Not very successfull with SDR - Advice

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joe36
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Location: Cass co. in. 46994

Re: Not very successfull with SDR - Advice

Post by joe36 » Wed Jun 07, 2017 11:03 am

At 4 in the morning and spell check. I am surprised that it is not worse. So if you don’t know that your ding-dang dongle is dangling. It is far beyond this posters ability to correct the situation!

Joe KA9UCN

rtlsdrblog
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Re: Not very successfull with SDR - Advice

Post by rtlsdrblog » Thu Jun 08, 2017 6:06 am

Username wrote: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:
Disagree that an LNA is absolutely required. At HF you generally won't need an extra LNA, as the coax losses are low, and the noise figure is dominated by the atmosphere.

At higher UHF frequencies and especially at L-band, an LNA can help improve SNR by reducing the noise figure and overcoming coax loss.

But remember that an LNA can make things worse if you have lots of strong signals in your area. In that case you'd need a filter to go with your LNA.

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Thu Jun 08, 2017 9:13 am

I talk about +30mhz. Sorry its insane to use an Discone Antenna (wo have ~ 0dm gain) on a dongle without an LNA!
He use an cheap and crappy dongle not the fancy net "optimized one".

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Re: Not very successfull with SDR - Advice

Post by rtlsdrblog » Thu Jun 08, 2017 10:33 am

Username wrote:I talk about +30mhz. Sorry its insane to use an Discone Antenna (wo have ~ 0dm gain) on a dongle without an LNA!
He use an cheap and crappy dongle not the fancy net "optimized one".
You still don't absolutely need an LNA with a Discone. A Discone + cheap dongle by itself works perfectly fine. Again, the LNA would only really help if you have long coax runs, or need the lower noise figure for UHF/L-band etc.

In fact a Discone is the most likely antenna to have problems with an LNA, because it receives all frequencies decently, and so you'd be getting strong broadcast band stations together with your weak stations. So the LNA would overload on those, or the extra gain would cause the dongle to overload.

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Thu Jun 08, 2017 10:46 am

in my case i could only receive anything beside of Radio when I use an LNA.

darrenyorston
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Re: Not very successfull with SDR - Advice

Post by darrenyorston » Tue Jun 20, 2017 1:51 pm

joe36 wrote: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


To be honest I am not trying to listen to anything in particular, just something. At the moment the only thing I can pick up is local FM and AM commercial radio stations.

I have the offset to -125,000,000. I have set SDR# to my local airports tower frequencies of 118.7MHZ and 121.8 MHz. Nothing there.

Taking the Ham It Up out of the equation what should I be able to hear on the dongle alone? At this stage the only audio traffic I can hear is on the FM radio range (88.5 MHz to 107.3 MHz) and AM commercial channels.

Without the HAM It Up should I be able to pick up 27MHz and 466/477MHz? At the moment with the offset on or off (@125,000,000) and the Ham It Up on either upconvert or passthrough I dont hear anything.

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Tue Jun 20, 2017 9:22 pm

I have the offset to -125,000,000. I have set SDR# to my local airports tower frequencies of 118.7MHZ and 121.8 MHz. Nothing there.
OMG sorry are you stupid or ignore what I say?!
The Board will have a Filter who everything above +30Mhz (???) get Filtered out!!!! :evil:
Without the HAM It Up should I be able to pick up 27MHz and 466/477MHz?
No* / Yes**

* You need the Upconverter for 27Mhz!

** You also need an LNA without you cant hear anything because the Dongle is deb.
I dont hear anything.
When you not doing what I say you will not hear anything in the Future!!!!

Again do you want do what I tell you or do you want ignore me in the future?

darrenyorston
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Re: Not very successfull with SDR - Advice

Post by darrenyorston » Tue Jun 20, 2017 10:50 pm

Username wrote:
I have the offset to -125,000,000. I have set SDR# to my local airports tower frequencies of 118.7MHZ and 121.8 MHz. Nothing there.
OMG sorry are you stupid or ignore what I say?!
The Board will have a Filter who everything above +30Mhz (???) get Filtered out!!!! :evil:
Without the HAM It Up should I be able to pick up 27MHz and 466/477MHz?
No* / Yes**

* You need the Upconverter for 27Mhz!

** You also need an LNA without you cant hear anything because the Dongle is deb.
I dont hear anything.
When you not doing what I say you will not hear anything in the Future!!!!

Again do you want do what I tell you or do you want ignore me in the future?
Actually the problem is that I am unable to understand what you are saying. Your English is insufficient for communication, hence why I responded to another poster, one who was able to construct a cogent sentence.

Username
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Re: Not very successfull with SDR - Advice

Post by Username » Wed Jun 21, 2017 9:04 am

Sorry but English is my 3rd Language I speak. :roll:

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

Re: Not very successfull with SDR - Advice

Post by darrenyorston » Wed Jun 21, 2017 1:21 pm

Username wrote:Sorry but English is my 3rd Language I speak. :roll:
I understand that and appreciate your help. If I had an issue with it I would have articulated it differently.

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