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Author Topic: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter  (Read 480 times)

K4BDA

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Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« on: November 07, 2020, 09:59:13 AM »

I'm new to SDR and have a NooElect R820T SDR & DVB-T and a NooElect Upconverter aka Ham It Up

I'm using SDRsharp software and I have it all working on HF and above.

I'm using a wire antenna that goes out the door by my desk and runs about 30 feet along the ceiling of our front porch.

On 75, 40, and 20 meters the noise floor is the same level as the ham radio signals. I can barely hear the stations because of the high noise or because of the low signal level.

1 - Any tips on how to get more of the radio signal into the radio?
2 - I'm wondering if the high noise level is coming from my computer... the SDR is plugged directly into the USB connector on the front of the PC. What do you think?
3 - Any tips welcome.
Thanks for the help.
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W1VT

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #1 on: November 07, 2020, 10:31:09 AM »

I find that if I move my HF antennas away from the house reception is improved significantly.  At a distance of 50 feet reception is pretty good, even on an 80M vertical.  Verticals aren't known for low nolse reception.  At a distance of 100 feet I've been able to work rare DX that own modest stations--100 watts to a vertical.

Zak W1VT
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VA3VF

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #2 on: November 07, 2020, 01:03:20 PM »

Did you try different gain settings?

How clean is you PC power supply?

The front end is wide. A bandpass filter may help.

While not directly related, the RTL-SDR is 8 bits only.
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K4BDA

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #3 on: November 07, 2020, 04:03:52 PM »

VA3VF, thanks for the reply.
Roger on the 8-bits & gain settings.
Regarding the baseband filter... how is that implemented? Internal to the unit or what?
Thanks,
K4BDA
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K6AER

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #4 on: November 07, 2020, 06:07:24 PM »

When you disconnect the antenna does the noise floor drop to zero, If so, you live in a high noise environment. The problem is not the receiver.

How close are other houses to you?
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VA3VF

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #5 on: November 07, 2020, 06:13:47 PM »

Quote
Regarding the baseband filter... how is that implemented? Internal to the unit or what?

That would be an external filter. It would help to know before hand what is causing the problem, if it's indeed caused by other signals.

If the problem is caused by high power MW stations nearby, this will help:

https://www.rtl-sdr.com/rtl-sdr-com-broadcast-block-high-pass-filter-now-sale/

If it's FM broadcasting, then this:

https://www.rtl-sdr.com/rtl-sdr-com-broadcast-fm-band-stop-filter-88-108-mhz-reject-now-for-sale

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G4AON

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #6 on: November 08, 2020, 12:13:12 AM »

These SDR receivers are very limited in performance. The max signal they can handle is barely in excess of S9, add the total lack of filtering and an inherently poor antenna (in terms of household noise pickup) and it comes as no surprise as to how poorly it performs.

I have a Nooelec SDR, mine is the type in the extruded aluminium case. To give you some idea of how poor they are at signal handling, on an indoor ground plane antenna mine produces phantom signals from a commercial VHF mobile radio base station on a hill 5 miles away, which will not be running over 25W ERP.

Other than being a low cost means to listen to your own transmission, or to listen to local FM radio stations, these type of receivers are of very limited use and do not come anywhere close to the performance of their more expensive SDR cousins, such as the Microtelecom Perseus, SDRplay RSPdx, etc.

73 Dave
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N6YFM

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #7 on: December 19, 2020, 11:15:30 PM »

Perhaps you get what you pay for in terms of performance?
I too have a NooElect SDR toy.  Also an RSP1.
But then, none of those work as well as my Icom 7300.
And the IC-7300 can't hear what my Flex Radio 6600 does.

And, by the way, a huge number of orbiting satellites use the same
hybrid SDR architecture as the Yaesu FT-DX101.

As you move up the price band, performance gets better.
Same with Cars, Cameras, Computers, Skiis and Golf Clubs.

Neal
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K9IUQ

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Re: Why Lousy Signal to Noise? I'm using a NooElect SDR & Upconveter
« Reply #8 on: December 20, 2020, 05:54:42 AM »

I'm new to SDR a
3 - Any tips welcome.
Thanks for the help.

Stop wasting time with the NooElect, they are pretty worthless. Nothing you do is going to make you happy. Yes I had one, and after 15 minutes with it I knew it was worthless.

Get something like a RSPdx, very good performance and the SDRUNO software that comes with them is vastly superior to SDR sharp or SDR console. Trust me, throw the Nooelect into your garbage can, otherwise be prepared for frustration.

Stan K9IUQ
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