Search found 76 matches

by NoelC
Thu Jan 12, 2017 11:45 pm
Forum: SDRuno
Topic: What is "Decimation"?
Replies: 10
Views: 3902

Re: What is "Decimation"?

Forgive me, but it's soaking in more slowly than I'd like. I'm fairly technical but have no background in radio and especially in the concepts of SDR. I have this feeling it will fall into place if I can get just a few more pieces of the puzzle in place... You're saying Decimation causes multiple su...
by NoelC
Thu Jan 12, 2017 7:35 pm
Forum: SDRuno
Topic: Initial Frequency On Startup Distorted
Replies: 7
Views: 1986

Re: Initial Frequency On Startup Distorted

Maybe it's an SDRuno thing, but when tuned to the center scale frequency and Zero IF is selected I don't see a notch so much as a ghost signal that distorts the reception. The sound for USB isn't bad, because the low frequencies are excluded, but AM stations just sound distorted. Examples: Center sc...
by NoelC
Thu Jan 12, 2017 2:35 am
Forum: SDRuno
Topic: What is "Decimation"?
Replies: 10
Views: 3902

Re: What is "Decimation"?

I've found some more online... It seems to be a way of reducing the sampling rate to "1 in N" samples, presumably to lower the load on the digital hardware. I'm not yet sure what practical advantages it has, though one person on the forum mentioned that it seemed to increase SNR under some...
by NoelC
Tue Jan 10, 2017 6:54 pm
Forum: General
Topic: RSP2 Upgraders - What Do You Find Better than RSP1?
Replies: 6
Views: 2118

RSP2 Upgraders - What Do You Find Better than RSP1?

I have only had my RSP1 for a short time, and frankly I don't find too many faults with it - I'm enjoying it immensely. But now that I am getting to know it, I'm starting to understand the limitations that led to the design of the RSP2. Whenever the IF Gain needs to be turned down I think to myself,...
by NoelC
Fri Jan 06, 2017 2:08 pm
Forum: SDRuno
Topic: Initial Frequency On Startup Distorted
Replies: 7
Views: 1986

Re: Initial Frequency On Startup Distorted

Thank you for the explanations, and for the "Low IF" vs. "Zero IF" workaround suggestion. Just poking around, I see that configuring "Low IF" also completely changes the choices for Sampling Rate and Decimation. Under what specific conditions does it limit the bandwidth...
by NoelC
Thu Jan 05, 2017 7:01 pm
Forum: New Users' experiences
Topic: Very good for the money and no problems at all here.
Replies: 3
Views: 1474

Re: Very good for the money and no problems at all here.

You wrote:

>No trouble with center spike, very little with images & birdies.

Just to be clear - you're okay with avoiding it, or you don't see a center spike at all?

I ask because I see a center spike all the time and have to avoid it to get a decent signal.

-Noel
by NoelC
Thu Jan 05, 2017 6:01 pm
Forum: SDRuno
Topic: Initial Frequency On Startup Distorted
Replies: 7
Views: 1986

Initial Frequency On Startup Distorted

I find there's always a fairly strong false line of "signal" showing center scale in the MAIN SP window. It exatly matches the "LO" frequency shown. I guess this is some kind of expected internal quirk or interference. Trouble is, this is precisely where SDRuno is tuned on a cold...
by NoelC
Thu Jan 05, 2017 4:59 pm
Forum: SDRuno
Topic: SDRUno RSP1 NB doesn't do much
Replies: 6
Views: 4977

Re: SDRUno RSP1 NB doesn't do much

Up until reading this thread I haven't found the NB feature useful at all, because I just didn't discover what kind of noise it would blank. Now that I see that it's for impulse noise, I tried it again and wow, it gives impressive results! Consider the night and day difference between the waterfalls...
by NoelC
Thu Jan 05, 2017 4:48 pm
Forum: SDRuno
Topic: What is "Decimation"?
Replies: 10
Views: 3902

What is "Decimation"?

Besides being yet another setting to fool with and find that it reduces bandwidth (and apparently increases SNR in some cases), what does the DEC (Decimation) setting actually do?

Please try to explain it in terms of someone who's not familiar with the design of the RSP1 hardware.

Thanks.

-Noel
by NoelC
Tue Jan 03, 2017 3:27 am
Forum: General
Topic: Shortwave Radio (aka HF 2000-30,000kHz)
Replies: 13
Views: 4867

Re: Shortwave Radio (aka HF 2000-30,000kHz)

My primary interest is digital. I love to search for and if possible, identify and decode digital signals. That's something that interests me as well, dsalomon, but I have to say, just getting started with it is daunting! Just the other night I managed to - finally - get a program, fldigi, to decod...

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