Dutch FM SDRs Online and sub-87.5 pirates

[bristolpirates]

I found this site today. It doesn't look like anybody posted it here already:
https://sonyleiden.nl/

If you check the Leiden SDR, you'll find pirates broadcasting below 87.5.

[Persona Non Grata]

Great stuff thanks for that,

I've always wondered why VHF/FM SDR's weren't more of a thing ?

[FMEnjoyer]

thx for info, unusual find.

[radionortheast]

They are quite lucky the dutch, they don’t have something scanning the spectrum, here I think an out of band transmission would be quite easly detected straight away and flagged up over at balderdock station, a music transmission in the normal fm range would be harder to detect (87.7 to 107.9 not at the band egde) over there its away from the commercial stations not bothering anyone so I guess thats why they do it.

[famefm]

What is the point of that? who has radios that can tune that low ?

[RadioSputnik.nl]

What is the point of that? who has radios that can tune that low ?

search for TEF Tuner

[Albert H]

What is the point of that? who has radios that can tune that low ?

Anyone who has a Japanese spec FM radio can tune down there. The FM band in Japan (and a few other countries) starts at 76 MHz.

[87to108]

I presume the regular FM band is full, so these hobbyists operate down there. Only Hams/ DXers /radio enthusiasts are likely to be listening to them. A similar situation above MW with similar people operating on frequencies above the regular MW band (up to 1700 approx) , which ordinary receivers with MW in Europe cannot usually tune to.
Brazil extended their FM band to 76-108, so receivers for that market would also do!

I see the Almere FM SDR appears to be down:

"502 Bad Gateway
openresty"

[Persona Non Grata]

They are quite lucky the dutch, they don’t have something scanning the spectrum, here I think an out of band transmission would be quite easly detected straight away and flagged up over at balderdock station

They do. I saw a report from Dutch TV about pirate radio and they had monitoring stations listening out for stuff maybe not on the same scale as the UK but its definitely a thing.

In this day and age its fairly easy to set up multiple unmanned/remotely operated monitoring stations at various points around the country and having it all feed back to somewhere central. Even COMREG in Ireland a few years back were looking for tenders/companies to set some up for them. Rotatable antennas and wideband reception (all operated from hundreds of Km away by one or two people) is fairly trivial to implement with 21st century technology. Looking out for pirates represents only a small slice of their workload though. They also monitor legal stations and non-broadcast frequencies making sure everyone' bandwidth and frequency stability is within spec.

A lot of folk assume the reason that little 10 watt pirate stations in the middle of nowhere don't get busted as often as big ones in the middle of London is that OFCOM don't know theyre there. The real reason is that theyre generally not considered worth the travel time/diesel/manpower although now and again they do like to take a little holiday.

Anyone who has a Japanese spec FM radio can tune down there. The FM band in Japan (and a few other countries) starts at 76 MHz.

In some former Soviet/Eastern bloc countries it goes down to 65.8 MHz. Brazil have extended their FM broadcast band downwards and the United States have been considering it.

[87to108]

A lot of folk assume the reason that little 10 watt pirate stations in the middle of nowhere don't get busted as often as big ones in the middle of London is that OFCOM don't know theyre there. The real reason is that theyre generally not considered worth the travel time/diesel/manpower although now and again they do like to take a little holiday.

Actual riads, it is surely fair to say is largely complaint driven, either from licenced stations, or complaints of interference.

A little 10W TX in London but just 0.2Mhz away from one of the regular licenced stations is of course likely to generate complaints , but elsewhere, for a start, there is usually more scope for comfortable frequency separation from stations serving the area etc. The prospects of a 10W in Band II out in the "middle of nowehere" getting attention is low unless a local or community station in the area gets a bee in their bonnet about their existence.

They do not need monitoring stations to discover stations that they then take action against. They will find out by complaints. A monitoring station however may be useful to confirm a station has not moved location, leading up to action.

[bristolpirates]

What is the point of that? who has radios that can tune that low ?

Tecsun
TEF
Probably lots of other portables
One of my old personal stereos that had a setting to change to Japanese bands
Any old FM radio from Japan
SDRs

Lots of options.

[Albert H]

My old Sony ICF7600 does 76 MHz up to 108 MHz.

[radionortheast]

Alot of pocket radios do tune below 87.5, I was thinking of transmitting down there, it would of been out of the way of in car transmitters I hear constantly, I worried about been a nusiance. I was worried about it been detected, (seeing manchester ringways video about unman monitoring station spooked me) even though most frequencies have been vacated.
Some pocket radios go all the way down to 66, there is the ham band at 70, I would go just below band II the aerial wouldn’t be tuned. I can transmit wideband signal all the way from 35mhz up to 6ghz, I have nothing decode the stereo beyond the 66-108 range. The dutch would hack old hifi separate tuners to tune below 87.5, they’ve also transmitted at uhf, they were quite ingenious, I think it is a ham radio thing with music, they problalby transmit to other people doing the samething.

[Albert H]

Most of my links back in the 80s were around 460 - 480 MHz, and the transmitters seldom developed more than 400 mW, but with TV Yagis at each end of the link, I could get clean stereo over as much as 15 miles! Lining up the Yagis could be tricky, since their beam angle was so tight, but TV aerials don't look out of place on any building, so they were ideal for clandestine links.

The very earliest of the Band IV links used the old Police Pye Pocketfone PF1 hacked about to work with broadband FM. The PF1 was particularly cost-effective because it came in two boxes - the transmitter (with its notorious pop-up whip aerial), and the receiver. The mods were quite extensive - we hacked off the crystal oscillator and phase modulator stages from the transmitter, and replaced them with a PLL circuit giving modulated signal at about 24 MHz. The multiplier and RF amplifier stages were still used - supplied with 18V - and could be peaked up to give ~150 mW, The receiver was also hacked about, with the crystal oscillator and multiplier still used, but the IF and audio parts removed. The original internal dipole aerial was removed and a socket fitted for connection to an outdoor aerial. The IF was replaced with a normal 10.7 MHz wideband IF strip and demodulator - usually the cheap kit from "Ambit" in those days.

I made up a dozen or so PF1-based link systems, but the supply of them dried up (or the original £7 price rose - I can't remember which), so I came up with my own circuits for the transmitter, with a 2N2866 final, and used a PLL-tuned TV tunerhead module into a crystal mixer (to down-mix the 35 MHz TV IF to 10.7 MHz) and then the usual 10.7 MHz IF board. Those UHF links were widely used for about 10 years!