Not very successfull with SDR - Advice

Main forum to discuss RTL-SDR related topics.
dlritter
Posts: 44
Joined: Mon Nov 23, 2015 1:08 am

Re: Not very successfull with SDR - Advice

Post by dlritter » Mon Jun 05, 2017 8:26 pm

lovely picture of a Ham-it-up 2 wanting a -125000000 entry in the SDR# offset line. Sharp's frequency entry is in HZ not Khz
good luck
73 N6DL

darrenyorston
Posts: 20
Joined: Thu Apr 20, 2017 6:17 am

Re: Not very successfull with SDR - Advice

Post by darrenyorston » Mon Jun 05, 2017 11:06 pm

dlritter wrote:lovely picture of a Ham-it-up 2 wanting a -125000000 entry in the SDR# offset line. Sharp's frequency entry is in HZ not Khz
good luck
73 N6DL
Tried that also. The attached screen shot is of SDR# set to the local international airports Approach/Departure frequency. I am listening to aircraft to tower approach/departure comms via a weblink but as you can see from the screen capture SDR# is showing no traffic on this frequency.

I emailed NooElec about an LNA. They said its not required.

Any advice as to what I am doing wrong?
Attachments
SDR.jpg
SDR.jpg (207.86 KiB) Viewed 6552 times

Username
Posts: 534
Joined: Sun Oct 09, 2016 7:27 am

Re: Not very successfull with SDR - Advice

Post by Username » Mon Jun 05, 2017 11:14 pm

Any advice as to what I am doing wrong?
again ok? :roll:
Remove the Upconverter and deselect Shift.
Calibrate your Dongle who I say before ok?

darrenyorston
Posts: 20
Joined: Thu Apr 20, 2017 6:17 am

Re: Not very successfull with SDR - Advice

Post by darrenyorston » Mon Jun 05, 2017 11:37 pm

Username wrote:
Any advice as to what I am doing wrong?
again ok? :roll:
Remove the Upconverter and deselect Shift.
Calibrate your Dongle who I say before ok?
Sorry that doesnt make much sense. Maybe its a translation issue.

Calibrate to what? What I am I correcting the frequency to?

If I remove the upconverter, reset SDR# to default, deselect shift and input a weather frequency there is nothing to adjust to.

Changing the Frequency correction (ppm) on the RTL-SDR Controller appears to have no impact. Whether it is 0 , 10 or anywhere between nothing seems to change.

This picture is of our Bureau of Meterologies weather frequency. As you can see SDR# is showing no traffic.
Attachments
weather.jpg
weather.jpg (175.79 KiB) Viewed 6550 times

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Tue Jun 06, 2017 8:54 am

Calibrate to what? What I am I correcting the frequency to?
an Weather Channel or any other Static Channel who get professional equitment.
You put the RF Gain to the right side and select Offset Tuning, RTL AGC ?

You cant see anything because the Antenna have no Gain and the Dongle also have no Gain. :D
Tune to the FM Radio Channels there you must receive something.

rtlsdrblog
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Re: Not very successfull with SDR - Advice

Post by rtlsdrblog » Tue Jun 06, 2017 12:33 pm

Wait, what exactly are you trying to do? Is it listen to VLF - HF?

In the first picture you've set the shift to -125,000,000 and you're tuned to 125,000,00. That's wrong.

In the second picture you've set the shift to 0, and you're tuned to 442 kHz. That's also wrong.

If you want to listen to 442 kHz what you need to do is set the shift to -125,000,000, and then tune to 442 kHz. Make sure that the upconverter is powered, and not set to pass through. Your Discone is not a good antenna for HF, it's rated down to 25 MHz. To receive 442 kHz you'll need a different antenna.

If you want to listen to 125 MHz, set the upconverter to pass through, remove the shift, and then tune to 125 MHz.

An LNA is not really needed for HF. You don't need it for a discone on VHF/UHF either really unless you have a long run of coax cable, or want improved sensitivity on UHF and L-Band.

Username
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Joined: Sun Oct 09, 2016 7:27 am

Re: Not very successfull with SDR - Advice

Post by Username » Tue Jun 06, 2017 12:38 pm

First i will start with VHF/ UHF.
sshhttt you are right he forgott 3x 000

dlritter
Posts: 44
Joined: Mon Nov 23, 2015 1:08 am

Re: Not very successfull with SDR - Advice

Post by dlritter » Tue Jun 06, 2017 7:43 pm

Remember that all frequency entries in SDR# are in HZ.. so 5mhz WWV is 5 000 000. AM 580 would be 580 000. With that -125000000 offset established. the machine will do the math for you.
NO, you don't have to enter an offset when you use the up-converter IF YOU want to do the math. so 5mhz WWV would be 130000000 on the dial.
On my Ham-it-up, the crystal osc module is loose and can pup up.. The HIU might be dysfunctional.. I have both the Spyverter and the Ham-it-Up (v2) along with the RTL-SDR V1, V2, V3, Airspy R1/R2 and RSP1
I like the Airspy/Spyverter for spectrum analysis, RTL for Linux tools, RSP1 for general use.
73 N6DL

joe36
Posts: 36
Joined: Wed Jul 20, 2016 11:09 pm
Location: Cass co. in. 46994

Re: Not very successfull with SDR - Advice

Post by joe36 » Wed Jun 07, 2017 9:07 am

The Ham-It-Up converter is designed to add the oscillator frequency of the converter. Depending on when the Ham-It-Up converter was made will determine the frequency that is adds. The old were +100 MHZ. The newest are 125 MHZ. This converter has internal filters that pass the frequencies of 0 to 70 MHZ. This means that if you want to listen to say 40 meter ham radio in the 7 MHZ range. You would set up SDR# with a 125 MHZ offset to subtract the 125 MHZ that was added by the converter. This allows you to input frequencies to SDR# as the frequencies you want. For 7 MHZ you would simply enter 7MHZ even though the frequency that is actually coming out of the converter is 132 MHZ (7 MHZ + 125 MHZ). As earlier explained. You could simply listen to the 7 MHZ signal without the offset but you would have to set SDR# to 132MHXZ. With the converter in line. You will be able to listen to from around 100 KHZ to 70 MHZ. Remember the converter adds 125 MHZ so the signals in the 100 KHZ to 70 MHZ are “re- transmitted” at 125.1MHZ on the low end to 195 MHZ on the high end.

The intent of the converter is to move the desired low frequencies to a higher frequency that the dangle can receive.

On your screen shot you have shift set for -125 MHZ. This would be correct for the newer models of converter.
For this set up. You would have the offset at -125 MHZ and directly enter a frequency from 100,000 cycles to up to 70,000,000,000 cycles. However there is no reason to go above 50MHZ as at the higher frequencies the dangle will work just fine without the up converter.

For frequencies of 50 MHZ and above. You would put the converter in the bypass mode, set SDR# offset to 0 and directly enter the desired frequency. 130 MHZ would be entered as 130,000,000.

Do you need an LNA? That is not as easily answered as it might seem. First get the set up right. Then determine if any strong local stations might not be so strong that they are causing desensitization or cross bleed. If so then an LNA only makes it worse. This is not the end but it is time to work with filters. A well balanced system with the proper filters when can most often help, but remember a LNA (low noise amplifier) is an amplifier. It will also amplify noise and further the chances of overloading the dangle. For this reason I would suggest holding off on installing the LNA until the basics are worked out.

Joe KA9UCN

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Wed Jun 07, 2017 9:15 am

the dingles are quite DEATH!
Without an LNA the are quite useless. You get Strom Radio/ TV Stations and maybe the local AFU Repeater and that it was. :roll:

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