How do I use the PTP 820 BNC connector (RSL interface) during antenna alignment?

Attach a volt meter to the BNC connector.

At the PTP 820 BNC connector, the voltage range is 1.20 to 1.99 volts.

The last two digits of the voltage represent an estimate of the Received Signal Level (RSL): 1.XY volts corresponds to –XY dBm.

For example, 1.57 volts represents -57 dBm.

Notice that the lower the voltage, the better the signal level.

Don’t forget the following footnote from the PTP 820 Technical Description documents: “Note that the voltage measured at the BNC port is not accurate and must be used only as an aid.

During antenna alignment, if at all possible, have at least two people at each end of the link: one person to adjust the antenna and read the voltmeter, and another person who’s logged into the PTP 820 radio to read the RSL values from the web page interface. (The web page interface RSL values are more accurate than the voltage measured at the BNC connector.)

I hope this helps!


any suggestion how to create and assemble a cable with bnc connector?

If you have a voltmeter or multimeter that does not have a BNC interface but alligator clips instead you can attach them to an unterminated BNC cable. These can be found from many electrical component distributors. 

What setting do I have to be on to get an accurate reading? AC voltage, DC voltage? Millivolts?

DC volts!

Do you need to telnet in and set alignment on?

Unlike PTP 800, PTP 820 does not have an alignment mode.

Log into the radio's web page during alignment.

During alignmnent, se t the radio a fixed modulation, lowest modulation mode, highest transmit power, ATPC off. (Be sure you have a link plan with these settings so that you know the expected received signal level.)

The person aligning the antenna uses a volt ohm meter connected to the BNC connector. They talks to the person at the base of the tower, who is logged into the web browser of the radio under alignment.

Once both ends are aligned, configure the radio to its licensed configuration, which may include adaptive coding and modulation, higher modulation mode(s), lower transmit power(s), and ATPC.

I hope this helps!


Thank you these radios are new to us.

You are welcome!

Do not hesitate to contact our excellent customer support team if you need more help getting your link up and running:

We have regular PTP 820 training classes that may be helpful to you and your team as well.

PTP 820 radios are powerful, and with that power comes complexity.

I hope this helps!


Dave, I was looking for answers in this old thread....but is this PTP 820 training class still held regularly?



Yes, we are still holding live classes!

Go here:

Left-click on "Filter" and "Classroom" for a list.

I hope this helps!


The easiest way to use the BNC port is with this adaptor:

Use one on each end of the link and you're golden! :-)