Sunday 23 February 2014

10m WSPR for an afternoon

As I had not tried to Use the Alexloop on 10m I thought today would be a good opportunity. I left the anan-10 running at 0.5W output while working on other projects and was impressed by the results:-

Stations who decoded WW2R:

UTC call grid km
  01:22  VK4ZBV   QG62ml  13413
  01:12  VK4FP   QH30ip  13602
  00:46  VA7DTP   DN09gv  2640
  23:26  VE7KDK   DO00jl  2665
  22:50  W7PUA   CN84io  2616
  22:38  KD6RF   CM97cq  2323
  22:20  VE6PDQ/1  DO33fl  2629
  22:04  KA1QG   FN43wt  2587
  21:58  N6RY   DM13id  1914
  21:52  N2NOM   FN22bg  2089
  21:52  K1CT   DM12jt  1910
  21:34  VK4WR   QG62kk  13430
  20:54  VE7KPB   DN29cm  2409
  20:54  N1EO   FN43gq  2481
  20:34  WA3QJU   FN20  2089
  20:34  CX2ABP   GF15wc  8664
  19:34  VE6EGN   DO23qe  2648
  19:02  WD9DUI   DM03ut  2000

Stations decode at WW2R

  00:56   VK3PD   QF21nt  14503
  00:56   W6OHM   CN87wp  2672
  00:00   VE7KDK  DO00jl  2665
  23:22   K9AN   EN50wc  1091
  23:18   JH1GYE  PM96mi  10364
  23:08   VE6PDQ/1  DO33fl  2629
  22:48   VE7KPB  DN29cm  2409
  22:48   W7PUA   CN84io  2616
  22:02   K1CT   DM12jt  1910
  22:00   KA1QG   FN43wt  2587
  22:00   CX2ABP  GF15wc  8664
  21:54   KD6RF   CM97cq  2323
  21:54   N2NOM   FN22bg  2089
  21:38   NH7SR   BL11ch  6098
  20:56   N1EO   FN43gq  2481
  20:56   VK4WR   QG62  13421
  19:08   VE6EGN   DO23qe  2648
  19:00   WA3QJU   FN20id  2059
  18:58   WD9DUI   DM03ut  2000
  18:38   N6KOG   CM97gs  2294
May have to keep a closer eye on the band and try CW!

Thursday 6 February 2014

A night on LF

Having repaired the wind damage to my WA1ZMS loop I thought I would take a listen around 500kHz

Using the loop to the Anan-10 with W5WC mrx software and wspr from K1JT I could see some local signals on wspr and the multimode signals (cw and psk) from WD2XSH/7 in LA. I quickly decoded the local signals as  WG2XXM (a new state for me OK!)  and WG2XIQ.

I then decided to hook up the anan headphone output to the Nexus 7 and see if Droidpsk could decode the PSK signal (while still decoding WSPR on the PC)

WD2XSH/7 is the signal in the green box. WG2XIQ is the signal at the 5 marker, WG2XXM is the signal slightly hf of WG2XIQ. You can see they are timed WSPR signals (but not decode them on android!)

I left it running for a while and started to see two more signals, WD2XSH/12 in CO (DM79) at 1092km and the best (WSPR) dx WG2XJM in EN91 at 1746km

I then had a listen on cw and heard WD2XSH/31 in VA again at 1651km   Signals faded out at 1236z, WD2XSH/12 in CO was the last signal seen

Not bad for an 8 turn loop!

Tuesday 4 February 2014

Prologix USB GPIB Converter

Over the past few days I have been upgrading my Dell laptops to win 7 64 bit Pro, after I discovered they support that version of the software. All went well until I tried to install the NI488.2 software to use my PCMCIA-GPIB card. When it said it was unsupported, it was time to look for alternates to capture screenshots from my 8563E Spectrum Analyser.

Having used the KE5FX 7470 plotter simulator software for a while I noticed it supports the Prologix GPIB adaptors, both the USB and Ethernet version. I saw good reviews of the the USB version from elsewhere so I went ahead and ordered one from Prologix directly for $149.95 + shipping.

When it arrived it will be very hard to miss, being bright yellow! I installed the USB drivers from the prologix site on the laptop then the GPIB toolkit from the KE5FX website. First the GPIB configurator programme has to be run to associate the virtual comport to the adaptor. After that the 7470A simulator worked reliably as it usually does, in both computer initiated and analyser initiated plot modes. Another problem solved!

Sweep of an Icom FL30 Crystal Filter

RTTY and PSK31 Transceive with a Nexus 7 2013

Thinking ahead to summer portable operation I needed a lightweight way of operating the "classic" digital modes PSK31 and RTTY. The Dell laptop was too heavy and bulky. Looking on the Internet I came across DroidPSK at which should work with my Nexus 7. For $5.49 It was worth trying, especially as my 2013 Nexus 7 has a mic input on the 3.5mm connector. Initially I tried it on receive by holding the Tablet near the speaker of the KX3. It worked well but was prone to room noise.

Next was to try it on Transmit.  There is a circuit of the interface that Wolphi sells on their web site wolphi-link  but the radio side connector would mean redoing my radio cables as the standard I had adopted was a 5 pin DIN. Looking in the junk box I found most of the parts to build it and a visit to the local component store realised the 4 pole "TRRS" plug and socket. I used a 2N2222A for TR1, but anything similar will do. The circuit was built on a piece of stripboard. Receive worked fine and transmit audio worked fine IFF the KX3 was manually keyed.  Using the PTT input on the mic connector did not work. The keying transistor did not pull the pin close enough to ground. I reconfigured the ACC2 connector as a PTT Input and this worked, but would require 3 cables from the Interface box to the radio.

In the past I had experienced similar issues with the Elecraft K3 which I had solved by using a keying FET not a transistor, especially the Darlington type. So the Interface was reconfigured to use a 2N7000. Now the "VOX" worked fine.

I was so impressed by the app that I went ahead and bought the RTTY version DroidRTTY. This uses the same interface. The only problem was that I was unable to set "my info" qth, name etc. What the manual didnt tell you is that as RTTY only transmits upper case characters, you can only enter Upper case characters in the text boxes!

The interface should only be plugged in after the Tablet has powered up. Having a resistor attached to the mic input while booting puts the tablet in a test mode which removes the bias voltage used to power the Interface. This caused some head scratching!