Remote RSP via USB/CAT5

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k4km.
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Joined: Sat Aug 18, 2018 11:11 pm
Location: Alabama, USA

Remote RSP via USB/CAT5

Postby k4km. » Sun Aug 19, 2018 12:06 am

Firstly, allow me to introduce myself as a new RSP2 user, just still learning some of all the functionality this neat little box brings into my radio room.
I have searched thru the forum content but cannot find reports (good or bad) that clearly discuss what I am considering for a remote RSP installation: out at the base of a longwire antenna situated away from the main residence structure and all of its electrical noise.
I want to locate my antenna with its 9:1 match at an outbuilding some 80-90 ft distant from the "shack" and the desktop PC and other radio equipment therein. I would like to extend the RSP's USB connection to the PC with a passive CAT5 Ethernet connection (using full-speed USB 2.0 compliant adapters), and power the RSP on the remote end with a local USB 5vdc power injector. The RSP would of course be well-grounded in a weatherproof enclosure, and I would probably place ferrites on both of the short USB cables at each end of the long CAT5 cable run between the RSP and the shack, to help knock down common-mode noise riding back out to the RSP from the desktop PC (I understand that the Ethernet cable interface is transformer-isolated at each end).
Can anyone report on their experiences in this sort of RSP installation / connection via CAT5 cable?
Thanks - Steve
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Roger
Posts: 153
Joined: Fri Dec 29, 2017 7:59 pm

Re: Remote RSP via USB/CAT5

Postby Roger » Sun Aug 19, 2018 7:28 pm

Unfortunately full-speed USB2 compliant adapters will not work because they only run at 12 Mbps.. The RSP devices send data at very high data rates and this requires the USB 2.0 to operate in isochronous high-speed (480 Mbps) mode.

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k4km.
Posts: 8
Joined: Sat Aug 18, 2018 11:11 pm
Location: Alabama, USA

Re: Remote RSP via USB/CAT5

Postby k4km. » Mon Aug 20, 2018 3:25 am

Thanks Roger - I have found several USB-Ethernet adapters that claim among their features: "Hi-Speed USB 2.0 compliant, with support for data transfer rates up to 480 Mbps..." The trouble, I don't know how much faith to place in the words "up to" in that featured item...
- Steve
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glovisol
Posts: 172
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Mon Aug 20, 2018 8:20 am

You could use a buffered USB cable. Some cables boast full speed USB 2 and a max. length of 200 ft. An example here:

http://www.usbgear.com/USBG-230X/200ft- ... on-booster

I am also very interested in remoting the RSP receiver, as I found very good noise rejection by placing the RSP at the long wire antenna terminals, using a transformer type balun, as shown in my posts. Please publish your results, once done.

glovisol

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k4km.
Posts: 8
Joined: Sat Aug 18, 2018 11:11 pm
Location: Alabama, USA

Re: Remote RSP via USB/CAT5

Postby k4km. » Mon Aug 20, 2018 12:23 pm

Yes glovisol,
that is exactly what I want to do, to locate the RSP out at the antenna itself, away from the main house and its myriad electrical noise sources. Certainly, an active USB cable with power capability would be a cleaner solution than the Ethernet cable adapters and separate external dc power supply for the RSP power needs.
I will contact the USB cable seller to inquire re: full 480mbps capability in the "USB 2.0 Compliant" claim...
- Steve
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Roger
Posts: 153
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Re: Remote RSP via USB/CAT5

Postby Roger » Mon Aug 20, 2018 4:20 pm

It says in the marketing literature that this cable acts like a hub. SDRplay tech support has posted several times that the RSP needs to plug directly into a USB port in order to work properly. The RSP also works best with isochronous transfer as opposed to the bulk transfer USB mode. This cable might not support isochronous mode.

I would be very interested in reading how this works out for you.

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glovisol
Posts: 172
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Tue Aug 21, 2018 12:36 pm

In my opinion the most suitable USB Buffer Cable for the projected application should be this:

http://www.usbgear.com/USBG-EXT-2X/2-po ... sion-cable

Cables can also be stacked. Black Box also markets a 15 m extension cable (USB 3 model USB3ACE-15M) at the prohibitive cost of $ 326.35: not suitable...

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k4km.
Posts: 8
Joined: Sat Aug 18, 2018 11:11 pm
Location: Alabama, USA

Re: Remote RSP via USB/CAT5

Postby k4km. » Wed Aug 22, 2018 11:12 am

The RSP - PC connection must pass thru underground conduit between the house and the antenna, so I cannot stack several shorter sections with their "repeater" modules attached - rather must have one long cable.
The usbgear tech support people say that this cable
http://www.usbgear.com/USBG-100X/usb2-p ... ac-adapter
has been tested to run in isochronous mode with a mass storage controller at >25 MB/s, but they also say that the cable "tends to have an issue with cameras and webcams".
So I don't know how to resolve the question without actually purchasing the cable for a trial, and risking the costs involved for return if it doesn't work.
- Steve
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glovisol
Posts: 172
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Wed Aug 22, 2018 2:10 pm

Hi Steve,

Please look at the following post:

viewtopic.php?f=7&t=3428

Text is:
I was fortunate enough to find a 50ft USB cable that worked very well. It had the active transceiver in the middle and a ferrite bead on each end. Recently, I went back to the same e-bay vendor to get another one and they sent one with the active transceiver at one end and no ferrite beads. Consequently performance was horrible and I sent it back. If anyone finds a new source for a 50ft USB 2.0 cable that works well, please post about it.


I have now written to RSP2user & asked hm to give me info on the "good" cable. Shall let you know if I get a reply...

Cheers,

glovisol

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glovisol
Posts: 172
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Wed Aug 22, 2018 3:03 pm


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