I think it may be a phasing issue: four signals arriving at slightly different times. If you had four identical dishes and four identical feed lines, same coax, same length and the same connectors you might have a chance. I had one of these that I used on my camper van. They are popular with the RV community. Good luck!

I think you're going to have difficulty making it work by combining all the RF feeds together. That will require a ridiculous amount of precision in your cabling and connectors. Instead you'll need to take in each feed separately and combine them digitally, using software to adjust for differences in phase, etc.

As a New Mexican who is quite familiar with the Very Large Array I really dig your Very Small Array.

It's not going to be practical to make an array on a back yard budget. The first issue (of many) is that each of those dishes has an LNB with a LO (local oscillator) in it, none of which are synced to eachother in phase or frequency. You need external reference LNBs which all sync to one reference oscillator (which themselves are expensive and hard to find), then all your reference distribution cables need to be phase aligned with eachother as well. The next issue is all of your IF cables (bringing the signal out of the antennas) need to be phase aligned, or you need to have a variable delay on each of them electronically or digitally to be able to align them. That's the real secret sauce to getting any array or beamforming working is very precise and accurate phasing control of each antenna.

Somebody get this man in touch with someone who knows what's wrong with it in the current set up. Call Tom Scott; call Adam Savage; call Hank Green.

You know you’re a science nerd when that thumbnail makes makes you laugh uncontrollably AND you’ve been to the real thing…

Take this from someone who definitely knows nothing about any of this, but I'm going to go out on a very long limb and say that's a frequency misalignment running into the combiner. The dishes fluctuate between constructive and destructive interference, resulting in that waterfall.

Uncertain if those antennas are performing down conversion, but if they are then you'd need to lock all 4 oscillators to the same reference so they don't drift. You could look into getting some units called RF delay lines to line up the phases before combining. Another approach would be using 4 A/D converters to create four separate digital signals, timestamp each of them, and calibrate out the phase delay before combining them. This is more sensible to do in an FPGA because you can make adjustments in discrete, fixed steps, and then send the combined digital signals to a software demodulator.

LOL did you say "Sportsball"?! 😅

would be interesting to see what would happen with just two dishes combined together, and the distance between them gradually varied to see what effect it has on the waterfall plot

we do this on quad satcom terminals, its called maximal ratio combining, but not at the RF level. We would run all four dishes, then the digital signal from the modem are sent to a digital signal processing FPGA, which performs time and phase alignemnt between all branches, and then all paths get weighted by their SNR value, then they are combined.

Really cool experiment. Enjoy everything you do!

Your 'try anything on a budget' attitude is so, SO cool to me.

What you need is a coherent SDR such as a KrakenSDR, which has multiple SDR's synchronized with each other. You also need to make sure the coax is the same across all of them, and that they are the same distance from the reciever. Once you do this, you can combine all 4 inputs (a technique called interferometry) correcting the delays between each dish depending on the position of each receiver (requires measuring the position accurate to within less than a wavelength and using trigonometry when receiving at an angle since the signal reaches one side before the other)

we do this on quad satcom terminals, its called maximal ratio combining, but not at the RF level. We would run all four dishes, then the digital signal from the modem are sent to a digital signal processing FPGA, which performs time and phase alignemnt between all branches, and then all paths get weighted by their SNR value, then they are combined.

As a young rf sales engineer, representing the biggest in the rf game! This was sick!

Your main phasing issue will be that the local-oscillators in the LNBs are each running independently. Which means that the phase relationship among all your dishes will be changing rapidly over time. A mess.

Really enjoy your videos and love your "learning by doing" approach!

Just discovered your channel and it has quickly become one of my favorites.

Do you see any "LO" or 10 MHz port on the tailgater units? The oscillators aren't locked together so the independent clocks may be drifting creating those oscillations.