FlightAware Discussions

Strain relief for ADS-B USB Dongles

I have two FlightAware Pro Sticks hanging off of a HP desktop. Each has coax cable attached to the SMA connector. The cables seem to put a lot of strain on the dongle’s USB connector and I’m afraid they will break. What do you use to relieve the strain on the dongle? Before I go rigging up some Rube Goldberg device I thought I’d ask. Thanks.

I have my dongle connected via a 0.12m usb extension cable.

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Great idea. Thanks! I wonder how much the length of the extension cable matters. I have a 10 foot extension cable I might try for a while. If that causes things to go haywire I’ll order a shorter cord.

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10 foot seems to be working OK, but I bought a pair of 1.5 foot cords on Amazon. Thanks again for the idea. I don’t know why I didn’t think of that. :yum:

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Be aware not all USB cables are created equal.

Many here report no loss of performance when adding a USB cable, while several I have used, degrade performance ~50%.

If you fine a good one, it’ll solve a lot of problems, but please judge it with a critical eye.b

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The quality of the USB cable decide about the impact.

I do have two different extension cables here.
One is 50 cm (1 1/2 foot), the other one is 2 Meter (7 foot)

While the 2 meter cable does not impact the reception, the short one reduces the amount of aircraft/messages by 30%
And you cannot “see” any difference in the cables beside the color.

So size doesn’t matter alone in all cases :slight_smile:

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I’ve got both of my setups on good shielded 1m USB cable extenders.

Besides strain relief, I’ve no idea how much rubbish RPis put out, so like to keep the dongles a bit further away.

I use a Nooelec SDR dongle for amateur radio stuff with my main PC and use a USB extension cable, as without it, the main trace is full of random spikes all over the place - by moving the Nooelec a metre away, the trace becomes almost flat.

Given ADS-B is a small window around 1090Mhz and I’ve got it filtered, I’ve no idea if this actually helps in reality, but can’t hurt… hopefully :thinking: :grimacing:

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Filtering on this very small frequency band is never a bad idea in most cases. Ideally with an amplifier. That’s why the FA sticks are in general not a bad choice.

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How about shielding the receivers with aluminum foil?

Yeah, agreed :+1:

Would be interesting to see the trace on a high frequency oscilloscope and see what, if anything, effects it.

Guess it wouldn’t hurt :thinking:

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you are likely to cook the receiver due to the lack of cooling.

Receivers like the RTL-Blog V3 use an aluminium case, but also have a large heat pad coupling the PCB to the case.
https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/

For a short term test of course, it’d be fine to try.

I am wanting to put up a Coaxial Collinear Antenna at a higher elevation and am trying to put the SDR right on the antenna and using an “LDKCOK USB 2.0 Type A Male to A Female Active Repeater Extension Cable 60ft, High Speed 480 Mbps” as my line between the SDR and the Piaware computer. Does anyone think the 60-foot active repeater USB cable will give me a problem, or should i be OK?

Depends on the active extension you choose delivering clean 5.0 V to the SDR.
Really hard to know if it’ll work without having tested the specific extension you’re gonna use.
I’d say the product you mention will likely not work but it’s only a guess.

Basically you need a boost converter where you connect the SDR, that means it needs to compensate for the voltage loss over the long cable.
Sadly the cables available don’t offer much technical info / specifications so it’s almost impossible.

Really it’s impossible to tell if it will work, likely the voltage for the SDR won’t be a clean 5.0 V.
Some people have reported success with some cables but it really depends on the cable and pretty much the only way to know if it will work is to test the specific product.

Also … you really should open a separate thread, this has little to do with strain relief.

Why are you scared of using Coax cable and leave the electronics inside?
I am using a filtered LNB, for years now, with a 150; coax RG6 cable.