How do I wire a PKE antenna (inductive transmitter) ?

I bought this $5 PKE antenna https://www.aliexpress.com/item/sensing-antenna-to-the-remote-only-use-in-HY-904-replacement-sensing-antenna/32800335616.html?spm=a2g0s.9042311.0.0.d7474c4d6CgKH4

I've not opened it yet, but I'm sure it's simply a copper coil around a ferrite rod, optimised for 125khz.

I want my arduino to use this to send low-speed data a short distance (3 meters, undersea, hence my need for using LF induction).

How would I do this? I expect it needs an AC sine-wave current fed into it (resonator?) - how would I wire my arduino to transmit ? I expect a capacitor is needed in series, and the arduino needs to clock something that generates an approximately 125khz sine wave...

My receiver is a 3-axis inductive coil and parallel capacitor connected for now to an oscilloscope.

by cnd
September 19, 2018
Add comment...

Please sign in or create an account to comment.


1 Answer

Answer by mikerogerswsm

Difficult to answer without seeing the product. It may be a ferrite rod with a winding or it may be same with a C in parallel. Try driving it from a sig gen with a series resistor (say 1k) and see where it peaks. If it doesn't, add a parallel C, say 500pF and see where it peaks then. Try other values.

Driving it should ideally be sine wave but square wave will work. See ham radio mags for better matching circuits.

125kHz sounds rather high for undersea work, VLF, 3 to 30 kHz, is more usual

Alternatives include optical and acoustic.

+1 vote
by mikerogerswsm
September 19, 2018

Thanks! When you say "peaks", what would I be measuring? Current/Voltage driving it, or looking for a signal on my receiving coil?

The chips which drive these things have selectable output from 250ma to 1amp - so I'm guessing I'll probably need one or two transistors at some point.

Clever comment re VLF, and yes, any RF above "tens of khz" simply does not go through salt water - which is why I'm not using RF, but magnetic inductance instead. I also want only a short range; a bit like a personal-area-network for divers.

by cnd
September 19, 2018

Voltage driving it.

by mikerogerswsm
September 19, 2018

Not sure how a ferrite rod behaves as a magnetic inductor.

You may find it works without a capacitor.

by mikerogerswsm
September 20, 2018
Add comment...

Please sign in or create an account to comment.


Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account


Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers


Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.


About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.