Bitcoin donations to: 1CE9UfWJcHBYkWPns7iqBqZgKhd5xfqEaM thanks!
Buy Bitcoins easily by clicking HERE and get $10 in free bitcoins!

Author Topic: MR100 Youtube Video / Calibration  (Read 3838 times)

andyzot

  • Newbie
  • *
  • Posts: 3
  • SMeter: +0/-0
    • View Profile
MR100 Youtube Video / Calibration
« on: April 07, 2017, 05:28:08 AM »
Hi, I've been looking up your the Radio Preppers videos on YouTube and found the one showing the calibration of the MR100.
I have the just purchased the SARK100 which is pretty similar but I'm very new to amateur radio and not great with electronics, can I please ask what rating of resistors and in what sequence did you make them suitable loads for calibration?
I have purchased several resistors which I thought would equate to the correct ratings but I'm having lots of problems getting it right, I have a meter which is giving some odd readings.
Thank you in advance.
« Last Edit: April 07, 2017, 05:46:00 AM by andyzot »

gil

  • Administrator
  • Hero Member
  • *****
  • Posts: 2576
  • SMeter: +67/-3
    • View Profile
    • Radio Preppers
Re: MR100 Youtube Video / Calibration
« Reply #1 on: April 07, 2017, 06:06:02 AM »
Hello,

You need 50ohm, 150ohm and 274ohm resistors.

I make a 50ohm resistor by putting two 100ohm resistors in parallel. To get 150ohm I add a 100ohm resistor to that bundle, in series. The 274ohm resistor comes in that value.

This way you only have to buy 100ohm resistors and a 274ohm resistor. I bought a bunch of 100ohm 2W resistors and with those left over made myself a dummy load  ;D

I hope this helps...

Gil.

andyzot

  • Newbie
  • *
  • Posts: 3
  • SMeter: +0/-0
    • View Profile
Re: MR100 Youtube Video / Calibration
« Reply #2 on: April 07, 2017, 06:16:59 AM »
Thank you Gil, appreciate the quick response, do I have to consider the power rating, I'm struggling to locate a 274 ohm resistor in the UK that's above 250mW.

gil

  • Administrator
  • Hero Member
  • *****
  • Posts: 2576
  • SMeter: +67/-3
    • View Profile
    • Radio Preppers
Re: MR100 Youtube Video / Calibration
« Reply #3 on: April 07, 2017, 07:08:40 AM »
Quote
I'm struggling to locate a 274 ohm resistor in the UK that's above 250mW.

You don't need more than that. The MR100 outputs a ridiculously small amount of power because that's all it needs... Any 274ohm resistor will do.

Gil.

andyzot

  • Newbie
  • *
  • Posts: 3
  • SMeter: +0/-0
    • View Profile
Re: MR100 Youtube Video / Calibration
« Reply #4 on: April 07, 2017, 10:41:05 AM »
Thank you.