What’s your normal radio reception range?

Banjo33

Banjo33

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Banjo33
I moved to a new area of the country a little over a year ago. However, yesterday was the first time I’ve filed IFR since making the move and I had some trouble receiving 2 different approach sectors outside of about 40nm from 7000-8000’ non-mountainous hot/humid like everywhere. I have a 530W and a 430W and have not had any maintenance performed. Outside of that 40nm, reception degraded very rapidly and I even received a guard call with one approach controller for a frequency change that I didn’t hear.

This range seems a little short to me, but wanted to ask the group before I start digging.
 
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Radio hobbyist here...

Are we talking 7000-8000' above the ground or altitude? Makes a big difference. A back-of-the-envelope calculation for radio line of sight for the situation you've described is about 100 nautical miles assuming 7000' above the transmitting antenna. VHF radio regardless of modulation (in our case, AM) generally has a line-of-sight plus 10% effectiveness. If you're within 40nm of the transmitter site and you're not receiving, there's likely an antenna problem. Check things in this order:

1) Antenna in good condition and coax connector secured.
2) Check coax connector to radio for tight and secure connection (secure as in no broken wires)
3) Check condition of coax cable. There's some tests you can do with a basic multimeter to ensure the coax is good and then there's an SWR test. A radio buddy might be able to help you here.
4) Have the radio checked by your A&P. Sometimes, the receive circuitry in the radio can go bad for a multitude of reasons. I've had a few radios over the years that worked just fine but slowly became deaf. In one such case, the antenna had gathered water in a loading coil. All tests showed that the antenna was good but it had become deaf and mute. When I opened the antenna up for inspection, all that water poured out and I found a resistor inside it had rusted apart. The water inside the loading coil gave me false positive test results.
 
KE5BM said:
Radio hobbyist here...
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Ground elevation is only 500-800’ here.

I can’t remember the last time the plane got wet, aside from washing. But, I went from a very humid part of the country to a not quite as humid part, so moisture could still be the culprit. Thank you for the tips, will start there!
 
I got about 40nm on an MX300. A bit more holding down the squelch button.
 
When were the radios installed?

Coax goes bad over time. Antenna mounts get corrosion. If a fiberglass encased antenna, there could be cracks and corrosion.

Any good avionics shop should be able to put a box on the coax and test coax and antenna.
 
Is it poor receive and transmit or just receive? I've had transmit range worse than receive with a failing coax. SWR was quite high with transmissions.
Do you receive better with squelch open?
Have you checked your squelch in the setup menu? Press and hold enter when powering up the 5xx. Squelch is adjustable in the setup menu.
Also, for your consideration, the newer radios seem to have much better receivers than the old 4xx 5xx units.
 
FORANE said:
Is it poor receive and transmit or just receive? I've had transmit range worse than receive with a failing coax. SWR was quite high with transmissions.
Do you receive better with squelch open?
Have you checked your squelch in the setup menu? Press and hold enter when powering up the 5xx. Squelch is adjustable in the setup menu.
Also, for your consideration, the newer radios seem to have much better receivers than the old 4xx 5xx units.
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As far as I know it’s only poor Rx, but that’s an assumption/not confirmed. It Rx just a hair better with the squelch open, but not enough to make much of a difference. Have not checked any settings, but the radio hasn’t been touched by anyone in the 9 years I’ve owned the plane. The 430W was overhauled by Garmin 5 or so years ago and its range was no better. Repeatable issue on separate radios leads me to think it’s an antenna or coax issue. Installed CGR engine monitor system about 4 years ago and the radios had to come out then for wiring, but don’t think this issue started at that time, but could be wrong. Not looking at upgrading radios at the moment, so want to ensure they’re operating properly.
 
I’ve gotten 120 or so miles many times around here.
 
RyanB said:
I’ve gotten 120 or so miles many times around here.
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Wow! Who are you contacting that far away? Or just checking weather on faraway fields? What equipment?

I wish I’d have thought about trying the weather when I began to suspect an issue as at least I’d know exactly where the transmitters were…that’ll be for next week.

Quite a range in here so far: dmspilot seeing ~40nm in a stand-alone nav/com, me at ~40nm on a 530 and 430, and your equipment at ~120nm.
 
I frequently hear pilots making unicom calls at an airport 100 miles away when I'm at 1000' AGL.
 
There is a formula… I don’t have it handy.

That said, uncontrolled fields are lumped together. That’s why you announce the name.
 
Dana said:
I frequently hear pilots making unicom calls at an airport 100 miles away when I'm at 1000' AGL.
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Sure would be nice if ATIS came in that far out. Such is life...
 
Banjo33 said:
As far as I know it’s only poor Rx, but that’s an assumption/not confirmed. It Rx just a hair better with the squelch open, but not enough to make much of a difference. Have not checked any settings, but the radio hasn’t been touched by anyone in the 9 years I’ve owned the plane. The 430W was overhauled by Garmin 5 or so years ago and its range was no better. Repeatable issue on separate radios leads me to think it’s an antenna or coax issue.
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Concur, this suggests antenna or coax issue. Of the two I would bet antenna. Can you swap out antennas as a test?
 
FORANE said:
Concur, this suggests antenna or coax issue. Of the two I would bet antenna. Can you swap out antennas as a test?
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Do you mean swap the antennas with another aircraft? No, that’s not an option for me. I’ll be able to check for corrosion, good connection, check ohms, etc (first three steps highlighted above by KE5BM). Anything beyond that will require me to take it to an avionics shop.
 
I would look for another antenna, install it and go test it in the air, but I'm experimental. On certified, sadly, I believe an a&p return to service sign off is required.
 
Kritchlow said:
That’s because both airplanes are at 1,000’

The ATIS transmitter is not.
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Actually not. If I'm trying to pick up ATIS from that far out, I'm probably going to be either at 0AGL or some cruising altitude above 3000.
 
A lot of good points raised here. I'd also look at the inside of the RF connectors (BNC), they need to be clean without oxidation, male pin and female socket or you'll see reduced range for sure. Silver contacts tarnish visibly, some folks say the tarnish is OK, but I prefer nickel plated contacts. Clean and cycle the connectors and see what you get.
 
asicer said:
Sure would be nice if ATIS came in that far out. Such is life...
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It seems for us 40mi is about the extent of range to pick up ATIS/AWOS. Are the weather ground transmitters the same power output as ground comm transmitters, or are they lower powered units?
 
Flying around at 2000 AGL I regularly hear traffic at other airports 75-85 miles away at least.

OT a little...When I got my G 650 for my com 1 and tried to keep the original ARC radio in for com 2 and nav 2. That arc radio was huge POS compared to the 650. I noticed huge reception and transmit differences and ATC confirmed that they could barely hear the arc radio. Had a G255 put in using the same coax and antenna and that got my com2 up speed.
 
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Another thing to consider is RF noise generated by modern avionics. Most radios don't have signal-activated squelch systems, they trigger based on noise level.
As such, if there's something on-board generating RF noise (even a Tail Beacon can put out a decent amount), it will result in your signal having to be stronger before the squelch opens. Open the squelch on the ground and start turning equipment off, paying attention to any changes in the noise. If you notice a chance, try it again in flight with the facility that was causing you trouble while keeping that equipment off.
Also, some ground stations have weak spots in the antenna patterns. Try the same facility from a different angle and at the same range. Results could be completely different.
 
Dana said:
I frequently hear pilots making unicom calls at an airport 100 miles away when I'm at 1000' AGL.
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That is because you are effectively a 1000 foot high tower to another 1000+ high tower.

I have seen over 100 miles radio contact from 3000 feet to an 800 foot tower with a 5 watt VHF FM handheld and rubber duck antenna, inside the plane.
 
Pinecone said:
I have seen over 100 miles radio contact from 3000 feet to an 800 foot tower with a 5 watt VHF FM handheld and rubber duck antenna, inside the plane.
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I accidentally forgot to change my APRS HT settings one day. My 5w signal was bouncing all the way up to Canada. About 30 minutes into my flight I realized what I'd done and turned it off. I didn't get any FCC or OO notices so...oops.
 
No rules against ham radio from an airplane.
 
i had an issue in my comanche with one radio not receiving well. It was a Garmin 530. The radio was old so I assumed it was the radio or a connection. Upgraded the avionics to a Garmin 650xi and on the ground it seemed to work, but in the air I couldn't hear Atlanta well (obviously, i live in the area). took it back to avionics shop and they replaced the antenna and no issues since (we did try tightening connections, etc.).
 
Pinecone said:
No rules against ham radio from an airplane.
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Certainly not which is why I had it on in the first place, but on APRS I prefer to use extra low power and no "hops" but my HT's default configuration is 5w with 2 hops. At 4500 feet, there's a BUNCH of ground stations that your first transmit out reaches and hops from.
 
Haven’t been able to check much more than whether things are connected, but did get to fly today and do more deliberate testing.

At 6500’, I could receive airborne traffic out to at least 93 nm pretty clearly. I could receive one class C control tower out to at least 70 nm. Another Class C tower I couldn’t hear within 60 nm (5500’). Results were same on the 530 and 430.

I’m beginning to think my radio range is fine (possibly a little degraded) and it’s just that facility (the tower at 60 nm was also one of the approach control I was having issues with in the original post—I don’t know if they are co-located) or terrain or something causing the reception issue.

Thoughts?
 
Banjo33 said:
I’m beginning to think my radio range is fine (possibly a little degraded) and it’s just that facility (the tower at 60 nm was also one of the approach control I was having issues with in the original post—I don’t know if they are co-located) or terrain or something causing the reception issue.
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That is a very reasonable hypothesis.
 
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