Remote RSP via USB/CAT5

General discussions
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 5:35 pm

Thanks glovisol!
The more I consider the question of struggling to find a pure USB-based solution using some sort of "snake oil" collection of repeaters, extenders, etc to deliver what is essentially a continuous full-duplex data stream across 100 ft at >12mbps, I think I may find a more legitimate solution in an Ethernet-based environment, and look for compatible USB-Ethernet adapters that can push the RSP data across CAT5/6 cable.
So the search goes on...
- Steve
Last edited by k4km. on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

Cjay
Posts: 1
Joined: Wed Jan 13, 2016 8:41 pm

Re: Remote RSP via USB/CAT5

Postby Cjay » Wed Aug 22, 2018 8:49 pm

I did try this:
https://www.startech.com/uk/Cards-Adapters/USB-2/USB-Extenders/usb-over-cat5-cat6-extender~USB2004EXTV
From a technical perspective it works fine and does what you would expect (USB over Cat5 - dedicated cable point to point), however the RFI generated was quite spectacular and for me negated any benefits associated with putting the RSP nearer the antenna!
Chris
Last edited by Cjay on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason

OH2BUA
Posts: 73
Joined: Mon Aug 29, 2016 8:58 am

Re: Remote RSP via USB/CAT5

Postby OH2BUA » Thu Aug 23, 2018 7:31 am

Hi,

think the best link for separating antenna and listening site is the internet.

Sorry for my wiseguy comment, but seriously, after tampering with extenders, repeaters and all kind of kludges at my backyard in a city suburb, I moved all my radio gear 130 kilometers away. LTE router as a connection there at countryside. I'm very satisfied, especially due to really low RFI-levels.

To start one just needs get to know with a cowboy ;)

73, Jukka

Reason: No reason

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

Re: Remote RSP via USB/CAT5

Postby k4km. » Thu Aug 23, 2018 12:05 pm

This 150m CAT5/6 extender appears to have appropriate features/specs - USB 2.0 up to 480mbps claimed:
https://www.amazon.com/dp/B01FHTCH68/?c ... _lig_dp_it
- I may give it a try for my ~35m separation from the radio room out to the antenna base via underground conduit carrying the Ethernet cable and power conductors to power the RSP at the far end...
-Steve

Reason: No reason

glovisol
Posts: 231
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Fri Aug 24, 2018 4:16 pm

Remoting the USB connection of RSP devices is very intriguing poblem indeed. Here are some pointers.

1) I tested my RSPduo with SDRplay and three different hubs I had in the junkbox, one looking extravagantly like a purple octopus with 4 legs, and found that the RSPduo worked no problem with all of them. Therefore any buffered cable looking as a single connection hub should work, provided it complies with the full USB 2 spec.

2) RFI generated by CAT 5e or CAT6 Ethernet is a very controversial point on the Internet. Looking at the comments, some report no RFI at all, others very strong RFI. Some advocate use of shielded Ethernet cable, supplemented by an extra external shield. Some draw the attention to the placing of the shielding ground(s) warning this to be an essential point. Others suggest liberal use of noise suppression toroids. One even suggests laying down underground metal pipes where to run the ethernet cable, in order to eliminate the danger of a very long noise radiating antenna just under the receiving antenna. Plastic unshielded ethernet connectors do not seem to help as well...

3) The "perfect" solution, promised good for hundreds of meters, could be USB over fiber, but a quick check shows prohibitive cost.

glovisol

Reason: No reason

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

Re: Remote RSP via USB/CAT5

Postby k4km. » Sat Aug 25, 2018 11:44 am

It seems that I may end up spending about the same $$ for an active USB extender installation to support the remote RSP, vs just simply running LMR-400 coax cable into the shack from the base of the longwire antenna, and keeping the RSP near the PC.... indeed a much simpler/more reliable install, and I think I can live with the cable attenuation at my frequencies of interest.
- Steve

Reason: No reason

glovisol
Posts: 231
Joined: Thu May 10, 2018 6:42 pm
Location: Piedmont, Italy

Re: Remote RSP via USB/CAT5

Postby glovisol » Sat Aug 25, 2018 12:02 pm

Hi Steve,

The entire point in setting up the SDR near the antenna terminals with just a balun in between feeding the receiver's balanced input is that you do away with thorny coax grounding issues, while using a configuration which surely minimizes interfering noise pick-up. Having already tested the noise advantage of this configuration (I had placed the receiver and the PC next to the antenna terminals, see my post: viewtopic.php?f=5&t=3352) I was courious to see the outcome of your installation.

Never mind, I shall organise the test with a buffered USB cable in the near future & post the results.

Cheers,

glovisol

Reason: No reason

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

Re: Remote RSP via USB/CAT5

Postby k4km. » Sat Aug 25, 2018 12:41 pm

Well, I have not firmly decided with way to go yet - as I am now using a simple RG8 feedline into the shack, I am keen to try a LMR-400 feedline, and check that performance, then I may get around to (in good old science-experiment fashion) installing an active extended-USB setup for comparison purposes to see any improvement over the "baseline" LMR-400 preformance.
I'll keep you posted as things go along...
- Steve

Reason: No reason

Roger
Posts: 169
Joined: Fri Dec 29, 2017 7:59 pm

Re: Remote RSP via USB/CAT5

Postby Roger » Wed Aug 29, 2018 6:50 pm

Have you considered using direct bury RG-8X cable? It has fairly low loss at HF and is not as expensive as LMR-400. Burying it in the ground should help with noise issues. You can also install some RF Line isolators to get rid of noise on the outer coax shield.

https://abrind.com/coax-guide/shop/rg8x-240uf-95tc-braid-100-foil-coax-cable-assemblies-pl259-connectors/rg8x-240uf-n-male-jumpers-lightweight/

https://myantennas.com/wp/product-category/cmc-2/

Reason: No reason

fresnoboy
Posts: 1
Joined: Wed Aug 29, 2018 7:52 pm

Re: Remote RSP via USB/CAT5

Postby fresnoboy » Wed Aug 29, 2018 7:54 pm

Why not just use a small remote remote computer and run the USB over an IP network? I'm planning to do exactly that in an upcoming install using a NeoPI.

See this thread here: https://www.rtl-sdr.com/forum/viewtopic.php?f=1&t=3403

thx
mike
Last edited by fresnoboy on Thu Jan 01, 1970 12:00 am, edited 0 times in total.
Reason: No reason


Return to “General”

Who is online

Users browsing this forum: glovisol and 8 guests