The air -to-air comms sounded like aerobatics display team practice, or formation flying training. Most likely a 'private' frequency allocated to that team or club so stay tuned and listen to the "chat" and it will become apparent where they're flying out of, call signs, what's for lunch, etc.
interesting comparison. repeating the test using a simple dipole cut for the band vs GA505 would be a better comparison. Noise floor is always lower on VHF with a horizontally polarised antenna as this reduces manmade hash. On ham bands horizontal to horizontal will usually out perform vertical polarisation for DX.
It would have been nice to see what the swr is, to test what frequencies it's resonant on. Would be helpful to test against a discone or dedicated airband antenna.
I did think about showing this, but it’s not meant for transmit and the swr is not changeable, well I guess you could cut down the elements but then again, I think the designers would of catered for that in the design. But I’m with you on your thinking, I much prefer resonant antennas. Thanks 🙏
No they are not, 137MHz is for space/satellite operations only. These were most likely private pilots since a lot of them don't even recognize the high speed VDL2 bursts. Military operations usually take place in the huge and distinct military air band, which starts above the DAB band in Europe and practically goes almost continuously from 225MHz(US) 240MHz(Europe) to nearly 400MHz (400-406MHz are weather balloons).
just as a point of reference when ever I test vhf air band antennas which i make under the name Broadsword antennas I use a atis/volmet as my reference point due to its consistency in transmission power, location etc. would have been interesting to see how the tested antenna compared to the 2m vertical which as its tri band im assuming its a 6/2/70cm antenna possibly a v2000 ? I compare my civ air twigs against a x510 which is also a 2m antenna
that effect you use to circle it made me very confused since it looks like a loading/buffering symbol, and since i live in australia im very familiar with that :P. i recommend using a solid circle and maybe use a colour other than white.
@@TechMindsOfficial i just thought the website was being broken for a good 5-10s but im all too familiar with the buffering because of how bad internet is here.
Thanks for the video. It is extremely misleading to use a stacked 2m ham antenna as a reference for a dedicated air band antenna, because the more it is stacked the more of a mismatch you will have on the air band, hence very low noise and weak but relatively clear air band signals, because the aircrafts signals are so very strong by design. It only makes sense to compare ground stations like ATIS, delivery, ground, tower, radar, flight information service and then switch between antennas, anything else is a waste of time because you will have line of sight most of the time, meaning a wet finger in the antenna socket will also work to some degree, while the ground stations are the challenge. Aircraft antennas for communication and ADS-B secondary radar transponders are vertically polarized, while some of VHF/UHF navigation antennas are horizontal. You can pick up aircraft signals (voice/ACARS/VDL2/ADS-B) from up to a little over 400km away, because then the curvature of the earth will cut the signal, even when the plane is way up at e.g. FL450 (45.000ft). As a general information for avid trackers, on shortwave via HFDL you can pick up aircrafts directly from literally all over the world! Look for High Frequency Data Link resources on the net and you will find plenty of HF frequency tables. But back to the GA-505 VHF antenna, is very surprising that the antenna does FM as well, because as a serious Air Band DXer any Broadcast signal is what you want to suppress as much as possible in order to use your receivers dynamic limitations wisely for air band exclusively. Also really strange is that they use a seemingly lossy cable on a passive antenna. On an active antenna loss doesn't matter, because the preamp defines the signal/noise and only a good coax shield is needed so that no noise from the shack is getting into the cable. Sometimes a few feet of thin RG-174 makes sense when rolling it along a ferrite material to reduce RF noise that travels along the outer shield of the cable. On the other hand as a serious FM-Broadcast DXer, you want a narrow beam with a good reflector and the ability to pick signals out of the massive amounts of high power stations all over place. This is a very weird choice to make the antenna pick up any FM BC signals at all. Anyway a comparison to a simple home made air band ground plane or ready made discone antenna would have been interesting, because the GP matches close to 50 Ohm in the center of this very wide band (127.5MHz + - 9.5MHz!) and offer a very good signal strength. This required wide bandwidth doesn't make any sense to play with a highly stacked home made antenna in the air band unless you want to use it for a specific frequency or a narrow part of the band. The fact that the antenna is symmetrical is good and I presume the black block inside contains a low loss balun, because that enhances the symmetricity while rejecting noise traveling along the coax, giving you the best possible signal to noise ratio from the local e-field.
Well, it's a Tri-Band antenna and the 2m part, which is the closest to airband in terms of frequency is a 6/8th wave. Not stacked, so not sure what you was looking at in the video. Secondly, it's the only reference antenna that I had, and believe me if I didn't compare this antenna to something else then there would of been a lot more people moaning in the comments section. Also, I believe quite a lot of Hams would use their Co-Linears for receiving airband, unless they are really into listening airband and have a dedicated antenna. So, I think it's not misleading at all, it's a real world example of what most people would use, in my opinion. Regarding comparing against a static station, that's exactly what I did in the video. Thanks for watching and thanks for your comment. :-)
@@TechMindsOfficial I think your 6/8 wave is secretly a 12/16 wave ... just kidding, so your 3/4 wave makes sense, because every uneven quarter wave the impedance is at a minimum, meaning there is not much transformation needed to get it to 50 Ohm. If it is a multiband antenna, it will contain 1/4 wave delay coils for 70cm, so that the 70cm part is stacked in phase, which is not much of a problem for the VHF characteristic. The trouble is that the 3/4 wave for 145 MHz ends up being 0.66 lambda for 128 MHz, which is near a 5/8th wave (0.625 lambda), which is just far enough away from the maximum mismatch, which is 0.5 lambda and close enough what is proven to be good if you use a proper match, which here you just don't have. In this constellation I agree that the air band capability could be worse, but isn't great either, may not be so bad unless you compare it to a discone, log periodic or a resonant dipole or groundplane that any enthusiast would use.
Your recent videos have had this odd high frequency distortion for a while now, but this one is much worse. Please find the source of this and filter it out, because it makes listening to your videos very uncomfortable. It's on your vocals only, and extends up to 10 kHz (!) according to my DAW's spectrum analyzer.
Hi Chris, I just put the audio from this video in to Audition and I think I can see what you mean within the spectral meter. In fact, it's chirps from Birds outside. They are quite noisy in the mornings when I do my voice overs. Think I will close the windows in future! Needs a very good ear to hear them so well done! Thanks
The law in the UK is that you are not allowed to listen to a transmission not intended for you. However, it's generally accepted that because civil and military airbands are in the clear the authorities would not prosecute. There are healthy numbers of listeners and there has not to my knowledge been any prosecutions of listeners to airband or indeed most everything else you can receive. Anything of any 'sensitivity' in the UK has been moved to Tetra.
@JohnSmith-wl8cv With all due respect, this is a video about an antenna, NOT a video about the legalities of listening to certain frequencies that literally ALL Hams and SWL'rs do. Thanks. Also, it would be like me commenting on a GUN review video saying GUNS are illegal..
As all internet, this channel has a worldwide audience. It simply impossible (without incurring in error) to make such a blanket statement that it is "totally illegal to listen to airband". There are places on this planet where this is is not illegal. Ask me how I know.
The air -to-air comms sounded like aerobatics display team practice, or formation flying training. Most likely a 'private' frequency allocated to that team or club so stay tuned and listen to the "chat" and it will become apparent where they're flying out of, call signs, what's for lunch, etc.
MIL aviation use other bands.
I have something similar that I made from 1/2 inch copper pipe... I have it mounted in the vertical dipole position and it works great...
interesting comparison. repeating the test using a simple dipole cut for the band vs GA505 would be a better comparison.
Noise floor is always lower on VHF with a horizontally polarised antenna as this reduces manmade hash. On ham bands horizontal to horizontal will usually out perform vertical polarisation for DX.
I'm dying to see inside the black box 😊😊
Nice work! Thank you
It would have been nice to see what the swr is, to test what frequencies it's resonant on. Would be helpful to test against a discone or dedicated airband antenna.
I did think about showing this, but it’s not meant for transmit and the swr is not changeable, well I guess you could cut down the elements but then again, I think the designers would of catered for that in the design. But I’m with you on your thinking, I much prefer resonant antennas. Thanks 🙏
137.200 and 220 are used by military air bands along with 143mhz usually dog fighting over the Pennines
No they are not, 137MHz is for space/satellite operations only.
These were most likely private pilots since a lot of them don't even recognize the high speed VDL2 bursts. Military operations usually take place in the huge and distinct military air band, which starts above the DAB band in Europe and practically goes almost continuously from 225MHz(US) 240MHz(Europe) to nearly 400MHz (400-406MHz are weather balloons).
we get them out of raf leeming
I did wonder if the transmission you heard regarding barrel rolls may have been civil aerobatic pilots practicing, most mil stuff uses UHF.
What computer program is this? How is it connected?
just as a point of reference when ever I test vhf air band antennas which i make under the name Broadsword antennas I use a atis/volmet as my reference point due to its consistency in transmission power, location etc. would have been interesting to see how the tested antenna compared to the 2m vertical which as its tri band im assuming its a 6/2/70cm antenna possibly a v2000 ? I compare my civ air twigs against a x510 which is also a 2m antenna
It is a Tri band, but it's 2/70/23cm :-)
Hi. You Can compare reception on air band on Atis frequencies
What software do you use for your SDR radio?
Hi it’s Paul from Kent what was the software you used not ACARS the other one can you send me the link and what frequency was it kindest regards paul
A lot of money for a dipole and probably a 1:1 balun.
that effect you use to circle it made me very confused since it looks like a loading/buffering symbol, and since i live in australia im very familiar with that :P. i recommend using a solid circle and maybe use a colour other than white.
I don’t remember adding a circle, are you sure it wasn’t buffering? 🤪
@@TechMindsOfficial i just thought the website was being broken for a good 5-10s but im all too familiar with the buffering because of how bad internet is here.
Try making a yagi from it, directivity and even more gain
Yes, they work well, thank you for sharing. John G4YDM
Nice!
Thanks for the video.
It is extremely misleading to use a stacked 2m ham antenna as a reference for a dedicated air band antenna, because the more it is stacked the more of a mismatch you will have on the air band, hence very low noise and weak but relatively clear air band signals, because the aircrafts signals are so very strong by design.
It only makes sense to compare ground stations like ATIS, delivery, ground, tower, radar, flight information service and then switch between antennas, anything else is a waste of time because you will have line of sight most of the time, meaning a wet finger in the antenna socket will also work to some degree, while the ground stations are the challenge.
Aircraft antennas for communication and ADS-B secondary radar transponders are vertically polarized, while some of VHF/UHF navigation antennas are horizontal.
You can pick up aircraft signals (voice/ACARS/VDL2/ADS-B) from up to a little over 400km away, because then the curvature of the earth will cut the signal, even when the plane is way up at e.g. FL450 (45.000ft).
As a general information for avid trackers, on shortwave via HFDL you can pick up aircrafts directly from literally all over the world!
Look for High Frequency Data Link resources on the net and you will find plenty of HF frequency tables.
But back to the GA-505 VHF antenna, is very surprising that the antenna does FM as well, because as a serious Air Band DXer any Broadcast signal is what you want to suppress as much as possible in order to use your receivers dynamic limitations wisely for air band exclusively. Also really strange is that they use a seemingly lossy cable on a passive antenna. On an active antenna loss doesn't matter, because the preamp defines the signal/noise and only a good coax shield is needed so that no noise from the shack is getting into the cable. Sometimes a few feet of thin RG-174 makes sense when rolling it along a ferrite material to reduce RF noise that travels along the outer shield of the cable.
On the other hand as a serious FM-Broadcast DXer, you want a narrow beam with a good reflector and the ability to pick signals out of the massive amounts of high power stations all over place.
This is a very weird choice to make the antenna pick up any FM BC signals at all.
Anyway a comparison to a simple home made air band ground plane or ready made discone antenna would have been interesting, because the GP matches close to 50 Ohm in the center of this very wide band (127.5MHz + - 9.5MHz!) and offer a very good signal strength. This required wide bandwidth doesn't make any sense to play with a highly stacked home made antenna in the air band unless you want to use it for a specific frequency or a narrow part of the band.
The fact that the antenna is symmetrical is good and I presume the black block inside contains a low loss balun, because that enhances the symmetricity while rejecting noise traveling along the coax, giving you the best possible signal to noise ratio from the local e-field.
Well, it's a Tri-Band antenna and the 2m part, which is the closest to airband in terms of frequency is a 6/8th wave. Not stacked, so not sure what you was looking at in the video. Secondly, it's the only reference antenna that I had, and believe me if I didn't compare this antenna to something else then there would of been a lot more people moaning in the comments section. Also, I believe quite a lot of Hams would use their Co-Linears for receiving airband, unless they are really into listening airband and have a dedicated antenna. So, I think it's not misleading at all, it's a real world example of what most people would use, in my opinion. Regarding comparing against a static station, that's exactly what I did in the video. Thanks for watching and thanks for your comment. :-)
@@TechMindsOfficial I think your 6/8 wave is secretly a 12/16 wave ... just kidding, so your 3/4 wave makes sense, because every uneven quarter wave the impedance is at a minimum, meaning there is not much transformation needed to get it to 50 Ohm. If it is a multiband antenna, it will contain 1/4 wave delay coils for 70cm, so that the 70cm part is stacked in phase, which is not much of a problem for the VHF characteristic.
The trouble is that the 3/4 wave for 145 MHz ends up being 0.66 lambda for 128 MHz, which is near a 5/8th wave (0.625 lambda), which is just far enough away from the maximum mismatch, which is 0.5 lambda and close enough what is proven to be good if you use a proper match, which here you just don't have.
In this constellation I agree that the air band capability could be worse, but isn't great either, may not be so bad unless you compare it to a discone, log periodic or a resonant dipole or groundplane that any enthusiast would use.
Expensive antenna. 😧
Your recent videos have had this odd high frequency distortion for a while now, but this one is much worse. Please find the source of this and filter it out, because it makes listening to your videos very uncomfortable. It's on your vocals only, and extends up to 10 kHz (!) according to my DAW's spectrum analyzer.
Could you send me a screen shot from your DAW Analyzer please. Thanks
Hi Chris, I just put the audio from this video in to Audition and I think I can see what you mean within the spectral meter. In fact, it's chirps from Birds outside. They are quite noisy in the mornings when I do my voice overs. Think I will close the windows in future! Needs a very good ear to hear them so well done! Thanks
Totaly illegal to listen to airband civil or millitary.
Oh no … Phone OFCOM
Where? Certainly not anywhere in the U.S. I'd be surprised if it was in the U.K. But then, the way they've been going, maybe not too surprised.
The law in the UK is that you are not allowed to listen to a transmission not intended for you. However, it's generally accepted that because civil and military airbands are in the clear the authorities would not prosecute. There are healthy numbers of listeners and there has not to my knowledge been any prosecutions of listeners to airband or indeed most everything else you can receive. Anything of any 'sensitivity' in the UK has been moved to Tetra.
@JohnSmith-wl8cv With all due respect, this is a video about an antenna, NOT a video about the legalities of listening to certain frequencies that literally ALL Hams and SWL'rs do. Thanks. Also, it would be like me commenting on a GUN review video saying GUNS are illegal..
As all internet, this channel has a worldwide audience. It simply impossible (without incurring in error) to make such a blanket statement that it is "totally illegal to listen to airband". There are places on this planet where this is is not illegal. Ask me how I know.