Inspired by the recent presentation on Windoms, Dave, KI4PSR with the help of Jon, KK4AIZ, Rob, KM4SOA , Paul, KM4PT and Doug, W4DML, built and tested the design during this past Tuesday’s Portable Ops. Dave said the SWR was great, just as described by Ted, W3TB.
“Station was Icom 7300, with battery and solar panels. We were able to tune 20, 40, 80, & 17. I made one contact into Western Pennsylvania; on 7.255 – missed NC callsign. Got a 5.6 report!”
Ted, W3TB gave a presentation at the March WCARES Monthly Meeting on Windom antennas. Ted discussed the use of Azimuthal Equidistant maps for antenna planning and aiming, gave a demonstration of modelling the Windom using the EZNEC demo and discussed building the Windom.
WCARES members were out in force for this year’s Winter Field Day.
So, a few hours before midnight; 30 degrees at best; Traffic on Moores lane is near zero; the small tent is keeping us warm; On 80 meters; Three portable antennas in the field; The operator (N4CCB) decides to run a frequency (call CQ); I’m logging and chomping at the bit; Tuned up; Boom! …Two, Three, then four contacts a minute; Canada, Wisconsin to Alabama, Ohio, Western New York inbetween.
Talk about a RUSH! The CW station had similar runs at kick-off time.
A Flex 6500 radio was used along with a number of software packages including SmartSDR, CWSkimmer, Slice Master and DAX:
CWSkimmer is the software that takes the I/Q output from the radio and decodes the CW
Slice Master 6000 which sits between SmartSDR and CWSkimmer (SDR Bridge is another option here)
Slice Master does a number of things but is primarily responsible for syncing the radio and CWSkimmer. This lets someone click on the CWSkimmer waterfall and have the radio automatically QSY to the frequency on which the user clicked. In the same way, a user can click on the SmartSDR panadapter and CWSkimmer will automatically scroll to that signal in its display. Slice Master is the “glue” that makes these two programs stay in sync when the user clicks either.
DAX is Digital Audio Transport
It’s Flex software that creates virtual audio cables for the signals coming into and out of SmartSDR.
It does this by creating a virtual soundcard for the incoming, outgoing, and I/Q signals.
By having these signals show up on your PC as soundcards, you can use any off-the-shelf ham radio software and configure that software to use the DAX signals. So, in your ham radio software for digital modes like PSK-31, FT8, etc…. if you want to tell the software where to get the incoming audio for decoding, you’ll select the “soundcard” in your PC’s audio picklist called “DAX Audio RX 1”. And, to tell the software where to send the encoded audio for transmission over-the-air, you’ll pick the soundcard called “DAX Audio TX”.
N1MM is the gold-standard software used by contesters
At the January, 2019 Monthly Meeting, Paul, WD9IOK gave a talk on his experiences making and using loop antennas mounted to fences. Check out the attached PDF and discover how to find those stations previously lost in the noise while complying with your HOA.
His talk covers some of the history of transmission line transformers leading to the development of baluns, ununs and choke baluns as well as definitions and theory. Some discussion on chosing the right balun included ideas on measuring common mode current, consequences of high- vs. low-power wiring, misconceptions about ratios, use of ladder line with baluns and grounding. Finally Dave walked us through a number of examples based on different antenna configurations including some being used by WCARES members.
If you missed the presentation or just want to review, Dave has provided his slides and text; You can find PDF copies at the following links: