Posts Tagged ‘High frequency’
Come Join the Fun With Olivia on HF (Shortwave Digital Mode Olivia)
November 22nd, 2017 | 
Author: For those of you who have dived into the crowded but fun pool of FT8 operation or one of the other Joe Taylor modes (such as JT65 or JT9) and are excited now about digital modes, here’s something you might enjoy, too. Unlike those modes that allow you to make quick work of getting DX stations into your logbook, simply by exchanging callsigns, a signal report, and a grid square, there are other modes that offer keyboard-to-keyboard conversational QSO opportunities.
One such mode is known as Olivia and this mode offers keyboard-to-keyboard chatting for when you want to relax, and maybe make a friend. Ham radio is the oldest electronic social networking infrastructure.
In 2005, SP9VRC, Pawel Jalocha, released to the world a mode that he developed starting in 2003 to overcome difficult radio signal propagation conditions on the shortwave (high-frequency, or HF) bands. By difficult, we are talking significant phase distortions and low signal-to-noise ratios (SNR) plus multipath propagation effects. The Olivia-modulated radio signals are decoded even when it is ten to fourteen dB below the noise floor. That means that Olivia is decoded when the amplitude of the noise is slightly over three times that of the digital signal!
Olivia decodes well under other conditions that are a complex mix of atmospheric noise, signal fading (QSB), interference (QRM), polar flutter caused by a radio signal traversing a polar path. Olivia is even capable when the signal is affected by auroral conditions (including the Sporadic-E Auroral Mode, where signals are refracted off of the highly-energized E-region in which the Aurora is active).
Currently, the only other digital modes that match or exceed Olivia in their sensitivity are some of the modes designed by Joe Taylor as implemented in the WSJT programs, including FT8, JT65A, and JT65-HF–each of which are certainly limited in usage and definitely not able to provide true conversation capabilities. Olivia is useful for emergency communications, unlike JT65A or the newly popular FT8.
Here is a demonstration of a two-way transmission using the Olivia digital mode on shortwave. I am in QSO (conversation) with KA5TPJ. There are two other Olivia QSOs just below our frequency. Just above us is a lot of FT8 activity. Below the two other Olivia QSOs are PSK31 QSOs. The band is active. Olivia is not dead!
The standard Olivia formats (shown as the number of tones/bandwidth in Hz) are 8/250, 8/500, 16/500, 8/1000, 16/1000, and 32/1000. Some even use 16/2000 for series emergency communication. The most commonly-used formats are 16/500, 8/500, and 8/250. However, the 32/1000 and 16/1000 are popular in some areas of the world and on certain bands.
This can cause some confusion and problems with so many formats and so many other digital modes. After getting used to the sound and look of Olivia in the waterfall, though, it becomes easier to identify the format when you encounter it. To aid in your detection of what mode is being used, there is a feature of many digital-mode software implementation suites: the RSID. The video, below, is a demonstration on how to set the Reed-Solomon Identification (RSID) feature in Ham Radio Deluxe’s Digital Master 780 module (HRD DM780).
I encourage ALL operators in any digital mode such as Olivia, set the RSID feature on as shown in this example. In Fldigi, the RSID is the TXID and RXID (I believe).
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 1: MixW doesn’t have RSID features. Request it!
+ NOTE 2: 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.
+ NOTE 3: some websites publish frequencies that are right on top of weak-signal FT8, JT65 and JT9 segments. Even if that is a matter of contention, follow the regulations and be kind: DO NOT QRM weak-signal QSOs! AGAIN: 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 x.074 or higher, as this is the sub-band for FT8, JT65A, and JT9.
Quick Reference: we in the active Olivia group suggest 8/250 as the starting settings when calling CQ on the USB dial frequency of 14.072 MHz with an offset of 700 Hz, on 20m–that translates to a CENTER frequency of 14.0729 MHz. On 40m, 7.072 MHz on the dial with an offset of 700 Hz (and again 8/250) which translates to a center frequency of 7.0729 MHz.
An example of the calling frequency on 20 meters with a center frequency of 14.0729 MHz, 8 tones, and a bandwidth of 250 Hz.
Also, do not quickly switch to other modes without calling CQ for at least a five-minute window. It is really horrid when people call CQ and change settings, modes, bandwidths, tones, every time they call CQ during the same session!
There are several key resources that we in the Olivia community are developing, to make it easier for you to enter into the great world of Olivia. One is an active support e-mail group to which you can subscribe at https://groups.io/g/Olivia — a group containing topical areas of interest which can be filtered so that you are not flooded by email containing topics of which you are not interested. It has a files section, as well, in which we will add helpful how-to instructions and so on.
Another resource is our Facebook group, at https://www.Facebook.com/groups/olivia.hf — also with a files area containing help files. This group is a great resource for getting help from like-minded Olivia digital mode enthusiasts.
Some more eavesdropping on an Olivia QSO:
And, two more:
One last note: Olivia is NOT a weak-signal mode. There are no points won by barely making a contact. In the USA FCC regulations, you are directed to use only the power necessary to make the QSO. Typically, with poor propagation, using Olivia with an output power of 100w is the minimum to establish a reliable circuit. You just cannot go beyond your rig’s duty cycle (don’t burn out the finals in your radio!). You also must be sure that you do not overdrive the audio chain into your radio. 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. After all, think about RTTY.
Welcome to Olivia! See you on the waterfall.
73 de NW7US
What is the big deal with amateur radio? What is it that you hear? (Part 1)
Shortwave radio has been a source for great sci-fi plots, spy intrigue novels, movies, and so on, since radio first became a “thing.” But, what is the big deal, really? What is it that amateur radio operators listen to?
In this video, I share some of the types of signals one might hear on the high frequencies (also known as shortwave or HF bands). This is the first video in an on-going series introducing amateur radio to the interested hobbyist, prepper, and informed citizen.
I often am asked by preppers, makers, and other hobbyists, who’ve not yet been introduced to the world of amateur radio and shortwave radio: “Just what do you amateur radio operators hear, on the amateur radio shortwave bands?”
To begin answering that question, I’ve taken a few moments on video, to share from my perspective, a bit about this shortwave radio thing:
Link to video: https://youtu.be/pIVesUzNP2U — please share with your non-ham friends.
From my shortwave website:
Shortwave Radio Listening — listen to the World on a radio, wherever you might be. Shortwave Radio is similar to the local AM Broadcast Band on Mediumwave (MW) that you can hear on a regular “AM Radio” receiver, except that shortwave signals travel globally, depending on the time of day, time of year, and space weather conditions.
The International Shortwave Broadcasters transmit their signals in various bands of shortwave radio spectrum, found in the 2.3 MHz to 30.0 MHz range. You might think that you need expensive equipment to receive these international broadcasts, but you don’t! Unlike new Satellite services, Shortwave Radio (which has been around since the beginning of the radio era) can work anywhere with very affordable radio equipment. All that you need to hear these signals from around the World is a radio which can receive frequencies in the shortwave bands. Such radios can be very affordable. Of course, you get what you pay for; if you find that this hobby sparks your interest, you might consider more advanced radio equipment. But you would be surprised by how much you can hear with entry-level shortwave receivers. (You’ll see some of these radios on this page).
You do not need a special antenna, though the better the antenna used, the better you can hear weaker stations. You can use the telescopic antenna found on many of the portable shortwave radios now available. However, for reception of more exotic international broadcasts, you should attach a length of wire to your radio’s antenna or antenna jack.
