❓ Frequently Asked Questions

SSTV stands for Slow-Scan Television. It is a way for radio amateurs to send still pictures through radio signals.

No. Normal television sends many moving pictures every second. SSTV usually sends one still image over several seconds or minutes.

You can receive photographs, test cards, callsigns, event images, weather-related pictures and special transmissions from radio amateurs around the world.

Yes. Radio amateurs still use SSTV on HF, VHF and UHF, and special SSTV events can attract listeners worldwide.

Licensed radio amateurs transmit SSTV. Shortwave listeners, scanner users and SDR users can also receive and decode the pictures.

No. You can start as a complete beginner. Begin by listening and decoding received signals before learning about transmitting.

Receiving your first picture can be simple: tune to an active frequency, feed the radio audio into decoding software and wait for a signal.

Yes. SSTV combines radio, photography, computers, geography and electronics, making it a useful educational hobby.

Radio conditions, limited bandwidth and analogue decoding can create noise, slant and colour errors. These imperfections are part of the character of SSTV.

Every received picture is proof that a radio signal travelled from one place to another. It combines photography, radio and the internet in one hobby.

In many countries, listening to amateur radio transmissions is allowed without an amateur radio licence. Local rules can differ, so check the regulations where you live.

Yes. Many people begin as receive-only stations or shortwave listeners. You can decode and share pictures without transmitting.

That depends on your equipment and location. The 20 metre band is popular for worldwide SSTV, while 2 metres can be easier for local FM activity.

Local VHF signals may travel tens or hundreds of kilometres, while HF signals can cross countries, continents and oceans when propagation is favourable.

Yes. Some bands work better at night, while others are stronger during daylight. Band conditions change with time, season and solar activity.

Sometimes. A simple indoor antenna may work for strong local signals, but an outdoor antenna usually gives better and quieter reception.

Yes. On HF, SSTV signals can travel thousands of kilometres when propagation conditions are good.

During announced SSTV events, the ISS may transmit pictures on 145.800 MHz FM. These events are temporary and must be confirmed before listening.

Most SSTV transmissions begin with a short identification tone followed by a distinctive sequence of changing audio tones.

Yes. Record the radio audio as clearly as possible, then play the recording into compatible SSTV decoding software.

You need a receiver, a suitable antenna, an audio connection and SSTV decoding software on a computer, tablet or phone.

Yes. An SDR is an excellent way to receive SSTV because you can see the signal on a spectrum display and route audio directly into decoding software.

A scanner can receive VHF or UHF SSTV when it covers the correct frequency and mode. Most scanners cannot receive HF SSTV unless they include shortwave SSB.

A handheld radio can receive local FM SSTV on VHF or UHF. For HF SSTV such as 14.230 MHz, you need an HF-capable receiver.

The best antenna is one designed for the band you want to receive. A dipole can work well on HF, while a vertical or directional antenna can work well on VHF and UHF.

No. Many beginners receive SSTV with simple wire antennas, compact verticals or basic SDR antennas. Correct placement often matters more than price.

Yes. Greater height can improve VHF and UHF range and can reduce nearby obstructions. On HF, antenna type, length, orientation and noise levels are also important.

Some multiband antennas cover several amateur bands. Wideband receiving antennas can also work, although performance may vary between bands.

Not always. Receive-only setups may work with a safe audio cable or virtual audio connection. For transmitting, a proper radio interface is strongly recommended.

It may work for reception at a low audio level, but check both devices first. Isolation and correct levels help prevent hum, distortion and equipment damage.

Popular choices depend on your operating system. MMSSTV is widely known on Windows, while other applications are available for Linux, macOS, Android and iOS.

MMSSTV is a well-known Windows program for receiving and transmitting analogue SSTV images.

Many SSTV decoding programs are free or available at no cost. Always download software from a trusted source.

Yes. SSTV decoder apps can listen through the phone microphone or an audio connection. Results depend on audio quality and the app used.

Yes. Linux users can choose from several SSTV and digital-mode applications, depending on their distribution and hardware.

Yes. There are SSTV applications and general digital-mode tools for macOS, although the selection differs from Windows.

Many programs use the VIS signal at the start of a transmission to identify the mode automatically. Weak or damaged signals can cause incorrect detection.

A virtual audio cable routes sound from one program to another inside the computer. It is useful when receiving SSTV with SDR software.

Check the selected audio input, radio mode, volume, squelch and frequency. The decoder must receive clean audio from an actual SSTV transmission.

Most SSTV programs can save received images. Some can also run scripts or upload the newest image to a website.

14.230 MHz USB on the 20 metre amateur band is one of the best-known SSTV activity frequencies.

It is an internationally recognised SSTV activity frequency on 20 metres, although band plans and operating practices can vary by region.

Use USB on 20 metres. Tune carefully so the SSTV audio tones fall correctly inside the receiver passband.

Yes. VHF SSTV activity exists on FM and other modes, but exact calling frequencies and band plans differ by IARU region and country.

No. It is commonly associated with ISS downlinks, but SSTV is only transmitted during announced events. At other times, different space communications may use the channel.

Propagation describes how radio waves travel. It determines which bands are open, how far signals reach and how strong they are.

HF propagation changes with solar activity, time of day, season, frequency and atmospheric conditions. Local electrical noise also affects reception.

Band noise is unwanted radio energy from natural sources, electronics, power supplies and other transmitters. High noise can hide weak SSTV signals.

Fading is a rise and fall in signal strength caused by changing radio paths. It can create bands, colour changes or missing sections in an SSTV image.

A report shows where a signal was heard, on which band and with what quality. Other amateurs can use this to understand current propagation conditions.

An SSTV mode defines how colour, brightness, lines and timing are transmitted. Different modes produce different image sizes, quality and transmission times.

Martin 1 is a popular colour SSTV mode often heard on HF. It offers good image quality and takes roughly two minutes to send a picture.

Scottie 1 is another popular colour mode used by radio amateurs. Its timing and colour sequence differ from Martin 1.

Robot 36 is a fast colour mode that sends a picture in about 36 seconds. It is useful when conditions are changing quickly.

PD120 is a colour SSTV mode with a wider image format and good detail. It is often associated with special SSTV transmissions, including some space events.

Longer modes can provide more detail, but the best result also depends on signal strength, fading, interference and receiver tuning.

Some modes send images in only a few seconds, while common colour modes such as Robot 36 take longer. Faster modes generally contain less detail.

Each mode uses its own number of lines, colour method and timing. That creates different resolutions and aspect ratios.

Yes. If the decoder selects the wrong mode, the image may have incorrect timing, colours or dimensions. You can often select the correct mode manually.

The VIS code is a short digital identification sequence sent near the beginning of an analogue SSTV transmission. It tells the decoder which mode is being used.

Yes, amateur-band transmitting normally requires an appropriate amateur radio licence and operation within your local licence conditions.

You usually study radio theory, operating practice and regulations, then pass an examination or assessment required by your national authority.

Prepare a suitable image, select an allowed frequency and mode, check that the channel is clear, identify with your callsign and transmit with clean audio.

Rules vary, but clearly identifying your station is good operating practice. Your licence may also require identification during or around the transmission.

Use images that are lawful, appropriate and suitable for amateur radio. Respect privacy, copyright and your licence conditions.

Use only the power needed for reliable communication and stay within your licence limits. Clean audio and a good antenna are often more important than high power.

Yes. Listen first and ask whether the frequency is in use before transmitting, especially on shared activity frequencies.

Yes. Licensed operators can transmit an SSTV CQ image or make a voice call before sending an image, following local rules and accepted operating practice.

Only when the repeater operator and local rules allow it. Long SSTV transmissions can occupy a repeater for a significant time, so permission and good practice matter.

Keep the computer or interface audio level moderate, disable unnecessary audio processing and monitor the transmitted signal when possible.

In many cases, received amateur radio images are shared for hobby and educational purposes. Consider privacy, copyright and local rules before publishing.

Shared images show real reception conditions, signal reach and current band activity. They help other amateurs and preserve interesting transmissions.

Software can monitor the folder where new images are saved and upload them to a website through FTP or another supported method.

It is a small utility designed to help upload newly received SSTV images automatically from a computer to a web server.

Not always. Some communities and station networks can display images for participating stations. Requirements depend on the service.

Yes. Receive-only stations provide valuable evidence of propagation and activity, even when the operator does not transmit.

Useful details include your callsign or listener ID, location, date, UTC time, frequency, band, mode and the transmitting callsign when known.

UTC gives everyone one common time reference and avoids confusion caused by time zones and daylight-saving changes.

A station needs a reliable latest-image source and basic station information. The exact participation method is described by the SlowscanTV project.

Yes, when unique credentials, restricted folders, encrypted connections where available and updated software are used. Never publish FTP passwords.

A callsign is the unique station identification assigned to a licensed radio amateur. It often indicates the country or licensing area.

SWL means shortwave listener. An SWL receives radio signals but does not necessarily hold a transmitting licence.

CQ is a general call inviting any station to respond. In SSTV, it may appear as text on an image.

73 is a traditional amateur radio abbreviation meaning best regards.

A QSO is a radio contact or communication between stations. An SSTV QSO may include exchanged images and voice.

A locator is a short code that identifies a geographical grid square. Radio amateurs use it to describe station location and calculate distance.

RST is a traditional signal report system for readability, strength and tone. For image modes, operators may also describe picture quality separately.

UTC is Coordinated Universal Time, the common time standard used internationally by radio amateurs.

The world is divided into three IARU regions for amateur radio coordination. Band plans and recommended activity frequencies can differ between them.

A band plan is a coordinated guide showing how parts of an amateur band are commonly used. It helps different activities share the spectrum.

The audio sampling rate or timing is slightly incorrect. Use the decoder's slant correction or calibrate the computer audio clock.

Incorrect tuning, the wrong mode, distorted audio or a weak signal can cause colour errors. Check frequency, mode and audio level.

Lines can be caused by interference, fading, electrical noise, audio dropouts or computer timing problems.

The signal may have faded, another station may have interfered, the radio squelch may have closed or the audio connection may have been interrupted.

A weak signal, poor antenna, high local noise, narrow filtering or incorrect tuning can all reduce picture quality.

The VIS identification signal may be weak or damaged. Select the correct mode manually and improve the received audio quality.

A ground loop, unshielded cable, power supply or incorrect audio connection may introduce hum. Isolation can often help.

Computers, screens, chargers, network equipment and switching power supplies can create radio noise. Increase distance, improve grounding and try quieter power supplies.

This may be caused by display settings, an unusual transmission format or software configuration. Check the decoder's image orientation options.

Start with the SlowscanTV Information Centre, local amateur radio clubs and experienced SSTV operators. Include your equipment, frequency, mode and a screenshot when asking.