Sub antenna-crazy idea #22

[Bob Gato]

I had posted something like this on another forum but it appeared that I couldn't get my Idea across. Here goes.. What if you calculated the full wave length of your radio say 75mhz which is around 3.9 meters, and ran a wire that long and put it in a weighted tygon tube - where it would stay dry. So while operating in clear water(swimming pool or clear pond) you would cast the tube out where it would lay on the bottom. During surface ops, you would use the antenna on your transmitter-during deep dives you would clip(or switch) to the extended antenna at the bottom of the pool where the sub is a lot closer to the transmission source....I think this is worth a try. (not for 2.4 gig radios-)

[Scott T]

So the antenna in the tube is attached to the transmitter?

[Bob Gato]

All you would need to do is clip it on (the full wave calculation would have to include the trans antenna length to the circuit board)-the antenna wire under water is in air within the tube-yes you would get the usual attenuation as if you were transmitting from above water to your sub 4feet down but you could operate the sub as if you had the transmitter right next to the sub (in theory-my head) and get that much further range. like I mentioned when you surface-the antenna(still on the bottom) is being distanced from the sub-so you would unclip the wire and operate on a surface 1/4 wave antenna..

[RCSubGuy]

Should work, I'd think. Having said that, I can't think of many instances where I've lost signal at periscope depth or close to it. In realistic terms, it's not often we're driving a 5ft sub from 150' away at a depth of 2ft. Our standard radio antennas seem to be working just fine in 95% of cases.

Now, I could see this being useful in a more heavily chlorinated pool, for instance. In that case, I've lost signal in as little as four or five feet of water with the boat right next to me. For sub runs at a pool, this could be something worth trying!

[Bob Gato]

Come spring, I have some experimenting to do.

Tip to pool owners: anticipate a sub run and let the chlorine run low-both for radio reception, metal part corrosion, and paint fade..

[type7]

I agree with Bob, standard 75mhz radios work just fine for the type of sub running most people do without trying to optimize the antenna in the sub.