The
Rockless QRP
Addendum-Corrections-Notices
Last Up Date: 6/ 15/2010
Drawing
Corrections:
It
has been noticed that there is inconsistency in component values between the
circuit board and the schematic and parts placement drawings supplied with
early kit shippments.
Please
take note of these Adjustments:
Capacitor Values:
1.The capacitor from Pin 1 to ground
on U3 should be 0.1 mfd.
2. the capacitor value going to the
base of Q3 from the VFO should
be 0.1 mfd.
3. The correct value from U1, Pin 4
to ground is 0.01 mfd.
Resistor Values:
1. Your kit includes a 510 ohm
resistor that may be used in place of the 1K
value shown as R19
NOTE OF
CAUTION ON RESISTOR CODES:
The 510 ohm and the 1 meg ohm
resistors have the same colors but in reverse
order. Be sure to use 1 Meg at R4.
The 510 ohm value at R4 will kill the receiver audio.
NOTE REGARDING
DIODE D6 IN SCHEMATIC:
Diode D6 is
drawn backwards on some schematic drawings
that came with some board kits.
It is shown correctly on the ARRL
schematic found on the binary file for the
Rockless QRP. The Binaries are found at www.arrl.org/files/qst-binaries.
Diode D6 is a 5 volt zener diode
used to regulate voltage to U3.
MISSING
OR WRONG PARTS IN KITS:
If any kit arrives missing parts please
email me immediately and I will send what was missing.
I recently found that a package that
was marked 120 pfd was actually 100 pfd. This was corrected
kits shipped after
KIT SHIPPING SCHEDULE:
Most kits
have shipped. I am waiting for one part to complete the last of current open
orders. All orders
now received should ship within a week.
Caution
When Wiring Multi-Turn Tuning Potentiometer:
Be sure to check your 10 turn
potentiometer with an ohm meter to determine which connections
are the ends of the 10K protion and
which terminal is the wiper
contact. The wiper contact should
go to the 100K resistor that connects
to the varactor diode. When measured against ground
the resistance at the wiper increases
with clockwise rotation. Likewise voltage to the varactor
diode should increase with clockwise
rotation.of the control. The higher the
voltage to the
varactor, the lower the capacitance
that it exhibits, hence you tune up in frequency as capacitance
becomes lower. Check this out before
you get it all together.
Reported
Source for MV209 Varactor Diode:
K8RRH reports that he has found the
MV-209 Varactor diode for the VFO at the following site:
Thanks K8RRH, this should be of great
help to many searching for this
part.
Search the site for diodes, “other” and you will find it.
VFO
Inductor and VFO Stability:
I have had reports that when first
applying power to some oscillator boards, that the frequency drifts
for some time.
Recently I built an oscillator board using parts supplied in recently
shipped kits and
found this same problem. I have traced it to a substitute 8.2 uHY
inductor used in the VFO which was
recommended as a replacement for the
original coil when I re-ordered the inductor. The coil in
question has multi-stripes, with gray
on the end and then red. (Color code for 8,2 uHY). The
original shielded inductors for this
value were all black in color and were very stable. Running a
sample test on on the replacement coils I had
in stock I found the substitute parts had poor
consistency of value and many were out of
tolerance. The original Black color
shielded coils all
test consistently in value and operate well in
the oscillator.
If you have trouble with oscillator
stability and your kit included the multi-striped coil, contact me at
rocklessqrp@comcast.net
and I will send you a replacement inductor.
I have recently changed this part
number in the Parts List to an unshielded 8.2 uHY coil made by
Delevan.. The unshielded coil is
Delevan part 1025R-42K. It has a Digikey part number of
DN7692-ND, and it is immediately
available in small quantities. Either
this unshielded 8.2 uHY coil
by Delevan, or the Black color Delevan
Shielded coil give good stable operation in the oscillator.
The shielded inductor is Delevan Part
1641-822K. Mouser lists their part
number as 807-1641R-822K,
and this part appears to be immediately
available from them.
The unshielded coil is smaller in
diameter and is solid sandy yellow in color. The value is stamped
on it.
Kits shipped after 12/28/2009 will have either
the black shielded or sandy yellow colored
unshielded coils for the VFO.
Volume
Control Suggestion
I have found another Volume control that
will ship with all future CK-1 kits. The 9mm square volume control
had been used because it would fit
in both size cases, and at the time I
couldn’t locate a better one to do the
job
However, I have recently found Mouser Part number 313-1500F-1M. It has audio taper and performs
very well in the Rockless. The body is about 16 mm (.63 inches) in
diameter, not counting the terminals,
which you can face to the side. The terminals are solder lugs. Remember to
short the center wiper to
one of the end lugs so that zero
resistance is in the full counter clockwise position.
Read
this Great RF Probe Tutoral:
If you don’t already have an RF Probe
for testing your Rockless and other projects involving RF, you can
find a
great tutorial for building one at this web page: N5SE's
Classic RF Probe Just click this
link and it
will take you to the site. This is a simple item to build, which every “building
ham” should have in his shack.
The Article includes a great discussion
of how it works.
Alternative
Audio Chip for LM1450:
The OP Amp chip LM 1450, 8 pin dip has
been getting difficult to locate. I have
found a substitute in
the Dual OP Amp KA4558. Mouser
stocks this chip as part number 512-KA4558.
No change in operation was observed when
using the KA4558 as the audio chip in the “Rockless Qrp”.