Hi there,
I'm using RTL-Dongles to drive my websdr online receiver.
At the moment 2 dongles in use, for 160~80M shortwave and 2M VHF.
The plan is to install 4 or more dongles over time to cover more Ham-radio bands.
Used hardware:
2x RTL-SDR v3 dongles
1x Upconverter 125 MHz (direct sampling is possible with patched rtl_tcp drivers but too much mixing products)
1x Dual-core 1.1GHz Intel Celeron running Debian
Have fun playing with it: http://heppen.be:8091
For other SDR online receivers: http://www.sdr.org
Greetings,
Bas - ON5HB
Web SDR with RTL-SDR dongles.
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- Site Admin
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Re: Web SDR with RTL-SDR dongles.
Very nice! Thanks for sharing, had a good time browsing.
Re: Web SDR with RTL-SDR dongles.
I ordered 2 more dongles to add even more bands.
I wonder how long it takes before my USB 2.0 bus will overload
The direct-sampling works way good, as it doesn't have PPM problems, it's right on the freq that is tuned, no floating around.
I tried with an 125 MHz up-converter, but there is no difference, in fact it has less mixing (ghost) signals then without.
I wonder how long it takes before my USB 2.0 bus will overload

The direct-sampling works way good, as it doesn't have PPM problems, it's right on the freq that is tuned, no floating around.
I tried with an 125 MHz up-converter, but there is no difference, in fact it has less mixing (ghost) signals then without.
Re: Web SDR with RTL-SDR dongles.
Problem solved!
I ordered attenuators and a NoElec Upconverter with TXCO.
The signal from my G5RV was overloading the dongles, so I added -10dB attenuator before the Upconverter.
Then after splitted the coax into 4 dongles, works great!
So I ordered another 2 dongles from you guys to add more bands.
These dongles are really good, direct sampling is nice and works but you can't regulate input gains, so they overload very quickly.
This is not a problem for people with a small antenna, but I'm using Ham Radio antenna's, they have a very high voltage level with big signals.
Heck if you touch the coax during static conditions (happens a lot) you will be shocked....as in electrocuted
Therefor the Upconverter is in place, it has protection and I can regulate the input-gain per dongle.
Current situation, see pictures.
The hub is powered and can handle 10 devices
Lesson learned, first attenuate the signals with -10dB, then upconvert....works well.
I ordered attenuators and a NoElec Upconverter with TXCO.
The signal from my G5RV was overloading the dongles, so I added -10dB attenuator before the Upconverter.
Then after splitted the coax into 4 dongles, works great!
So I ordered another 2 dongles from you guys to add more bands.
These dongles are really good, direct sampling is nice and works but you can't regulate input gains, so they overload very quickly.
This is not a problem for people with a small antenna, but I'm using Ham Radio antenna's, they have a very high voltage level with big signals.
Heck if you touch the coax during static conditions (happens a lot) you will be shocked....as in electrocuted

Therefor the Upconverter is in place, it has protection and I can regulate the input-gain per dongle.
Current situation, see pictures.
The hub is powered and can handle 10 devices

Lesson learned, first attenuate the signals with -10dB, then upconvert....works well.
-
- Site Admin
- Posts: 2432
- Joined: Mon Nov 19, 2012 11:54 pm
Re: Web SDR with RTL-SDR dongles.
Looks good! Yes attenuation, or filtering may be required for direct sampling mode if you have a very good antenna.
But I worry about your statement that the antenna constantly shocks you with static. It sounds like your antenna is not grounded properly/safely, or doesn't have any ESD or lightning protection built in? If you have a large outdoor antenna prone to static you should be taking care of that first.
The dongles and ham-it-up do both and ESD protection, but I think with constant shocks either one could eventually wear out and fail.
But I worry about your statement that the antenna constantly shocks you with static. It sounds like your antenna is not grounded properly/safely, or doesn't have any ESD or lightning protection built in? If you have a large outdoor antenna prone to static you should be taking care of that first.
The dongles and ham-it-up do both and ESD protection, but I think with constant shocks either one could eventually wear out and fail.
Re: Web SDR with RTL-SDR dongles.
Great pictures and setup 
Which distances can you run the USB at with a powered hub?
I have run into issues when trying to go above 5 meter from the computer (Using unpowered USB extender cables, which do state they have a length-limit)
Can you get 10 or 15 meters if using powered hubs? Any downsides of using such devices?
I know they sell optical USB cables, but they cost a fortune.
About the 'shocking' antenna connection, here in Denmark the standard TV wall-outlet-connection will also shock you if you touch it. Enough so you learn to avoid repeating touching it once you've been hit a few times
DO take care!

Which distances can you run the USB at with a powered hub?
I have run into issues when trying to go above 5 meter from the computer (Using unpowered USB extender cables, which do state they have a length-limit)
Can you get 10 or 15 meters if using powered hubs? Any downsides of using such devices?
I know they sell optical USB cables, but they cost a fortune.
About the 'shocking' antenna connection, here in Denmark the standard TV wall-outlet-connection will also shock you if you touch it. Enough so you learn to avoid repeating touching it once you've been hit a few times

DO take care!
Re: Web SDR with RTL-SDR dongles.
I use a cable of about 1.5m in length.
But I use Belkin cables, those are very good and very thick wires, never had problems with those.
And the hub is Logilink 10 ports 2.0 with 3.5A 5V powersupply.
There is no shocking anymore, probably because I replaced the motherboard, it stopped doing so after.
Everything is grounded here to HF and heating earth.
Or it could be because I added 2 extra dongles, it's running 6 dongles at the moment.
Maybe in a few weeks again few more until the hub is filled
But I use Belkin cables, those are very good and very thick wires, never had problems with those.
And the hub is Logilink 10 ports 2.0 with 3.5A 5V powersupply.
There is no shocking anymore, probably because I replaced the motherboard, it stopped doing so after.
Everything is grounded here to HF and heating earth.
Or it could be because I added 2 extra dongles, it's running 6 dongles at the moment.
Maybe in a few weeks again few more until the hub is filled

Re: Web SDR with RTL-SDR dongles.
Position?
Sadly here all my Ports are close so I cant access your SDR.
Sadly here all my Ports are close so I cant access your SDR.
Re: Web SDR with RTL-SDR dongles.
How did you get multiple dongles to get recognized in websdr? I need to use 3 dongles.
im currently using this line for one dongle:
device !rtlsdr 127.0.0.1:1234
while using rtl_tcp.
Is there a better way?
73
Nick N4BUT
im currently using this line for one dongle:
device !rtlsdr 127.0.0.1:1234
while using rtl_tcp.
Is there a better way?
73
Nick N4BUT