Futaba receiver antennas getting hot?

[Steve White]

One more issue I see with running long antennas.

The extra length going up the tube is just folding over at speed anyhow.

The receiver antenna works considerably better and is meant to be vertically polarized. You ever watch a long antenna tube at 60 mph.

The long antenna tube is bowed over and your long antenna is not an iota taller than the shorter one was and it is laid over flat not sticking up vertical like it should be.

The tube is laid back with the end horizontal and back over or closer to the prop roost.

4-6" straight up or a 8"-12" folded back to the same 4-6" height but now it is laid flat.

The straight 4-6" one is going to give you the better range.

Noticed I haven't almost poked the ole' eye out since we got rid of those long stranded wire antennas the FM radio used to have to have.

The short antenna was all the rave of the 2.4 GHZ. Now you want to go back long for no reason whatsoever.

Decrease your range and maybe poke your eye out too. Nice.

The short vertical antenna will have better range than a long antenna when underway at speed.

I've always ran vertical whip on boats and rc cars that can flex.

With stage wireless mic systems we run receiver antennas at 45 degrees relative to vertical as nobody holds a mic vertical. Model aircraft don't use vertical antenna orientation.

Boats are a different animal relative to the RF as they operate on the water. Nobody I've ever seen has held a transmitter with antenna in a vertical orientation. Position varies on transmitter antenna from near vertical to near horizontal - somewhere in between. Worse orientation is transmitter antenna pointed at model, which is easy to do with aircraft.

Speculation for me would be 45 degrees on a boat would be closer to optimal to align with transmitter antenna. Being so close the water vertical as you state may be best for boats. They are a unique application for sure. Just for the record, perpendicular orientation between receiver and transmitter antenna is the worst possible condition.

Something else to think about for sure.

 

[Steve White]

...........I pulled everything apart, the receiver I chose for the installation had a long antenna on it.

When I popped open the receiver I found the antenna not even attached to the board, and some green corrosion on the IC...

That receiver now resides at the bottom of the lake. That's how I fix radio problems.....

Same here Frank. I like the way you think.

I recently dumped ethernet routers new still in the box into the recycle bin. First one I installed in a pro audio rack had issues, figured it was a fluke and swapped it out, second one worked. Then sent one to California to a buddy in a rack I built up for him. He too had problems with the router. So, they all went into the recycle bin.

Radio problems, had a few over the years. Back in the early days running Kraft Brick radio's in Veco 19 powered Northwind's radio problems were common. Then I discovered Futaba. I think the Brick's just went into the trash can. But I've definitely sent a few problems to Neptune.

 

[Daniel's Racing]

Ever notice how some people will go on and on to try and sell their point of view?

Ever notice how some people are so hardheaded that you have to go on and on to get them to even hear your point of view.

I already knew there was absolutely ZERO chance of you getting it but there are others reading that may have a open mind to some common sense.

You would never understand. It isn't your point of view so it is obviously wrong.

 

[Grimracer]

I've always ran vertical whip on boats and rc cars that can flex.

With stage wireless mic systems we run receiver antennas at 45 degrees relative to vertical as nobody holds a mic vertical. Model aircraft don't use vertical antenna orientation.

Boats are a different animal relative to the RF as they operate on the water. Nobody I've ever seen has held a transmitter with antenna in a vertical orientation. Position varies on transmitter antenna from near vertical to near horizontal - somewhere in between. Worse orientation is transmitter antenna pointed at model, which is easy to do with aircraft.

Speculation for me would be 45 degrees on a boat would be closer to optimal to align with transmitter antenna. Being so close the water vertical as you state may be best for boats. They are a unique application for sure. Just for the record, perpendicular orientation between receiver and transmitter antenna is the worst possible condition.

Something else to think about for sure.

I have posted test data on this.. a few years ago.. (its around here someplace)

 

[Steve White]

I have posted test data on this.. a few years ago.. (its around here someplace)

If you ever come across it, I'm interested.

Here's a good explanation of things in relative terms: Does antenna orientation (vertical/horizontal) matter?

Most RF noise is known to be vertically polarized. Not suggesting that amounts to a hill of beans with RC models, just a condition worthy of mention for the discussion.

Interesting topic.

 

[Grimracer]

https://www.intlwaters.com/threads/futaba-usa.76115/page-2#post-742530

 

[Steve White]

https://www.intlwaters.com/threads/futaba-usa.76115/page-2#post-742530

Thanks Mike, good stuff there. Looks like for boats, vertical orientation is the ticket - as the boat turns with vertical antenna orientation it never hits the "antenna pointed at" dead spot.

Going to have to remind/retrain myself to maintain transmitter antenna orientation to vertical or close to it.

 

[Terry Keeley]

Just wanted to dig up this old thread for the naysayers that don't believe the issues with short antennas in our boats.

My FAST buddy Mike Nowicki has a brand new JAE 21 and new Futaba 4PM Plus system with R304SB rx that would go maybe 400' and failsafe, the stock antenna was mounted as shown.

We checked everything, battery, switch, radio was dry, antenna tip was taped at the top of the tube, etc. etc. As a last resort we put a long antenna on it and wala, no more issues. YMMV.

 

[Grimracer]

right.. the 304 is not a diversity RX.. so that extremal antenna is ALL YA GOT!..

Team Futaba Marine recommends using a 400mm antenna in all marine applications.

the BEST choice of RX when in an RC boat is a Diversity RX. (the RX will say Diversity right on it!)

Grim

 

[Terry Keeley]

right.. the 304 is not a diversity RX.. so that extremal antenna is ALL YA GOT!..

Team Futaba Marine recommends using a 400mm antenna in all marine applications.

the BEST choice of RX when in an RC boat is a Diversity RX. (the RX will say Diversity right on it!)

Grim

From what I've seen I want mine to say FASST on it, do they all practice diversity, equity and inclusion?

 

[Grimracer]

the FS is.. the FF is not!

 

[Terry Keeley]

the FS is.. the FF is not!

FS = Fur Shur

FF = Friggin Flakey

 

[Bryan haley]

If you've never had a radio box leak, you haven't been boating very long.

I've been using balloons to put my receivers in been doing it since the early 80s when I started out running Tamiya frogs and hornet since nothing was waterproof back then I even put them on the old school mechanical speed controllers when they had those white ceramic resisters that got hot as hell

 

[Timbo Whalen]

Just wanted to dig up this old thread for the naysayers that don't believe the issues with short antennas in our boats.

My FAST buddy Mike Nowicki has a brand new JAE 21 and new Futaba 4PM Plus system with R304SB rx that would go maybe 400' and failsafe, the stock antenna was mounted as shown.

We checked everything, battery, switch, radio was dry, antenna tip was taped at the top of the tube, etc. etc. As a last resort we put a long antenna on it and wala, no more issues. YMMV.


View attachment 326646

Define long, in inches, please.

 

[Terry Keeley]

Define long, in inches, please.

400mm, close to 16". I use a 12" long antenna tube, like the second drawing:

 

[Rick Sowell]

nice art work, sign of a true professional. lol

 

[Mike Hughes]

Terry
You need to work on that prop. Your throwing too much water up in the air. Not enough thrust out the back........LOL

 

[Timbo Whalen]

400mm, close to 16". I use a 12" long antenna tube, like the second drawing:


View attachment 326657

Thank you

 

[John Beardslee]

400mm, close to 16". I use a 12" long antenna tube, like the second drawing:


View attachment 326657

All of our early Bru-Line antennas were curved due to coil set. At the time I bought virgin nylon in a coil and built a bench and cutter for the girls to cut in 16” lengths. In later years we were able to have our supplier provide it in 64” straight lengths and then we would cut it to 16” straight pieces. Funny, now people want the curved. From an aerodynamic standpoint, if you had a straight one the length as the distance to the tip of the curved one it would probably have the same reception for the receiver as a curved one.

 

[K F Wheeler]

One thing Terry's drawing shows but, easily over looked is the fact that, whatever length you use, mounting the antenna further forward helps!

Ken