Setting up satellite dishes can be a finicky business. To aid in the alignment of these precision antennas, satellite finders are often used which can display audio and video feeds from the satellite while also providing signal strength readouts for accurate adjustment. However, these devices can also be used in interesting ways for more terrestrial purposes (Youtube link).
Using the DMYCO V8 Finder, [Corrosive] demonstrates how to set up the device to pick up terrestrial amateur streams. Satellite reception typically involves the use of a low-noise block downconverter, which downconverts the high frequency satellite signal into a lower intermediate frequency. Operating at the 1.2GHz amateur band, this isn’t necessary, so the device is configured to use an LNB frequency of 10000, and the channel frequency entered as a multiple of ten higher. In this case, [Corrosive] is tuning in an amateur channel on 1254 MHz, which is entered as 11254 MHz to account for the absent LNB.
[Corrosive] points out that, when using an F-connector to BNC adapter with this setup, it’s important to choose one that does not short the center pin to the shield, as this will damage the unit. This is due to it being designed to power LNBs through the F-connector for satellite operation.
By simply reconfiguring a satellite finder with a basic scanner antenna, it’s possible to create a useful amateur television receiver. If you’re wondering how to transmit, [Corrosive] has that covered, too. Video after the break.
Thank you for the (youtube link) bit, much appreciated here.
You can probably disconnect the 12/18v power supply easily by removing the inductor that injects it. It will be very unhandy to have DC on your antenna…
Yeah but then that ruins it’s main purpose, and these things aren’t cheap. Better to just take care when you’re messing about with amateur TV.
Or better yet, just use an off the shelf device called a “Dc block” which is cheap and readily available . If you don’t want to buy one or can’t wait, it’s just a capacitor. So, you could easily make your own, but buying one pre-made is probably just as about as cheap..
Or mod the device to add a switch for the DC injection, or find out if it’s configurable in software somewhere. LNBs often use a 13v/18v voltage to choose polarization, so the device can almost certainly switch the voltage, it may also have an “off” setting.
Use 75 ohm DC blocker my Friend 73 from va3fk !
it is safe with an omnidirectional antenna like one on the video , but if u use an external antenna u must add add a capacitor to prevent DC shortcut
Out of interest on the frequency, is it a multiple of 10 or an addition of 10000? As the frequency given is 11254 MHz (which would be an addition of 10000, but the article says “the channel frequency entered as a multiple of ten higher” which would be 12540 MHz. Only wondering because I definitely intend to try this myself!
Your frequency plus 10000 of the 10000 love is selected
Article is incorrect, the “channel frequency entered as a multiple of 10 higher”. He means, enter the channel frequency by adding it to the (fictional) 10 GHz LO frequency (10,000 MHz). Does that makes sense?
Yes, absolutely. Many thanks
Neat system and price. Wondering how works with 2.4 and 5.8GHz cameras and the scanning capabilities. Looks like will work with FTA also. Is there a list of the decoders and capabilities for this unit somewhere?
About all I can find is the software (not finding open source) and sales specs :
http://www.freesat.cn/forum/viewtopic.php?t=1746
Features:
1.V8 Sat Finder 3.5 inch LCD Colour Screen, Lithium-ion 3000mA Battery, Normal work up to 4 hours
2.System capabilities: Full HD DVB-S/S2 Compliant, Fully DVB compliant,6000 channels TV and Radio programmable, it has Live FTA Digital Picture and Sound
3.Video Decode: AC-3,MPEG-4 MP HL;H.264 BP MP&HP L4.1;AVS profile L6.1/4.0/2.0
PAL/NTSC: Automatic PAL/NTSC conversion
4.Channels Number: 6000 channels TV and Radio programmable
5.Favorites: 8 different favorite groups selection
6.OSD Color: 16-bit OSD with anti-flickering
OSD Language: English\German\French\Portuguese\Spanish\Italian\Russian\Turkish\Polish\Arabic \Farsi\Espanol\Deutsch
7.Channel Search: Channel search in automatic, manual and network search
8.Channel Edit: Various channel editing function(favorite,move,lock,skip,delete,rename,find,sort)
9.Easy Menu: Plug and Play installation, with an easy to use Menu System
10.Soft Upgrade: Software upgrade through USB
11.Save Channel: Automatic save for last channel
Parameters:
System Resource: Flash Memory: 64MB Serial Flash DDR3 Memory:1GB DDR3
Li-oN Battery: Battery 3000mA
Power Supply: DC12V/1500mA (Input 100V ～240V, 50/60Hz)
Panel display: 3.5 Inch LCD Screen
LNB/Tuner input
Connector:F type, male
Frequency range:950MHZ-2150MHZ
Input Impedance:75
Active Ant Power:13/18V DC 400mA MAX,Overload Protection
LNB switch control: 22KHz
DiSEqC: Ver 1.0/1.1/1.2
-Demodulator:
Front end: QPSK(S);QPSK,8PSK,16APSK,32APSK(S2)
Modulation range: 2Mbps~45Mbps
SCPC and MCPC Capable: Yes
Spectral inversion: Auto conversion
Panel display: LCD
Display Color: Colour Screen
Output Interface: LNB IN*1, DV OUT, AV OUT, AV IN, USB,Power supply
HD: HD(up to 1080P) output
Package Included:
1* Digital satellite meter
1* User’s manual
1* AV cable
1* Car charger cable
1* Adaptor
1* Carrying bag and strap
A LNB in a satellite dish has a mixer which downconverts the signal from the satellite which is probably in the frequency range of 10.7GHz to 12.75 using a selectable LO’s of say 9.75GHz or 10.6GHz (switched via a 22 kHz signal on the supply voltage) down to an IF somewhere in the frequency range 950MHz to 2150MHz.
e.g.
Input signal: 10.95 GHz – 12.15 GHz
LO in LNB: 10 GHz
Output IF from LNB: 950MHz 2150MHz
So the hardware as is will not be able to decode anything outside of 950MHz to 2150MHz.
So no support for 2.4GHz or the 5.8GHz bands
Even with additional downconverter hardware it can still only decode DVB-S/S2 signals.
This only works with DVB-S/S2 sources. The listing mentions security cameras but only that you can plug them into the monitor using the AV-in option. If you have a portable receiver for 2.4 and 5.8ghz cameras you could use that.
An F-to-BNC adapter which shorts the center pin to the shield would not be very useful.
I think he’s referring to the fancy ones that have a circuit to convert impedance, which might be a short at DC.
So, purchasing a commercial device and using it as designed and described in the manual, but posting a walkthrough video constitutes a hack?
Really: it says so right on the tin: Frequency range:950MHZ-2150MHZ, and the ‘tuber is feeding it a 1254 MHz signal, with a modulation mode it already supports.
Using a convenient fake offset frequency of (say) 10 GHz for a LO or LNB to avoid doing silly arithmetic in your head is SOP. Anybody who’s spent more than 5 minutes with a SDR already knows that — and that would be approximately 100% of the audience interested in this hardware.
Though it’s a handy tip if you’re not the datasheet-reading type or familiar with the general principles of radio.
You gave me the decompile’ation sensation. The .bin file just has a script.cfg file. Hhhmmm…
I dug a little deeper into the firmware and saw:
Board: mips CPU:
4KEcR1
R4000
unknown
U-Boot 2012.04-hg955-de40a599ac98-dirty (Feb 24 2016 – 18:32:17)
@Truth et.al., Good call, my mistake. I meant to say firmware. Definitely would need another downconverter… I wasn’t sure of the options prior to my second comment with the specs. Definitely is a limited system… though seems more cost effective and more versatile than the other similar cost FTA receivers. Plus, might not be a bad system to hack into a more versatile portable system.
If hardware decoding… then would have to tap the signal on the board somewhere to decode with another system right? Preferably compact. Not sure if an SDR would be the portable way or just a slip stream switch and circuit. Hardware processing seems the best route ideally… unless some form of tricky encoding that is easier with software… then again… seems like the cracking software can be embedded.
@DMYCO V8 Finder Owners, Please open up and show some detailed images of the board (s).
It would be a hack if you could install you own custom firmware. But I suspect that the DVB-S/DVB-S2 is actually carried out in hardware, so there would no real advantage to using your own firmware unless the decoder chip supported other standards like ISDB-S and/or DVB-S2X. It would have been nice if they popped the cover and showed a few images of the chips used in the DMYCO V8 Finder.
I thought about this a bit more and a mobile handheld device with a screen, 32-bit MIPS CPU (with built-in 8MiB SRAM and 2MB flash – I think, not positive, after doing a quick strings on the firmware), keypad, 3000mAh battery and a USB port with 64MB of serial flash and 1GB DDR3 memory and a speaker Is probably enough to run a tiny Linux distribution and maybe support a RTL-SDR dongle or possibly an Airspy HF+
Thinking about it even more, it is probably not worth the trouble, easier to hack an android phone.
This thing is really cool. It’s a handheld DVB-S2 receiver, with a screen and a battery for $60. That’s worth it alone just to dig out my old dish and see what weird signals I can still find on the ku-band feeds. Not to mention being able to potentially use it for DATV too. Since it has an AV-in plug, you could get video out from a Raspberry PI on it too.
While you’re musing, have a look at the Es’Hail 2 satellite’s amateur-radio payload:
https://amsat-uk.org/2017/09/13/cat17-videos/
If you happen to be under that thing’s footprint (EMEA), you’re definitely gonna want some satellite toys real soon!
Can someone help me please. I’m trying to locate my Directv satellite using GT Media v8, what can I do.
Hello. I purchased this unit to be able to check the signal strength and actually see the picture quality of a cable (CATV) signal. I cant seem to get this device configured to do so. How do you configure it for “simple” cable TV signals?