[amsat-bb] funcube dongle

[Jim Sanford]

There is software available for the RaspberryPi which will let you 
extend USB as far as you can run Ethernet.  One USB port is free, more 
than that requires a license.

I have not tested it yet, but will use it to put a FCD connected to omni 
antennas on my tower as a monitor receiver.  The tower is 350' from the 
house.

73,
Jim
wb4gcs at amsat.org

On 2/11/2015 11:50 PM, Pavel Milanes Costa wrote:
> On the subject of using ethernet UTP CAT 5/6 cable for making USB 
> extenders...
>
> I have a kind if experience on that, you can reach about 15-20m runs 
> easily without losing connection to the usb dongle (even wifi dongles)
>
> If you want to go for sure, don't use more than 12m... from there on 
> is a challenge, I use on daily basis a run of 14m switching from 
> RTL-SDR and a WIFI dongle, as always your mileage may vary.
>
> The better way to cable the extender with UTP CAT 5/6 is this (my 
> experience):
>
> The UTP5/6 has 4 pairs of cable:
>
> - Use one pair (two wires) for the GND
> - Use one pair (two wires) for the +5V
> - Use one pair for the data transfer, one wire for D+ and the other 
> for D-
>
> If your dongle get disconnected or errant behavior use the free pair 
> to add one more wire to each GND and +5 volts lines. (more wires in 
> parallel = less resistance = less voltage drop)
>
> Put a little ferrite core (1 cm OD, 3mm H) at each end of the cable 
> (just a pass trough) plus a 10nF and 10uF at the far end from the 
> computer between the GND and +5V (10uF is electrolytic, watch out the 
> polarity)
>
> The ferrite will protect you a little from a nearby TX station (full 
> duplex?)
>
> With this setup I can run a wifi dongle at runs from 12, and some 
> times I put the RTL-SDR there too...
>
> Don't be tempted to put more uF on the far end 10uF is good, you can 
> kill your USB port by putting something in the order of 3300 uF or 
> more (Been there, done that, got my USB port killed)
>
> Don't use this extension cable on accessory USB ports, use only the 
> rear ports of your motherboard.
>
> You will lose some bandwidth, My RTL dongle runs easily 2.8 Mhz on the 
> PC and on the far end of the extension it only reach about 2.2 Mhz
>
> Things to note:
> - UTP cat 6 is better
> - Shielded UTP is even better, the shield must be connected only on 
> the PC side and not to the USB GND line, but to the PC chassis.
> - if not shielded cable, you may get a USB reset if you TX on HF with 
> high power, but 2m 50W don't seem to harm on my case (if you forgot 
> the ferrites you will be killed by 2m TX too)
>
> I hope this can help, 73 from CO7WT.
>
> El 11/02/15 a las 21:41, Stephan Greene escribió:
>> This approach would work well, I think for portable ops, too. Maybe 
>> without
>> extenders, just a long USB cable.  I think USB 2.0 is rated to 10-15 ft
>> without boosting the signal.
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