Making Antennas

@Axeman, isn’t the impedence of a simple half wave centre fed dipole closer to 75ohms (73.13 Ohms in free space) whereas a folded dipole is closer to 300ohms…A 1:1 balun would be all that is required.

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Thanks. I always get things like that mixed up if I’m not looking at lits.

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@fltech - Daniel,

Looks REAL good…! Perfect wind for that antenna. Let us know how it performs in your application.

73 de Marty, KN0CK

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Yay, thanks Marty!

Ok, I barely got more than white noise last night on RX1_W.

So today, I put a pigtail on RX1_L and can get a local radio station, but its about 50-70% fuzzy. Can’t really make out what they are saying. But I’m happy though I’m making progress.

Switching the antenna to LNAL helped a little. I don’t know what it means, I’ve just been changing variables.

I don’t know if it makes a difference, but I have the Lime plugged into the side of my laptop. I don’t currently have a female to male USB3 cable.

Also, as per one a forum post, I looked for the MN18 coil to remove it, but I don’t see it or couldn’t find it on this board. Its a v1.4s.

(While I’m asking, is this the best SDR viewer to but using?)

Any ideas?

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I was just doing a little reading on helical wound antennas and saw a rule of thumb that you use a half wavelength of wire to equal an electrical quarter wavelength after it’s wound.
I have some copper strap two inches wide and about a millimeter thick. I have a few thousand feet of this in various multi-hundred foot lengths. I want to build a wideband antenna for 160-10 meters out of this material. or maybe some two or three antennas. A cage monopole comes to mind. Any other ideas? I also have some very tall trees to work with. But I have power lines that cut right through my property.

For VHF - UHF ham band antennas, a great place to start is with Kent Britain’s Cheap Yagis. Look for the Cheap Yagis PDF.


@fltech - Daniel,

How about the gain settings in the LimeSDR? I see that you’re using Cubic SDR (GQRX would be a better choice) because there are gain settings for the LimeSDR that need to be adjusted to get the best signal gain. I recall using CubicSDR and not having a fun time adjusting anything gain-wise, but then again I was spoiled by SDRConsole and GQRX early on - - these days I’m using SDRAngel. I would highly recommend that you use GQRX or SDRConsole to receive things since it has a more intuitive interface and you can adjust gain settings easier. Then you can graduate to SDRAngel (it’s a little more tricky to set up, but it’s a wonderful app).

Let us know what you’re seeing for gain settings for Cubic and get back with us here.

73 de Marty, KN0CK

Has anyone experimented with Pothos and getting a lime to measure the VSWR of an antenna?
i.e. using the Lime to generate the noise on a Tx pin and measuring the response across a return-loss bridge?

There has been talk about using the “Ham It Up!” noise converter and an RTL dongle… so I assume it’s possible here using the lime to generate noise…

I take it you’ve also seen:

I hadn’t until now… Haven’t even had the board running a whole week yet. Was really hoping it’d be possible without a coupler - but hey, that’s life.

Super useful. Thanks @andrewback!

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Hey Guys,

After over a week, with some software setting changes, different driver and new line to the antenna, I can get pretty good reception with Gqrx. Thanks to people in this forum. Several of the points were not listed in documentation I could find.

So the next step is finding out what’s the best for trancieving. I’m particularly interested in using LimeSDR as a wide band combo spectrum analyzer and signal generator, for lab testing not related to communications. Though it would be cool to use Lime for developing more ham skills.

What apps are there for creating different waveforms? Sine, square, triangle, etc?

In looking through the forum, it looks like there was some debate about what was good for this, with some programs working then not working, over the course of some months.

I tried to get the Qspectrumanalyser running, but it didn’t want to work. It doesn’t recognize the Lime at all.

Thanks guys!

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@fltech - Daniel,

If QTSpectrumAnalyzer isn’t working and it does not see your Lime, then there’s a pretty good chance that this is because the driver you have installed won’t operate for that app. If you’re using Windows and If I miss my guess, I would think that QTSpectrumAnalyzer uses the Cypress driver that loads auto-magically from Microsoft because it’s the ‘Signed Driver’ for LimeSDR. It’s likely (I think) that if you had ZADIG running on your setup at all (for other apps) that the Cypress driver will be removed and the Win-driver from ZADIG will take its place. It’s an annoyance, but it’s the most likely cause why this is happening. If you have the Cypress driver and QTSpectrumAnalyzer is not working, then it may need the ZADIG Win-driver to make it work. Again, the annoyance with this is that you can’t have both at the same time - it’s an either/or situation with this.

Try some things and let us all know how you’re getting along, Daniel -

73 de Marty, KN0CK


I swapped out the different drivers with zadig, but the only combination that would work was the auto magic driver from windows with Gqrx.

Now however, none of them work. I’ve gone into device manager and deleted, uninstalled, reinstalled, rebooted, etc, and even the windows “updated” driver won’t work on anything. Its windows 7 btw.


Hey Marty (and fellow Limers),

System restore got Gqrx working again. Just trying to fix the driver wasn’t doing anything. I work in IT, and fix computers through the week, so I’m plenty used to driver fixing. Though there’s always more to learn.

I’m wondering if Windows 8 or 10 might work better with LimeSDR. Or maybe it’s just this computer.

I’m thinking I might double or triple boot this thing to find out. Thus having 7,8 and 10 on the same computer. I haven’t done that before with 10, but i’m guessing it might work.

Also, what are the transceiver apps to work with?

Are there any other recommended spectrum analyzers or waveform/signal generator programs?

Thanks guys.

@fltech -Daniel,

I’m using Windows 10 on my LattePanda to play with SDRAngel (which uses the ZADIG application to install the WinUSB driver) for full duplex receive and transmit for Amateur Radio. It’s a wonderful app and it runs incredibly well on receive and transmit. It does have some controls that need specific adjustment, but once you get it set up and understand the controls it’s a very powerful app for transceiver operations.

I’m not as familiar with spectrum analyzer apps for the Lime but I do know that they exist. I would think that running through the threads in the MyriadRF forum would yield that info for you.

Hope this helps - 73 de Marty, KN0CK

From my experience, an app that uses the GNU Radio APIs needs to be recognised by the soapy util…

i.e. SoapySDRUtil --find=“driver=lime”
(More info: )

Apps with native lime support through the limesuite driver (i.e. Console SDR) doesn’t seem to need soapy support. (I’ve also begun some testing with the limesuite driver as I’m really not thrilled with the usability of the limesuite utility…)

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Cool indes, I’m going to try this today. I’ve installed a bunch of SDR programs by now, and GNU ones are on there too.

Anyone know how to use a Lime as a frequency counter? I think this is what I need most, at least for the front of the process.

I’ve found mention online of people using an SDR as a frequency counter, that X or Y program could do it, but there was no explanation of how to do it.

I’d need something that can scan the whole range of MHz to lower GHz and show maybe the top 1-10 frequencies. Probably filtering by signal strength or proximity.

Is this possible with the right program or code?

Thanks guys!

Regarding antenna making…

Biconic dipole, cones IKEA original :smiley:
SWR less than 1:2 from 800 to 1500 MHz
Some more measurements =>
663 to 1865 MHz SWR is less than 2.5:1
Best SWR 1.37:1 at 1025 MHz