How to check antenna signal?

How to Measure a TV Antenna Signal Strength
July 10, 2016 – 01:58 pm
How To: Increase your wireless

TV antenna signal strength is measured in NM(db), or noise margin in decibels, and Pwr(dBm), or power ratio in decibels-milliwatts. Initial measurement tells you exactly how “clean” the sign is, meaning exactly how much residual fixed maybe not from the actual program is included in signal. The second measurement offers you the sign strength. NM(db) is essential because a station might be right next door from your antenna and start to become broadcasting with substandard or damaged gear, plus reception would nevertheless be “snowy” and “flutter.” Calculating these because of the right gear is relatively simple, but calls for some ability.

Things Youwill need

  • Pen and paper
  • Pwr(dBm) meter
  • NM(db) meter
  • Compass


Disconnect the 75-ohm coaxialial cable operating to your television from the antenna installed on your homes roof or from your own interior antenna.

Step 2

Connect the “F” connector after the 75-ohm coaxial on feedback connector on your own Pwr(dBm) calculating device.


Start your Pwr(dBm) measuring product, and turn the tuner towards the least expensive numbered channel broadcasting locally. For those who have an antenna rotor or a directional indoor antenna, change the antenna through to the Pwr(dBm) meter hits its highest amount. Record the outcome.


Use a compass to read through the direction of the greatest signal power. Record the outcome.

Action 5

Proceed aided by the measuring of each and every succeeding channel, rising the scale until you get to the highest number. Record each result.

Action 6

Detach the 75-ohm coaxial “F” connector from Pwr(dBm) calculating device, and then attach it into input in your NM(db) measuring device.

Action 7

Proceed with similar measuring process used with the Pwr(dBm) unit, recording each result in a line beside the past dimension. Note any differences in compass readings.

Step 8

Make use of your compass readings to determine an average when it comes to optimal sign power path should you not have a rotor-controlled antenna. If you use a rotor, put a list of the optimal compass headings for each station close to your rotor control package to help you switch your antenna for the reason that way when tuning directly into that one channel.

Recommendations & Warnings

  • The apparatus outlined right here - next to the compass, pen and report - is pricey. To set the maximum roof antenna way for your local television reception, use a portable battery-operated television, a map, compass while the needed tools to make your antenna. Connect a short coaxial line to the roof antenna from portable television, and utilizing the compass, change the antenna toward it broadcast tower or towers in your area, adjusting it unless you get the best reception. You simply will not get actual dimension information, but you will accomplish similar objective.
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