technical question about 3D2LNBR0-02

[PE2BZ]

Hi,
short introduction, I am Ben, radio amateur from the Netherlands ( Callsign PE2BZ ) and I like to find orbiting satellite signals and identify them with the use of strf tools.
strf tools

For now I have received signals up to 3400 MHz and the beacons from starlink in the KU band.

I am now trying to receive orbiting signals in the KA band, 18 GHz, for amazon / kuiper satellites.

I started with CoPilot about the LNB with model number 3d2LNBR0-02 and the usability to tune into 18 GHz with IF output to an SDR (HackRF and Adalm pluto available) which suggested that for this LNB I had to power it with 21 Volt DC and 22 kHz inserted to switch to the 18 GHz RHCP polarity.

Now, after ordering the LNB from the US of A and checking with copilot again it tells me I need some special command to send to the LNB to have it switch to that frequency which has to be sent from a directtv receiver which I don't have.

Is there any documentation which describes how I would manually be able to set the LNB to my preferred frequency range ?

Thanks for your time,

Ben

 

[Titanium]

13 years ago, i was experimenting with DirecTV SWM LNBFs and I had posted this on the forum:

Post in thread 'SL 3 LNB KA Band + FTA receiver in europe' SL 3 LNB KA Band + FTA receiver in europe
A lot of great information on KA hardware usage in the thread!

Been many years since my experiments, but i recall supplying 21Vdc and accessing the Ka portion of the bandstacked multisat LNBF with 22KHz tone ON.

Here is an example of a 22KHz tone insertion device: GME 22khz Tone Generator

The SWM Ka low band RHP signals are band stacked between 250-750 IF. I never snooped the high band.

 

[Tom Speer]

Hi Ben, this is Tom , N2HF. Unfortunately, Copilot misdirected you to a DirecTV Single Wire Multiplex LNB. The SWM system uses out of band signals from the receiver to the LNB to have the LNB place the IF output from a specific band and feedhorn onto one of 21 different frequencies on the coax. Each tuner on multiple receivers are assigned the SWM channel through negotiation. A number of us have tried for years o determine how that control signaling works, without success. There is no documentation.

DirecTV Legacy LNBs used voltage and Tone to switch the feed, and stacked The Ka and Ku bands onto different IF frequencies.

 

[PE2BZ]

Hi Ben, this is Tom , N2HF. Unfortunately, Copilot misdirected you to a DirecTV Single Wire Multiplex LNB. The SWM system uses out of band signals from the receiver to the LNB to have the LNB place the IF output from a specific band and feedhorn onto one of 21 different frequencies on the coax. Each tuner on multiple receivers are assigned the SWM channel through negotiation. A number of us have tried for years o determine how that control signaling works, without success. There is no documentation.

DirecTV Legacy LNBs used voltage and Tone to switch the feed, and stacked The Ka and Ku bands onto different IF frequencies.

Thanks Tom. I might need to find another way to access that frequency range now. My VU+Duo2 receiver appears to support Unicable protocol so is that worth a try ?

 

[Titanium]

The VU+ Duo supports Unicable (Band Stacking) for typical "one wire" LNBs , but the satellite tuner does not support the IF range of a SWM LNBF for the Ka B-band (250-750 MHz). Maybe the terrestrial input could be used as it covers the lower input frequency range. The lower IF range is not an issue for a SDR tuner.

A FTA STB typically supports only IF above 950 MHz. A B-band converter shifts the IF to a range that a FTA STB covers.

Example of a converter for bringing RHP LO into the range of your VU+Duo2 satellite tuner: https://www.amazon.com/ZINWELL-Directv-Converter-Non-SWM-Installs/dp/B00HWYBTIY

 

[Tom Speer]

Thanks Tom. I might need to find another way to access that frequency range now. My VU+Duo2 receiver appears to support Unicable protocol so is that worth a try ?

It is worth a try. But DirecTV tends to use proprietary standards for their systems. I am not familiar with Unicable, a European standard, but reading about it online indicates it operates very similar to what DirecTV does. If DirecTV uses DiseqC commands, I am unaware of it. The SWM system here has to provide LHCP and RHCP signals from the three bands Ku , KaHi and KaLo. See the Band Plan in our Directv Technical technical information. The DirecTV Ks band signals are modulated in such a way that ordinary Ka band receivers cannot even lock onto them, but I don't know i'f that is taken care of in the SWM LNB or the receiver. I have always thought that was handled in the DirecTV receiver.

 

[Tom Speer]

What Titanium is talking about requires a Legacy DirecTV LNB, not a SWM LNB.

 

[PE2BZ]

Thanks all for your replies.

Would there be anyone over here with access to the MXL865 datasheet ? I opened the LNB to see what's inside and there is an MXL865 inside which can move parts of the 5 IF inputs to / or combined in the IF output, the chip has uart and i2c bus too, but trying to register to get more as the 2 pages product sheet is declined because I am not using an business email address ?

 

[FTA4PA]

View attachment 184375

 

[Tom Speer]

I don't have access to that datasheet. It probably was a proprietary chip made for DirecTV, I suspect it is the heart of the SWM functionality, which under control of the DirecTV receiver, switches one transponder on a specific frequency, LHCP or RHCP on one of the three feedhorns to a specified SWM channel on the coax. The SWM channel 0 is tuned to Ku Band, 101W TPN 27 that provides the slow program guide to all receivers in low data rate PID/SCID streams in addition to the A/V streams there. Each of the other tuners in each receiver are assigned a SWM channel to use. SWM channel 0 is centered at 974 KHz. I am attaching a SWM frequency chart that I developed 15 years ago.

If a SWM LNB is powered up without being connected to a DirecTV receiver, and therefor receives no commands, it puts out a signal tuned to a transponder on the center (101 Ku) feed horn. It could be on TPN 30 which previously was the guide data channel. This signal can be used with a simple meter to align the dish (here in the US) with a process called "dithering" to get the much sharper Ka feeds from 99.2 and 102.8 W aligned.

 

[Titanium]

A few members on www.satellites.co.uk forum have done a lot of SWM hacking mods. Might be a good resource for your project.