RF "nobody can tell you with a straight face how this works". Thank you for risking your baby, this was fascinating.

you can replace those heatsinks with cheap glue-on aluminum ones after peeling the old ones off to see what those two chips are. the Marvell chip next to the ethernet magnetics transformer is likely an ethernet PHY. I'm curious what SoC(s) it's running; given the era, the smaller chip under a heatsink is giving me Marvell Kirkwood vibes.

Hi Derek, thanks for all the super interesting videos, you have inspired me to start experimenting with satellite reception, it would be interesting if you could do a series on some of the different satellites that have interesting downlinks available to receive, what they transmit and how to receive them, maybe starting with geostationary satellites

Unfortunately, these devices are blocked from accessing the internet. You will get Uplink and Downlink (data traffic) if you contract a plan with the VSAT operator, just having the Ka band signal does not guarantee access. When you contract an internet plan with the operator, they grant access through your modem's MAC and configuration software that the operator's technician loads onto this modem.

@dereksgc

2 ай бұрын

getting internet access is not the goal, mainly it's just about looking at how this technology works and if there is anything it could be repurposed for

2 ай бұрын

Let me know if you need root shell on this modems ;) You can even use internal tools to generate RF signal.... communication with TRIA / ODU is via simple ASK/OOK. You can read and write control data to manipulate output power etc....

I had to take apart some 5G prototype hardware (LTE picocell) for a job back around 2010, and it had anti-tamper features: A battery-backed up RAM with the encryption keys and subscriber information, and a thin wire, embedded into both halves of the plastic case, connected the two. It was like a spider's web. I was warned of this situation so was able to find and bypass wire before opening. :D

LOL since I've no idea how LNBs work every time I heard those clicks I thought that the LNB applied a strong magnetic field to change the magnetization of some piece of steel to also change the polarization, because it sounds very similar to the clicks that output transformers of fence chargers make when a high voltage capacitor (bank) is discharged into the primary using a thyristor. The original Surfbeam "1" (SM2000/SM2100) modems and their TRIAs had the two coax connectors but it seems the newer Surfbeam 2 (RM4100) works with the same early TRIAs just by putting a terminator on the RX F connector of the TRIA. I was looking at pictures and it seems that units that were upgraded by their "certified" techs have a terminator covered with a heatshrink cap but others have the RX F connector replaced by a male threaded terminator that resembles and allen screw and that looks more like factory work, maybe those are refurbished units. And of course there are some with the cheapest unbranded terminator that may be for indoors and not even have a sealing oring, those are probably amateur "upgrades" Then the later RT4000N TRIAs already came without the hole on the casting for the RX connector. Anyway if that's the case the TX connector was always a combined TX/RX/POWER and the RX was... to make a simple and/or cheaper modem?

Cool kool from England UK thanks

That "waveguide" with the ribs is actually a polarizer / depolarizer. It converts from circular polarization at the feedhorn to linear polarization going into the LNB/BUC. There's not really much to see to take it apart - they're deceptively simple (physically - I'm sure a lot of work went into the design / simulation of it to make sure it actually works at 30GHz), and the have alignment pins so the go back together easily. And yes, the older systems used 2 separate coax - one for Tx and one for Rx, so that's why there's another footprint for an F connector on the modem.

Will somebody PLEASE get this man a spudger!? Thanks for the great content, but seriously man, get a nice spudger set. It’s tough to see you almost cut yourself 😅

Super Video

You can get serial terminal via this pin headers and then use uboot to extract firmware of this modems. Super interesting platform to learn hardware hacking and e.g. repurposing this platform as SDR as you have access to ADC and DAC on rf front end. There is also access to JTAG but you need to bridge couple of resistors. Overall powerful hardware platform considering design date. There is no much difference between modems for civilians and modems for army :)

I would guess that the SOIC-8 packge next to the PA is just a run-of-the-mill P-FET that switches the power to the PA. Pins 1-3 and 4-8 are shorted together, and hat big heap of caps right next to it also points in that direction.

I think you might have an option to add another channel there for greater bandwidth. Super interesting though. Thanks for the great video!

RF voodoo magic in the LNB

You wouldn't need that many pins for programming, but it could be extra I/O used as debug/trace outputs. It seems more likely to me that J9 (on the other side of the FPGA) is the programming port, it is about the right number of pins for JTAG. Same with J22 for the SoC.

2 ай бұрын

To enable eJtag, you should modify modem's board so eJTAG connection will be exposed to J21 (TCK, TMS, eTDO, TDI, TRSTL) . To activate it Make jumper connection of R519 (ejtag-TDO) and Move R520 (JTAG) resistor to R419 so eJTAG-TRSTL will be enabled. After successful eJTAG connection you should see CN5020 processor.

Your content is awesome, like, I wish more people made more videos like this... and btw at 9:10 - maybe J-TAG, ----> aka. fun stuff lol (18:50 too)

2 ай бұрын

There is eJTAG connector for CNMIPS MCU and JTAG / interface for FPGA. You can access (or provide yours ) bytecode from the linux shell level.

34:32 rat race coupler used as balun.

you need to take a look into your lighting solutions for video recording. that circular led light looks bad on video on anything reflective.

it has an ALTERA FPGA

What is needed to get ANY data from Juno? What would be the minimum diameter of antenna and other equipment and any rational for them? I am thinking any radio signal from Jupiter is impossible to get, because Jupiter is such a radio noisy planet. Am I about right? But I want to prove me wrong, so could you provide minimum specs to get the data from Juno or other planetary probes, and any calculation that can justify it? Are those equipment within reach for say, $10,000 budget?

@dereksgc

18 күн бұрын

x.com/uhf_satcom/status/1429196861131329543

@sbkarajan

18 күн бұрын

@@dereksgc Thank you so much! But how does he know if the signal is from Juno, not from some radio station or roque antenna nearby? Does he have any video or paper that explains how he validated his data?

@dereksgc

18 күн бұрын

@@sbkarajan The signal frequency matches the Juno allocation, the signal Doppler shift matches the Doppler generated by the relative movement of the Earth and Jupiter plus Juno's own orbit, and most simply a visual confirmation as the dish antenna used for something like this is highly directional and Jupiter is quite a bright object, seen even in daylight if you use a telescope and know where to look (plus the az/el readings would match the current position of Jupiter)

@sbkarajan

18 күн бұрын

@@dereksgc I want to believe you. So, what's the signal frequency of Juno & the doppler shift that's expected? And where do you get those numbers? (references?)

@sbkarajan

17 күн бұрын

@@dereksgc For Juno, what would be the S/N ratio? -100 dB? -1,000 dB? -10,000 dB? Can it ever work in such situation?