Low resource SDR Software

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kkiddkkidd
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Low resource SDR Software

Post by kkiddkkidd » Fri Aug 18, 2017 9:40 am

Although not exactly AM hardware related....

Anybody know of a low resource SDR software that runs in Winders?

I am setting up an SDR to record the AM band during the eclipse and my secondary laptop is a dual core Atom Netbook. It runs SDRUNO and HDSDR fine but stutters when trying to record that wide of a swath of spectrum.

I would rather use the netbook for recording and my good Toughbook for logging, etc.

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mrmodulation
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Re: Low resource SDR Software

Post by mrmodulation » Sun Aug 20, 2017 5:06 am

Hi Kevin, I have been playing with SDR radios for over 15 years. I am currently using a RTL SDR that looks like this:
http://www.cnx-software.com/wp-content ... R_USB.jpg

It tunes 100khz - 1.7ghz and runs fine on an old 2.4 ghz p4 machine with 1gb ddr ram and XP.

I have tried most freeware SDR software and I have found HDSDR to be the most stable and least system demanding. The user interface is amazing:
http://www.hdsdr.de/

If you need to know more this is the site to visit
http://www.rtl-sdr.com/

If you are getting audio breakup I would suggest you run the laptop as the receiver and record the audio via the soundcard output into a mp3 player, I use my iriver E100 via the line in port and the sound is excellent.

Clinton
VK2FTDX

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kkiddkkidd
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Re: Low resource SDR Software

Post by kkiddkkidd » Sun Aug 20, 2017 6:46 am

Clinton,

I am using HDSDR already. And it does appear to be the lightest of the popular packages. I actually like the software (SDRUno) that SDRPlay gives away with the receiver but it's IQ record is buggy. SDRUno is an OEM version of Studio1.

I have a unit similar to what you have but also have a couple of the SDRPlay units that cover the entire range without physically switching upconverters or antenna's. It also has 3 antenna inputs that are switchable via the software. I use one here at the shop to monitor clients and local ham stuff while traveling. I usually have the other in my brief case to listen on the road if I get bored.

I am not recording audio but the raw IQ stream so that I can go back and examine various frequencies at various times during the eclipse. My quad core I7 office computer just loafs at less than 5% CPU while recording IQ but the little dual core Atom netbook is wheezing pretty hard before I start the record and it starts skipping badly during IQ record. My I5 Toughbook laptop handles it fine but I was wanting to use the larger Toughbook for SEQP logging rather than squinting at the little netbook.

There appear to be some 'nix apps that will record from a command line but I don't have the time nor inclination to dive into them right now.

mrmodulation wrote:
Sun Aug 20, 2017 5:06 am
Hi Kevin, I have been playing with SDR radios for over 15 years. I am currently using a RTL SDR that looks like this:
http://www.cnx-software.com/wp-content ... R_USB.jpg

It tunes 100khz - 1.7ghz and runs fine on an old 2.4 ghz p4 machine with 1gb ddr ram and XP.

I have tried most freeware SDR software and I have found HDSDR to be the most stable and least system demanding. The user interface is amazing:
http://www.hdsdr.de/

If you need to know more this is the site to visit
http://www.rtl-sdr.com/

If you are getting audio breakup I would suggest you run the laptop as the receiver and record the audio via the soundcard output into a mp3 player, I use my iriver E100 via the line in port and the sound is excellent.

Clinton
VK2FTDX
--
Kevin C. Kidd CSRE/AMD
WD4RAT
AM Ground Systems Company
http://www.amgroundsystems.com
KK Broadcast Engineering
http://www.kkbc.com

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Re: Low resource SDR Software

Post by w9wi » Sun Aug 20, 2017 7:46 am

This is probably off the mark but... What are you recording to? Internal HDD?

I'm doing essentially the same thing, but using a fairly beefy desktop. (HP Z400) Using HDSDR since it has a decent scheduler and I cannot be home during the eclipse.

I wanted to record to an external 5TB USB HDD. Unfortunately, the box doesn't have any USB3 ports (the drive does) and USB2 isn't fast enough to make useful recordings. I'm going to have to record to the internal HDD.

I assume you're using the minimum (and default) 2MHz BW?

Is it possible there are other processes causing problems? My box is running Windows 10 -- while Cortana wasn't causing problems, it was using a surprising amount of system resources. (and it's amazingly difficult to kill) Windows Antimalware is pretty resource-heavy too. If your box isn't going to be on the Internet I'd consider disabling any antivirus for the duration of the recording.
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Re: Low resource SDR Software

Post by kkiddkkidd » Sun Aug 20, 2017 9:12 am

I am recording to the internal HD. I tried various USB mem sticks and USB HD's on my i5 laptop and as expected, USB2 isn't up to the speed requirements. A good USB3 drive worked part of the time and then would cause HDSDR to lockup after an hour or so.

I cleared enough space on my good laptop to store 4 hours at the time and am planning on moving the files over to an ext HD as they complete. Hopefully that won't make HDSDR puke. I think that I am going to record in either 15 or 30min segments.

My shop computer has over 1tb available on an internal drive so am recording directly to the HD there.

I am using a shielded NRSC loop at my portable location near Carthage and will orient it along the path of totality. The shielded loop is sort of deaf but hopefully the lower noise floor will be worthwhile. The USB and coax cables look like they are diseased with all of the lumps and bulges... I have toroids on both ends of most to choke down the common mode noise.

My shop receiver in Lawrenceburg is now connected to an OCF dipole and hears pretty good.





w9wi wrote:
Sun Aug 20, 2017 7:46 am
This is probably off the mark but... What are you recording to? Internal HDD?

I'm doing essentially the same thing, but using a fairly beefy desktop. (HP Z400) Using HDSDR since it has a decent scheduler and I cannot be home during the eclipse.

I wanted to record to an external 5TB USB HDD. Unfortunately, the box doesn't have any USB3 ports (the drive does) and USB2 isn't fast enough to make useful recordings. I'm going to have to record to the internal HDD.

I assume you're using the minimum (and default) 2MHz BW?

Is it possible there are other processes causing problems? My box is running Windows 10 -- while Cortana wasn't causing problems, it was using a surprising amount of system resources. (and it's amazingly difficult to kill) Windows Antimalware is pretty resource-heavy too. If your box isn't going to be on the Internet I'd consider disabling any antivirus for the duration of the recording.
--
Kevin C. Kidd CSRE/AMD
WD4RAT
AM Ground Systems Company
http://www.amgroundsystems.com
KK Broadcast Engineering
http://www.kkbc.com

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Re: Low resource SDR Software

Post by w9wi » Sun Aug 20, 2017 10:13 am

I've got a low 160m dipole connected to mine. (oriented east-west but at its elevation I'm not going to predict the directivity, if any!) The site is pretty quiet. Diddling around with it last night I was surprised how well it hears on *FM* -- stuff like Evansville and the Nashville Catholic LPFM 25 miles away. It's also interesting to listen to DTV pilot carriers -- there's one detectable in CW bandwidth on about 80% of UHF channels.

I've got it programmed to record 11am-3pm. I'll be able to RDP into it to make sure it's recording. (and kick it off manually if necessary)

Other than the notes about competing processes I don't have any good ideas.
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Pleasant View, TN EM66

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Bill DeFelice
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Re: Low resource SDR Software

Post by Bill DeFelice » Sun Aug 20, 2017 11:00 am

I'd personally like to find one that has software for both Windows and Mac platforms.
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Re: Low resource SDR Software

Post by w9wi » Sun Aug 20, 2017 12:33 pm

GQRX is supposed to work with either RSP unit & OS/X. I don't have a Mac available so haven't tried it.
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Re: Low resource SDR Software

Post by w9wi » Mon Aug 21, 2017 7:43 pm

Well. This is going to take awhile:)

There was a dramatic improvement in conditions as totality approached.

At 1645z (roughly 90 minutes before totality) most of the expanded-band was empty -- there's a weak signal from Huntsville 100 miles away on 1700, and a poor signal from the TDOT TIS stations on 1680 about 20 miles away.

At 1830z (a few minutes after totality) the expanded-band was full. Except for 1610 which has of course no full-power signals except CHHA. Most frequencies had easily readable signals.

I was somewhat surprised to hear good signals from points I thought were well outside the path of totality. Indianapolis, two Peoria stations, KCJJ in eastern Iowa. My recording also encompassed the 160-meter ham band, where a special eclipse event was in progress. Probably the biggest surprise was a conversation between WD5R in central Arkansas and VE3CSK near London in south-central Ontario.
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Re: Low resource SDR Software

Post by Deep Thought » Mon Aug 21, 2017 8:49 pm

Remember that skywave is dependent on conditions at geomagentic midpoint latitude, not necessarily the geographic midpoint. It would be interesting to see what the signal levels were.
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Re: Low resource SDR Software

Post by Bill DeFelice » Wed Aug 23, 2017 4:57 am

w9wi wrote:
Sun Aug 20, 2017 12:33 pm
GQRX is supposed to work with either RSP unit & OS/X. I don't have a Mac available so haven't tried it.
Looks like it works until I upgrade past MacOS 10.11. I just need to pick up a compatible SDR now.
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Re: Low resource SDR Software

Post by w9wi » Wed Aug 23, 2017 6:10 am

I have (I think) the same hardware as Kevin -- the SDRPlay RSP1. I'm happy with it. Good strong-signal handling; with a 260-foot center-fed antenna attached, not a hint of spurious reception in either the AM BCB or shortwave. (or FM although it's clearly not an FM antenna:) )
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Re: Low resource SDR Software

Post by kkiddkkidd » Wed Aug 23, 2017 8:25 am

Both of mine are SDRPlay RSP2. One is the plastic cased model and the other is the metal cased "Pro" model. I typically keep one of them here at the shop so that I can check clients and listen to our SkyWarn net when I am traveling.

I like them because they have 3 software selectable antenna inputs. All for $169...
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AM Ground Systems Company
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Re: Low resource SDR Software

Post by ernie » Wed Aug 23, 2017 11:59 am

mrmodulation wrote:
Sun Aug 20, 2017 5:06 am
Hi Kevin, I have been playing with SDR radios for over 15 years. I am currently using a RTL SDR that looks like this:
http://www.cnx-software.com/wp-content ... R_USB.jpg

It tunes 100khz - 1.7ghz and runs fine on an old 2.4 ghz p4 machine with 1gb ddr ram and XP.

I have tried most freeware SDR software and I have found HDSDR to be the most stable and least system demanding. The user interface is amazing:
http://www.hdsdr.de/

If you need to know more this is the site to visit
http://www.rtl-sdr.com/

If you are getting audio breakup I would suggest you run the laptop as the receiver and record the audio via the soundcard output into a mp3 player, I use my iriver E100 via the line in port and the sound is excellent.

Clinton
VK2FTDX
I own this same SDR and i'm finding the performance on AM/HF to be quite horrible, Is there any special configurations needed for this one?

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Re: Low resource SDR Software

Post by kkiddkkidd » Wed Aug 23, 2017 5:37 pm

They are definitely not super duper Flex or TenTec receivers but does everything that I need for remote monitoring and this sort of interesting projects. And they cost $169 bucks.

One of the best things that I did was add common mode chokes on the USB and coax cables at both ends. I had a box of #43 toroids of various sizes that were put to good use. The noise floor was much better with the digital junk choked down. Play with the LNA gain vs AGC in the driver app (I think) for best SNR.
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WD4RAT
AM Ground Systems Company
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KK Broadcast Engineering
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