Contents :

A collection of thoughts, and my notes about experiments and ideas, technical or otherwise, connected to Amateur Radio, Satellite working and monitoring and other electronics.

Monday, March 29, 2010

WSPR on the Mac

This past week end I have, among other stuff, made a few attempts to get WSPR running on a Mac running Snow Leopard.

Tried a few "Tips and Tricks", using MacPorts and other stuff but none of the tricks were useful.

I was finally pointed to a HowTo for making the install, and this is what will be going on next in that part of the story.

SpectrumLab seems to be running under Wine for the Mac, so it looks like that part is usable.

Fldigi exists as a package and runs, if a bit touchy in the user interface.

Update :

WSPR installed mostly according to the guide, but only on a pristine installation. Not ideal. Thanks to G4KLA for assistance. Now I need to see if I *can* get it installed on my already installed system.

One problem, however : While the >WSPR program starts and runs, it exits at unexpected times with an input overflow message, so not very useful for long term deployment. Back to using Windows for WSPR. (Or possibly Linux, will have to be tested)

Sunday, March 14, 2010

Active antenna experiment.

Having visitors this week end put a limit to my radio activities, but one thing got done.

I built (did not take that long) a small balanced amplifier with a TL592 IC. The aim is using it with small loops and ferrite antennas.

The amplifier can be found at Low Frequency Antennas , I made it for a bit higher gain and with a manual tuning capacitor in stead of the varicap, but essentially everything is as in the circuit diagram.

Going through resonance on 80m and 160m the noise increases by 20 - 30dB, so the noise figure and amplification looks good. It looks like the amplifier will support even smaller antennas than my 80-160m tunable loop.

Further experiments with the amp. should include smaller loop/frames and ferrite antennas. It could be interesting to see if the small (50 - 60mm long) ferrite antennas from small transistor radios will work in the indoor noisy environment, or even what they will do outdoors in the open (less noise)

Sunday, March 7, 2010

A bit of 500kHz experimentation

The new cardboard box frame antenna with better wire turns out to be a bit better. A few dB increase of S/N has been gained.

The loop was at first connected to the HF-3 receiver, and gave some WSPR spots from local stations like PA0A, PA3EGO (also seen with QRSS) and PA3FNY, with relatively good signals if considerably lower than Joachim gets with his Octaplumb. Also G4JNT during night time and one or two other spots from G stations. All in all not very impressive, but not too bad for an antenna inside the noise field of the apartment. Also every night DI2AM with QRSS, and occasionally a good signal from OK0EMW.

A test with the ATS909 receiver, using just the built-in ferrite antenna gave surprisingly good results, almost as good as the cardboard loop with the HF-3, with DI2AM in every evening.

Test with the FT-817 gave a marginal improvement over the HF-3, maybe 1 - 2 dB.

Test with a FRG-100 receiver showed that the receiver is considerably more sensitive than the FT-817, but due to "antenna noise" (apartment noise) the improvement was again marginal, 1 - 2 dB.

The antenna has now been moved upstairs, still indoors, and another 1 - 2 dB has been gained. interesting to see how much signals will come from the G stations now.

An improved loop for outdoor mounting, like Joachim's Octaplumb will be built here, and some tests with larger transmit antennas are in the plans. Well, and a TX, too, probably beginning with some 50 - 100 mW, so ERP will be in the microwatt range.

This week I am having a visit from a friend staying over, so not much time for building activities, but after that it should go on.

I still have some experimentation on the Rockmites and a Warbler, so more than enough to do here.

Also some experiments with the TL592 amplifier for active antennas (LF,MF,HF) is in the thoughts here, such as variations on the antenna from this site