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Messages - K5KNT

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Your best bet for a low cost SDR may be the AFEDRI SDR. The interface is supposedly the same as the RF Space SDRs, so it should work with SdrDx and CuteSDR, which are both native Mac OS X apps.  I do not have one, but Desmoface has one on the way to him, so I am sure he will report how it works for him.

Personally I think it is good to support SDR manufacturers and software authors that natively support the Mac, rather than relying only Windows apps under Parallels or vmware. That's the only way we'll get more SDR apps (and radio apps in general) for the Mac. Obviously I'm biased, since I write Mac software.  I do write Windows apps as well, so perhaps I am not completely biased :-)

I agree with supporting manufacturers, both hardware and software, that natively support the Mac. I only go to Windows when I can't find an app that is native OS X.  I am intrigued by the AFEDRI and will await any reports on this unit.

Speaking of OS X native apps... Is there any app that is similar to Spectravue or is this just another SDR app? I've seen it used in several of the videos Token has posted on youtube. I've downloaded the manual to see what is is and how it works, but if there is something else I'd like to know.

I'm using sdrsharp also right now. I have an iMac and I'm running windows 7 under Parallels8. I am hoping to find something that is OS X native.

I just ordered the ham-it up-converter. I have the NooElec R820T SDR & DVB-T dongle. Am I correct in assuming that I will still be limited by what software supports RTL dongles or does the up-converter solve that issue?

SDR - Software Defined Radio / Re: Unattended Recording
« on: March 29, 2013, 1853 UTC »
SdrDx does support recording I/Q files, and is native for the Mac.

I don't think it does scheduled recording, but I just leave it running overnight and on the weekends.

How large of file to you get by leaving it running overnight?  I don't think SdrDx will support my dongle. I'll download it anyway.  I guess I may have to wait until I can get a different piece of hardware.

SDR - Software Defined Radio / Re: Unattended Recording
« on: March 29, 2013, 1847 UTC »
Being able to do scheduled recording is a function of the software that you are using with the SDR hardware.  I do not think SDR# supports this function.  I do not know of anything Mac native that does.  The software that I know of that does support scheduled recording would be SpectraVue, HDSDR, SDRDX, and SDR-Radio Console.  Possibly HDSDR and SDR-Radio will support your RTL SDR, so you might give them a try (I have heard they do, but never confirmed it for myself).


Thanks. I was able to get HDSDR to recognize my RTL SDR, but I could not get any audio, even from a local FM station. SDR# seems to work fine running with Windows 7 in Parallels.

EDIT TO ADD: I also didn't like that the waterfall in HDSDR "flowed" from bottom to top. I couldn't find a way to change that.

SDR - Software Defined Radio / Unattended Recording
« on: March 29, 2013, 1320 UTC »
I currently have the NooElec R820T USB dongle and I am awaiting delivery of the Ham it Up converter. I'm running SDR# on my mid-2011 iMac using Parallels.  I'm still in the early stages of learning the software, but I was wondering if there is any way to set up unattended recording.  I would like to be able to record while I am at work or asleep, but don't want to leave the recorder running all that time.

I guess what I would like to do is schedule the recording to start and stop at a certain time.  Does anyone do this? If so, is it specific to a particular piece of SDR software or is there a script or something that will do this?



I am beginning how limited the dongle sdr that I have is. So, now the next question would be what does the group here recommend regarding hardware and software for beginners with a fairly limited budget?  I have a mid-2011 27" iMac with 12GB RAM.  I would prefer something that is OSX native, but could also run a Windows XP or 7 virtual machine.

I'm still experimenting with my dongle and SDR# at the moment, but it is hard to tell what problems I come across is hardware or software related.



SDR - Software Defined Radio / SDR# Waterfall
« on: March 15, 2013, 0305 UTC »
I decided to try SDR# running on Windows 7 in a VM on my iMac.  It seems to be working OK, but the background on the waterfall is yellow. It looks like yellow is a mid-value according to the scale on the right. It goes down to black, but it doesn't show up in the screen shot.  The color change in the background resulted when I switched to full screen mode.  Any idea what would cause this?

General Radio Discussion / Re: Waterfall Display
« on: March 14, 2013, 1506 UTC »
skeezix and Tokin, thank you again for more great information. Maybe this could be put on the wiki?

General Radio Discussion / Re: Waterfall Display
« on: March 13, 2013, 1321 UTC »
Thanks. Things are beginning to make some sense now. Using the same image, would the line to the left of 6840 be a carrier signal?

General Radio Discussion / Re: Waterfall Display
« on: March 13, 2013, 1213 UTC »
skeezlx and Token: Thank you for the replies they were very helpful.
Token, I have answers to your questions and some more of my own interspaced below.

A waterfall display in what application?  Are we talking an audio based waterfall of the detected signal or are we talking something wider banded, such as on the IF of a traditional receiver or as is commonly found with many hobby SDRs?

I was thinking generally, but more specifically I am trying to get Gqrx running on my iMac and on an Eeepc with Ubuntu, so Gqrx for specifics.

Intensity or signal strength is often in the Z axis.

What exactly is the Z axis?

With relatively little exposure you can tell signal mode at a glance also.  AM signals can be easily differentiated form SSB.  USB and LSB can each be visually identified.  CW signals are clearly identifiable.  More complex signals, such as various digital modes, can often be visually identified to specifics of the signal, such as the shift of an FSK signal.  On much more complex signals, like radars, the modulation techniques used and basic performance capabilities can sometimes be quickly approximated by the visual representation.

This, I think, is getting to what I was really trying to ask. Exactly how does one tell the difference and are there images of them somewhere on the web?  With what little I've experimented, I haven't been able to tell the difference visually. For example I have seen some solid lines and when clicking on them and going though the various modes (AM, FM, USB, LSB) I will finally hear a tone, usually on either of the side bands but I couldn't tell the difference just by looking.

Since I am currently limited to one of the VHF/UHF USB dongles and the supplied antenna haven't been able to locate AM signals. I would like to see what some of the data signals look like. I know that some of the local hams are using APRS, so that shouldn't be too hard to find.

Waterfalls are a completely different way to deal with signals.  If you have never used one it is like opening your eyes for the first time (in my opinion) and if you have used one going to a situation without a waterfall is like losing a dimension or a sense.

I would agree and I'm looking forward to learning more and getting an opportunity to use them more.

Thanks again,


General Radio Discussion / Waterfall Display
« on: March 12, 2013, 2146 UTC »
I'm looking for resources on how to read/use a waterfall display. Google search hasn't been very helpful or I'm just not using the correct terms. Does anyone here have some advise or care to point me to some references? Preferably not too technical.


General Radio Discussion / Re: Question about Logging Receptions
« on: March 08, 2013, 1546 UTC »
Thanks for the replies. It looks like "low tech" is the preferred. I think I'll give that a try to start.

General Radio Discussion / Question about Logging Receptions
« on: March 07, 2013, 1425 UTC »
I'm curious as to what member here are using to log their receptions. Are you using logging software, spreadsheet or something else? If using a spreadsheet, what data do you track?

For Amateur Radio Operators:  Do you log your ham contacts separately from your monitoring receptions?



Hi kent,

if you do have a PC around give sdrsharp a try for your dongle its what most people seem to use you can get it at sdrsharp.com, also give the rtlsdr yahoo GRP a try its pretty active.


Hi Kelvin,

I have a iMac but I do have Windows XP and 7 running in VMs. I also just recovered a netbook currently running Ubuntu Linux.

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