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SSTV and DATV
Slow and Fast scan Digital TV
At Pacificon, we'll be demonstrating two different ways to send pictures over the air: Digital Amateur Television (DATV) and Slow Scan Television (SSTV).
DATV allows you to transmit live video, similar to a traditional television broadcast, while SSTV lets you send individual pictures using audio tones using FM or SSB
We'll be demonstrating both modes at Table NP-15, located at the far north end of the main hallway, near the doors leading to the parking area. We'll also have an SSTV Selfie Station, where you can have your picture taken and sent over the air.
You don't have to be at our table to participate in SSTV! Tune to 447.800 MHz FM and send pictures from anywhere at Pacificon.
The Transmitter Hunt (T-Hunt) booth will also be participating in SSTV, so stop by and see what they're sending.
Whether you're familiar with DATV and SSTV or just curious about how they work, you're welcome to visit, ask questions, and see the demonstrations.
Digital Amateur Television (DATV)
Digital Amateur Television, or DATV, allows you to transmit live video and audio using digital modulation. It's similar to traditional broadcast television, but operates on amateur radio frequencies. This is also commonly called Fast Scan TV
At Pacificon, we'll be demonstrating DATV using the Mount Diablo Amateur Radio Club (MDARC) television repeater system.
Our setup starts with an analog NTSC video signal at our table, which is sent to the nearby MDARC communications van. There, the video is encoded into a digital DVB-S signal, amplified, and transmitted on the 1.2 GHz band to the repeater on Mount Diablo.
The repeater then re-transmits the video using DVB-S on a separate 1.2 GHz frequency, allowing you to receive the live broadcast with any Free-to-Air Satellite receiver and a 1.2ghz yagi.
We'll also have a second 1.2 GHz input for other DATV stations, so you may see other hams joining in and transmitting their own video through the repeater.
You can also watch the repeater live at http://w6cxatv.mdarc.org/
In addition to the RF transmissions, we'll be connected to the Amateur Television Network (ATN) through Whereby, allowing us to share video and communicate with other amateur television stations.
You can join us on whereby at https://whereby.com/atn-az
For more information about the repeater, including frequencies and technical details, check out the MDARC Amateur Television page.
Slow Scan Television (SSTV)
Slow Scan Television, or SSTV, lets you send still pictures over a regular voice radio channel. Unlike DATV, which transmits continuous video, SSTV sends one picture at a time.
SSTV works by converting a picture into a series of audio tones, which are transmitted over the air. On the receiving end, SSTV software decodes those tones and reconstructs the picture, one line at a time.
At Pacificon, we'll be using Robot36, an SSTV mode that takes approximately 36 seconds to send a color image.
How to Join in on SSTV at Pacificon
Frequency and Mode
447.800 MHz FM — Robot36 Low power - No more than 2w.
For the observant, Yes this is a repeater input frequency in NorCal. This frequency is chosen as it's a standard SSTV frequency used at conventions. The closest repeater is in PaloAlto and Vallejo and both of these are too far from San Ramon for a HT to interfere. We still ask you to use a low-power setting.
What You'll Need
If you'd like to send your own SSTV pictures, you'll need:
A radio/HT capable of transmitting on 447.800 MHz FM. Baofeng, Anytone etc. Make sure to use a low power setting.
A laptop, tablet, or smartphone to run your SSTV software.
An audio interface to connect your device to your radio. A DigiRig, AIOC, or similar sound card interface works well. Some radios have Bluetooth and usb that work well, some smartphone apps can also work using your phone's speaker and microphone without a wired connection.
SSTV software that supports Robot36.
Here are a few software options:
Windows MMSSTV
MacOs MultiScan
Linux QSSTV
Mobile (Numerous)
You aren't limited to these programs. Any software that supports Robot36 should work.
Getting Your Pictures Ready
Before transmitting, grab a few pictures you'd like to send!
You can use photos you've taken, pictures of your radio projects, drawings, or just about anything else you'd like to share. Most SSTV software will automatically resize your pictures to fit the transmission format, so you don't need to worry too much about the image dimensions.
If you want to send text instead of a photo, you can use a plain black or white background and overlay your message.
Make sure to include your callsign somewhere on your picture. Most SSTV software lets you overlay text before transmitting.
If you'd like to have an SSTV QSO, you can also add another station's callsign, a greeting, or a short message to your image.
Memes and funny pictures are welcome too! Just keep everything PG and family-friendly. Remember, there are kids at Pacificon!
A Few Operating Tips
Since we'll all be sharing the same frequency, please listen before transmitting. Each Robot36 picture takes about 36 seconds to send, so wait until the current transmission finishes before sending yours.
Try to leave a little time between pictures to give everyone a chance to participate.
Remember to follow normal amateur radio identification requirements when transmitting. For SSTV this is normally handled by your callsign on the picture.
SSTV Selfie Station
Don't have an SSTV setup of your own? You can still see how it works!
We'll have an SSTV Selfie Station at Table NP-15, where you can have your picture taken and see it transmitted over the air using SSTV. You don't need to bring any equipment to try it.
The T-Hunt booth will also be participating in SSTV during Pacificon, so be sure to stop by and see what they're sending.
Whether you're trying SSTV for the first time or already have experience with it, you're welcome to stop by, ask questions, share pictures, and see what everyone else is sending.
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