Receiver antenna - Inside WTC or out?

[jdbostrom]

I have planned all along to run my rx antenna out of my WTC inside a piece of vinyl tubing. That was until just recently when I realized how difficult it is to stuff a limp antenna wire into a tube. After getting about 6 inches to a foot inside the tubing, it just kinks up and won't go any further. So now I have decided that either I find some way to make a removeable end on the tube that allows me to slide something like a piece of wire through the length of the tubing and then thread the antenna though or I just keep the antenna inside the cylinder. Before I go to any more trouble trying to figure out how to do the former, do any of you have any opinions on the advantages of running the antenna out of the WTC? Is there really any noticeable difference in range when you have the antenna outside?

One thing that may help if I decide to go with the antenna inside the main WTC is that the drive motor is in a seperate cylinder, reducing the interference some. One problem with having it inside the WTC is that things are pretty cramped in there and there is not a lot of room for a 3.3' antenna.

Also, how much range can I expect when I finally get this thing in the water?

Jonathan

[boss subfixer]

Jonathan,
If one end is already

Jonathan,
If one end is already sealed you could use a piece of round styrene rod to push your antenna in, tape the end of the antenna parallel to the rod and make the rod only as long as the tube for the antenna and just leave it there. I wouldn't use wire to do this as it may give you some type of radio interference.
Just a thought.
BSF

[jdbostrom]

Thanks Boss, that's a good

Thanks Boss, that's a good idea. How long of styrene pieces can you get that should still be strong enough?

[boss subfixer]

Most of what I've seen

Most of what I've seen in my local hobby shop is only around 12 inches long. If you have the room (not sure what diameter tube your using) you could get styrene tube that your rods will fit into and cut off small sections to make couplings and make the push rod as long as you need by glueing the joints. As far as what would be strong enough you could get away with something that is around 1/16" dia, maybe a little heavier. Remember the rods are going to be stiffer than the wire so when you push on them they will bend till they make contact with the wall of the tubing for your antenna but it should still feed the wire through. You may have to go back and forth a little.
As far as your other questions I'll let the experts answer those, I haven't crossed that bridge yet myself. I do know that a wet antenna is a bad thing so you want to be very careful with that route.
Take care
BSF

[jdbostrom]

OK, thanks. http://www.subcommittee.com/forum/icon_smile.gif

OK, thanks.

[liftmys10]

On my subtech albacore manual,

On my subtech albacore manual, it says to run the antenna wire out of the WTC.

[JWLaRue]

I've run with antennas both

I've run with antennas both inside the WTC and outside. For all practical purposes, I can see no difference in range and performance. YMMV depending on the mineral content of the water you are running in.

I am not a fan of using a tube to run the antenna outside the WTC. That's just an invitation for a leak. My preferred way of doing it is to drill and tap a hole in the WTC bulkhead and then glue a short piece of threaded rod through it. The rod would extend slightly from both sides....enough to get a couple of washers and a nut on to it.

Then cut the antenna wire and connect it to the threaded rod.....the shorter receiver part on the inside of the bulkhead and the longer 'free' part on the outside of the bulkhead. Cover the external connection liberally with RTV to seal it (and make sure the end of the antenna is waterproof too) and you're good to go.

-Jeff

[bigdave]

Jonathan,
Check out www.microantenna.com.
I

Jonathan,
Check out www.microantenna.com.
I have converted two of my subs to the Black kat antenna so far with excellent results. Dave.

[jdbostrom]

Thanks everyone. I have to

Thanks everyone. I have to say that I would prefer to make do with what I've got instead of buying something like a new antenna (thanks anyway Bigdave ). So even though it sort of scares me I might go with cutting the antenna wire. Before I do this though I want to be reassured that I am not hurting anything. I have always heard that you cannot change the length of the antenna AT ALL. Apparently this is not really true?

Jonathan

[bigdave]

That is true! Any change

That is true! Any change in the length of the antenna will detune the receiver. But to what extent depends on the ammount of change you make. What you are going to do should not detune the receiver enough to make a difference in the operation. Even the Black Kat will detune the receiver a little, but it has been adjusted to get the lowest possable detuning, and still have a compact antenna. . In most of my subs I run the receiver wire out a length of Golden Rod. It is a pushrod casing used in model airplanes. Dave.

[Guest]

Dave,

Depends on the design of

Dave,

Depends on the design of the receiver.

For instance, I have a tiny little receiver made by a company called JMP. I use this for peanut scale aircraft, and the receiver is designed to accept different aerial lengths. Shortening the aerial will reduce range, but does not affect the reciever tuning.
Not all receivers are designed this way though, so caveat.

Andy

[chips]

Dubro Products makes a 36

Dubro Products makes a 36 inch antenna tube, part #511. The hobby shop may have it back with the R/C airplane stuff.



Edited By chips on 1113666732

[captain nemo12]

I would suggest putting the

I would suggest putting the antenna inside the periscope, that is depending on your WTC setup, not having to remove the conning tower when you take the cylinder out. Antenna will always be on the surface when in periscope depth.

[jdbostrom]

Unfortunately I cannot do this

Unfortunately I cannot do this because of the way the conning tower is built (being a Gato). Thanks for the idea though.

Jonathan



Edited By JDBostrom on 1113679543

[jdbostrom]

OK, I have decided to

[color=#000000]OK, I have decided to run the antenna out of the cylinder in some silicone tubing. My question now is]