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Handling two DDS Modules in the Library
I had an email today from Jan, pa0dmm, who has been using my library for the AD9850 DDS.Jan wanted to know if it was possible to modify the library to control two DDS modules, such as I have done on my...
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Patriot Games
I came home from Dayton to be presented with a TenTec Patriot, all thanks to my friend and benefactor, g6ybc...The Patriot is a QRP CW and sideband rig for 40 and 20 metres, built on the ChipKit UNO 32...
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Nokia 5110 Display
I have been playing with a little monochrome LCD display, of the sort used in the original Nokia 3110 and 5110 phones...I was interested to see if this kind of display technology would be of any use...
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New User Interface
Having sorted out the software to allow my "Occam's Dirk" rig to use the Nokia 5110 display, I decided to rationalize the hardware. I made a new user interface board...This board, almost exactly the...
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Displaying Variety
Having seen my adventures with the new display for the little Occam's Dirk rig, Dennis, g6ybc, from Kanga sent me a sample of a Nokia display rated for 5V operation.I tried a hook up direct to the...
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Prototyping with Small Outline Transistors
A recent circuit idea I've been fooling with required a complementary pair of MOSFETs. I'm tripping over the familiar n-channel devices, but p-channel MOSFETs don't seem to breed in the m0xpd junk box....
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Patriotic Display
My TenTec Patriot is usable but user-hostile without a display. Fortunately, adding a display is the work of moments...I haven't had many moments to spare since getting back home from the USA, but I...
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Two Receivers
Two receivers are being prototyped on the bench here at m0xpd. Interestingly, they sit close to opposite ends of the spectrum. Not the frequency spectrum - but what might be called the spectrum of...
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Sandford Wattmeter
Just made up the Sandford Wattmeter kit from Kanga UK, which has been sitting in my "in tray" since last year...This meter uses some 50 Ohm thick-film resistors to form a 50-Ohm dummy load and a...
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Stand-alone Total Response Measurement
I've now implemented a stand-alone measurement system to measure the overall RF to AF response of a receiver...The method, first introduced in this post then used extensively in my presentation and...
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Bridging the Gap
The best things in life are either free or simple. Here's an example of the latter...I'm a big fan of Return Loss Bridges, enjoying the fact that they give you useful information pretty much for free....
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Acorn II
Eagle-eyed readers in the UK with their fingers on the pulse will have noticed that one of the receivers discussed in prototype on the bench a few weeks back, the "Acorn II", is to be the subject of...
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The URMSTON Regen Receiver
Now that the cat has been let out of the bag on the Kanga website, I guess it is OK to tell you - the second of the two receivers I was playing with a few weeks back is now revealed to be a...
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RSGB Convention
Just back from the RSGB Convention...where I managed to avoid having too much over-ripe fruit and vegetables thrown at me by hecklers in my lecture, just before lunch on Saturday...In fact, rather than...
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Powermaster Rectifier Replacement
After last week's RSGB Convention I called in at my Father-in-Law's, to be rewarded by a brace of vintage train controllers...These devices, made by Hammant and Morgan Ltd, formerly of Watford, are the...
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Channel Separation in Parallel IF Receivers
The "Parallel IF" scheme, developed in this receiver, described in the January, 2015 edition of RadCom and described and demonstrated at FDIM 2015, steers the incoming signal in a superhet receiver...
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ADC Converter Accuracy in the Arduino DUE
I've been playing with the analog to digital converter in the Arduino DUE, using it to read the output of a simple RF detector. I am interested in measuring the lowest possible voltages with both the...
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Bridge Measurements
The little bridge you saw back in September is now producing - in concert with the AD 7896 analog to digital converter and a few other little wrangles - some nice, calibrated measures of reflection...
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Regeneration
I have just given in to the pressure of the last six weeks' relentless TV advertising and decided (with great reluctance - Bah Humbug) that it might be time to turn on the Christmas lights at...
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The Instant of Christmas
Christmas has - for as long as I am able to remember - been defined for me by one very precise instant. This instant...It is part of the organ accompaniment to the final verse of David Willcocks'...
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