Antenna length question

[chuck chesney]

I have been running R/C boats since shortly after Noah built his ark, but am curious about antenna lengths. I have always been almost anal about never cutting the length of a factory installed antenna, but what are the implications of lengthening an antenna? Will it increase the range of radio reception, or simply cause other problems? The length of an increased antenna would probably be no more than double the length of the factory installed antenna.
This question is for use in a surface model, a 1:96 Belknap class guided missile cruiser thats six feet long that I am putting the finishing touches on. The radio in question is a Futaba FM on 75 mhz, but the same question applies to AM radios.
I know that the SubCommittee is the home of some truly gifted electronics types, and I thank you in advance for any help.

[ccontrol]

Re: Antenna length question

When I went to college I was privileged to work for a wonderful older gentleman from England that used to say, “Electronics is a Black Art, but don’t worry, it’s not there to stay”. The Blackest of Black arts is Radio Frequency or RF. Most transmitters and receivers are carefully tuned to a particular antenna length and react badly when mere mortals mess with that relationship. Shortening the antenna typically has a bad influence on range and I never tried lengthening one. I have never had trouble running a model boat on the surface out almost beyond visual distance, especially a warship where the gray paint actually does work to disguise their location.

I too am from the dark ages of model electronics and Ace RC used to sell a base-loaded whip antenna kit. That allowed you to trim the receiver antenna to 4” and use the 6-8 inch rigid Ace antenna on the model. I have buried those in the plastic or wood superstructure of a model, disguised them as an actual antenna on the model, or laid them horizontally in a submarine. To the receiver, the base loading coils made the antenna still appear to be 36” long so there was no degradation of performance. If you must wrap the antenna up, do it in as long a pattern as is possible. Frankly I would save the 75 mHz radio for a sub and go 2.4 ghz for a surface boat.

With a 6 foot cruiser, you will not have any trouble with reception if you keep the antenna at full length, don’t wrap it up into a small coil, and keep it dry.

[ccontrol]

Re: Antenna length question

FWIW, here is an ad for the antenna system. Can't tell if it is still available.

http://wsdeans.com/products/antenna/index.html