Futaba transmitter module RF output
#1
XPS,

I used an Immersion RC RF meter to measure the power output from two Futaba Tx modules and two JR modules.  Using the same SMA adapters and directly connecting the same meter:

Futaba Tx module #1, 18.5 dBm

Futaba Tx module #2, 20.3 dBm

JR Tx module #1, 18.6 dBm

JR Tx module #2, 18.6 dBm

The ImmersionRC meter has two measurement modes:  Average and Peak.  These values were taken using Peak mode.  In Average mode the meter doesn't even see the signal, so I cannot be sure about the absolute peak output values.  But the relative difference was consistent.

Would there be any issue with reliability using the Futaba module running at a higher relative output compared to the other modules?

Thank you,

Paul
Reply
#2
The difference in peak power is probably the u.FL to RP-SMA connector... or it could be that the particular module is just higher output power due to its construction. We purchase the RF portion pre-made and use our own firmware. I would not be concerned. The difference in range is not that much. It takes 4 times the power output in order to double the range. By comparison it only takes 3dBm of sensitivity gain to double the range for a receiver.

You can't read the average power because it is exactly what you see.. hardly anything. This is because the duty cycle is extremely short (32 microseconds per byte being sent, with 12 byte to 27 bytes, depending on the number of channels in use).
Reply
#3
Thanks for the explanation. Paul
Reply




Users browsing this thread: 1 Guest(s)