Rx Antenna Question

[CloudyIFR]

Hello,

I'm operating a 72Mhz air Futaba transmitter and receiver. My antenna was sliced inadvertently and I'm wishing to splice it together. To obtain the proper length with the wire I have on hand I'll have to splice it just outside the receiver and then about 30 inches down the length with another splice. This is to obtain the 39.37 inches or 1000mm required length.

I was planning on twisting the two wires together, solder, then place some heat shrink over it.

I'll range check of course but any thoughts on issues with range over a perfect length piece of wire without splices?

Thanks
Curtis
Montana

[vintage1]

No issues, and frankly, the length is fairly unimportant. 'about a meter' is probably as precise as it needs to be. They are not tuned whips.

[jkettu]

Splice or continuous wire, they are both electrically exactly the same. Just make the heat shrink long enough so you won't develope fatigue cracks at solder/wire boundary.

[poulsbobill]

Another question. What about very small wire...say 38 ga or so to save weight. Same thing.. OK?

Thanks

Bill

[jkettu]

Same thing.. OK!

[vintage1]

More or less. Watch for single strand fragility tho.

There are SOME size effects at high frequencies like the skin effect, but unless you are a man who used gold plated hi-fi cables you probably don't care. :D

[ghoti]

If the Rx has a lot of flying history you might open it and unsolder the old wire right at the circuit board and replace it all with a single new length. The wire at the exit point gets a lot of flexing and in about 2 years I find breakage inside the insulation where it is not visable. Constant flexing from use and swapping airplanes will eventually work harden the copper there where is flexes and then fracture the wire which is very bad because it strikes unexpectedly and the damage is completely hidden. A range check will show it up if it happens but better to avoid altogether. I have had this happen twice in ten years of flying.

[CloudyIFR]

Thanks folks. I soldered the antenna together and flew for an hour today without a hitch!

Curtis

[poulsbobill]

Thanks Guys. Who uses gold cables?

Bill

[Brandano]

Audiophiles. I even heard one affirm that the quality of an optic fiber will affect the quality of the audio. Mind you, the fiber in question would only transfer a digital signal, and as long as 1's and 0's are received correctly the reproduced audio will be the exact same irrespective of cable or fiber quality. At least in the digital realm you can count lost packets.

[vintage1]

There was even someone selling red felt tip pens that you wiped on the back of your CD's to tune the things to the alleged Laser wavelength to 'improve CD quality'.


There was a bit of a fashion for multistranded LITZ wire on MW and LW tuning coils in the days where one coil was all you probably used, due to the price of valves..you needed the best one coil..and the Litz wire - silver plated stranded each strand insulated from the next with cotton wound insulation IIRC - was definitely a shade better than single strand copper.

Then valves got cheaper, and two copper coils was ten times better than one Litz one, and suddenly people no longer cared... ;)

Even the cheapest set today on MW would have at least 4 tuned circuits.