The Model 43 requires
plug-in elements (often referred to as "slugs") for the frequency range and power range for which the meter is going to be used.
There is a large selection
of elements available that cover the frequency range from 0.45 MHz to 2.5 GHz in power ranges from less than one watt to
more 10,000 Watts. The Bird Model 43 is an in-line wattmeter that reads forward and reverse power. From these two measurements
it's possible to easily calculate the SWR (Standing Wave Ratio) from the RF load (antenna, amplifier, filter, etc.).
The connectors on the Model 43 can be Type N, UHF, TNC, BNC, etc., and are easily changeable with only a screwdriver required.
Many users purchase multiple connectors and have them available for quick changes when needed.
It's a good idea to have an RF Load available to terminate one end of the
wattmeter if you are going to measure transmitter output power and do not want
to use the antenna as a load. The RF shop has a large selection of
RF Loads
for you to choose from.
Coaxial Dynamics is another manufacturer that offers high quality RF power measurement products similar to the Bird Electronic products. The two manufacturer's plug-in elements are interchangeable.
These meters cover a wide frequency and power range without the need to purchase expensive elements.
The meters have front panel
switches that select the power range from 5 Watts full scale to 500 Watts full scale.
Although, these broadband RF Wattmeters are
more expensive initially, you will avoid a lot of expense by not requiring
multiple plug-in elements or slugs in the future.
Telewave, Inc. manufacturers a low frequency (2-200 MHz) and a high frequency (20 MHz to 1000 MHz) model of this type meter. You should note that the maximum power of 500 Watts on these style, as well as other RF wattmeters. is the RMS or average rated power. If you are measuring single side band (SSB) PEP (peak envelope power) the meter can be used at much greater than 500 Watts. As long as the average power is less than 500 Watts it will be displayed correctly on the wattmeter. When measuring RF power of SSB voice transmissions wattmeters will display the average power which is considerably less than the peak power. In other words, a 500 Watt maximum power scale will be adequate to measure SSB voice transmissions up to 2000 watts. For more details on this subject visit this link Power - What's It All About. To measure true peak power you will need a peak measuring wattmeter like the Bird Model 43P, 4314 and APM-16. See more on these meters below.
With the Model
4410(A) only a few elements are required to cover the frequency range of 0.5 to 1000 MHz and 1 Watt to 10,000 Watts. This meter
provides the ultimate in RF power measurement versatility.
This is one of our best selling models and is available in several packages.
Bird Wattmeters
For an example, the 4410(A) with one HF element (2-30 MHz) has seven full scale power measurement ranges
of 1 Watt, 3 Watts, 10 Watts, 30 Watts, 100 Watts, 300 Watts and 1000 Watts. The
Bird 4410(A) elements as listed separately and are not interchangeable with the
Model 43 elements. If you plan to measure power at a lot of different
frequencies and power levels the 4410(A) will save you money in the long run by
drastically cutting the number of elements you will need to have on hand. Before
I discovered the 4410(A) I was carrying around 15-20 elements to cover the many
uses that I have for an RF wattmeter.
The Bird APM-16 employs active circuitry to deliver
accuracy of ± 5% for multiple-access technologies such as CDMA, TDMA, FDMA and
other digitally-encoded communication systems.
As the name implies these wattmeters have a RF termination, usually 50 Ohms.
They are available in a variety of shapes and sizes and can be air cooled or oil
filled. They are typically good to about 100 Watts, however, there are some
models that will handle as much as 1-2 KW, for example the Bird model 694. Adding a cooling fan to the heat radiator can extend the useful power
range of the RF load. The RF shop offers a good selection of terminating wattmeters and RF loads available at
these two links
Wattmeter/RF Load
and
RF Loads
In-line wattmeters can be used as a terminating wattmeter by connecting a RF load to one of the RF connectors on the wattmeter.
The intermittent power ratings on these RF loads are much higher than the
continuous power rating.Calibration of broadband RF wattmeters requires some very specialized and expensive equipment. In almost all cases a NIST traceable calibration can only be performed by the manufacturer. The RF Shop checks each meter and element that we sell for accuracy using high quality calibrated wattmeters and test equipment, however, this is not a traceable calibration. If you require a full calibration we can have the product calibrated for you by the product manufacturer for an additional cost. This usually takes about 2-3 weeks and costs from $75-$400.