Skipjack 1/72

[greenman407]

Ok, here we go with how Im hooking up my accessories to my reciever. If anyone sees something out of place, speak up. After Consultation with HWSNBN I have edited this post to reflect the recommended order.

CH. 1 Rudder servo
CH. 2 ADF- Rear Planes Servo
CH. 3 Sail Plane Servo
CH. 4 LIPO Guard-ADF Failsafe- Y connector-SAS Pump
...........................................Y connector-ballast vent servo
CH. 5 Blank
CH. 6 Speed Control
CH. 7 Blank
CH. 8 BEC


Ch. 6 I have assigned to the rotary control on the upper left on the Polk. I use it for throttle on all my subs for 1 screw and for two screws I use the rotary knob on the right for the other prop.
Weird thing is that on my Polk, ch. 3 and ch.4 are reversed in the radio. Perhaps because I asked Polk to send me a radio with a ratchet action left stick. Perhaps they plugged the wrong plug into the wrong slot. Possibly. Anyway, when I go into the menu to reverse servo direction. I have to change ch.3 if I need to change 4. Confusing aint it.

[greenman407]

Yeah..........what you said.......yeah

[roedj]

I wonder how a "loaded" antenna would work underwater. The model airplane guys use them and I have one on my Airboat.
Maybe I shouldn't add complexities. If it works....dont fix it.

The question of a "loaded" antenna is, well, a loaded question - sorry, sometimes I just can't help myself.

Seriously, if by loaded you mean to insert a coil (inductance) at the base of the antenna to lower its resonant frequency - then yes you could do it. But to what end? By cramming this straight antenna (again, this discussion assumes that the antenna is of a resonant design and not an "active" type) into the confines of a submarine hull you have already added inductance (some of the antenna looks like and acts like a coil) and capacitance (some of the antenna will have parallel wires somewhere) which alter the resonant frequency in different directions. Inductance in series lowers the resonant frequency - capacitance raises it. After cramming that wire in there a 'super computer' couldn't figure out the resonant frequency so why should we try to intentionally adjust it?

As I said, don't sweat it. Do the best you can and be thrilled the damn thing works at all.

Dan

[greenman407]

I wonder how a "loaded" antenna would work underwater. The model airplane guys use them and I have one on my Airboat.
Maybe I shouldnt add complexities. If it works....dont fix it.

[trout]

Thank you Dan, that was helpful! Very helpful.
David likes to say "it is not rocket science" and I am learning how in so many ways that is true, but antenna dynamics seems to go beyond rocket science it goes into the realm of magic and pixie dust to me.
Alec, I hope my question did not come across as questioning you or your abilitities. It is not. I respect your skills and knowledge immensely. It is me just trying to sort out the little knowledge I have.

[roedj]

If you are shielding the rf interference are you not also shielding the regular signal too? If that is true does that mess up the ideal antenna length for the wavelength being used?
Curious minds want to know more......

I have experience designing antennas for amateur radio usage.

Basically, the antenna length as supplied is dependent on the antenna being straight and in free air (no surrounding metal close by) if it is a resonant frequency design.

Any variation from those two conditions will change the resonant frequency of the antenna. This assumes that the antenna is of a resonant frequency design. If it's not, if it's an 'active' antenna, then length still matters just not so much. I have been trying for years to get a manufacturer to state which type of antenna they use - so far without luck.

If it is a resonant design then twisting it up in a ball or loop, shielding a part of it or any other variation from the conditions listed above will completely change the resonant frequency.

If it were my concern - I wouldn't be overly concerned. I've seen antennas that look like a rat's nest still work.

Dan

[alad61]

Tom I'm only shielding the antenna wire that runs near the motor not the entire length.

[trout]

If you are shielding the rf interference are you not also shielding the regular signal too? If that is true does that mess up the ideal antenna length for the wavelength being used?
Curious minds want to know more......

[alad61]

New location for the Sombra. The BEC will go right underneath it under the shelf, above the pump.
[ATTACH=CONFIG]23937[/ATTACH]

Mark i put the rx on its side up against the vertical section, the adf on the horizontal and bec under the shelf as you suggest for your bec

[alad61]

Your point is well taken, Mark. And that antenna is indeed in the worst possible location -- but design drove me to put it there.

But, why tempt fate and let RF into the receiver board when you don't have too?! Distance (the inverse, square law) works for us if we use it.

M

i put a couple of heat shrink lengths over the aerial wire where it sits near the motor then I slipped a length of styrene tube over that to help shield the wire from interference re the motor. To me it seemed to cut back on the glitching and occasional jitters coming out of the rx.

[greenman407]

New location for the Sombra. The BEC will go right underneath it under the shelf, above the pump.

[greenman407]

The preferred method of smoothing and sealing your silicone, spit on your finger and carefully wipe around your victim. If you dont like the spit idea ,you can use Petroleum Naphtha, Paint thinner/mineral spirits, xylene, or lacquer thinner to coat your finger. Just dont press too hard or youll remove all your silicone.

[greenman407]

Very well sir, Thy will be done. Ive scoped out a spot upfront for it.

[He Who Shall Not Be Named]

Dave....you are the Man, but heres my thinking on Receiver placement. Ive been using D&E WTCs for about 8 years now. On all of them including the Subdrivers, the antenna wire lies alongside and the Antenna post is almost touching the electric motor. Since the most likely path into the receiver is thru the antenna wire, and I have had no ill results ,I wouldnt think that there would be a problem. Also this is a Sombra with superior stray signal rejection.

I will now slink away into the corner with my Dunce cap on.:biggrin:

Your point is well taken, Mark. And that antenna is indeed in the worst possible location -- but design drove me to put it there.

But, why tempt fate and let RF into the receiver board when you don't have too?! Distance (the inverse, square law) works for us if we use it.

M

[He Who Shall Not Be Named]

Dave....you are the Man, but heres my thinking on Receiver placement. Ive been using D&E WTCs for about 8 years now. On all of them including the Subdrivers, the antenna wire lies alongside and the Antenna post is almost touching the electric motor. Since the most likely path into the receiver is thru the antenna wire, and I have had no ill results ,I wouldnt think that there would be a problem. Also this is a Sombra with superior stray signal rejection.

I will now slink away into the corner with my Dunce cap on.:biggrin:

Your point is well taken, Mark. And that antenna is indeed in the worst possible location -- but design drove me to put it there.

But, why tempt fate and let RF into the receiver board when you don't have too?! Distance (the inverse, square law) works for us if we use it.

M