Posts Tagged ‘longwave’
The FCC has authorized amateur radio use of the 630 and 2200-meter bands, effective October 16, 2017, providing registration procedures have been followed and no objections are received within 30 days.
The PLC (Power Line Communications) database is live and hams may begin registering immediately. They may begin operating on 472 kHz (630 meters) and 137 kHz (2200 meters) as early as October 16 if they register today and receive no objection in the next 30 days. Hams may not operate on the bands without going through this process.
Please fill out the UPC Form, today, to register your station, even if you don’t have any plans on transmitting on these new bands.
It is imperative that all amateurs register, even if they don’t plan to use these bands in the near future, as the FCC rules prohibit UTC (the Utilities Technology Council) from deploying PLC in these bands closer than one (1) kilometer from registered stations. Registration now will protect your ability to use our new MF/LF bands in the future.
Many places in the world, low power transmitters in the medium wave band are allowed. I am talking about regulations like in the US where FCC part 15 allows up to 100 mW input.
In Norway we have a particular permission for members of the Norwegian Radio Historic Society to transmit up to 500 mW on 216 kHz. I’m not sure if this is output or input power. The permission is meant to cover a collection of historic radios. The frequency is the one used by the main transmitter north of Oslo from 1954-1995 running 200 kW. The frequency is still allocated to Norway, so I guess that is why we may use it this way.
There are several low power transmitters around that can be purchased, but most of them only cover the mediumwave band and not longwave (153-279 kHz). Further they are quite complicated as the frequency necessarily has to be user settable.
I looked for a simpler way to make a single-frequency transmitter and found that the function generator chip XR-2206 which I happened to have in my junk box could both generate this frequency and do the amplitude modulation. The RC-oscillator seems to be stable enough for this low frequency although I haven’t tested this much.
Here are the first results with images of the circuit on a Veroboard and the oscilloscope picture of the modulation with my Tandberg TP41 70’s radio on top of it listening to Dire Straits from Spotify streaming over longwave.
Too bad that the XR-2206 is obsolete and not recommended for new development!