File extracts for three summer contests from four skimmer stations for May 2014’s CQ WPX and June’s JARL All Asia and ARRL FD. Â The files are by skimmer spotting station and are sorted in datetime order.
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Some repairs to the skimmer station set up have been made after losing the 20m and 10m softrocks. Â Both were probably damaged due to modifications I made to the voltage regulation circuits. Â That appeared to eventually fry the QSD chip, which is the heart of a softrock. The 20m skimmer was replaced completely with a new softrock lite. Â 10m is pending re-work, but replacement would probably be the best bet. So for WPX 2013 there are five bands available, 160m through 15m. Â These will be active during WPX intermittently. Â I intend to bring them up and down based upon my own operating. Â The skimmer will be down when I am operating. Other changes made to the skimmer station include loading windows XP onto the Optiplex 360 that had been running windows vista. Â Vista was able to run one instance of CW skimmer, but was not able to support two instances simultaneously due to sound card conflicts. Â Windows XP does not seem to have a problem with the two sound cards, and is an OS supported by CWSkimmer(Vista is NOT supported by skimmer).
A thread over on the softrock user group list spurred the curiosity…..: http://groups.yahoo.com/group/softrock40/message/68324 G4ZFQ has  RightMark test data for a high end Xonar D2X card, as well as several others.  An internet search found other RightMark tests of several other Xonar cards, all of whose test data show curve trends remarkably similar to those of the D2X, albeit with somewhat worse IMD, spurious, and noise figures. The curiosity is the test data shows a roll off on the frequencies above 50khz.  The nature of the loopback test is an issue, but it also seems likely that using a sound card as the source may be having an effect on the test results at the higher edges of the sound card frequency response.  But signal generators as input to the tests shows the same general trend.  SDR at wider bandwidths pushes at these edges of a ‘sound’ card’s ability….So perhaps the SDR software is compensating for the expected performance drop-off at frequencies above audible levels? The Test- (Pertinent Excerpt from list post): Having not yet thought of a better way to do a meaningful real-world test on the sound card with what is available in the KazShack, I fired up the 80m softrock on the xonar DX. Test condx: fq….—-SNR(dB) 3543-3593-42-40 3603——37 After CW skimmer collected a bit of data, the SNR readings above 3600 improved to 37-39. So the worst case for CW skimmer(as currently configured) using a Xonar DX is being 6db less sensitive at the upper edge of the 192khz bandwidth than it is at the center. That is actually a lot better than I expected for an audio device pressed into service outside normal audio ranges (and I already liked the Xonar DX). My curiosity is now nagging me to run the same tests on all of the other in-shack cards more methodically at their maximum scan rates(mostly 96khz), and to find a lower level outside signal source. I’ll try to recruit a fellow in the near field who will better be able to generate a low level test signal.  It would be useful to see what happens at the band edges when the best copy close to the center of the SoftRock’s scan range starts out at 20dB, 10dB, or 6dB SNR. But with the WX here improving, all of that might not happen for several months. Engineer the Possible… Added a new page to the skimmer station fun facts list. The new page describes observations from using several different sound cards for both music and as the interface for SoftRock software defined radios and the CW Skimmer software. Ran across the hyper dog ball launcher a couple of years ago, and the potential for re-purposed applications as an antenna launcher for hanging antenna supports seemed obvious.  It is not as much fun as a pneumatic launcher, but it sure is easily understood by any boy of 8.  No air pump required.
The normal slingshot type Wrist-Rocket/Crossman slingshot launcher has served the purpose for years, but not always without problems.  A 1-oz(28g) lead weight works, but not without a relatively high rate of mis-fires, line tangles, and “Oh S**t!” moments.  The hyper dog is a lot less likely to draw whining complaints from those inclined to wring their hands and moan about things that don’t really concern them..”See, its just a tennis ball.  Now p**s off!” The hyper dog has a much larger pouch designed for use with tennis balls.  A slight bit of hacking to the hardware gives a nice re-purposed tool for lofting lines into all of those beautiful deciduous biological antenna supports lining the back yard.  So far it has been a lot more reliable in actual usage than the ole trusty Crossman, although Field Day proved its not impossible to Dork Up.  [You Know Who You Are….lol] The reel deal:Here the body was altered by adding a cheap spin-cast zebco reel picked up for $2 at a yard sale. A spinning reel or open faced casting reel might be better, but I have used the zebco’s since I was 6yo.  Being more familiar with the Zebco quirks and limitations is useful. For most, a spinning reel is probably the best option.  10 or 12lb test line has proven the best choice over the years – light enough to fly, strong enough to pull, and not impossible to break if it becomes hopelessly snarled at altitude. The reel is simply attached below the ball carrier with a couple of hose clamps.  That was later wrapped with an ugly mess of electrical tape just to reduce the number of exposed sharp edges. Yes, the tennis balls work FB.To modify the tennis balls, they were  just drilled with a 9/64 bit. A loop of 1/8th braided nylon cord is secured to a small hardware store drywall toggle bolt/spring bolt. Then just cram the bolt/cord through the hole, reaming the hole out slightly if needed[leaving most of the loop of cord hanging out!].   The base of the cord is sealed at the hole with a goop of liquid nails or hot glue or some-such.  The loop of cord is about 6 inches long(~150mm), and the spring bolt serves the same purpose it normally does by providing a large area preventing pull-out.  After drying completely – good to go. The tennis balls seem to be a good compromise between weight and a non-destructive & non-threatening projectile. [Just don’t try to pull them back up through the tree-too fast!].   The ‘trick’ to success with it seems to be making sure the cord on the tennis balls clear the end of the slingshot. It seems to work best when the corded end of the ball is facing  up(i.e., at the top of the pouch when pulled back for a shot). What’s the catch?The only genuine problem I have with it is that it has a “long draw”.  Being impishly short my arms are not long enough to get the maximum performance out of the rig. But despite that it works much better than the regular slingshot with fewer snags and mis-fires. It easily sends the tennis balls up to about 90 feet(~30m).  The canopy here prevents anything higher, so no real top-end found yet. I suspect golf balls would be the ultimate high-flying projectile for rural locations. Too much window glass and nervous-Nelly neighbors around the home QTH for me to try golf balls here.  A day-break early morning experiment for the future…. 😉 There is somebody here on the east coast marketing these re-branded as antenna launchers Too easy to homebrew from the $22 Amazon original to peel out Well, their answer sure sounds plausible to me. Not close to April 1st…. It is a question most will ponder at some point. Link from KI3O via PVRC mail list.
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 to be simply identifying the other parts. The numbers on the capacitors were difficult to read, and the color bands on the resistors all look like brown. Lots of light and magnification? Better, but still some confusion. Most of the issue is progressive myopia, but I had not realized that color-blindness might also be progressive. Not so Fast! In order to get a second opinion, NumberTwoSon took a second look. Even with his 17 year old eyes and 20/13 vision, he also had difficulty.  So, after rolling out the ToolTimeTim’s XL 2550Super’scope, the parts were sorted. After sorting, building was trivial. Ran first skimmer test on both units on night of May 10th. Its interesting to see the spots a local skimmer finds versus thoses several hundred miles away. A whole project in itself…. So….Who will be the first to hack one of these things to use for hauling antenna lines up into trees for Field Day?  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.  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.  Which leads to the question of “what’s the payload capacity(if any)?” Sweet. * Well, going back to the salt mine after 1:00an local proved to be a waste of time. Conditions had not improved to areas in the Western US/Canada….or to anywhere else. Actually, the QRN was lower, and the 8’s and 9’s were louder, as well as stations from AL, GA and FL. There just were not enough callers to justify Butt-In-Chair. Set the clock for a couple of hours with the hope of getting the early risers….NOT. Slept right through the alarm, so Saturday morning was lost. bleh. |
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