Topics

Vhf airband

info
 

Anybody tested the hf+ dual vs the discovery on vhf airband ?
Are they both as sensitive etc ?

Any sensitivity measurements done ..?

Ie; 0.5uv for 10db sinad is what I need.

Thanks

Tom
 

I'd also like to know that question.
 
Or in other words: Which cheap SDR recceiver (up to about $300) is best suited for receiving ATC in the VHF Airband? Especially weak signals.

Thanks, Tom

Silverfox
 

Any sdr receiver will do that for far less than $300.  $25-$35 should suffice.  Put your money into a decent antenna.  I assume you know that you need a computer to support the SDR.

Alan

 

 

From: airspy@groups.io [mailto:airspy@groups.io] On Behalf Of Tom
Sent: Friday, November 29, 2019 1:51 PM
To: airspy@groups.io
Subject: Re: [airspy] Vhf airband

 

I'd also like to know that question.

 

Or in other words: Which cheap SDR recceiver (up to about $300) is best suited for receiving ATC in the VHF Airband? Especially weak signals.

Thanks, Tom

David Eckhardt
 

If you go with the cheapies, $25, for weak signals, you will need a preamp (+/< 15 dB gain and decent noise figure).  And that may overload the 8-bits of the cheapie USB sticks, especially if you live in a medium or large city.   

Dave - WØLEV


On Fri, Nov 29, 2019 at 11:32 PM Silverfox <alan.r.hill@...> wrote:

Any sdr receiver will do that for far less than $300.  $25-$35 should suffice.  Put your money into a decent antenna.  I assume you know that you need a computer to support the SDR.

Alan

 

 

From: airspy@groups.io [mailto:airspy@groups.io] On Behalf Of Tom
Sent: Friday, November 29, 2019 1:51 PM
To: airspy@groups.io
Subject: Re: [airspy] Vhf airband

 

I'd also like to know that question.

 

Or in other words: Which cheap SDR recceiver (up to about $300) is best suited for receiving ATC in the VHF Airband? Especially weak signals.

Thanks, Tom



--
Dave - WØLEV
Just Let Darwin Work
Just Think

jdow
 

He also left off an important criterion. The Funcube can give excellent performance on a single frequency or very small set of frequencies in the ATC band. Is about 2.1 MHz simultaneous coverage sufficient for his needs? Is 8 MHz (AirSpy R2) sufficient? If he needs more I am not sure 300% is sufficient. Although there is Lime to be considered. It requires some ability to find a box that it will fit in and then fit it to the box. For the full aircraft band including nearby CAP frequencies that has gone past "cheap".

{^_^}

On 20191129 15:44:36, David Eckhardt wrote:
If you go with the cheapies, $25, for weak signals, you will need a preamp (+/< 15 dB gain and decent noise figure).  And that may overload the 8-bits of the cheapie USB sticks, especially if you live in a medium or large city.
Dave - WØLEV
On Fri, Nov 29, 2019 at 11:32 PM Silverfox <alan.r.hill@... <mailto:alan.r.hill@...>> wrote:
Any sdr receiver will do that for far less than $300.$25-$35 should
suffice.Put your money into a decent antenna.I assume you know that you need
a computer to support the SDR.____
Alan____
__ __
__ __
*From:*airspy@groups.io <mailto:airspy@groups.io> [mailto:airspy@groups.io
<mailto:airspy@groups.io>] *On Behalf Of *Tom
*Sent:* Friday, November 29, 2019 1:51 PM
*To:* airspy@groups.io <mailto:airspy@groups.io>
*Subject:* Re: [airspy] Vhf airband____
__ __
I'd also like to know that question.____
____
Or in other words: Which cheap SDR recceiver (up to about $300) is best
suited for receiving ATC in the VHF Airband? Especially weak signals.
Thanks, Tom____
__
--
*Dave - WØLEV
*
*/Just Let Darwin Work/*
*/Just Think/*

David J Taylor
 

Or in other words: Which cheap SDR recceiver (up to about $300) is best suited for receiving ATC in the VHF Airband? Especially weak signals.

Thanks, Tom
===============================================

My choice would be the Airspy HF+ Discovery:

https://airspy.com/airspy-hf-discovery/

It has good weak-signal performance, and a ~600 kHz bandwidth which can be viewed at once. I guess you might also want scanning, for which there is an add-on to the free SDR# software.

You might even get it at the 30% off current discount!

Cheers,
David
--
SatSignal Software - Quality software for you
Web: http://www.satsignal.eu
Email: david-taylor@...
Twitter: @gm8arv

Tom
 

Thanks David

Since I already have a few RTL based dongles as a liveATC feeder, I know their advantages and disadvantages. That's why I try to make a qualitative step forward.
 
I also had the Airspy HF+ Discovery in my sights. You are now encouraging me in my idea. And the current discount of 30% sets the bar even lower... I order this one and see how it works in comparison to the RTL sticks.

Many thanks!
Tom

jdow
 

You still left out whether you want to cover an instantaneous bandwidth of the whole ATC subband or are willing to do it in steps as you look in depth for particular frequencies. Full coverage would be beyond an AirSpy R2. Partial coverage is in the range of however.

Depending on your location's noise level a good antenna (vertical beam on a rotator up about 40' or more) may produce better results than the lowest noise figure could ever deliver. That mentioned antenna would probably greatly surprise you on a good receiver. But it's not cheap. How, you can build a beam out of wire coat hangers very effectively - if you can find the real thing anymore. I worked 2 meters for a long time with such an antenna with fantastic coverage. A small set of long nested fence posts stuck deeply into the ground for stability could produce a nice 20-25' "tower". The rotator would have to be a small lightweight unit to make the mast safe if you don't guy it. It can be relatively cheap and give very good results.

The next step would be a very low noise high dynamic range preamp on the antenna. The gain should be maybe 6 dB to 10 dB greater than the coax loss. You can add attenuation if that creates dynamic range issues. The R2 is better than any cheap dongle in that regard.

Something to bear in mind is that the loss increase for a distance increase raises VERY rapidly as you hit the radio horizon. A 10 dB improvement in noise figure may buy you a 10% increase in range if even that. You can play with the calculator at "https://www.commscope.com/calculators/qegli.aspx" to see how this effect plays out. Local terrain will change the exact results. But it will show you how fast RF vanishes in the diffraction region.

This is all vague with little in the way of specifics. It is parameters so you can figure out what you want to do and how to do it best.

{^_^}

On 20191130 00:10:23, David J Taylor via Groups.Io wrote:
Or in other words: Which cheap SDR recceiver (up to about $300) is best suited for receiving ATC in the VHF Airband? Especially weak signals.
Thanks, Tom
===============================================
My choice would be the Airspy HF+ Discovery:
 https://airspy.com/airspy-hf-discovery/
It has good weak-signal performance, and a ~600 kHz bandwidth which can be viewed at once.  I guess you might also want scanning, for which there is an add-on to the free SDR# software.
You might even get it at the 30% off current discount!
Cheers,
David