ZCZC Brings back memories... I used one of those in the 70s to receive WX and news on HF and I had a few RTTY QSOs with it too... A ~30kg heavy metal mechanical UART designed in 1931! NNNN 73 Johan S
Hello Peter, I expected to find the tube at http://www.tubedata.org/ where Frank Philipse has been collecting tube data sheets for 15 years but it wasn't ... It must be a very exotic tube! 73 Johan S
Hi Stefan, G3YXM was mobile on 136kHz many years ago. See http://www.wireless.org.uk/mobile.htm , scroll down to middle of page. If it is possible on 136kHz then it should be a piece of cake on 475 7
There is a schematic diagram and a BOM in the assembly manual: http://icas.to/idc-136ii/idc-136ii-kit-manual-eng.pdf 73 Johan SM6LKM Andy Talbot skrev den 2015-06-04 14:44: Haven't seen / played / ev
Hi, Google Maps has added a lot of Street View pictures from the SAQ site. For example, you can stand in the middle of a mast base and look straight up and also walk around inside the main building a
Move the mouse with the left button pressed. Zoom with the mouse wheel. 73 Johan John Bruce McCreath wrote: Johan....thanks for the link! What a treat it was to "walk" around the transmitter hall and
Is it really necessary to mix down to baseband before doing the A/D conversion? Wouldn't direct sampling with fs = four times the carrier frequency do the trick? I think that an I/Q signal at zero b
Aha... Thanks Andy. I assume that the second -S2 in your _expression_ of Q is a typo. If changed to -S3 it all makes sense and the mixing with a quadrature LO at Fs/4 becomes clear. It was something
Hi Dimitrios, Stefan, I did a little sunday afternoon hack, maybe you can use this to generate CW from ASCII: https://dl.dropboxusercontent.com/u/107227836/cwtx_c_code.zip
Solid copy here too, 79.3km (4.547 lambda) from SAQ's feedpoint. Almost pure far-field signal :-) 73 de Johan SM6LKM Den 2015-10-24 kl. 12:14, skrev pws: Hi Clemens et al., Confirming from Kiel: http
I did, but was too lazy to write a comment. After all the answer 121uOhm was correct :-) SO..... How come no one else spotted the equation worked out incorrectly :-)
Andy, probably not Boulder as you should see the BPSK with 180 deg. phase reversals which, when present, are located in the -17dB dips. http://www.nist.gov/pml/div688/grp40/upload/NIST-Enhanced-WWVB-
Yes, D7 will charge C8 when drive is present, and the time constant of C8, R15, R16 and RV3 is about a millisecond, so IC1b is most likely a drive supervisor. The 29T winding together with D11 clamps
Andy, on the '688, set both BRG16 and BRGH bits and the baudrate formula becomes baud = Fosc / (4 * (N+1)) with 16-bit baudrate divisor in SPBRGH:SPBRG. In other words, set BRG16 = 1; BRGH =
Another advantage of the push-pull amplifier is that the output signal is symmetrical (assuming the drive is too). A perfectly symmetrical waveform contains no even harmonics whatsoever, regardless o
Been there.... Done that... Direct flux linkage between windings, capacitive coupling, magnetic coupling through the core, funny core behaviour at RF etc. etc. For a start, google bifilar trifilar tr
The attached picture shows an autotransformer wound on a a 58mm (58/41/18mm) Philips (now Ferroxcube) core made of 3C85 ferrite. The transformer was used by SM6PXJ and me at 7S6SAJ in 2000 to bring t
But if the winding is bifilar, usually a twisted pair, then, from the core's point of view, it will look almost like a single wire carrying current in alternating directions. The core has no way of k
Railway QRG is 16 2/3 Hz in Sweden too. 73 de Johan SM6LKM John Rabson wrote: I seem to recall that some railway systems use at about 16 2/3 Hz (one third of 50 Hz) for traction. ... Can someone say
