One for Kelly, Mike et al - Radio Communications.

John

The business end is an e-probe antenna designed by Roelof Baker PA0RDT which covers from 10 kHz to HF. A good set of photos is at https://www.merseyradar.co.uk/uncategorized/hf-receiving-antenna-pa0rdt-mini-whip/   I bought mine - a bnc version - direct from Roelof some years ago. After a good rub down with glass paper! It is at the top of the pipe, sitting on a length of 20mm uPVC conduit.  The Receiver is a RF-SPACE SDR-IQ again about 15 years old and sadly now discontinued (I believe one of the ic/s became unobtainable). This rx only has three connects, a bnc aerial i/p a USB and a 9-pin which is used for external receiver control to tap-off from the IF. In turn, the SDR-IQ connects to a  Silex SX-2000U2 USB network adapter connected to a network switch in the room the other side of the wall. My pc has a program SpectraVue http://rfspace.com/RFSPACE/SpectraVue.html which in the case of an SDR-IQ, lets me observe or record a 190 kHz spectrum. Demodulation is  carried out within the software. The reason for external receiver control is to use an SDR-IQ as a panoramic adaptor.


My interests tend to be VLF/LF.


The only problem I have had is capacitor failure in the linear 5v psu - switch mode psu's often being being noisy.


As an aside, one morning I thought that I had discovered a new, unknown VLF transmission. A rock steady signal pulsing on and off in a regular manner a couple of times a minute.  Got excited and went into our kitchen to hear the washing machine in action in our utility room. Washing over, so was my "new" station...


On VLF, I am a follower of Grimeton Radio/SAQ This is their CW Morse message on 1st July 2018 on 17.2 kHz from a high frequency alternator.
http://ancient-mariner.co.uk/public/2018.07.01%20-%20SAQ%20Alexanderson%20Day.bmp


Here is a screen shot of the leap second on 31st December 2016 http://ancient-mariner.co.uk/public/2016.12.31%20-%2023-59-60%20Leap%20Second.pdf  SpectraVue is showing the 60 kHz time signal from Anthorn and the window on the left is showing the UTC time as 23:59:60  which was the leap-second.  This is from my Trimble 10 MHz GPS frequency standard, now neatly cased

 http://ancient-mariner.co.uk/public/IMG_1364.JPG rather than wires all over my bench.

Sadly due GPS rollover, that piece of software now shows the wrong date, but the 10 MHz is fine. There is other software which corrects the outputted data. Trimble "meanly" decided not to supply updated firmware.


Besides QRM from VDSL, I am about 250 metres from 132 kV overheads, so reception not too bad.  I have never seriously tried the above combination on HF, must get round to it.


So, no good for transmitting!


You can get PA0RDT mini-whip kits, but I have one where the circuitry had either been strangely modded, or something had gone wrong when laying out the pcb tracks.. The actual metalic antenna, is about the size of a large postage stamp.

73's Clive

John

The business end is an e-probe antenna designed by Roelof Baker PA0RDT which covers from 10 kHz to HF. A good set of photos is at https://www.merseyradar.co.uk/uncategorized/hf-receiving-antenna-pa0rdt-mini-whip/   I bought mine - a bnc version - direct from Roelof some years ago. After a good rub down with glass paper! It is at the top of the pipe, sitting on a length of 20mm uPVC conduit.  The Receiver is a RF-SPACE SDR-IQ again about 15 years old and sadly now discontinued (I believe one of the ic/s became unobtainable). This rx only has three connects, a bnc aerial i/p a USB and a 9-pin which is used for external receiver control to tap-off from the IF. In turn, the SDR-IQ connects to a  Silex SX-2000U2 USB network adapter connected to a network switch in the room the other side of the wall. My pc has a program SpectraVue http://rfspace.com/RFSPACE/SpectraVue.html which in the case of an SDR-IQ, lets me observe or record a 190 kHz spectrum. Demodulation is  carried out within the software. The reason for external receiver control is to use an SDR-IQ as a panoramic adaptor.


My interests tend to be VLF/LF.


The only problem I have had is capacitor failure in the linear 5v psu - switch mode psu's often being being noisy.


As an aside, one morning I thought that I had discovered a new, unknown VLF transmission. A rock steady signal pulsing on and off in a regular manner a couple of times a minute.  Got excited and went into our kitchen to hear the washing machine in action in our utility room. Washing over, so was my "new" station...


On VLF, I am a follower of Grimeton Radio/SAQ This is their CW Morse message on 1st July 2018 on 17.2 kHz from a high frequency alternator.
http://ancient-mariner.co.uk/public/2018.07.01%20-%20SAQ%20Alexanderson%20Day.bmp


Here is a screen shot of the leap second on 31st December 2016 http://ancient-mariner.co.uk/public/2016.12.31%20-%2023-59-60%20Leap%20Second.pdf  SpectraVue is showing the 60 kHz time signal from Anthorn and the window on the left is showing the UTC time as 23:59:60  which was the leap-second.  This is from my Trimble 10 MHz GPS frequency standard, now neatly cased

 http://ancient-mariner.co.uk/public/IMG_1364.JPG rather than wires all over my bench.

Sadly due GPS rollover, that piece of software now shows the wrong date, but the 10 MHz is fine. There is other software which corrects the outputted data. Trimble "meanly" decided not to supply updated firmware.


Besides QRM from VDSL, I am about 250 metres from 132 kV overheads, so reception not too bad.  I have never seriously tried the above combination on HF, must get round to it.


So, no good for transmitting!


You can get PA0RDT mini-whip kits, but I have one where the circuitry had either been strangely modded, or something had gone wrong when laying out the pcb tracks.. The actual metalic antenna, is about the size of a large postage stamp.

73's Clive