter or a well designed and filtered DC power supply.
PROBLEM: Signals have unpleasant distortion.
SOLUTION: Quadrature coil L2 is not adjusted properly.
PROBLEM: Oscillator inoperative or wrong frequency.
SOLUTION: In addition to checking solder joints, be sure that L1 is tuned
correctly, and the frequency determining capacitors, C11,12 are the correct
values.
PROBLEM: Unit receives when L1 is adjusted, but not able to be tuned with
Tune control.
SOLUTION: Check position of varactor diode and capacitors; C6,14. A careful
check of all construction WILL solve your problem. Over 95% of the kits
returned for repair have nothing more than a simple assembly or construction
error! Have another pair of eyes check your work first.
OTHER HOOK-UPS:
ALTERNATE POWER SOURCES
Most of the FR1 circuitry can be operated from 6 to 14 volts without damage or
significant modification. However, it is quite important that you carefully hook up
with the correct polarity - reverse polarity or excessive voltages WILL damage
your kit.
DIGITAL READOUT
A novel hook-up is to add a general purpose frequency counter such as the
Ramsey CT-90 to give a direct readout of oscillator frequency. Of course, we
know that the oscillator is not oscillating at the same frequency that we're
receiving - it's actually 10.7 Mhz above the dialed in frequency.
This may seem like overkill, but we mention it to point out the possibilities that a
low cost kit offers you in experimenting and just plain 'fooling around'! And we
don't mind suggesting that a Ramsey counter makes an attractive, matching
companion to your Ramsey kit as well as being a valuable tool with lots of
practical uses for any electronic hobbyist.
While you could experiment with an RF pickup loop or tuned circuit and counter
preamplifier to boost the oscillator's tiny output to a level suitable for the
counter, the most reliable method is to wire a high-impedance counter probe
line directly to pin 7 of the SA602, terminated to a rear-panel frequency counter
connector of your choice. This will consist of a short piece of mini - coax to a 1
megohm resistor bridged by a 27 or 33 pf capacitor as shown: