Antenna under the cowl?

[Kez]

I still prefer to run my Airtronics EXZES and Futaba for a number of reasons. I am trying to decide how and where to route the receiver antenna on a sport 40 that I have been working on and off for almost 10 years.

I bought the shell on this forum about 12 years ago. I have been told it was a Mutt 1 that someone pulled from the molds. It was a lot of work. With advice from the designer and a couple of members, I made a mold to make two fuel cells under the deck. I carved the cowl with a technique inspired by another forum member. Not the best job I've done but I just want to test her when the pond becomes liquid again.

I have the base coat on. But I need to decide how to run the antenna. Will it work if I run the antenna under the cowl?

Thanks and Happy New Year!

kez

 

[FloridaScaleBoater]

Not being familiar with the EXZES radio,,, Are they 2.4 DSM radios or 75meg fm

DSM under the cowl, unless the cowl is carbon fiber. 75meg I would run straight up, out of the cowl

 

[Kez]

Hi Rick,

It is a 75 MHz radio.

I have been looking at the spec sheets of all the 2.4 radios and the RF power is very low at about 100 mW. It may be OK for a surface radio and I am sure it is far superior in terms of interference. But I am not sure if the range will suffer on RC planes and gliders.

kez

 

[Kez]

Here's a picture of the boat. The cowl is glass covered foam.

kez

 

[FloridaScaleBoater]

Kez,

That is a good looking sport-40,

You are above my head with the RF power at 100mW Talking Greek to me there,,,

I do know they offer different RX's for surface and air. Maybe that makes the difference with the DSM

I have just recently started using the 2.4 radio (Futaba both FAAST & FHSS) and have yet to have a problem. Some of my antennas are under cowls, but most are deck mounted and only sticking up a couple of inches

Where is you radio box mounted?

 

[Kez]

Hi Rick,

Before 2.4, the RF output of our transmitters was about 500 mW. I remembered measuring some early Airtronics (Sanwa) at 600 mW. The 2.4 radios today typically have about 1/5 the power. I am not sure if the lower power will mean a shorter range for RC planes.

Thanks for the compliment. I wanted to make the Mutt into a sort of scale Executone. Because of the front mounted radio box, I need to extend the nose to accommodate the radio gear. Here is a picture with the cowl removed. You can see the two fuel cells I molded. I made the rudder push rod out of an aluminum arrow shaft so I am not sure if running the antenna under the cowl is a good idea.

kez

 

[FloridaScaleBoater]

Kez,

That is an OS Max 46!!!

Have I talked to you about the "stash" of OS stuff I have?

I have 5-6 engines and various parts,, would you be interested

 

[brad nichols]

Buy and install the FRsky 2.4 conversion in your EXZES radios as they give you great range and the receivers are about $18.00 and you can get a Telemetry setup if you want.

Brad

 

[Lennard Cuenco]

fs603 fasst reciever (i think it has internal and external antennas), antenna left in taped up box, CF cowl, CF surroundin box in the hull

works good so far

 

[shoboat]

Kez,

I would use a short antenna mount up front by the radio box.

That would be too nice of a boat to lose with a radio problem.

Safe not sorry.

Just My Opinion,

Mark Sholund

 

[dr gary turner]

Agree with Mark

 

[julianconde]

I run the long antennas and stick them way out the boat. That's what I would do.

 

[Mark Stein]

This was interesting readin from 2011 and discusses 72 mhz vs dsss and fhss. May shed a little light around.

If your receiver is buried in carbon get the antenna straight up out of the boat. You wont see it anyway on the water. never heard anyone say thats an ugly antenna on that boat but have heard that was a spectacular wreck

. Was the dock ok?

http://www.modelairplanenews.com/blog/2011/05/30/2-4ghz-is-it-all-its-cracked-up-to-be-join-the-discussion/#comment-area

 

[Kez]

Kez,

That is an OS Max 46!!!

Have I talked to you about the "stash" of OS stuff I have?

I have 5-6 engines and various parts,, would you be interested

Hi Rick,

I bought the OS 46 VRM used many years ago but was disappointed to find out it was modified. The previous owner drilled out the mounting lugs to accept size 8 bolts. I am good for parts as I bought a part engine. But I will take it offline with you to see what you have.

Thanks,

kez

 

[Kez]

Buy and install the FRsky 2.4 conversion in your EXZES radios as they give you great range and the receivers are about $18.00 and you can get a Telemetry setup if you want.

Brad

Brad,

I started looking up on the Frsky 2.4 conversion kit. Can you send me a link? I am hoping they make a 2.4 RF module that I can plug into the transmitter. I am curious to see the RF output power of this conversion kit.

Thanks,

kez

 

[Kez]

fs603 fasst reciever (i think it has internal and external antennas), antenna left in taped up box, CF cowl, CF surroundin box in the hull

works good so far

Lennard,

Good to know that the receiver worked fine with the antenna left in the box. If I convert to 2.4, I am hoping that I can run a short antenna outside of the radio box.

kez

 

[Kez]

Kez,

I would use a short antenna mount up front by the radio box.

That would be too nice of a boat to lose with a radio problem.

Safe not sorry.

Just My Opinion,

Mark Sholund

Thanks Mark.

If I can figure out some way that I can fish the antenna through the cowl after starting the engine that would solve my problem. I cannot mount the antenna on the deck at this point since the deck is already joined to the hull.

Thanks,

kez

 

[Kez]

I run the long antennas and stick them way out the boat. That's what I would do.

Julian,

Can you post some pictures of your Sport 40? I run the antenna on my tunnels through the cowl because I do not have to remove the cowl to start the engine.

On a sport hydro, I will have to fish the antenna through the cowl quickly after starting the engine or I mount it on the deck.

Thanks,

kez

 

[Kez]

This was interesting readin from 2011 and discusses 72 mhz vs dsss and fhss. May shed a little light around.

If your receiver is buried in carbon get the antenna straight up out of the boat. You wont see it anyway on the water. never heard anyone say thats an ugly antenna on that boat but have heard that was a spectacular wreck

. Was the dock ok?

http://www.modelairplanenews.com/blog/2011/05/30/2-4ghz-is-it-all-its-cracked-up-to-be-join-the-discussion/#comment-area

Thanks Mark for the link. Very interesting read. I will digest it again later. What was not mentioned in the article / discussion was the lower RF power of the 2.4 radio. I have never measured the RF output of a 2.4 transmitter but the spec sheet said about 100 mW. I am wondering if the much lower RF power will reduce the range especially for aerial application. My old radios all have 500 to 600 mW of power.

"If your receiver is buried in carbon get the antenna straight up out of the boat. You wont see it anyway on the water. never heard anyone say thats an ugly antenna on that boat but have heard that was a spectacular wreck

. Was the dock ok?" LOL. That is very true!

Happy New Year everyone!

kez

 

[Mark Stein]

It is not a carbon boat. Depending on how your cowl goes on you could possibly have a tube mounted in the cowl to slide the antenna in. Great job on your Mutt BTW. Mine is a Mutt II.

Couple things that caught my attention were the ability to disrupt the signal by reflection from waves and the antenna plane. I am not sure exactly how relevent it is to a new radio today receiver transmitter but the signal package is still the same. Did some distance testing with an off brand receiver the other day in a carbon tub w/antenna enclosed and laying down at 500ft was fine but the lost signal integrity when the boat was set on the ground. Using a Futaba 3PMX transmitter. The whole thing has me thinking may need to dig into it a bit further.