RE: Easy Antenna Modification
 

I just built one of these and added it to my Tiger that I have apart right now. Took it out in the back yard and it zoomed around to every corner, so this tip will be going into every tank, and I 'll loose the whip antenna's.

Thanks for posting this great idea.

Tell me more about this "tuning" operation.

Thanks

RE: Easy Antenna Modification
 

All I know is that my brother said to cut the coil wire to the length of the metal antenna you want to replace. Example if the metal antenna measures 13" then cut the wire to 13", if you want a scale metal wire antenna say 3" and the original length was 13" then the coil should be 13" minus the 3" leaveing 10" for the coil. Put the coil between the 3" wire antenna and the antenna lead wire.

RE: Easy Antenna Modification
 

Clever tip, I think I'll use this on my PzIII and put a non-functional scale antenna on.

Similarly, I seem to recall that my Futaba FX-10 race car suggested that the any excess RX antenna (soft wire antenna) be coiled up on a piece of cardboard and tucked inside the car. But, I wouldn't recommend trying this with any airborne RC gear (planes or helis) as a coiled up antenna does pick up less signal that a fully extended one.

You can get shorter but "nearly" full range antennas by properly loading the antenna. Deans micro antenna, Flywire for 72mhz (http://www.uoguelph.ca/~antoon/gadgets/flywire.htm), or calculate the inductor required yourself (http://homepages.which.net/~paul.hil...RadioBody.html). But, RF is a very complicated topic...it's important to keep in mind that there's always a tradeoff somewhere, and it may not work for everyone (e.g. perhaps another brand of tank has weaker signal rejection and can't handle a coiled antenna).

Cheers,
D.

RE: Easy Antenna Modification
 

The antenna idea does work. I recently adapted his idea to 75MHz and it works well.

With a one wavelength at about 13 feet of coil, I was able to get almost 2X range. By coiling the antenna wire you can get the ideal 'one full wavelength' along the wire which is the best design for an antenna to get the strongest signal but usually impractible for low frequencies.

Another interesting benefit is the interference or temporary signal loss was decreased by using this method since the entire antenna coil can be placed maximally distant from the electronics and motors!

The custom tuned wound antenna:
http://img.photobucket.com/albums/v1...ical-tuned.jpg

Installation:
http://img.photobucket.com/albums/v1...hz-antenna.jpg

Thanks again pzrwest for bringing this to light!

RE: Easy Antenna Modification
 

I am really pleased that this mod has taken off like it has. It's almost like I have invented a new safety pin.... lol. But the bottom line is I was happy that I was able to contribute something to other rc modelers that works and is simple to do and is benificial just something as re-payment for all the help and advice others have given to me, I don't feel like just a "taker" but a contributor to this hobby

RE: Easy Antenna Modification
 

Do you wrap that around a glue stick?. I never thought of that. Looks like it works good.

OK what is the wave length of 27 Mhz????

RE: Easy Antenna Modification
 

This is a great idea! I lopped off the antenneas to half the length on my Tigers, Pershing and Panzer III and they still work fine but my T-34 goes about 10 feet and craps out with a shorter antennea. I will definatly give it a try on that.

RE: Easy Antenna Modification
 

'bout 12 yards

RE: Easy Antenna Modification
 

If you divide 300 by the frequency in MHz, you get the approx wave length in meters (ie: 300/75MHz= 4Meters, 4Meters * 39 inches/Meter= 156 inches, 156 inches/12 inches per foot= 13 feet wave length for 75MHz.

300/27MHz= 11.111111...Meters, 11.1111*39=433.3329 inches, 433.3329/12=36.111 feet

Theory says that the optimal length is a full wavelength, but you can get close performance using even sub-multiples (1/2, 1/4, 1/8) with minimal loses. (My applolgies to you, Pzr, as it does seem that antenna length does matter in recv mode, just nowhere near as critical as xmit). Which is why you don't have to go around with a 30 foot CB antenna and/or a 40 foot chunck of wire hanging out of your tank... The more critical factor is the 'loading' issue Darith brings up. But, bottom line with HL electronoics, IMHO, you don't have to be that tight th get it to work. I don't know wether or not we would be better off using a open air coil (Pzr's design) or a loose loop (the bigger the coil or loop diameter, the less your antenna will electrically look like an inductor to the front end of the recvr. Pzr's design seems to work like a top. As time alows, I intend to try the open loop variant and see if the difference is worth bothering with.

In a transcvr (xmit/rcv) circuit, the feedline (the wire from the output stage to the antenna proper) falls into the equation. As I recall, the feedline is usually even multiples of one full wavelength at center frequency, then you add on the antenna (at 1/8, 1/4, 1/2. or 1/1 wavelength).

Thanks again to Pzr for the idea.

RE: Easy Antenna Modification
 

swathdiver what type of glue did you use to glue the ring to the gear ring?

RE: Easy Antenna Modification
 

Thanks for your great idea, Pzrwest. Now I have all the HL tanks whip-antenna free and achieved a wider range of radio signal coverage. I found the position of the antenna plays a very critical role in the sensitivity for the receiver. Tried different places inside the hull of the tank, a sweet spot can be finally found.

I also impressed by your 360+ degree turret rotation mod since after removing the stick-out antenna. I tempted to do the same mod as well, the question is how to find a suitable wiring from the control board to the turret. Swathdiver's wiring device is very nice but the tube is not easy to find locally and the spring contact need great skill to do that. However, I found a little gadget may do the job nicely. It is Belkin Twist-Free Telephone Cord Adapter - Clear (see the photo), the construction is very similar to Swathdiver's design, but it only costs a few buck only and it is ready to go. However, this adapter only has 4 wire to connect (it is orginally for phone use [:o] ), after examining the HL tank turret wiring diagram, I am afraid I have to scarify the BB gun motor. I am not sure, 4 wires should be good for 3 motors (points it out if I am wrong). My idea is using a plastic strip and sit this Belkin adapter on the center of bottom of the turret. It should work perfectly.

Heading to the Wal-Mart to see they are selling this adapter.

RE: Easy Antenna Modification
 

What tube?

There are only 3 main wires going into the turret of a Tiger, Panther, Pershing, PZIII, the Walker has the antenna wire. They are a power wire and 2 grounds, 1 for the barrel elevation unit and one for the gun. The little doublestrand wire is for the machine gun if installed.

RE: Easy Antenna Modification
 

Sorry, it should be the ring with groove on the side.

That is the turret wiring diagram copied from Tank FAQ. It should be 1 ground, 2 +ve to the gun and shot motors, and one ground and +ve to turret motor, all 5 wires together, just wonder why the turret motor cannot share the same ground with gun/shot motors. LED wire is not a concern after rewiring.

RE: Easy Antenna Modification
 

In the HL Tiger I and the PzrIII L I got there are 2 red wires and a black wire for the gun and the elevation and red and black wires(thin) for the turret mg led. I removed the mg led in the turret and removed the wires for it from the sleeve covering the wires in my PzrIII which just leaves me 3 wires going to the turret

RE: Easy Antenna Modification
 

I already removed the MG LED from the turret of Tiger 1 to the back of the actual MG. I made a fiber optical/shrink tube MG to replace the stock plastic one.

Anyway, should we start a thread talking about 360+ degree turret in order to fit the thread title??;)

RE: Easy Antenna Modification
 

PZRWest: CA Glue.

patpatballball8888: That diagram is for a T-34 conversion. There's only one + wire going into the turret to power the gun and barrel elevation motors. They are activated from the board by the ground wires.

I'm working on the Walker right now, maybe I'll put a 360 turret in that and post pictures and a "how to", stay tuned...

RE: Easy Antenna Modification
 

swathdiver I did a test with cyano I glued a small piece of styrene rod to a spot on the ring gear but when the cyano cured it came off very easily. I believe the ring gears are made of polyethylene and cyano won't adhere to that stuff it's similar to kids plastic toy cars and pails

RE: Easy Antenna Modification
 

[link=http://www.bsiadhesives.com/Pages/hobby/ca.html]BSI[/link]

This is exactly the stuff I used, the Maxi-Cure one. Still holding up.

RE: Easy Antenna Modification
 

Pzr,

There's s Metheline Chloride compound that is supposed to melt just about all plastics. Sorry, can't remember the modeler's name for it. I have been using a version called 'Attack' manufactured as a epoxy disolver. Nasty stuff, but works well in small quantities.

As I recall, WhitewolfMcBride is the guy that told me about it.

Hope this helps.

Splat

P.S. Your antenna mod is a dream. Using an open loop doesn't seem to increase range over your close wound coil.

RE: Easy Antenna Modification
 

Close wound??? it's just a length of wire wrapped around a plastic tube and only one end is connected the other end isn't connected to anything

RE: Easy Antenna Modification
 

I think he meant a closely wound coil instead of stretched out or elongated wire.

The coil even closely wound help reduce mutual interference of antenna wire since essentially the signal 'sees' a field in the same direction.

RE: Easy Antenna Modification
 

123splat:

MEK is available at most plastics stores (used to assemble plexi and other styrenes)

The hobby equivalent of it, often much more expensive in quantity, is Tenax-R. I use the MBS (Canadian) equivalent as its half of Tenax's price, part # APSC-1.

RE: Easy Antenna Modification
 

Thanks again Wolf. You're a good man to have around.

Splat

RE: Easy Antenna Modification
 

pzrwest, do you still have the original pics from the first post of this thread?

RE: Easy Antenna Modification
 

Yes I do bhop73, don't you see the pics I posted at the start of this thread?