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August came and went…
31 August 2015 | by August is always a month when we have to entertain our youngest daughter, keeping her active during the school holiday proves harder each year as she gets older, especially when it doesn't seem we have had any real Summer to help us along.
The best day out was a trip up to Blackpool, we do this trip every year, taking the train from Stafford, and heading North, changing at Crewe, and on to Preston.
We like it up here spending the day walking the Golden Mile, the people are always friendly and the food great! There are lots of interesting little shops not just on the sea front, but also in the back streets which we like to peruse at our leisure. I know there is Amateur Radio activity up here from the front sometime close to the water, but I didn't see any sign of anyone.
Getting back into Amateur routine along with other chores the Autumn approaches and the MDT kit has to be built during the next few weeks. I have no planned visits to any rally in the next few months, so I decided to make a little purchase from Martin Lynch & Sons the Wouxun KG-UV8D, Handheld, 2.5K step version has been dropped in price making it a very attractive purchase for £69 including FREE shipping to UK. This beats any best ebay price I have seen, and makes it easier should it have to be returned under warranty. I ordered one at the weekend, I expect it will arrive about Wednesday, as today is a Bank holiday here in the UK when most take a rest, or extend their weekend break, as it is the last Bank holiday now before Christmas.
I look forward to making a few tests with the Wouxun comparing it with one or two other handhelds, taking it out on location.
Steve, G1KQH, is a regular contributor to AmateurRadio.com and writes from England. Contact him at [email protected].
Lakeland APRS
The picture on the left, from APRS.fi shows the level of coverage by APRS iGates in Wasdale (A lake district valley that is home to Scafell Pike, England’s tallest mountain). You can see that the coverage is fairly limited to heights above about 400m. That really isn’t very good.
I had walked from the road north of the river Irt and up what was a quite steep hill to Whin Rigg. What makes the lack of gates even more disappointing was that there is a clear view of the Isle of Man as well as southern Scotland as you move up the ascent.
So why is it so bad? Well the geography doesn’t help. Like many hilly areas the western lakes is a series of valley that lead out to sea so when you are low there is not much scope for RF to go anywhere. this also explains the patchy mobile phone coverage. Another aspect was the stock antenna on my vx-8. It really isn’t that good compared to other larger aftermarket options.
So what? well first off we hams aren’t the only people to us APRS or a similar protocol. The mountain rescue also use a proprietary system. They must suffer with the same lack of coverage despite a sizeable array at the head of the valley.
So what do other areas use? do they use APRS in hilly areas? are there low cost self powered digipeaters or iGates about? is APRS out-dated now that digital modes are so popular (not here mind you)? I’d like to know simply because I like APRS and think its a under utilised system here in IO84, perhaps elsewhere.
Alex Hill, G7KSE, is a regular contributor to AmateurRadio.com and writes from Cumbria, UK. Contact him at [email protected].
Lightwave Scatter
As it is at present, the modulator consists of a 556 tone generator, capable of either a steady tone for CW keying or a two-tone FSK 'beaconing' signal used to help the other station in aiming alignment.
For the slow QRSS CW narrow-bandwidth modes required for the scatter tests, I've always known that a tone which is much more stable and of precisely known frequency would be needed. The tone from the 556 does well as an aural CW keyed tone but would probably be all over the place when viewed in a very narrow-bandwidth and not nearly as stable as it sounds by ear.
The little modulator uses a 4500 KHz crystal (pulled from a old VCR several years ago) in a 4060 oscillator-divider. In this case, output from the chip is taken from either the 'divide-by-8192' pin 2, which outputs a precise frequency of 549 Hz or from the 'divide-by-4096' pin 1, which outputs a frequency of 1099Hz.
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| courtesy G3XBM: http://g3xbm-qrp.blogspot.ca/search/label/nlos |
This tone is then used to drive an IRF 540 power MOSFET which controls current through the 1W Luxeon Deep Red LED in the transmitter. The 4060 modulator will be keyed via a QRSS software keying program that I have used for many years to key my LF transmitter.
The lightwave receiving station will look for the QRSS audio signal with an audio spectrum viewer such as Argo or Spectran. The ability to make automatic overnight screen captures will allow the receiving operator to get a good night's sleep while the system diligently watches for any traces of a signal.
An example of a strong signal capture showing a repeating "SL" identification is shown below, as it would appear in a perfect world. In this case (QRSS3), the short 'dots' are 3 seconds long while the 'dashes' are 9 seconds.
Huge signal gains (the ability to dig into the noise for signals) can be had by slowing things down and using narrower receiving bandwidths. Just going from a normal 12WPM speed CW (aural copy) to QRSS3 yields a gain of ~15db. At QRSS10 (10 second dots), an additional 5db is gained while slowing to QRSS60 (60 second dots), a whopping 28 db over 12WPM CW is gained!
Of course all of this extra 'hearing power' comes at a cost and in this case, the cost is 'time'. On an overnight of automated computer monitoring, time is not much of an issue ... it only becomes critical in 'QSO mode' when some QRSS QSOs can take several hours to complete. In any case, it will be interesting to see if any traces of lightwave signals will show up while bouncing around in the clouds.
The Georgia Strait scatter tests will not take place for some time but in the meantime, I hope to do some local tests here, from one side of my island to the other but will build a new portable receiver for these tests and leave my main system intact.
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].
Creating open-source ham radio hardware with Kickstarter
When I started my company last year, it was mainly set up as a design consulting outfit to pick up a few jobs on the side. At the end of 2014, it became much more when I decided to plunge full-time into my own work. At the time, one of my respected friends and colleagues, Don Powrie of DLP Design, said to me that the only way to make consistent money is to have a product line rather than rely on consulting work. I’ve been thinking of how to bring that to market ever since. I could certainly design some familiar products to me, but they would get lost in the plethora of similar items. I needed something unique.
I started out with a 5V @ 5A design. I drew the schematic and completed the PCB layout and started to check pricing and availability of the parts. Most everything was available at Digi-Key, and the Anderson Connectors from Mouser, but the total was getting close to where I wanted the selling price to be. For a $35 computer, I couldn’t justify a $70-$80 power board!! The DC-DC converter also had a very large ground pad for heat dissipation. I wanted this project to be able to be hand-soldered and started wondering about that large pad. That design got scrapped and I started looking for another buck converter. There were several TI and Linear products I considered, but they would have required a reflow oven – either with a center pad, as a BGA, or leadless formats. Then I found the Alpha & Omega AOZ1031AI. This is a 8-pin SOIC without any special pad. The only heat-dissipation suggestion was that pins 7 and 8 do not have any thermal relief, but connect fully to the surrounding plane. I selected larger commodity parts (0805) that could be seen without a microscope and created the layout, and all parts were in stock at either Digi-Key or Mouser Electronics. I got everything on order, and even managed to get a couple free PCBs from Pentalogix. I had attended a Pentalogix-sponsored Cadsoft Eagle webinar at Newark and the perk was a code for two boards. I just had to cover shipping.
I did other tests: Let it run for 8 hours (check), ramp voltage from 6 to 18V input (check). At 7V input, the Pi kept rebooting. At 8V, it was solid – well past the design spec. Same at 18V.
Next up was the load test. With 2A going direct to load resistors, I was still able to run the Pi with all four USB ports occupied. I even dipped the supply to 8V. The bench supply showed about 1.8A output. Based on an approximate 80% efficiency of DC-DC converter, I calculated I was drawing about 3.5A on the 5V side – a little past its limit, so backed off the load. I’ve been running this directly from my radio supply now for several days, and the Pi keeps chugging along.
I’m a believer in open-source hardware and software. This project will be published in the coming days, probably on GitHub. Eagle uses XML design files, so version control should work just fine. I still need to write the manual, but everything will be made available as soon as I get the proper README and LICENSE files in place. All of my work for this project is published under the Creative Commons Attribution and Share-Alike license. The hardware itself is published under the TAPR Open Hardware License.
Bob Recny, N8SQT, is a special contributor to AmateurRadio.com.
Colorado 14er Event: Mount Antero (W0C/SR-003)
For the 2015 Colorado 14er Event, Joyce K0JJW and I activated Mount Antero (W0C/SR-003) on the 2m and 70 cm bands. Alan NM5S joined us on the summit, operating mostly HF plus some 2m fm.
We took our Jeep Wrangler up the moderate 4WD road and parked at 13,800 feet. This makes for a very manageable hike to the 14,269 foot summit. Of course, you can always choose to start the hike from lower on the mountain, but you’ll end up walking along the road. This web site provides a good overview of the 4WD road. The 14ers.com web site and summitpost.org are additional sources of summit info.
Here’s a short video of our operation on the summit.
Here’s the K0NR log on the 2m band, fm and ssb:
August 2, 2015 K0NR Log, time in UTC 15:09 144MHz FM K0JJW 15:13 144MHz FM W0CP 15:16 144MHz FM KC5JKU Mt Elbert 15:17 144MHz FM KD0WHB Grays Peak 15:21 144MHz FM N0XDW Pikes Peak 15:37 144MHz FM KD5HGD Mt Elbert 15:42 144MHz FM KD0MRC 15:42 144MHz FM KE0DMT 15:44 144MHz FM NQ0L Franktown 15:45 144MHz FM KE0EUO Mt Democrat 15:46 144MHz FM K7SO Mt Democrat 15:50 144MHz SSB KD0YOB W0C/PR-005 15:53 144MHz SSB W0BV Buena Vista 15:53 144MHz SSB K0YV Buena Vista 15:57 144MHz SSB W0STU Monument 16:06 144MHz FM KD0WHB Torreys 16:13 144MHz FM KI6YMZ Mt Elbert 16:19 144MHz FM KE0EKT Mt Elbert 16:29 144MHz FM WZ0N 16:29 144MHz FM KE0DAL 16:31 144MHz FM WO9S 16:33 144MHz FM K0UO 17:10 144MHz FM KD2FHB Pikes Peak
It was a great day on the mountain with quite a few Summit-to-Summit (S2S) SOTA contacts. See you next year on a Colorado mountaintop!
73, Bob K0NR
The post Colorado 14er Event: Mount Antero (W0C/SR-003) appeared first on The KØNR Radio Site.
Bob Witte, KØNR, is a regular contributor to AmateurRadio.com and writes from Colorado, USA. Contact him at [email protected].
Ham College episode 8
Ham College episode 8 is now available for download.
Ham College, the new show for those new to the hobby and those wishing to get into Amateur Radio.
In episode 8 we discuss the radio bands available to hams. More questions and answers from the Technical class question pool. We also tell you how you can win an Icom T-shirt and cap and about the AmateurLogic.TV 10th Anniversary contest where someone is going to win a nice HF transceiver and accessories.
55:14
George Thomas, W5JDX, is co-host of AmateurLogic.TV, an original amateur radio video program hosted by George Thomas (W5JDX), Tommy Martin (N5ZNO), Peter Berrett (VK3PB), and Emile Diodene (KE5QKR). Contact him at [email protected].
Sparking-Up On 2200m
An e-mail alert from Toby, VE7CNF, on the other side of Georgia Strait, indicated that everything was ready for a two-way test on 2200m and he was looking for his initial contact on the band. Having not been on the band for such a long time, some review of my 'tune-up' procedures were in order as well as the need to burn out the spider webs in my outdoor loading coil.
Since being on 2200m, I had modified my 2200m kilowatt transmitter so that it could also be used on the new 630m band. To change bands from 630m back to 2200m, I needed to swap the frequency-sensitive power divider back to 2200m as well as re-set the DDS frequency.
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| 2200m Power Divider |
When modifying the transmitter, three years ago, I had also changed the transmitter's input frequency divider from a 'divide-by-four' to a 'divide-by-two' scheme. My original system on 137KHz started with a DDS frequency in the 5.48MHz range and then was divided by ten before being fed to the transmitter's input where the 548KHz signal was then divided by four. Using a higher DDS frequency allowed for greater frequency resolution at 2200m and allowed for very small frequency adjustments across the band. I would have kept the same system for 630m except that my 'divide-by-ten' chip was not very happy at 18MHz and refused to divide.The newer system now only allows me to move around the band in 4.5Hz steps. It's really not much of a problem as there is presently a minuscule amount of activity in Canada on 2200m, but as previously mentioned, this may change when U.S. amateurs gain access to the band.
Having sorted out my transmitter problems and confirming that all was well, the next task was to check antenna resonance and impedance matching as it would more than likely not be the same as I had left it. A low-power check using the 'scopematch' indicated that both resonance and impedance were not optimized. Tapping down on the loading coil by one-turn took care of resonance while adjusting the impedance tap in my matching transformer to its lowest value (see matching scheme below) resulted in a near perfect match on the scope.
I'm guessing that the resonance change was due to the recent heavy trimming of the 80' Balsam that supports one end of my 'inverted-L' and large three-wire flatop.
The tree's crown had previously been very dense and some of the branches were almost touching the flatop. The close proximity always made me worry about possible flashover at the antenna ends as voltages here would be several kilovolts. Removing much of the wet green tree branches directly beneath the flatop also likely contributed to the slight change in resonance.
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| Impedance Matching Transformer On TV Flyback Cores |
The sked with VE7CNF went smoothly and it was nice to see another new Canadian station taking an interest in the band, along with all of its challenges. Toby's 200W signal was a solid 559 here even with his small antenna system yet to be fully optimized. As well, he was bothered by heavy switching-power supply QRM from a nearby neighbour. Unfortunately, such noise sources seem to be increasing in numbers and are making operation on LF, already a big challenge, even more challenging. Toby has taken up the challenge with enthusiasm and has now had contacts on 2200m well as on 630m, adding to the ranks of active VE7's on LF and ... demonstrating yet again that amateurs can enjoy the LF bands with small 'backyard' antenna systems. Don't let living in the city be a reason to avoid our new LF bands.
Wouldn't it be great to see some activity from our neighbours in VE6 or VE5, both easily workable on both bands from the west coast... maybe you're up to the challenge!
Steve McDonald, VE7SL, is a regular contributor to AmateurRadio.com and writes from British Columbia, Canada. Contact him at [email protected].
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