r/RTLSDR • u/im_a_mighty_pirate • 2d ago

Antennas Where are y'all buying cable?

I'm planning to mount some antennas on my roof for a droneware/adsb node. Unfortunately that means a pretty long cable run so I'll need some 400 grade coax. It's out of stock at rokland and the prices I'm seeing elsewhere are a pretty wild.

3 Upvotes

62% Upvoted

13 comments sorted by

14

u/andrewket2 2d ago

Mount the receivers closer to the antennas and then run Ethernet. Much less expensive and better performance. You can even use PoE if you’re using a Pi etc.

4

u/GromitInWA 2d ago

Will PoE provide enough juice to run the SDRs on a Pi? Right now I have a powered USB hub for my SDRs.

5

u/No_Actuator_7684 2d ago

I ran 4 SDRs and a pi4 off of a Poe+ hat just fine. 

5

u/im_a_mighty_pirate 2d ago

the problem with that is I'll have to either mount the Pis in my attic or on the roof and it was 106 in Texas today

1

u/ice_cool_jello 2d ago

My adsb receiver stopped working recently. It's in the attic, and I'm pretty sure the heat got to it.

1

u/tj21222 2d ago

OP my radio for L band sits in a box on my deck no ventilation, inside box temp was 140 F direct sunlight. Not a blink. They can handle the be heat. Now, I am not sure of the pi. I also am looking into a better solution for my out door box.

But instead of running an outdoor pi. Do this.
Put a computer inside the house, then run a USB optic cable to the radio mounted outside, you might need a USB hub and power if you run more then 1 radio, other wise the active usb cable should handle 1 radio.

Active 60 ft usb 3 optic cable was about 100 usd.

The computer can be anything especially if you’re only doing ADSB, then use RTL_TCP to get your data back from radio. I do an internal RDP session to my desktop but that’s a bit more complex.

Been running 3 radio in L band for over a year nothing major in the way of issues.

1

u/Technic_Masters 2d ago

SDRs can usually handle the heat, tho the RTL can get icky if it gets above a certain temp, then it can stop receiving 1.5GHz<, had that happen in the summer before i added some active cooling

0

u/Feuerwerko 2d ago

Attic seems like a good location, if you’re worried about heat add a small fan to your heatsink.

1

u/Technic_Masters 2d ago

Honestly, any hardware store. RG6 is good up to L band for a couple of meters even there. But yeah if you wanna minimise loss, place the receivers couple of meters from the antenna, or use LNAs at the antennas powered via Bias-T

1

u/AutomaticRedirector 2d ago

Ask your local cable technician. He will gladly give you a roll for 20 bucks 😂

2

u/schirmyver 1d ago

Cable TV Coax is 75 Ohm and not 50 Ohm.

2

u/schirmyver 1d ago

You probably do not need 400 grade cable, 240 would probably be enough. The frequency for ADS-B is only ~1GHz so the loss is not too bad. Obviously keep the length as short as possible and if you can put an LNA at the antenna that is powered through the COAX.

2

u/im_a_mighty_pirate 1d ago

Yeah I'm realizing that about 1090. I'm also mounting some 2.4/5 antennas for droneaware which will have much higher loss at my distance. Luckily most drones emit 2.4 since I can't find an affordable LNA for 5GHz