Dear Janne,
Congratulations! You have here the Collectors Item QSL card, which is only issued once between mid-December and the first week of January, if you have responded to a Radio Intersound broadcast during this period! Some listeners receive multiple QSL cards with a different design, as they have heard Radio Intersound more often during this period.
We are very happy with your reception report and your enclosed mp3 link. I hope the Finnish symphonic Christmas metal show was appreciated. We hope to hear from you more often, Janne. Thanks!
Unfortunately, we hereby announce a temporary stop regarding new QSL designs. Previously, listeners received a different QSL card with each response, but now there is a big difference in number between one listener and the other. Since 2022, a total of 18 different QSL cards have appeared and 2 (one of which is this one) one-off Collectors Items. There are only a few listeners who have almost completed the entire series, but the vast majority are far behind. In order to give them a chance, there is a temporary stop for those who have received the (last) design (see below QSL no. 18) completed.
2024 was a busy year for Radio Intersound. Halfway through the year, the DDS of our homemade -all-band- transmitter (13 Watt) stopped working and we were hoping to get another one from a German supplier, since it has a lifetime warranty. After waiting for a while, my good friend Skylab Radio and I started messing around to build a new transmitter.
After some searching on second-hand sites, Alibaba and messing around with the soldering iron ourselves, we had enough material to even complete two transmitters. Of course, they were again all-band transmitters, since I like the freedom of being able to reach multiple pirate frequencies, such as the 48-meter, 76-meter and the MW-bands. Moreover, you don’t even pay that much more.
As most people know, we use an Inverted-L antenna, which is only 8 to 9 meters high and about 13 meters long, which we match via a home-made antenna tuner (PI-principle for the highest efficiency) with quite some capacity as far as the L (120uH) and C’s (1500pF) are concerned. Our piece of wire can be easily tuned 1:1.1 on the MW without any problems, as well as the CB-band on the other side of the scale.
The “silver” transmitter on top (see photo below) produces 30 watts on 48 meters to 50 watts carrier on 76 meters and MW. The “old black” transmitter below (with a refurbished Yaesu power-amplifier) gives about 20 watts carrier on all bands. That is a lot more power than before and that is noticeable. The reception reports showed an improvement compared to before. This is also because our old transmitter of 13 watts modulated back, which actually put about 9 watts on the air. These two new transmitters simply modulate up, as they should. On the MW, Radio Intersound is about 1 S-point stronger than before (an S 9 at a distance of 33 km with a KiwiSDR with mini Whip antenna, and that fits the theory that 4 x the power is 1 S-point more).
During our test broadcasts, we received comments about the modulation being too loud. Personally, I like to push the boundaries of sound (certainly on SW), but in the meantime I have adjusted the home-made compressor/limiter (model PIRA) a bit and hope that this is sufficient.
The speech would not sound good either, so we started experimenting with various dynamic and condenser microphones, whereby we preferred the voice sound of a dynamic one to that of a condenser, in price ranges between 20 and 200 euros. Strangely enough, the more expensive microphones with their wide frequency range up to 20 kHz sounded very good on the computer, but lousy via the transmitter in AM modulation. In the end, the choice for our transmitter fell on a cheap dynamic one (karaoke) microphone with a fairly limited frequency range!
So much for the troubles of a pirate station from the Frisian forests. It remains for me to thank you very much for your response, because without you Radio Intersound would not exist!
Below is a small impression of our studio “the shelter bunker” in wintertime, our latest QSL design and our new transmitters.
Wishing you a HEALTHY, PROSPEROUS and much LISTEN ENJOYABLE 2025!
Roland Visser, Radio Intersound.
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