North East Blog Directory

December 19, 2014

Alistair's Blog

433MHz Antenna Lengths

I use a cheap 433MHz transmitter modules often and every time I need to work out what antenna length I should use because I never write it down. This blog post is me writing it down. The length needs to be an harmonic of the wavelength. The wavelength is speed of light divided by the frequency, or 299,792,458 m/s divided by 433,000,000, or 692.361334873 mm for short.

So the acceptable lengths are…
433MHz Transmitter Module

  • 692.36 mm
  • 346.18 mm
  • 173.09 mm
  • 86.545 mm
  • 43.273 mm
  • 21.636 mm
  • 10.818 mm
  • 5.4091 mm
  • 2.7045 mm
  • 1.3523 mm
  • 0.6761 mm

In reality I normally go for 87 mm, or 43 mm if I am tight for space and don’t need a strong signal. I did once use a 17.3 cm antenna and the coverage was amazing.

by Alistair MacDonald at December 19, 2014 11:34 AM

December 15, 2014


Everyone(scientists and artists) loves slime mould

Slime moulds are strange organisms, who attract artists and scientists…


Heather Barnett and Adam Adamatzky

Slime mould

by Brian at December 15, 2014 12:00 PM

Community IT Academy

Christmas closure

Christmas closure

CITA will close on Friday 19 December 2014 and will reopen again on Monday 5 January 2015.

Existing customers can call Lewis Atkinson on his mobile phone for urgent enquiries - 07958 482 509.  Otherwise please contact us using our contact form and we will get back to you in the new year.

We would like to take this opportunity to wish all of our customers a merry Christmas and a happy new year.

by (William Mortada) at December 15, 2014 10:13 AM

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