Softrock Lite 6.2
Adventures in Electronics and Radio
Elecraft K2 and K3 Transceivers
27 March 2011
I built a one-off 125 KHz low pass filter today, and
thought it would be of general interest, so I added a web page describing the
filter, its construction and measured results. You can view the page at
125 KHz LP Filter
25 March 2011
I've completed a manual and web page for the Z1500A Common
Mode choke. The page is available by clicking
The Z1500A common mode choke is not a kit; I
do not intend to provide parts. However, the manual is detailed to permit you to
build a choke and includes parts sources and approximate pricing.
These chokes are not inexpensive; a pair will cost at
least $75 in parts alone. But they are the best chokes I've seen and are usable
from 20 KHz to 30 MHz. This requires a multiple core strategy which increases
the cost over a simple ham band only common mode choke.
20 March 2011
In a discussion with Ron, K8AQC, the subject turned to
"soldering iron" and "soldering copper." Ron retired from Michigan Bell
Telephone and what we know as a "soldering iron" is a "soldering copper" in Bell
In searching Popular Science Magazine on-line, it seems
that both "soldering iron" and "soldering copper" were used at least as far back
as 1916, but by 1940 or so, "soldering copper" was replaced with "soldering
Of course, modern soldering irons use copper tips (usually
iron plated now) and the old direct heat devices were made from a pound or more
chunk of solid copper. In that sense, "soldering copper" is a more accurate
descriptor. But, from what I can tell, and certainly what I recall from my first
exposure to the subject around 1960, soldering iron has replaced "soldering
copper" in common use.
18 March 2011
Last week, I built three Z10022A high pass filters (passes
1800 KHz and above) for customers. I took advantage of the unusual circumstance
of having three filters on hand to see how closely they tracked.
The plots below show the three filters - I was pleasantly
surprised to see that the the filters are, for all practical purposes,
identical. (Vertical axis is 1 dB/division on both plots.)
I can't promise all filters match this closely, but at
least in this instance where I built all three filters in one sitting, the
agreement is amazing.
14 March 2011
The last two months have been very busy, and it's also
been income tax preparation time here in the US.
The photograph below shows some�not all�of the paper
required for income tax preparation here at Clifton Laboratories. Receipts for
every resistor, screw, lockwasher, etc. that goes into my kits. Ditto for every
post office shipment and stamp purchased, etc. Records on what parts to into
what kits, and details on prototype kits and experimental projects that made it
into new kits, or were abandoned or will make it into new kits in 2011.
My wife, who is neither an accountant nor an engineer,
organizes the receipts and then computes how many resistors, screws, nuts, etc.
go into each kit and how much each cost from these receipts. I help with
identifying parts and maintaining spread sheets with cross references and part
numbers and component breakdowns for each kit, but she uses paper and pencil for
the parts receipt to kit reconciliation. It's about two months work for her. If
I had to hire an accountant to do this, I would be out of business. Mind you, I
still use a tax accountant to prepare the tax return and depreciation schedules,
etc. The combined state and federal tax returns run about an inch thick when
completed with all the supporting schedules.
14 March 2011
I've removed the kit type poll and the weather link - the final poll
results are below.
What is interesting is the divergence between 2% who say
they prefer assembled products and my actual order experience. I don't have a
detailed breakdown, but in terms of assembled versus kit sales, my estimate is
the ratio is closer to 40% assembled and 60% kits, with the Z1501D active
antenna probably running more like 80% assembled.
14 March 2011
As usual, the prior month has been moved to an archive
page, readable by clicking here or via the
navigation table at the top of the page.