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Amateur Radio Group

69 posts
kmikemoo

Field Strength Meter

Posted by kmikemoo Nov 30, 2019
RF (Radio Frequency) Enter Your Project for a chance to win a Spectrum Analyzer for the Most Innovative RF Project! Back to The Project14 homepage Project14 Home Monthly Themes Monthly Theme Poll   Today, I shift my focus to RF.  As part of the November 2019 Radio Frequency challenge, I plan to test antenna radiation patterns.  But I'm also cheap.  So... I plan to do this with simple radio frequency detector circuits.  Why not? There are many variations of the RF d ...
M0DCD

Make do and bodge?

Posted by M0DCD May 1, 2017
I've already had my tribander down once when it decided to go off tune. Having taken it apart of course I did find that broken solder joint. Once tuned it was working again on 2m and 70cm however it never really worked well on 6m. The reason is that it's tuned around 52MHz which for this region of the world is the top end of the band. Never mind I thought as I do have the 6m Moxon I can use which is significantly more use on 6m SSB. Back to its other problems. I did replace a radial, usual "M0 ...
M0DCD

Warming up a little

Posted by M0DCD Mar 5, 2017
The daffodils are showing the odd flower, the weather's a bit warmer although still a bit wet underfoot for my liking. So a chance for walk on Ilkley Moor with Dave 2E0IVY and "K9-2". It's become noticed that one of my radios has a tired battery, my trusty Yaesu FT60 which has had 13 years or so good years of service. So we're bringing it a third traunch of batteries as the NiMHs are showing distress at having 1600mA pulled out of them on transmit. Turn the power down from 5W and you get a b ...
M0DCD

Back end of the year

Posted by M0DCD Nov 17, 2016
So the time flies and so does the radio. As you've been following me you'll know that I'm a regular operator on VHF contesting in England, I suppose it is a rare place to get DX on 2m, having landed France, Germany, Wales, Scotland and Northern Ireland from a spot 273m above sea level and with a cracking view if it's not misty.   Admittedly this time of the year does tend to make you think twice about turning out. When the weather forecast threatens snow then you do stay put. Well it did l ...
It's the last weekend in April and once again hundreds of runners are poised to do the “Marathon with Mountains”, that is the annual Three Peaks Race in the Yorkshire Dales. After last year (2015's) where I was getting wet in Northumberland, I was to be back in this one. Only thing is there were new challenges.   The first was getting there on Friday. You see where the “tin snail” is stored is just off the route of another event going on that weekend, notable the & ...
M0DCD

Making the most of Spring

Posted by M0DCD Apr 5, 2016
We've survived winter. Well the geraniums and my antennas came through unscathed. However up at 800ft above sea level and somewhat exposed the ones at the farm didn't. The 20m beam lost its feed point, and the rotator fixing on the 40m beam broke - wound itself round the feeder and then snapped it off. So that was the first set of jobs to do. However we'd lost the use of the cherry picker but Neil had gone out and bought a scaffolding tower.   So it's part one - start fixing things! First ...
http://www.rtl-sdr.com/red-pitaya-and-software-defined-radio/ http://redpitaya.com/red-pitaya-and-software-defined-radio/ http://pavel-demin.github.io/red-pitaya-notes/   The Red Pitaya is marketed as a type of digital oscilloscope, and is more accurately described as a type of digital measurement and control tool that sells for about $220 USD. However the technology behind its operation (high speed ADCs) is basically the same as what is used in a software defined radio like the RTL-SDR. ...
M0DCD

Starting off 2016

Posted by M0DCD Jan 7, 2016
Finally you've packed away all the decorations, have eaten the last of the mince pies and are determined not to do as much next time Christmas comes around. Then along comes that list of things you'd like to do this year. So here's a few of mine to start you off.   1. RSGB UK Activity Contest   Well I'm in the 305th position out 667, which I don't suppose is that bad considering I don't have a mega contesting setup or did all the sessions. Here are the results.   My first sessi ...
It seems to be engrained in many engineer's thoughts. That VHF radio is just "line of sight". Well it seems to fit the maths but forgets what should be obvious, we have an atmosphere.   True, that anything above 30MHz ( assuming the defininition of VHF is 30MHz to 300MHz ) doesn't feature F-layer propagation like HF does, it does occasionally have E-layer propagation, but by it's name "Sporadic-E" is precisely that. Not a reliable mode of communication.   However, it is necessary to ...
M0DCD

Getting Contesting

Posted by M0DCD Sep 7, 2015
Phew. It's been a busy week. I've been in two contests. One the RSGB's UK Activity Contest on 2m. That's on the first Tuesday of the month, and is in the evening.   Well I've adopted a different approach and decided, after last month's trip to the North York Moors, to get to another good high spot. The one chosen was Brimham Rocks, as I knew where to park. So it was operating from the car. With not exactly the most complex antenna, an HB9CV. The weather was good, although it was cool ...
Years ago I worked for Pioneer in their factory in Castleford. I was working on one of the tuner lines and they introduced a new model. The kit arrived, we built the boards but when it came to test them we had problems. One of the figures quoted 0.316% THD at a specified input signal, but most of them were well above this. To get them to meet this spec involved having to tweak around the circuit. This meant adjusting a prebuilt front end module which was supposedly already aligned. With a cer ...
M0DCD

Is my HF radio deaf?

Posted by M0DCD Aug 14, 2015
You know the scenario, you put the radio on and you can hardly hear anything. You check the connections, maybe take down the antenna and suspect that you've broken something. Well it's not your fault. Yes conditions are not so good. Now it's not that far down the cycle, but you might have to change your plans.      We have still had some action on 28MHz, but you might have to be working harder to take advantage of it. Like listening for the beacons for one. You could even ...
For the PSoC 5LP roadtest I built a software defined radio. I think this group will be interested. You can find it here: http://www.element14.com/community/roadTestReviews/2065   73's, Gerrit. ...
M0DCD

A Tale of two Contests

Posted by M0DCD Mar 22, 2015
It's Spring, we've had a clutch of members of the club pass their Foundation Exam, so we'd though that taking part in one of the weekday contests that happenned to coincide with club meeting might be a chance for them to hone their operating skills.   The planning was minimal, we had a club rig, cables and a computer. Only if we'd known.   That to install the latest version of N1MM Logger needs an update in the ".NET" framework and hence an internet connection. Ah we hit a problem th ...
M0DCD

Raspberry Diversions

Posted by M0DCD Jan 17, 2015
The Raspberry Pi has many uses, and when you come across a need for something and you get a bit of an idea.   Take one Raspberry Pi, one of those USB battery units to charge your phone and a USB stick. Add a copy of openELEC.   Now what it is, when running these contests, you read and write to a single log file for the pair of workstations. Being located on a farm that is liable to the odd outage it'd certainly tax a UPS, and what with current milk prices the budget doesn't go that ...

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