August 21, 2024

Exploring Russian and International Analog TV From Leaky Cable TV Networks via the Airspy Server Network

Thank you to RTL-SDR.COM reader Micha for submitting a story about how he has been able to use SDR# and the Airspy Server Network to explore cable TV stations across the globe via cable TV signal interference.

If you were unaware, the SDR# software from Airspy.com has access to the Airspy Server Network, which is a collection of public Airspy SDRs available all over the world that can be accessed freely over the internet. To access these SDRs simply select "Airspy Server Network" as the source in SDR#, and click on the "..." button next to the server address entry. A map will pop up where you can select from SDRs all over the world.

Using Airspy SDRs in Russia, and in other countries (Guatemala, Brazil, Chile, Uruguay, Mexico, Dominican Republic, Argentina, Indonesia, Vietnam, Micha found that there were several analog TV signals found at frequencies that should not have terrestrial TV signals there. Upon further investigation, he realized that these are actually cable TV signals that are leaking and causing interference across the RF bands. Micha notes that he's also observed how the leaking signals often change in frequency and intensity too, making it difficult to keep track of them.

Combined with the TVSharp SDR# plugin, Micha was able to recover some (very rough) images from these interfering signals. Micha has provided several images shown below that demonstrate Russian cable leakage, as well as for Mexico and Argentina.

Vote

56 Comments

Inline Feedbacks

View all comments

Micha

1 month ago

#263497

Canada/ ..British Colombia is back. Not perfect, but better than before
thanks Walter!

Greetings Micha

Micha

1 month ago

#263496

Yesterday's images from Thailand were most likely actually over-range signals. This remains a snapshot in time. It would be interesting to know where the signals actually originate. According to the information I have, there are no longer any analog broadcasts in Thailand, Malaysia, Laos, or Singapore. Only in Cambodia did I find a hint that the last signals will be switched off in 2025...

The analog TV signal on 503.25 MHz even outshone a DVB-T carrier.

khmertimeskh.com/501043343/govt-signs-deal-to-switch-to-digital-broadcast/

Micha

1 month ago

#263489

At least two analog TV channels can be received via the online SDR sdr://61.7.183.95:5555/
on a Thai island, "Ko Samui." 

There could even be four different channels. Unfortunately, two frequencies are mercilessly lost in the noise. Only signals that fit the frequency grid can be detected here.

The signals vary from very clearly detectable to completely disappearing. This is probably due to over-range. Identification has not been possible so far.

According to Wikipedia and other sources, these channels were probably shut down long ago.

Ch/ Video/Audio

21  471.25  476.75

23  487.25  492.75

25  503.25  508.75

29  535.25  540.75

Those who like TETRA will get their money's worth here. There are enough data and voice channels around 855MHz.

.asiawaves.net/thailand/thai-tv.htm
en.wikipedia.org/wiki/List_of_analog_television_stations_in_Thailand

Micha

2 months ago

#262937

The online SDR, by Chimoo Lee, in South Korea, Seoul broadcasts analogue TV from South and North Korea.

Two programs obviously interfere with each other on 191.25 MHz video and 197.75 MHz audio. The frequency 195.667MHz may help to differentiate. 

On 223.25MHz/video and 229.75MHz audio, Central TV broadcasts live from Pyongyang/North Korea!

These frequencies are at 

wikipedia.org/wiki/Television_channel_frequencies

listed. Depending on the table, the frequency is 191.25/ 197.75 MHz, the channel K6 or channel 7.
The frequency 223.25/ 229.75 MHz is the channel K10.


- kcnawatch.org/korea-central-tv-livestream/

- scheida.at/scheida/Televisionen_Nord_Korea_Fernsehen.htm

Micha

Micha

2 months ago

#262438

After a long Christmas and New Year break, the SDR from Canada/ British Columbia is active again on Graham Island.
I made and evaluated countless videos in the hope of at least once recognizing a CTV station logo. That seems impossible. Only people can be seen in the snowy pictures. Not even vehicles or landscapes. A direct comparison with a live stream is also not possible here due to geoblocking.
All that remains is to compare with photos and videos on Google, YouTube and the CTV homepage.
The sound cannot be evaluated either. Because the NTSC channel 6 transmits on 83.25 MHz (video) and 87.75 MHz (audio), the sound theoretically radiates into the FM radio band and is broadcast at a reduced rate in order to avoid possible interference.

TV 6 analog audio can be heard on FM 87.75 on most broadcast radio receivers as well as on a European TV tuned to channel E4A or channel IC, but at lower volume than wideband FM broadcast stations, because of the lower deviation. (en.wikipedia.org/wiki/Television_channel_frequencies).

Broadcast by the station “Prince Rupert”, the sound falls by the wayside on the 120 km journey to Graham Island. A high-performance directional antenna with a good amplifier could help, but unfortunately it is not available – a shame.

I’m now pretty sure I’ve identified the program “W5” from the CTV-2 channel.

A frequently broadcast Saturn silhouette probably comes from a commercial.

The GAIN of this SDR has been adjustable for a few days now and the bandwidth has been increased to 8 MHz. Unfortunately the TV signal is now significantly worse.

Micha

Walter

Reply to Micha

1 month ago

#263094

Micha, a very interesting thread, especially since I am the owner of this remote SDR. You are correct that I switched out the HF+ Discovery for an Airspy One VHF SDR. The antenna is the same as before. It’s normally always pointed towards the SE and not to Prince Rupert (more or less due East). It’s a 6 element Yagi at about 25′ elevation. We have a lot of winds in Masset. My QTH is actually about 14 km east from where you thought. I know Charters well, as it’s across the road from my in-Laws home! I will be in Masset from March 16th to the 30th. I’ll make it a point to rotate the antenna towards Prince Rupert. Hopefully, that will improve the signal. I do have a question: how do you demodulate the image. I monitor this SDR using Airspy SDR#. Thank you, and good detective work. Channel 6 is an old analogue TV transmitter. Years ago, it was the only channel received in Masset. Call sign was/is CFTK. It used to carry some CBC programming. I don’t know about it now. You can reach out to me at CANSWL at Gmail dot com.

MICHA

Reply to Walter

1 month ago

#263427

Sorry..Erst jetzt gesehen…Danke für die Antwort…ich melde mich in Kürze….

Ich nutze SDR SHARP mit dem TV plugin, für PAL, SECAM, NTSC….eine kleine, aber sehr leistungsstarke DLL Datei….

Micha

3 months ago

#261904

The next, terrestrial TV channel from Novosibirsk, has now been clearly identified. 
The channel broadcasts on Channel 25/ 503.25 Mhz/ Video and 509.75 Mhz/ Audio 
“Суббота!” = “Saturday!”.

An online program newspaper can be found here, for example:

//tv.starhit.ru

For comparison, you can find the program online here, among others:

//smotret.tv/subbota

There are different information about the switch-off dates of analogue television in Novosibirsk. Today is obviously not one of them. It could definitely go on for a few more years. It remains exciting.

Micha

3 months ago

#261870

“R9OOM TEST” with its SDR has been online again in Novosibirsk for a few days. You can still receive 3 terrestrial TV channels here. In all lists the Disney Channel is listed on channel 33/567.25 MHz. However, that cannot be true, as Disney Channel has no longer been active in Russia since summer 2022. An indication of which station is broadcasting instead can be found at:
telepedia.fandom.com/ru/wiki/Канал_Disney.

The successor is the station “the Sun”/ “Солнце”

A direct program comparison between the SDR and the online live channel is not possible! There is a time difference of at least 2 hours between the two programs.
Micha

Micha

4 months ago

#261502

I've been watching CTV from Canada/British Colombia since October. The online SDR was marked on the spy server map on Graham Island. This fits perfectly with the received TV Channel 6
(Video 83.25 Mhz/Audio 87.75), broadcast from Prince Rupert, approximately 120 km away. That's a long way away, but a look at the channel map shows that Graham Island is still at the reception limit.
The signal is severely disturbed and only a few images can be recognized with a few tricks.
There was a total failure for a short period of time, but after a short time the signal was back in the old quality. Because the sound signal is already in the FM broadcast range, it is broadcast much weaker in accordance with standards. Unfortunately, the audio signal cannot be received.
At first I assumed it was CTV news. But that doesn't seem to be true. It must be CTV-2. A comparison with TV Guide agrees. To make matters worse, the broadcast location is called Prince Rupert, CFTK-TV1. At times, program content from CTV-News and CTV News-Regional is taken from the CTV-News continuous loop program.
By the way, this is the only program that can be received live online here. The regional news from CTV-Windsor can only be seen shortened in the online media library 1-2 days later. The live program is blocked.
According to the guide, CTV1 and CTV 2 broadcast identical programs at times.
A new online SDR with a different address in Fort St. John has been registered for a few days. What's strange here is that the signals (TV and radio) are completely identical to the SDR in Graham Island. In addition, there is no option to receive Channel 6 here. The distances to both Channel 6 stations (Prince Rupert/Kamloops) are far too great. Since then, the SDR in Graham Iskland has no longer been accessible. It is likely that the location in the map is entered incorrectly.
The sequences of images show how the disturbances change every second.

Micha

« Previous 1 2

Related posts: