Olivia Digital Mode Radioteletype on HF Olivia@groups.io
Basics about the Olivia MFSK Digital Mode
Olivia MFSK is an amateur radioteletype protocol designed to work in difficult (low signal-to-noise ratio plus multipath propagation conditions on shortwave bands. The typical Olivia signal is decoded when the amplitude of the noise is over ten times that of the digital signal! It is commonly used by amateur radio operators to reliably transmit ASCII characters over noisy channels using the high frequency (3-30 MHz, HF) spectrum.
Olivia modes are commonly referred to as Olivia X / Y (or, alternatively, Olivia Y / X ), where X refers to the number of different audio tones transmitted and Y refers to the bandwidth in hertz over which these signals are spread. Examples of common Olivia modes are 16/500, 32/1000 and 8/250.
The protocol was developed at the end of 2003 by Pawel Jalocha. The first on-the-air tests were performed by two radio amateurs, Fred OH/DK4ZC and Les VK2DSG on the Europe-Australia path in the 20-meter amateur band. The tests proved that the protocol works well and can allow regular intercontinental radio contacts with as little as one-watt RF power. Since 2005 Olivia has become a standard for digital data transfer under white noise, fading and multipath, flutter (polar path) and auroral conditions.
Please join our Olivia-mode email group:
Also, be aware that we have a Facebook group dedicated to instant communication for spotting, scheduling, and so on, at https://www.facebook.com/groups/olivia.hf/ -- please join this group, if you are on Facebook.
Since Olivia signals can be decoded even when received signals are extremely weak, (signal to noise ratio of -14db), signals strong enough to be decoded are sometimes below the noise floor and therefore impossible to search for manually. As a result, amateur radio operators have voluntarily decided upon channelization for this mode. This channelization allows even imperceptibly weak signals to be properly tuned for reception and decoding. By common convention amateur stations initiate contacts utilizing 8/250, 16/500, or 32/1000 configuration of the OLIVIA mode and then switch to other configurations to continue the conversation. The following table lists the common center frequencies used in the amateur radio bands.
Olivia (Center) Frequencies (kHz)
It is often best to get on standard calling frequencies with this mode because you can miss a lot of weak signals if you don't. However, with Olivia activity on the rise AND all the other modes vying for space, a good deal of the time you can operate wherever you can find a clear spot--as close as you can to a standard calling frequency.
Note: some websites publish frequencies in this band, frequencies that are right on top of weak-signalJT65 and JT9 segments. DO NOT QRM weak-signal QSOs!
We (active Olivia community members) suggest 8/250 as the starting settings when calling CQ on the USB frequencies designated as “Calling Frequencies.” A Calling Frequency is a center frequency on which you initially call, “CQ…” and then, with the agreement with the answering operator, move to a new nearby frequency, changing the number of tones and bandwidth at your discretion. Even though 8/250 is slow, the CQ call is short. But, it is narrow, to allow room for other QSOs nearby.
1.8269, 3.5729, 7.0729, 10.1429, 14.0729, 18.1029, 21.0729, 24.9229, 28.1229, and so on.
See the pattern?
(Why the …9 frequency? Experts say that ending in a non-zero, odd number is easier to remember!)
For those new to waterfalls: the CENTER frequency is the CENTER of the cursor shown by common software. The cursor is what you use to set the transceiver’s frequency on the waterfall. If your software’s waterfall shows the frequency, then you simply place the cursor so that its center is right on the center frequency listed, above. If your software is set to show OFFSET, then you might, for example, set your radio’s dial frequency to 14.0714, and place the center of your waterfall cursor to 1500 (1500 Hz). That would translate to the 14.0729 CENTER frequency.
Also: Do not switch to other modes without calling CQ for at least a five-minute window. It is horrid when people call CQ and change settings, modes, bandwidths, tones, every time they call CQ!
TURN ON RSID (TXID and RXID in FLdigi)!
Common Windows of Olivia Operation on HF
(this is still a work-in-progress; your input is welcome)
+ 160m: 1835 kHz - 1837.9 kHz
+ 80m: 3571 kHz - 3573.9 kHz
+ 40m: 7071 kHz - 7073.9 kHz (500, 250, or 125 Hz configurations mostly)
+ 30m: 10141 kHz - 10144 kHz (500, 250, or 125 Hz configurations mostly)
+ 20m: 14071 kHz - 14073.9 kHz (500, 250, or 125 Hz configurations mostly)
14104.5 kHz – 141079 kHz (1000 or 2000 Hz wide configurations mostly)
+ 17m: 18102.65 kHz
+ 15, 12, 10 and 6m: Usually 500 Hz above PSK activity – 21071.4 kHz, 24921.4 kHz, 28121.4 kHz
+ 50.291 MHz ???
Note: First, make sure that your signal does not cross into other sub-bands where weak-signal modes are active. For instance, do not have any part of your signal at 14073.5 kHz or higher, as this is the sub-band for FT8, JT65A, JT9.
DO NOT QRM WEAK-SIGNAL MODES such as WSPR, JT65A, and JT9! BE AWARE OF THE BAND PLANS OF THOSE MODES!!
1. Please make sure you are using the RSID (Reed Solomon Identification - RSID or TXID, RXID) option in your software. RSID transmits a short burst at the start of your transmission which identifies the mode you are using.
When it does that, those amateur radio operators also using RSID while listening will be alerted by their software that you are transmitting in the specific mode (Olivia, hopefully), the settings (like 8/250), and where on the waterfall your transmission is located. This might be a popup window and/or text on the receive text panel. When the operator clicks on that, the software moves the waterfall cursor right on top of the signal and changes the mode in the software. This will help you make more contacts!
+ NOTE: MixW doesn't have RSID features. Request it!
+ 2nd Note: A problem exists in the current paid version of HRD's DM780: the DM780 RSID popup box to click does not work. HRD support is aware of the problem. You can still use the textual version that you can select in the settings so that it appears in the receive text areas. If you click the RSID link that comes across the text area, DM780 will tune to the reported signal, and change to the correct settings.
2. Olivia is NOT a weak-signal mode. There are no points won by barely making a contact. In USA FCC regulations, you use the power necessary to make the QSO. Typically, with poor propagation, 100w is the minimum to establish a reliable circuit. You just cannot go beyond your rig's duty cycle. You also must be sure that you do not overdrive the audio chain into your radio. Also, be sure that you do not have RF coming back into your audio chain. Yes, 100 watts is acceptable. Don't let anyone convince you otherwise.
3. Some older information that might be helpful is at this website: http://www.oliviamode.com/ -- this has older information (so do not rely on the frequencies listed!), but most of it is STILL perfectly pertinent to the current operation. Just be aware of frequencies, and other software choices.
GET ON THE AIR AND STAY AROUND FOR A WHILE, TRYING. THE RESULTING RAGCHEW COULD VERY WELL BE WORTH THE WAIT!
73 de NW7US and the Olivia Community
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