I once had to search for an aircraft on the field which had its ELT going off. Presumably someone had landed with the aircraft's ELT activated and put it away in the hangar. But which hangar? Search and rescue advised me to use a handheld and walk around the field searching for the hangar which eminated the strongest signal. Of course, on 121.5, the signal would be heard everywhere, so they advised me to remove the antenna from the handheld and turn to 122.5, suggesting that the signal would be heard on near-frequencies if I was cloase to the source. It was - in fact - when I was at the correct hangar I could hear the ELT on nearly all the frequencies.
So... my questoin is this. If your ELT was going off, wouldn't you hear it on your radio on whatever frequency you are on?
Checking 121.5 at shutdown
Moderators: sky's the limit, sepia, Sulako, lilfssister, North Shore, I WAS Birddog
-
dctthefield
- Rank 0
- Posts: 12
- Joined: Fri Mar 26, 2004 9:08 pm
- Location: CYYZ
dctthefield - Good thought but basically the answer is maybe. It is something called frequency tolerance. Now I am not a radio tech, this is just what I grew up with. If you had an old 180 or 360 channel radio in your airplane, that would work because the tuning devices were not able to keep the radio transmitter on the proper frequency so the reviver had enough "tolerance" to vary and recieve the transmissions. As congestion increased and the problem of "splashover" became a problem, the frequency tolerance of the whole radio frequency spectrim was narrowed down to allow first 100 khz spacing, (118.3 to 118.4 etc) then 50 khz spacing (118.30 to 118.35 etc) and finally to 25 Khz spacing (118.300 to 118.325 etc) and now 8.33 khz spacing. The simple reciever in the handheld will not hold the reciever in as close tolerance as the TSO'd aircraft reciever so you will get splashover if you are close to the transmitter. Especially if you defeat some of the recievers sensitivity by removing the antenna. Your aircraft radio has tuning devices designed to offset this "problem". The regulators tried to outlaw the older radios without much sucess. What did them in was reliability. It became cheaper to replace rather than fix, so old radios became doorstops and boat anchors.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
Our aircraft have Garmin radios that were installed in 1995 and they will pick up the ELT from several frequencies away.
Once had a Falcon pilot do a walk around jus across the fence from our aircraft (about thirty yards). When we fired up and turned on 121.9 (ground) we heard the ELT going off. At first I thought it might be our so I selected a higher frequency and was able to lose it. Back on 121.9 the tower was talking to one of the airport trucks trying to guide him to the aircraft or vicinity of the signal. I had my student taxi across our apron and we lost the signal. I called ground control to suggest that it might be the Falcon. They thought not, but the fellow in the truck went to him anyway and he shut off his ELT.
Frequency rejection from thirty yards not good. Frequency rejection from sixty yards better.
Once had a Falcon pilot do a walk around jus across the fence from our aircraft (about thirty yards). When we fired up and turned on 121.9 (ground) we heard the ELT going off. At first I thought it might be our so I selected a higher frequency and was able to lose it. Back on 121.9 the tower was talking to one of the airport trucks trying to guide him to the aircraft or vicinity of the signal. I had my student taxi across our apron and we lost the signal. I called ground control to suggest that it might be the Falcon. They thought not, but the fellow in the truck went to him anyway and he shut off his ELT.
Frequency rejection from thirty yards not good. Frequency rejection from sixty yards better.
Pilots get higher, SCUBA Divers do it deeper!
Had fun one day chasing an ELT signal. It was just screaming on the handheld inside the hangar but we were losing the signal moving away from the building.
Checked all the aircraft in and around the building and found nothing. We even disconnected one ELT from an airplane that we thought was the culprit. We took the portable com and used it like a pointer. The signal got stronger in two different directions. Surprise surprise there was a large stack of freight that the signal seemed to be coming from. Went through and found a box addressed to an avionics shop. There was an ELT inside with the switch to the on position.
Not a good way to ship any ELT's IMHO.
Made for an interesting chase though.
Checked all the aircraft in and around the building and found nothing. We even disconnected one ELT from an airplane that we thought was the culprit. We took the portable com and used it like a pointer. The signal got stronger in two different directions. Surprise surprise there was a large stack of freight that the signal seemed to be coming from. Went through and found a box addressed to an avionics shop. There was an ELT inside with the switch to the on position.
Not a good way to ship any ELT's IMHO.
Made for an interesting chase though.
I have found that AME's are the worst culprits. Set them off installing them. Also read where SAR followed a ship out of YVR. seems a chopper was being shipped with an ELT still installed. I also read where cell phones will send false signals to the satellites. Like about 100 per day. It is a very serious problem. Anybody heard anything about this?
Ace McCool from Down East International Airlines wanted to lease the Mudgaurd, the worlds greatest airplane, to the CAF for search and rescue and to attract traffic, he planned to send an airplane across Canada with a full load of ELT's and every half hour or so, would toss one out the window. Searchs would last all summer. At least that was the plan.
Ace McCool from Down East International Airlines wanted to lease the Mudgaurd, the worlds greatest airplane, to the CAF for search and rescue and to attract traffic, he planned to send an airplane across Canada with a full load of ELT's and every half hour or so, would toss one out the window. Searchs would last all summer. At least that was the plan.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
Dct
The best way to do it in close proximity with a handheld is as you say, remove the ANT. But when you do so, hold the radio against your chest. If the ELT is in front of you the radio will pick it up. If the ELT is directly behind you, your body will stop the signal. Picked out an ELT at Parry Sound with 7 AC's parked on the deck using this method. SAR Tech from Trenton showed us that method.
Cheers
A
The best way to do it in close proximity with a handheld is as you say, remove the ANT. But when you do so, hold the radio against your chest. If the ELT is in front of you the radio will pick it up. If the ELT is directly behind you, your body will stop the signal. Picked out an ELT at Parry Sound with 7 AC's parked on the deck using this method. SAR Tech from Trenton showed us that method.
Cheers
A
A pilot with experience should never have to answer to a pilot with only a theory
Great points folks. I would like to add one more.
If your ELT has been going off for a while and you managed to detect it and shut it off, please give the regional JRCC (Joint Rescue Coordination Centre) a call and let them know what happenned. The phone number should be in the inside cover of all phone books.
This I ask as a SAR pilot. It may save us a launch on a false alarm. Thank you.
If your ELT has been going off for a while and you managed to detect it and shut it off, please give the regional JRCC (Joint Rescue Coordination Centre) a call and let them know what happenned. The phone number should be in the inside cover of all phone books.
This I ask as a SAR pilot. It may save us a launch on a false alarm. Thank you.
Shut down one day after an uneventful x-cntry, SO i thought, before i stopped the jugs, I took a listen, and if it werent for that, I wouldnt have found my buddy upside down right away on the rwy 
. Wicked winds that day! It pays to use your control inputs i tell ya.....
. Wicked winds that day! It pays to use your control inputs i tell ya....."Shut up over there"
