F
Revised firmware release 610 for Z90 is now available
The revised firmware permits you to reverse the sweep
direction, thereby placing signals in their correct orientation when the Z90
is used with equipment that inverts the IF frequency, such as the K2 on most
bands. Download the firmware at the Software Updates
page. (04 Nov 2007)
F
Revised firmware release 2.2 for Z100 is now available . Z100
Firmware release 2.2 implements an additional operating mode, central green LED
plus high/low direction indication. Download the firmware at the
Software Updates page. (15 Dec 2007)
Second Run - Z10000-K2 and Z10000-U
Buffer Amp Boards Now Shipping
The Z10000 buffer amplifier is now shipping. For more information, click
here.
New Kit-the Z10040B broadband Norton
amplifier is now available. For details, click
here.
The latest weather in Clifton VA from my Davis Instruments
weather system.
You can click on the image to jump
to data from my weather station at Weather Underground. Or, you can click
here for 24 hour data uploaded directly to
my Clifton Laboratories web site.
02 July 2009
I've completed a major revision of my antenna
multi-coupler prototype and have a set of new printed circuit boards ordered. I
expect to receive the boards in 10 days or so. Assuming the new design works as
well as the individual pieces spread across my workbench, I'll then revise the
enclosure layout and wrap up a couple of associated tasks. If all goes according
to plan, the multi-coupler kit (or assembled) will be available around the first
of September.
I've also resumed the mechanical work on my active antenna
kit. These tasks involve revising the enclosure and antenna rod elements. When I
have a final enclosure, I will revise the PCB layout to fit in the enclosure.
There are a couple of related elements to the active antenna that I've
also been working one. One is a common mode choke and the second is a revised DC
power injector. These fall into the same category as the active antenna - the
electronic part is finished, but I have more work to do on the packaging.
I've also been working on several small kits. One if a 3
dB hybrid combiner or splitter. The difference between a combiner and a splitter
is the direction of signal flow. A splitter divides an input signal into two
equal outputs. A combiner sums two signals into a common output, with isolation
between the two inputs. Same device, the difference is which ports are used for
inputs and which for outputs.
A prototype version of the coupler is pictured below. The
extra holes are from an earlier project housed in the same enclosure.
Version two of the prototype 3 dB hybrid coupler.
My objective is performance, measured in terms of splitting
loss, input return loss, and isolation, to at least equal Mini-Circuit's
ZFSC-2-6+ hybrid, at a lower price, when assembled by the user, over the range 1
MHz to 50 MHz. So far, my prototype is performing quite well, superior to the
ZFSC-2-6+.
The image below show port-to-port
isolation of the ZFSC-2-6+ and my two prototypes over the range 300 KHz to 100
MHz. The lower the curve, the greater the isolation. The more isolation, the
better. At 1 MHz and below, all three hybrids are about the same. Above 5 MHz,
both of my prototypes have significantly better isolation than the ZFSC-2-6+.
The plots below show the hybrids used as a splitter. The upper plot is the
return loss (similar to SWR) of the input port when used as a splitter and the
two output ports terminated with 50 ohm loads. The horizontal reference line
(marked with the > symbol) is -20 dBm return loss, corresponding to an SWR of
1.22:1. The greater the return loss, the lower the SWR. Greater return loss
shows as a lower trace on the plot.
The lower plot
is coupling loss, i.e., the power out of one of the output ports
compared with the input power. Since the input power splits two ways, a coupling
loss of 3.01 dB represents a perfect hybrid. Anything over 3 dB represents loss
within the coupler. In this plot, the higher the trace, the lower the 'excess'
loss and the better the coupler performs.
In both return loss and splitting loss, my prototype
designs are performing at least as well as the ZFSC-2-6+, and in most
frequencies, my prototypes perform better.
02 July 2009
As usual, I've moved June 2009 Updates to an archive page.
Click here to view it, or use the archive navigation
table at the top of this page.
