• Effective immediately we will be deleting, without notice, any negative threads or posts that deal with the use of encryption and streaming of scanner audio.

    We've noticed a huge increase in rants and negative posts that revolve around agencies going to encryption due to the broadcasting of scanner audio on the internet. It's now worn out and continues to be the same recycled rants. These rants hijack the threads and derail the conversation. They no longer have a place anywhere on this forum other than in the designated threads in the Rants forum in the Tavern.

    If you violate these guidelines your post will be deleted without notice and an infraction will be issued. We are not against discussion of this issue. You just need to do it in the right place. For example:
    https://forums.radioreference.com/rants/224104-official-thread-live-audio-feeds-scanners-wait-encryption.html

HackRF One, GQRX & Discone.

DJT7787

Member
Joined
May 6, 2019
Messages
5
Hi All,

I’m new to SDR and radio in general, I have a Hack RF One running through GQRX on Mac. I have a Discone antenna installed in my attic which I connect directly to my HackRF one using RG58 cable. Does anyone have any tips on optimal set up in GQRX etc? I can pick up a few signals on the air band but not as many as I was expecting! I’m based in Cumbria, UK. Not a huge amount of air traffic overhead but thought I’d be able to get a lot better range than i’m currently getting with the Discone. The clearest signal I get is on 126.300 which I believe is Prestwick Airport.
 

morfis

Member
Joined
Jan 24, 2004
Messages
889
Radio waves travel in straight lines so you could easily be limited by terrain near you...For example if you are in Wasdale Head you'll struggle to get anything...on the other hand if you are on Walney or in Silloth you'd likely get a good mix of traffic.
Equally, the quality of your antenna system will make a big difference to what you might hear. A 'discone' is a reasonable compromise kind of antenna for wideband use on VHF and UHF but not so good for HF. Up high with good connections and good low loss coax is where you want it. Actual cable run kept as short as practical. RG58 is more suited to HF than V/UHF and definitely not the best choice for long cable runs at UHF.

There should be plenty of aircraft within range of you unless you are in a hole....you might only hear them and not the ATC side of things (depending whether you are in range of Great Dun Fell, Snaefell, Lowther Hill etc.
126.300 isn't Prestwick airport it's an area control frequency. Do you get two way communication on it?

Optimal set up of your software is dependent on what you are wanting to receive there is no general magical 'best'.
 

DJT7787

Member
Joined
May 6, 2019
Messages
5
Thanks for taking the time to reply appreciate it!
Since I wrote the post this morning, I have moved my Discone right into the top of the loft and it’s picking up a lot better, getting loads more signals now. I haven’t had time to have a proper listen but will do tonight. What type of cable would you recommend for longer runs, the one on the Discone is RG-58 about 5-6M but was thinking of extending it in the future so I can connect in downstairs. Do you think an in line amplifier would make much difference too? Something like the Moonraker MRP-2000?


Sent from my iPhone using Tapatalk
 

morfis

Member
Joined
Jan 24, 2004
Messages
889
Your best course of action would be to get the 'discone' outside and above your roof...up high in the clear (though bear in mind that there are some general restrictions regarding planning permissions....and maybe stricter ones if you are in the national park area....of course, many people ignore the planning rules and hope no-one ever notices).
Purists will tell you about losses in connections and impedence mismatches. I'm going to suggest that you don't need to worry too much about impedence mismatches in your situation. A 'discone' will not present as a 50ohm impedance across it's whole receive range so you don't need to worry about using 50ohm cable. RG6 satelite cable is cheap as chips and is far lower loss than RG58. It's 75ohms but who cares (you haven't mentioned using a transmitter on the same cable an antenna...I'd advise differently then).

I have no idea what the moonraker amplifier you refer to is (and my only experience of moonraker as a brand has been sight of abysmal quality antennas). IF you were going to add an amplifier then it needs to be at the mast head (antenna end) of the cable run and NOT at the receiver end. Wideband amplifiers amplify all the noise and unwanted signals not just the actual thing you want.....net result is more often worse rather than better unless you spend a lot of money on filters.
 

DJT7787

Member
Joined
May 6, 2019
Messages
5
Your best course of action would be to get the 'discone' outside and above your roof...up high in the clear (though bear in mind that there are some general restrictions regarding planning permissions....and maybe stricter ones if you are in the national park area....of course, many people ignore the planning rules and hope no-one ever notices).
Purists will tell you about losses in connections and impedence mismatches. I'm going to suggest that you don't need to worry too much about impedence mismatches in your situation. A 'discone' will not present as a 50ohm impedance across it's whole receive range so you don't need to worry about using 50ohm cable. RG6 satelite cable is cheap as chips and is far lower loss than RG58. It's 75ohms but who cares (you haven't mentioned using a transmitter on the same cable an antenna...I'd advise differently then).

I have no idea what the moonraker amplifier you refer to is (and my only experience of moonraker as a brand has been sight of abysmal quality antennas). IF you were going to add an amplifier then it needs to be at the mast head (antenna end) of the cable run and NOT at the receiver end. Wideband amplifiers amplify all the noise and unwanted signals not just the actual thing you want.....net result is more often worse rather than better unless you spend a lot of money on filters.
Thanks for that Morfis, as I said originally I’m just starting to get into this so I’m not intending on going out and spending thousands on gear just yet haha. I have no intention of Transmitting at this point, I’ll end up getting in trouble! I got the Discone right in the top of the loft and it’s working a lot better now, I’m picking all sorts up. I originally had it in the attic room which won’t have been doing anything for the signal. I’ll probably hold off on the amp for now. I am going to consider running the cable downstairs though so cheers for the advice.

I wonder if you can use GNU Radio to build in filters using the SDR rather than having actual hardware filters. Plenty to play about with.... hardly any gear & no idea! Haha!

Thanks again!


Sent from my iPhone using Tapatalk
 

spongella

Member
Premium Subscriber
Joined
Feb 21, 2014
Messages
496
Location
Western NJ
Nice to hear from you DJT7787. I've had a few HackRFOnes in the past connected to a discone mounted on the roof fed with RG/6 coax . They worked well as my location is 1/2 way between NYC and Philadelphia. Software used was SDR#, worked very nicely. RG/6 is commonly used for VHF/UHF reception and readily available so you might want to use that for longer coax runs.

General antenna rule is, higher is better, bigger is better, outside is better than inside. If you are interested in aircraft comms only then check out antennas for 108 - 136 MHz.

You may have noticed that air band signals are sporadic and short. Pilots have their own lingo too. Not sure about the UK but in the USA there are ATIS (Automated Terminal Information Stations) that continuously broadcast weather and local info for pilots, those are fun to locate and listen to. There are also VHF radiobeacons on the aircraft band.

GNURadio, yes, fooled with it a bit but could never master it. Mike Ossman has a number of tutorials on the HackRFOne and GNU radio.

Have fun with your HackRFOne and discone.
 
Last edited:

morfis

Member
Joined
Jan 24, 2004
Messages
889
Not sure about the UK but in the USA there are ATIS (Automated Terminal Information Stations) that continuously broadcast weather and local info for pilots, those are fun to locate and listen to. There are also VHF radiobeacons on the aircraft band.
ATIS is used all over the world - as for whether there are any within range of the OP...all depends where in Cumbria he is located. Carlisle is probably the only airfield busy enough to use ATIS in Cumbria...... and that's not exactly a busy airfield.

Creating filters is easy enough but you should always aim to get the best signal you can to start with. Put your effort and money into that rather than trying to fix problems further down the system....in the long run you'll spend less time and less money getting things right to start with.
 

DJT7787

Member
Joined
May 6, 2019
Messages
5
Nice to hear from you DJT7787. I've had a few HackRFOnes in the past connected to a discone mounted on the roof fed with RG/6 coax . They worked well as my location is 1/2 way between NYC and Philadelphia. Software used was SDR#, worked very nicely. RG/6 is commonly used for VHF/UHF reception and readily available so you might want to use that for longer coax runs.

General antenna rule is, higher is better, bigger is better, outside is better than inside. If you are interested in aircraft comms only then check out antennas for 108 - 136 MHz.

You may have noticed that air band signals are sporadic and short. Pilots have their own lingo too. Not sure about the UK but in the USA there are ATIS (Automated Terminal Information Stations) that continuously broadcast weather and local info for pilots, those are fun to locate and listen to. There are also VHF radiobeacons on the aircraft band.

GNURadio, yes, fooled with it a bit but could never master it. Mike Ossman has a number of tutorials on the HackRFOne and GNU radio.

Have fun with your HackRFOne and discone.
Thanks for reply Spongella! Yeah going to have a proper play around when I get more time! I am starting to get my head around the Pilot lingo!

I’ve watched a few of those Mike Ossmann videos they are quite good. I managed to build an FM Receiver following his instructions, haven’t done much more than that though! HackRF seems fairly versatile in terms of what you can do with it, imagine a lot of people are using them for different reasons though haha!


Sent from my iPhone using Tapatalk
 

DJT7787

Member
Joined
May 6, 2019
Messages
5
ATIS is used all over the world - as for whether there are any within range of the OP...all depends where in Cumbria he is located. Carlisle is probably the only airfield busy enough to use ATIS in Cumbria...... and that's not exactly a busy airfield.

Creating filters is easy enough but you should always aim to get the best signal you can to start with. Put your effort and money into that rather than trying to fix problems further down the system....in the long run you'll spend less time and less money getting things right to start with.
Morfis, yeah that’s a fair comment, I’m quite happy with the signal now in the loft, or at least I think it’s good anyway!! I live in Broughton Moor quite close to the coast and quite high up. Getting really good signals on Scottish control etc. Haven’t picked anything up from Carlisle airport yet but as you say it’s a fairly quiet airport!


Sent from my iPhone using Tapatalk
 

morfis

Member
Joined
Jan 24, 2004
Messages
889
Morfis, yeah that’s a fair comment, I’m quite happy with the signal now in the loft, or at Ought to be a reasonable amount of PMR stuff withing range of you there. Ground stuff from Carlisle unlikley though.
Not bad for maritime comms too.
 

spongella

Member
Premium Subscriber
Joined
Feb 21, 2014
Messages
496
Location
Western NJ
You might want to try receiving ADS-B, frequency is 1090 MHz. Free download of software can be found on the 'Net.
 
Top