Interfacing a Bird Single Line Section MB-1:

These notes assume that you will be using the Bird Line section from a Bird meter such as the Bird 43. The same procedure applies if you are using a stand-alone Bird Single Line section except that if you are using the line section from a Bird meter, you must first disconnect the DC cable from the meter movement since MB-1 needs to see the open circuit voltage from the Bird element.

The DC output of the Bird line section is connected to the MB-1 FWD coupler port that you intend to use (coupler 1 - 4) using a single RCA cable. Connectors and cables are readily available that make this a simple procedure (see the pictures below).

The associated MB-1 coupler calibration trim pot should be set to its maximum sensitivity (full CW position). If you are doing your own calibration, this will give you the best resolution since the Bird line section will never exceed MB-1's maximum input of 6.14 volts. Furthermore, if you are using the updated MeterBuilder OEM  calibration table that contains the Bird calibration table, the trim pot must also be set at its maximum value since that is the condition under which the calibration table was generated.

The single Bird Line Section is used with MB-1 the same way it is used with the Bird meter, namely, either the FWD power or REFL power can be measured at any one time based on the orientation of the slug. Both the FWD and REFL power are displayed as a FWD power measurement on MB-1 since only the FWD coupler port is being used.  You can turn off line 3 on the MB-1 LCD, which normally displays Reflected power and SWR, since these are not applicable when using a single Bird element. Likewise, on the 7-segmnet displays, Reflected power and SWR can be turned off, or substituted with a different measurement that is valid for the single slug configuration. Once you have configured MB-1 as described, you can save the settings in a configuration set for easy recall.

In this single slug configuration, MB-1's Instantaneous power (TUNE), Average power,  Peak power, and Min/Max functions are available.  And as mentioned previously, since the Bird slug itself provides compensation across the entire HF band, no band correction is required for 160 meters - 10 meters. If you are using the MB-1 OEM calibration table with your Bird line section, band correction factors have been included in this table for the 6 meter band so that you can use the single HF slug from 160m - 6m. If you are doing your own custom calibration, you can do the 6 meter band correction as part of the calibration, if you want to also use the HF element for 6 meters.

Since only a new calibration table is required to interface your Bird section to MB-1, no firmware update is necessary.

The photos below show the DC connector from the line section being disconnected from the meter movement and being connected to an RCA cable that can plug directly into an MB-1 coupler port.  (RCA jack).

Some A/B Measurement Comparisons between the MB-1/Bird Element and the Measurement Reference

The measurements below were taken after calibrating the Bird element using the Alpha 4510 as the reference. Any accurate reference can be used including the MB-HF-1 coupler in combination with a digital multimeter. The Alpha is left in line below so that the tracking between the MB-1 and the measurement reference can be checked. 

7-Segment LED Configuration:

Bird Dual Line Sections