What usable range is realistic for handheld VHF on ground to airborne VHF?
Thread Starter
What usable range is realistic for handheld VHF on ground to airborne VHF?
We are always taught about VHF being essentially line of sight and we have all experienced the impressive range of aircraft to aircraft range when on 126.7 at different airfields.
My question is what range is realistic and what have you all experienced when using a handheld on the ground transmitting to an airborne aircraft?
I am often supervising solo students in the circuit when on the ground and am in contact with them on the CTAF with a handheld and occasionally will have an inbound RFDS, Qlink or Rex flight make a 20nm or 10nm inbound call which I receive very clearly on the handheld. When I have tried to transmit back to them to warn them of new solos in the circuit, they can barely make out my transmission at 10nm and doesn't really become usable until they are within the circuit area themselves.
I have been standing outside with what would be clear visual range in the direction of the inbound aircraft and find it disappointing they are unable to hear me at a mere 10nm. I have had the issue with different models of handheld and they are generally capable of transmitting at around 5 watts.
Anyone have any input or have shared similar experiences (or alternatively actually had a particularly good transmit range from a handheld)?
My question is what range is realistic and what have you all experienced when using a handheld on the ground transmitting to an airborne aircraft?
I am often supervising solo students in the circuit when on the ground and am in contact with them on the CTAF with a handheld and occasionally will have an inbound RFDS, Qlink or Rex flight make a 20nm or 10nm inbound call which I receive very clearly on the handheld. When I have tried to transmit back to them to warn them of new solos in the circuit, they can barely make out my transmission at 10nm and doesn't really become usable until they are within the circuit area themselves.
I have been standing outside with what would be clear visual range in the direction of the inbound aircraft and find it disappointing they are unable to hear me at a mere 10nm. I have had the issue with different models of handheld and they are generally capable of transmitting at around 5 watts.
Anyone have any input or have shared similar experiences (or alternatively actually had a particularly good transmit range from a handheld)?
Muchos comprimisos with handheld VHF transceivers. Short antennae; all the metal planes/no metal planes nearby does weird stuff to RF energy; everyone else's squelch and volume is adjusted by reference to 'most' aircraft VHF transmissions...
Have you tried more than one handheld?
Have you tried more than one handheld?
Thread Starter
I would say from experience, probably not much further than the circuit area, unless you are fully out in the open.
Receiving on the ground you could expect well and truly 50 miles if the aircraft is high enough.
I've got a family member who has one at their house for when we fly over and it really doesn't go that far. It's 5 watts.
Receiving on the ground you could expect well and truly 50 miles if the aircraft is high enough.
I've got a family member who has one at their house for when we fly over and it really doesn't go that far. It's 5 watts.
Thread Starter
Just trying to work out how most light aircraft installations are around 10 to 15 watts max and can seemingly go 100 miles or more, yet 5 watts can barely manage 5 miles.
- Better antennae that are usually fitted in a way that will work better than a short stub on a little box held by a human hand
- The transmissions from that short stub held in that hand on the ground will be 'affected' by 'stuff' nearby - buildings, vehicles, fences, human heads... - whereas the 'stuff' nearby an antenna fitted to an aircraft in the air usually (but not always) does not have the same effects
- '10 to 15' is 2 to 3 times more than '5' ...
Unsurprisingly, my handheld performs better when it is plugged into the antenna at the end of a pole strapped to a corner of my hangar. Same power output and receiver sensitivity, but a much better antenna positioned in a much better place.
- The transmissions from that short stub held in that hand on the ground will be 'affected' by 'stuff' nearby - buildings, vehicles, fences, human heads... - whereas the 'stuff' nearby an antenna fitted to an aircraft in the air usually (but not always) does not have the same effects
- '10 to 15' is 2 to 3 times more than '5' ...
Unsurprisingly, my handheld performs better when it is plugged into the antenna at the end of a pole strapped to a corner of my hangar. Same power output and receiver sensitivity, but a much better antenna positioned in a much better place.
Last edited by Lead Balloon; 15th May 2024 at 06:49. Reason: Correct a typo
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Maximum output for a hand held is limited to 5w, that's for safety. If you want more power (range) you will need a base station with remote aerial. I would also say to please not try to communicate with CTAF traffic on handhelds regularly, as you can't hear a lot of what is going on you can just add to the mess of over transmissions and make things worse. Solo students should be sent with the skills to deal with traffic, if that is normal there, otherwise send them solo at quiet times when it's not busy.
Aircraft sets are 25w, with external antenna and transmitting from altitude.
Just trying to work out how most light aircraft installations are around 10 to 15 watts max and can seemingly go 100 miles or more, yet 5 watts can barely manage 5 miles.
I agree with much of what you've said, 43", but I think you'll find that most 'light aircraft' VHF transceivers aren't 25 watts. Transport category? Yes.
True that, 10-16w seams to be the GA fleet, but yes, and aircraft transmitting on the ground with belly antennas will not have much range compared to airborne. It can make a difference about which radio antenna is on the roof for best range on the ground. So center calls seam clearer when taxiing than CTAF calls as the roof antenna is used for com 1 and the belly for com 2. That's if your aircraft has an arrangement like that. If both are on the belly then both will be weak on the ground.
I onced used a handheld 5W UHF (around 476Mhz) at 100 km/ 53 NM from my destination, transmitting at about 5500 feet (GME brand, I think) to a farm house. They had a a honking 2m long UHF antenna at the top of a ~20 metre pole the end of maybe a 40m copper cable that was probably 25mm in diameter - no doubt a fair bit of insulation in that, but it was a thicc cable.
They were quite surprised to hear my transmission when I told them my location, and mentioned my transmission was quite clear.
I used an accessory pust-to-talk speaker/mic system somewhat like this in the handheld unit:
https://www.radioparts.com.au/product/08601797/MC007
and simply held it up to my headset microphone and could hear them about 3.5/5 too.
So, there's something to be said for antenna height and gain.
For direct 5w-5w walkie talkies, you're probably looking at 10km max.
A handheld UHF airband (5W transmit power) with maybe a 2-3 dBI garbage antenna 3dBi is doing maybe 7.5-10W of transmit power.
The aircraft you're talking to is using a 25W transmitter with a 3-6 dBi antenna (2-3x multiplier), so perhaps 50-75W of transmit power.
This is why you can hear them but they can't hear you.
They were quite surprised to hear my transmission when I told them my location, and mentioned my transmission was quite clear.
I used an accessory pust-to-talk speaker/mic system somewhat like this in the handheld unit:
https://www.radioparts.com.au/product/08601797/MC007
and simply held it up to my headset microphone and could hear them about 3.5/5 too.
So, there's something to be said for antenna height and gain.
For direct 5w-5w walkie talkies, you're probably looking at 10km max.
A handheld UHF airband (5W transmit power) with maybe a 2-3 dBI garbage antenna 3dBi is doing maybe 7.5-10W of transmit power.
The aircraft you're talking to is using a 25W transmitter with a 3-6 dBi antenna (2-3x multiplier), so perhaps 50-75W of transmit power.
This is why you can hear them but they can't hear you.
Last edited by AbsoluteFokker; 15th May 2024 at 14:26.
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Handheld radio range will be improved if its possible to remove and replace the stock short antenna with a "high gain" airband antenna, which is longer.
Contact one of the flight shops with your radio make and model to see what's available.
An example:
High Gain Airband VHF Antenna with BNC fitting for ICOM A6/A24/A15/A16/A25
Contact one of the flight shops with your radio make and model to see what's available.
An example:
High Gain Airband VHF Antenna with BNC fitting for ICOM A6/A24/A15/A16/A25
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As a cross country glider pilot I often maintained contact with my ground crew at distances well over 50 miles. Ground crew iniially had a low power hand held with a 5/8 wavelength base loaded antenna mounted on the roof of the crew vehicle. Change to a different crew vehicle required a change to a sleeve dipole antenna. Antenna gain and radiation pattern are of far more importance than the power output of the ground station.
As they say in the DX world - if you can't hear them you can't work them.
As they say in the DX world - if you can't hear them you can't work them.
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I once used a 1W hand-held to communicate with another station at 60 statute miles range - but only just !
I was up on a significant hill and the receive point was several hundred feet up a large transmitter tower, and the frequency was 76MHz.
The handheld I was using was a professional unit, made by Storno, and since we aligned and maintained them ourselves in our technical workshop, I know it would have been transmitting as well as it was designed for - bang on frequency, bang on modulation and bang on output power.
Your units might also be well lined-up pro units, but they might be "domestic" or "semi-pro". They might not actually be transmitting 5W, and/or might need aligning to give full transmit output. They might be slightly off frequency. The antenna might be damaged internally, and therefore the unit might not actually be radiating its full output.
Height will always improve RF radiation, and it's also worth getting away from anything around you that will absorb your transmissions, hangars, trees, hedges, ridges, yourself. A professional dipole or ground-plane antenna fixed to the top of, say, the clubhouse roof and plugged into even a handheld unit will work better - as long as the feeder, (aerial wire), is as short as possible and a decent sized low-loss type. Anything thinner than the size of your little finger will be much too lossy - you can easily lose a couple of watts in a bad feeder.
The theoretical maximum VHF transmission range in nautical miles between two stations A and B; is given by 1.25 x ( sq. route of Height A + sq. route of Height B). Heights in feet.
So for example, a transmitter held at 6' would have a maximum theoretical range of about 58 nm to an aircraft at 2,000'. BUT, this assumes a perfect free-space path, with nothing in the way of the propagation, and does not take into account transmitter power etc. But if you were standing in clear space, or on the roof of your clubhouse, you should be able to reach 10nm to an airborne station with a true 5W transmit power. If it isn't working, you might have a duff or a "toy" handheld, or there might be too much around you absorbing and reflecting your transmissions.
Or as others suggested, the aircraft squelch might be set too high. Obviously, if their radio's squelch blocks your transmissions completely, they won't hear anything or know to reduce the squelch.
.
I was up on a significant hill and the receive point was several hundred feet up a large transmitter tower, and the frequency was 76MHz.
The handheld I was using was a professional unit, made by Storno, and since we aligned and maintained them ourselves in our technical workshop, I know it would have been transmitting as well as it was designed for - bang on frequency, bang on modulation and bang on output power.
Your units might also be well lined-up pro units, but they might be "domestic" or "semi-pro". They might not actually be transmitting 5W, and/or might need aligning to give full transmit output. They might be slightly off frequency. The antenna might be damaged internally, and therefore the unit might not actually be radiating its full output.
Height will always improve RF radiation, and it's also worth getting away from anything around you that will absorb your transmissions, hangars, trees, hedges, ridges, yourself. A professional dipole or ground-plane antenna fixed to the top of, say, the clubhouse roof and plugged into even a handheld unit will work better - as long as the feeder, (aerial wire), is as short as possible and a decent sized low-loss type. Anything thinner than the size of your little finger will be much too lossy - you can easily lose a couple of watts in a bad feeder.
The theoretical maximum VHF transmission range in nautical miles between two stations A and B; is given by 1.25 x ( sq. route of Height A + sq. route of Height B). Heights in feet.
So for example, a transmitter held at 6' would have a maximum theoretical range of about 58 nm to an aircraft at 2,000'. BUT, this assumes a perfect free-space path, with nothing in the way of the propagation, and does not take into account transmitter power etc. But if you were standing in clear space, or on the roof of your clubhouse, you should be able to reach 10nm to an airborne station with a true 5W transmit power. If it isn't working, you might have a duff or a "toy" handheld, or there might be too much around you absorbing and reflecting your transmissions.
Or as others suggested, the aircraft squelch might be set too high. Obviously, if their radio's squelch blocks your transmissions completely, they won't hear anything or know to reduce the squelch.
.
Last edited by Uplinker; 16th May 2024 at 16:47. Reason: clarification
Thread Starter
Maximum output for a hand held is limited to 5w, that's for safety. If you want more power (range) you will need a base station with remote aerial. I would also say to please not try to communicate with CTAF traffic on handhelds regularly, as you can't hear a lot of what is going on you can just add to the mess of over transmissions and make things worse. Solo students should be sent with the skills to deal with traffic, if that is normal there, otherwise send them solo at quiet times when it's not busy.
And of course students are only sent solo with skills to deal with traffic. However, such skills are still developing and I would say even many private pilots (and some commercial) don't appear to have adequate traffic management skills in a CTAF. If there is a solo student in the circuit and a dash 8 calls inbound, there is no harm in a quick transmission saying "just advising there is a solo in the circuit". The airline crews have always been very appreciative of the heads up for the benefit of their own situational awareness and risk assessment etc.
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I'll qualify why I posted that. I've been involved in sending a few hundred solos, in GAAPs, CTAFs, and a few other places. Never have I used or needed a handheld let alone felt the need to broadcast my students were in the circuits etc... On the other end I've been in the RPT Turboprop (Dash & SAAB) that's flying into and out of the all the busy ports mentioned here, for more than a decade, and yes with many solos flying around, again never have I needed to talk to the instructor. I've congratulated a few first solos after sharing the circuit with their moment whilst plying the RPT routes. Never have I had an issue with a solo student, all I ask is that they make the required calls and speak up if they feel there is a conflict, and turn that transponder on so TCAS can see you. The last thing I want is random other radio calls adding confusion in a busy environment. All I want to hear is a callsign, type, where you are and what you are doing, then I can form a mental picture of the traffic. If you want communication with your students then use a company frequency on the other com while they solo. As mentioned before you will not hear low level aircraft from other ports, you might here inbounds but there are many other calls on some of these busy frequencies that you will not hear on a heldheld on the ground, so keep ground to air coms to a minimum and let the airborne stations sort themselves out. Places like Mildura you have Wentworth and the Glider field on frequency, both a ground based radio will not hear and risks over transmitting.
As for the quasi ATC RPT drivers out there, if you are really worried about the circuit traffic SLOW DOWN, fit in with it. If the traffic offers to make way, then ok, but don't make them do cross country navs to avoid a single Dash/SAAB if it's really a problem ask them to full stop and start again after you've landed (nicely). Remember that some of the students may be only circuit trained, so asking them to bugger off out of the circuit can make more issues than it solves.
And as for ground traffic relays, please no. There's already a few ATS members out there who feel the need to give every single VFR traffic in a circuit and you lose SA just having to listen to it, rather than just talking to them. I remember several occasions where I had to wait several minutes to make a traffic broadcast to alert traffic in my area because ATS was passing on multiple VFR in a circuit somewhere. It even delayed a few times where we were trying to communicate with other IFR aircraft to arrange mutual separation.
As for the quasi ATC RPT drivers out there, if you are really worried about the circuit traffic SLOW DOWN, fit in with it. If the traffic offers to make way, then ok, but don't make them do cross country navs to avoid a single Dash/SAAB if it's really a problem ask them to full stop and start again after you've landed (nicely). Remember that some of the students may be only circuit trained, so asking them to bugger off out of the circuit can make more issues than it solves.
And as for ground traffic relays, please no. There's already a few ATS members out there who feel the need to give every single VFR traffic in a circuit and you lose SA just having to listen to it, rather than just talking to them. I remember several occasions where I had to wait several minutes to make a traffic broadcast to alert traffic in my area because ATS was passing on multiple VFR in a circuit somewhere. It even delayed a few times where we were trying to communicate with other IFR aircraft to arrange mutual separation.
Last edited by 43Inches; 17th May 2024 at 23:12.
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Just noticed this old thread.
First, its VHF "AM", and its a rats race if you receive more than one person at a time of similar strength.
That jet you hear inbound may have a 50 Watt Transmitter on AM, He or she sounds "loud".
Those puny hand helds claim to be One Watt and in reality, their Transmitt modulation is generally on the poor side.
I'm always streaining to hear what anyone says on a hand held.
The radio you hear on say a Bell 206 or a Beech 1900 is probably 16 watts .
I've got a KY196 that runs off 28 V and puts out 16Watts with a very nice Transmitt Audio
and great receive Audio. Lots of later model radios just dont use that same beautiful technology.
The average GA aircraft is putting out 5 watts with decent transmitt audio but its generally not going to sound
as good as the "golden radios" that just sound great.
You can put a KY196 in a box with a battery pack, antenna , small 20 watt audio amp and an old Telex mike
and then you can be heard as far as you can hear that airborne high power radio.
Hope that helps.
First, its VHF "AM", and its a rats race if you receive more than one person at a time of similar strength.
That jet you hear inbound may have a 50 Watt Transmitter on AM, He or she sounds "loud".
Those puny hand helds claim to be One Watt and in reality, their Transmitt modulation is generally on the poor side.
I'm always streaining to hear what anyone says on a hand held.
The radio you hear on say a Bell 206 or a Beech 1900 is probably 16 watts .
I've got a KY196 that runs off 28 V and puts out 16Watts with a very nice Transmitt Audio
and great receive Audio. Lots of later model radios just dont use that same beautiful technology.
The average GA aircraft is putting out 5 watts with decent transmitt audio but its generally not going to sound
as good as the "golden radios" that just sound great.
You can put a KY196 in a box with a battery pack, antenna , small 20 watt audio amp and an old Telex mike
and then you can be heard as far as you can hear that airborne high power radio.
Hope that helps.
