FASST RECIEVER WARNING!
- Thread starter Patrick Mulvany
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Hydro Junkie
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This is the $10,000 question, unless you have an electrical background. Let's see if I can clear things up for you:
On the lower frequency receivers, the antenna length was what "tuned" the antenna. This was due to the entire length of the antenna picking up the signal.
On 2.4GHz systems, the transmitted wavelength is extremely short. Due to this short wavelength, only the last 1" is actually needed for the receiver to pick up a usable signal. Now, obviously, a 1" antenna would be borderline worthless, especially in a CF boat. To give some flexibility in antenna locations, a longer antenna wire is needed. To preserve the 1" active antenna length, the rest of the antenna wire is shielded by the braided shield between the outer jacket and insulation around the center conductor. This means that, as long as only 1" of the antenna is bare, it's going to be properly tuned. Now, if you put a sharp bend into the wire, you open up a hole in the shield. This hole "detunes" the antenna and causes problems in reception. As for a receiver having a plain wire antenna, I've never seen that. What brand of receiver have you seen with that configuration? Maybe someone else can answer that one
On the lower frequency receivers, the antenna length was what "tuned" the antenna. This was due to the entire length of the antenna picking up the signal.
On 2.4GHz systems, the transmitted wavelength is extremely short. Due to this short wavelength, only the last 1" is actually needed for the receiver to pick up a usable signal. Now, obviously, a 1" antenna would be borderline worthless, especially in a CF boat. To give some flexibility in antenna locations, a longer antenna wire is needed. To preserve the 1" active antenna length, the rest of the antenna wire is shielded by the braided shield between the outer jacket and insulation around the center conductor. This means that, as long as only 1" of the antenna is bare, it's going to be properly tuned. Now, if you put a sharp bend into the wire, you open up a hole in the shield. This hole "detunes" the antenna and causes problems in reception. As for a receiver having a plain wire antenna, I've never seen that. What brand of receiver have you seen with that configuration? Maybe someone else can answer that one
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What 2.4ghz receivers have you seen using stranded copper regular wire ?Can someone tell me why some 2.4 receivers have a coax antenna and others have a normal antenna wire?Also would a longer wire change the "tune" on a 2.4 receiver ?
Thanks
Don
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How is it that you determined it is regular stranded copper wire.
Certainly have no way of knowing but willing to bet that is coax also. Thinking it is just a manufactured piece made just for being a antenna rather than bulk wire everyone else uses and strips back the end.
The stripped back part is just hidden by a outer covering. Imagine it is part of getting a waterproof specification. Sealed up wire to keep water intrusion from coming up the wire.
The reason I say this is all other Airtronics 2.4ghz receivers use regular coax like everyone else. I would imagine it would take some serious changes to the circuitry to run regular wire if even possible. I don't think they would make that much change while designing the waterproof model.
Certainly have no way of knowing but willing to bet that is coax also. Thinking it is just a manufactured piece made just for being a antenna rather than bulk wire everyone else uses and strips back the end.
The stripped back part is just hidden by a outer covering. Imagine it is part of getting a waterproof specification. Sealed up wire to keep water intrusion from coming up the wire.
The reason I say this is all other Airtronics 2.4ghz receivers use regular coax like everyone else. I would imagine it would take some serious changes to the circuitry to run regular wire if even possible. I don't think they would make that much change while designing the waterproof model.
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Daniel, The antenna wire broke right at the case. (my fault,too much strain) I replaced it and is working fine, but is still a little short to get out of the hull far enough to make me comfortable. I replaced it with 26 ga. copper stranded wire. I have other Airtronics receivers that have coax and have the last inch exposed. Thus my original question.
Don
ps HAPPY ST. PADDYS DAY
Don
ps HAPPY ST. PADDYS DAY
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Interesting. I never would have thought it was stranded copper wire in one.
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Hydro Junkie
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I'd be worried about it catching a bunch of noise and causing reception problems with an unshielded antenna that long
I just recently purchased the Futaba 2.4 Telemetry radio system and I am using the R203GF S-FHSS receivers in my nitro and gas boats. Some of my boats have the antennae go through the radio box lid and some out the side of the radio box then vertical. Most of the antennae wires stick up vertically about 4 inches. I have a Crackerbox where the wire is vertical only an inch out the top of the back of the hull. Is this a concern?
It bothers me enough as it is that there are these short receiver wires, a short transmitter antennae and the transmitter runs on just four Double A batteries. I can not find one of those black and yellow books for Dummies to help me out.
In the old days on 75 mghz, to radio check my system I would drop down the transmitter antennae and walk away from the boat, continuing to move the rudder left and right to see how far away I had reception. Will this method just prove useful with 2.4? I will admit that I walked so far away down the street, I couldn't see my boat and everything was still working fine ............ I was told.
Thanks,
Al Waters
It bothers me enough as it is that there are these short receiver wires, a short transmitter antennae and the transmitter runs on just four Double A batteries. I can not find one of those black and yellow books for Dummies to help me out.
In the old days on 75 mghz, to radio check my system I would drop down the transmitter antennae and walk away from the boat, continuing to move the rudder left and right to see how far away I had reception. Will this method just prove useful with 2.4? I will admit that I walked so far away down the street, I couldn't see my boat and everything was still working fine ............ I was told.
Thanks,
Al Waters
Hydro Junkie
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Al, this is from my post on page 3 and may answer some questions:
"On 2.4GHz systems, the transmitted wavelength is extremely short. Due to this short wavelength, only the last 1" is actually needed for the receiver to pick up a usable signal. Now, obviously, a 1" antenna would be borderline worthless, especially in a CF boat. To give some flexibility in antenna locations, a longer antenna wire is needed. To preserve the 1" active antenna length, the rest of the antenna wire is shielded by the braided shield between the outer jacket and insulation around the center conductor. This means that, as long as only 1" of the antenna is bare, it's going to be properly tuned. Now, if you put a sharp bend into the wire, you open up a hole in the shield. This hole "detunes" the antenna and causes problems in reception."
As far as the transmitter batteries, I installed a 6.6 volt LiFe pack into my 4PLS. From what I can see, I have plenty of power and, since the transmitter actually has a setting for that type of battery pack, it's a non-issue. Since you didn't say which radio you purchased, I checked the manual on the 4PX and found it has the same battery type settings as the 4PLS so if you're running one of the two, you should be fine with any battery pack listed in the manual.
As far as a range test, have someone else do the walking and you watch the boat. You can see where they are as well as what the radio is doing. A cell phone or two way radio to give instructions to the "walker" would be helpful as well
"On 2.4GHz systems, the transmitted wavelength is extremely short. Due to this short wavelength, only the last 1" is actually needed for the receiver to pick up a usable signal. Now, obviously, a 1" antenna would be borderline worthless, especially in a CF boat. To give some flexibility in antenna locations, a longer antenna wire is needed. To preserve the 1" active antenna length, the rest of the antenna wire is shielded by the braided shield between the outer jacket and insulation around the center conductor. This means that, as long as only 1" of the antenna is bare, it's going to be properly tuned. Now, if you put a sharp bend into the wire, you open up a hole in the shield. This hole "detunes" the antenna and causes problems in reception."
As far as the transmitter batteries, I installed a 6.6 volt LiFe pack into my 4PLS. From what I can see, I have plenty of power and, since the transmitter actually has a setting for that type of battery pack, it's a non-issue. Since you didn't say which radio you purchased, I checked the manual on the 4PX and found it has the same battery type settings as the 4PLS so if you're running one of the two, you should be fine with any battery pack listed in the manual.
As far as a range test, have someone else do the walking and you watch the boat. You can see where they are as well as what the radio is doing. A cell phone or two way radio to give instructions to the "walker" would be helpful as well
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Kevin Krogness
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Tape a piece of bigger card board to your rudder and paint one side a different color you will be able to see it moving. I bought the turnigy life battery and can run it for days!
Patrick Mulvany
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I have been running the FASST Radios since they have come out!! I have run "Open Offshore" with my Cat Boat with a short antenna with no problem and I have run courses from Ohio to Texas to Florida and never had a problem!!
Later!!
Pat
Later!!
Pat
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I just changed a couple of my receivers to the long wire for a carbon scale boat. When you pull the connecter from the board they come straight up, not from the side as I would have thought. Managed to pull the short antenna wire from the connecter that way. A fine set of needle nose made this job easier.
