Radio W4KAZ

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Skimming During WPX

“Don’t get cocky kid….”

Just when everything seems to be going smoothly, Murphy arrives. Two days before the WPX contest, it became clear the 80m softrock had developed an issue and was useless. It lost half of the signal, and so was useless(on 5/27) and required repairs. Sideline that issue for now….

The 40m skimmer session kept right on chugging. A couple of problems became clear.

The softrock will need better band pass filtering if they remain active during operations, or switching to shut them down during transmit running CW skimmer at 192khz sample rate used a great deal of CPU time, averaged 45-50% CPU utilization. Limiting the number of decoders helped somewhat Reducing the scan rate to allow a 96Khz bandwidth drastically reduced the CPU usage. Running at 96khz required an average of 15-20% of the CPU, even with the limit on the number of decoders increased. The K9AY rx antenna worked well for the 40m SR skimmer. The problem is it will need to be split and amplified for 80m and 160m as well.

All together, it looks like the skimmer posted about 8K spots while it was active during WPX. Trying to figure out a way to check for errors. Low priority – spot checking the spots showed most to be valid.

The 80m SR problem was resolved on Monday evening. After having made three passes over the op-amp section, I made a fourth pass, concentrating on components in the “ring” side of the op-amp output, as […]

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Skimming CW at W4KAZ

Note….Post dated this material to original date written…superseded by new reality…..

“All is proceeding as I have foreseen it…………..”

Been just about four years since the CW skimmer stuff really hit the contest rotary impeller. A bit of review…..

First impressions in May 2008. More observations June 2008. And I sure wish I had plagiarized W4PA completely in July 2008, his original post was clear, concise, and 100% accurate. But lost in the internet rabbit hole….

So in hindsight – I’m glad contest sponsors read my blog. 😉

Since the rule-parsing panned out to my immense satisfaction, it is easier to concentrate on the toy itself. Since then, skimmer stations sprouted, and the Reverse Beacon Network was born. That is a really interesting project. Its a great tool for checking propagation, comparing station signals, and getting impartial signal reports. Outstanding resource.

Unfortunately there is not a local skimmer station that is feeding the RBN. Spots from MD are not always useful in Central NC.

So it with the moon in phase and the planets approaching the grand alignment, it seemed like time to look into the subject of skimming.


The Skimmer software comes with a component that is designed to work with the QS1R SDR. That combination is likely the ideal solution. So all I need is a fast Pentium i7 Quad core, and a thousand samolies…… Great idea, just not possible.

Much more possible….Combine a few Softrocks with some cast off circa 2008 computers. Yup, that’s the ticket. […]

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Softrock Lite II

After some large amount of initial interest, I quit paying attention to the Softrock. As the years trickled by, the Softrock project kept moving. Lots of projects, mods, versions, and changes.

Here in the present, I had an older Softrock v6.2 sitting on the ‘ToooDooo” batting lineup since around December. It had originally been built as a 9Mhz IF kit, to be used as a panadapter. It was a gift from W3DQ. When I saw the NorCal group had a run of kits available, I ordered a pair. Wish it had been three….

But….it seemed like a good point in time too examine the IF kit, with an eye on re-working it for one of the bands of interest. As it was built, it required only four changes to put it on 40m. The Softrock Lite II kits come with components for building any band from 160m-20m, so the needed crystal was available from one of the kits. The mods took only a few minutes. That got done first.

On a roll, it was time to sift through one of the kits to see what the build was going to take. One thing leads to another….build it! The smell of solder smoke was soon wafting about. The “most difficult” surface mount parts were the first on the plate. As it turns out, these are not the smallest of surface mount parts. An ordinary 15w RatShack iron with a fine tip was sufficient for the task. The difficult part turned ot […]

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Feel Day Hack Challenge

So….Who will be the first to hack one of these things to use for hauling antenna lines up into trees for Field Day? Â They will be forever honored in the Halls of HamHacks.

A simple solenoid that is remotely activated to pull a pin and drop the line should do the job. Â The challenge is probably finding a solenoid that is light enough to be lifted by the drone when combined with the weight/drag of the line. Â Which leads to the question of “what’s the payload capacity(if any)?”



Rocky rocks softly

After a lot of procrastination, the dormant Softrock v6.2 project became timely. The job was to convert a Softrock v6.2 from its intended IF usage(IF 9.001?) to something a wee more interesting fer the KazShack main op, namely a 40m Softrock v6.2. The WB5RVZ pages are the place to go for build information. A fabulous job of documentation on the many SR permutations.

Turns out, the conversion was fairly simple. As built, there were only 2 component changes, add the RX enable jumper, and add a wire for the second “ring” line output. Oh….also change the crystal. A few resistance and then voltage checks. Use the K2 as frequency meter to check the crystal oscillator frequency, and its F/4 from the divider. (28.220 and 7.055+/-).

Fired off “Rocky”, VE3NEA’s SDR program. Putz around with the settings for Rocky and the sound card….Success! Sweet.

Now the question…….What the heck is this transient!!???!!


So…..the project is not quite complete. There are two full ready to build kits waiting on the sidelines (hat tip to AE5X for noting the availability). Still need to find a suitable enclosure. It also seems like inserting isolation transformers in the line-outs will be worth the time, and maybe the cost. A search on the radio shack site comes up empty for their audio iso xfmr. Mouser or Digikey.

Job one is a nice shielded enclosure, although there are lots of warnings about being wary of creating ground loops. Probably put an isolation transformer and front end […]

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