Radio link and system performance

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Radio link and system performance

 

Radio link menu bar

Edit

Use Copy to send a copy of the active form picture to the clipboard.

Use Export to... to save profile data in a file and open the RMPATH program.

View

Use Profile to initiate execution of the profile extraction and link performance calculation between the units selected in the left and right lists. Changing units in either list or changing the net (middle list) will initiate the same process. The left unit transmits toward the right unit.

Use Swap to exchange Tx and Rx units.

Use Details for a short performance report, such as distance, azimuth, mode of propagation, and system data.

Use Range to view the signal and distance relationship. The cursor is positioned at the distance where the signal does not meet the required performance (range).

Use Distribution to view the signal statistical distribution relative to receiver performance.

Use Observe and select either the 5°, 10°, 20°, 40° or 80° angle of view to visually observe the right unit as seen from the left unit.

Profile picture

Clicking on the profile picture will move the receiver along the path. The label indicates the distance, clearance or obstruction, and signal. The 0.6F1 symbol means 0.6 times the first Fresnel zone.

S-meters

Each of the green lights correspond to one S-unit, the red lights each correspond to an additional 10 dB over S9. The right S-meter corresponds to the signal received for a transmission from left to right. The left S-meter corresponds to the signal received for a transmission from the right to the left. The values may differ if the system gains are different in each case.

Radio link performance

The performance of a radio link is calculated as per the following:

                T (dBm) = 10 log10 (Transmit power in Watts) + 30

                 L1 (dB) = Transmitter line loss

                A1 (dBi) = Transmitter antenna gain relative to an isotropic antenna

                P (dB) = Radio propagation loss from the Longley-Rice model (including required fade margin)

                A2 (dBi) = Receiver antenna gain relative to an isotropic antenna

                L2 (dB) = Receiver line loss

                R (dBm) = 20 log10 (Receiver threshold in microvolts) - 107

 

The performance shown in dB:

                M (dB) = Received signal (dBm) - R (dBm)

                M (dB) = (Tx - L1 + A1 - P + A2 - L2 ) - R

 

The performance shown in S-Units for frequencies < 30 MHz:

                S0 (M <= -3dB)

                S1 (M > -3dB and M <3dB)

                S2 (M >= 3dB and M <= 9dB)

                S3 (M > 9dB and M < 15dB)

                S4 (M >= 15dB and M <= 21dB)

                S5 (M > 21dB and M < 27dB)

                S6 (M >= 27dB and M <= 33dB)

                S7 (M > 33dB and M < 39dB)

                S8 (M >= 39dB and M <= 45dB)

                S9 (M > 45dB and M < 54dB)

                S9 + 10 (M >= 54dB and M < 63dB)

                S9 + 20 (M >= 63dB and M < 73dB)

                S9 + 30 (M >= 73dB and M < 83dB)

 

The performance shown in S-Units for frequencies >= 30 MHz:

                S0 (M <= -1.5dB)

                S1 (M > -1.5dB and M <1.5dB)

                S2 (M >= 1.5dB and M <= 4.5dB)

                S3 (M > 4.5dB and M < 7.5dB)

                S4 (M >= 7.5dB and M <= 10.5dB)

                S5 (M > 10.5dB and M < 13.5dB)

                S6 (M >= 13.5dB and M <= 16.5dB)

                S7 (M > 16.5dB and M < 19.5dB)

                S8 (M >= 19.5dB and M <= 22.5dB)

                S9 (M > 22.5dB and M < 27dB)

                S9 + 10 (M >= 27dB and M < 39dB)

                S9 + 20 (M >= 39dB and M < 49dB)

                S9 + 30 (M >= 49dB and M < 59dB)

 

© Copyright G3TVU

23rd January 2014