From 99842e20689fec2d01f91633a3de67504e0855bf Mon Sep 17 00:00:00 2001 From: Michael Ossmann Date: Fri, 4 Dec 2015 17:05:28 -0700 Subject: [PATCH] additional USB cable tips --- Tips-and-Tricks.md | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/Tips-and-Tricks.md b/Tips-and-Tricks.md index 6ffeadb..42ba288 100644 --- a/Tips-and-Tricks.md +++ b/Tips-and-Tricks.md @@ -2,11 +2,13 @@ ## USB Cables (and why to use a noise reducing one) -The USB cable you choose can make a big difference in what you see when using your HackRF and especially when using it around the 480mhz area where the USB is doing all its work. +The USB cable you choose can make a big difference in what you see when using your HackRF and especially when using it around between 120 and 480 MHz where USB is doing all its work. -For this reason, when choosing a cable it is best to purchase one that has a ferrite core (or ferrite beads). These cables are usually advertised to be noise reducing and are recognizable from the plastic block towards one end. +1. Use a shielded USB cable. The best way to guarantee RF interference from USB is to use an unshielded cable. You can test that your cable is shielded by using a continuity tester to verify that the shield on one connector has continuity to the shield on the connector at the other end of the cable. -Trying anything larger than a 6ft cable may yield poor results. The longer the cable, the more loss you can expect and when making this post a 15ft cable was tried and the result was the HackRF would only power up half way. +2. Use a short USB cable. Trying anything larger than a 6ft cable may yield poor results. The longer the cable, the more loss you can expect and when making this post a 15ft cable was tried and the result was the HackRF would only power up half way. + +3. For best results, select a cable with a ferrite core. These cables are usually advertised to be noise reducing and are recognizable from the plastic block towards one end. Screenshot before and after changing to a noise reducing cable ([view full size image](http://i.imgur.com/e64LASK.jpg)): ![Before and after showing the change when moving to a noise reducing USB cable.](http://i.imgur.com/e64LASK.jpg)