Ok. Here's what's happening:
RTL.SDR HF RX Issues
- Thread starter mfn002
- Start date
- Status
Ok. Here's what's happening:
Token
Member
This type of RTL SDR has only one USB connection, there is not a separate USB for the upconverter. The unit has one mini USB at one end of the enclosure. If the SDR works at all then power is not an issue.
Although I have not used the model being discussed here, the pictures show no switch. Also, in this video ( 接收AM广æ’*—在线æ’*放—优酷网，视频高清在线观看 ) you can see the unit working and the "Shift" box in SDR# is not checked but the SDR is receiving HF. There is no upconverter offset and quite likely no upconverter. There are several ways this can be done by modifying the basic RTL hardware. My guess is that someone is marketing such a modified design. Unfortunately there is almost no information to be found online for this device.
T!
2 things. Where it says shift, that should be set to something like -100,000,000 or -125,000,000, and make sure its checked, also bring your range levels down a bit.
To get best audio for AM broadcast and most HF am broadcast set your bandwidth to 4000. 200,000 is best for fm broadcast radio, 5000 for fm/nfm, and somewhere around 3000 i think for USB/LSB.
Fizz306
Member
It appears that you're over-driving your RTL stick. Click on the gear icon and turn down the gain on the stick.
Two pictures attached show a proper level of gain and an over-driven signal. Note the difference in gain as indicated in the red circles.
Additionally, as IdleMonitor indicated, if there is an upconverter in the device, you're going to want to utilize the shift option.
Attachments
Token
Member
Check the video I posted, it is from a vendor selling this model and it clearly shows no shift box checked or an offset in place, and yet the SDR is still working, in the video, on HF. Combine that with the fact that there is no switch to select HF / VHF or to bypass the upconverter and I think it indicates this SDR does NOT require an offset or shift to display the correct frequency.
As for the range level, I agree it needs to be pulled down, but that is purely cosmetic, it would not prevent the SDR from showing activity.
T!
Last edited:
Token
Member
Don’t go by the level of the noise floor as an indication of the gain setting of the RTL, in SDR# the floor level cannot be calibrated and so, at least for all of my examples, the floor is always high, up around -70 to -50 is common. And even if it was overdriven, gain cranked up too high, there would be something shown on the waterfall, just like in your image of the waterfall with gain too high. Mfn002’s post shows no activity, as if the device is not getting or sampling any RF.
T!
Well, all adjusting the shift did was send it to the VHF air band, but it still says it's in HF territory.
Fizz306
Member
Depending on the AGC and manual gain settings, it would be possible in SDR# to raise the noisefloor above the strongest HF signals for a particular band, but I agree with you here. We would most likely see something, anything on the waterfall, no matter how faint.
Fizz306
Member
So shift isn't the fix here then. If you're dead on the HF bands then the hardware has issues. Either faulty hardware, or falsely advertised as being able to hear the HF bands.
This very well be a case of poor Chinese manufacturing, as well as "you get what you pay for." Again, I'd definitely check out NooElec (they have all of their stuff on Amazon as well), and pay the premium for stuff you know will just work right out of the box.
I think you're right about the hardware issues. I'll look into other manufacturers, but in the meantime I've ordered another one from a different seller.
Kinda slightly OT, but is there an easier way to scroll through frequencies on SDR#?
Kinda slightly OT, but is there an easier way to scroll through frequencies on SDR#?
Fizz306
Member
I'm not aware of any better way to scroll in SDR#.
In my opinion, there are much better alternatives out there for HF/SWL listening. In particular, either HDSDR, or my favorite, SDR-Radio V2. Good set of preset bandwidth ranges based on mode, decent onboard DSP, and intuitive layout for HF band scanning.
Once you get a working setup, you may want to consider these alternatives and play around with them!
In my opinion, there are much better alternatives out there for HF/SWL listening. In particular, either HDSDR, or my favorite, SDR-Radio V2. Good set of preset bandwidth ranges based on mode, decent onboard DSP, and intuitive layout for HF band scanning.
Once you get a working setup, you may want to consider these alternatives and play around with them!
Well, I got the new one today, and guess what? SAME ISSUE. Anyone have any suggestions for a low-cost SDR?
I know there is a bit of a learning curve with these. But what exacty are you trying to do? Get hf stuff? My screenshot I provided is how i have my settings and works just fine.
Have you turned the RG gain up at all to actually bring in your signal? The RTL-SDR controller? This is your configure button. I know even with updated installs everything gets reset.
Fizz306
Member
Buy a ham it up converter and put it inline with your antenna feed. This will work for you.
This is as low cost as you'll get without spending hundreds on a funcube dongle or a hackrf.
On the plus side you have two RTLSDR's. You can do plenty of fun stuff with this including trunk tracking and digital voice decoding if you are interested.
This is as low cost as you'll get without spending hundreds on a funcube dongle or a hackrf.
On the plus side you have two RTLSDR's. You can do plenty of fun stuff with this including trunk tracking and digital voice decoding if you are interested.
I know there is a bit of a learning curve with these. But what exacty are you trying to do? Get hf stuff? My screenshot I provided is how i have my settings and works just fine.
Have you turned the RG gain up at all to actually bring in your signal? The RTL-SDR controller? This is your configure button. I know even with updated installs everything gets reset.
Well, I've tried everything I can think of to get it to pick up HF, but no luck. I've played with offset, gain, etc. and nothing seems to work. I did notice, however, that unlike the previous one, the static will change tone when the antenna is removed. It seems that when I connected the HF antenna to the VHF/UHF connection, I started picking up interference, which I wasn't before.
Which one do u have now that you didnt have before?
Same one as before. I just bought it from a different seller. Anyway, I ordered the NooElec NESDR Mini 2 HF Bundle. I'll see what that does.
- Status
Similar threads
