Comparing meters is like comparing apples and oranges; meters vary in features, form and in function. It's very difficult to compare two meters directly against each other so the main goal of this article is to highlight the indiviudal features and quality of each meter. For this review we picked three meters that sell for around the $100 price point. The Astatic 600 and Workman P5000 are basically identical three-window meters with some key differences, while the Dosy is a single window meter that also sports most of the same features as the other two.
Pricing can vary for these units online so it's best to shop around for the best deal.
The Astatic 600 is a three-window meter that measures SWR, RF Power (Wattage), and Modulation percent. The meter has three individual windows so that you can see each measurement simultaneously. This meter also comes with an AC to DC wal-wart power supply which is required to power the meter's lamps for illumination. Each meter has its own individual lamp.
The meter has a lamp on/off switch on the left side, next is a REF / FWD control. The REF position is used when setting or calibrating the SWR meter and the FWD position is then used to check the SWR. The knob just to the right of that is your SWR calibration knob.
In the middle of the meter is the power setting control with settings of 10, 100, 1000, and 5000 watts. When using the meter it's important to set the meter to the proper power scale for your input. For example, if you intend to use a 300 watt amplifier you should set the meter to the 1000 watt setting.
On the right side of the meter the next knob after the power scale control is the modulation meter calibration knob. This knob is used for calibrating the modulation meter prior to taking your modulation readings. To the right of that is the modulation set/mod control. The set position is used during calibration and once calibrated the mod position is used for measuring modulation. The last switch on the right is the Peak/Avg power switch which toggles between average power readings and peak power readings.
At the back of the unit you'll find the SO-239 coax connectors and the DC IN socket for your power input.
SWR - The Astatic 600 did a good job of measuring SWR and its readings were very close to other meters and my MFJ-259B. The calibration process was easy enough and once set (as long as you don't change power levels) you're ready to go.
Wattage - Power readings were a little low on this meter about 20-25% off of actual wattage. This meter was fairly consistent across the different power levels but once into the 1000 watt scale there was some variance.
Modulation - The modulation meter seemed to give a good portrayal of modulation but it's important to keep in mind these types of meters are designed to give the user a "good idea" of their modulation, not laboratory results.
ASTATIC 600 SUMMARY
GRADE = C+
This meter falls into the under $100 range and offers three window simultanous measurement of SWR, Wattage and Modulation. At this price range it's a popular choice for CBer's and it offers measurements that are "good enough" for most of the CB crowd. It's lacking in its wattage accuracy and while it will display peak output it isn't a true active peak reading meter so the readings aren't as accurate as more expensive higher end meters.
The Workman P5000 and the Astatic 600 are almost exact copies of each other. The meters use the same case, similar components inside, and the same layout for knobs and controls.
Two of the most noticeable differences between the Workman and the Astatic versions of this meter are that the Workman P5000 doesn't come with the wal-wart (it comes with a plug with wires to connect to a 12V power source) and it has the addition of a headphone jack where you can plug in the included headphones to monitor yourself (talkback basically).
The Workman P5000 features the same three window setup as the Astatic 600 and the knobs and functions on the front of the radio are identical to the Astatic 600 so we won't go into detail describing each function again.
At the back of the meter you will notice that it looks different than the Astatic 600 due to the addition of the "sound" control potentiometer which allows you to adjust the volume of the headphone jack on the front. This control is supposed to have a knob on it but this brand new unit was missing it when I unpacked it. The variable control isn't really that variable and I found it didn't do much until the very end of its range where you had to very carefully adjust the volume as it went quickly from quiet to loud.
While the meters are almost identical, there are some quality differences and one of the first things we found is that one of the knobs turned but didn't do anything on the meter. There wasn't any positive engagement on the switch and it took me a minute to figure out what was going on. While the Astatic 600 knobs worked well, the Workman P5000 knobs seemed much cheaper and they had an outer shell that slid onto the clear plastic portion. This black outer shell wasn't connected to the inner piece via glue, pressure, or any other method and so it freely slid along the surface, making the knob useless. To actually move the meter switch I had to pull the knob completely off the meter.
SWR - The Workman P5000 performed well for measuring SWR and it showed readings very similar to the Asatic 600, which would be expected.
Wattage - Power readings were actually slightly more accurate than the Astatic 600 which would indicate that from meter to meter (Workman P5000 or Astatic 600) there may be some variance in how the meter is calibrated from the factory. Readings were still 10-15% low. Again like the Astatic 600 this meter was fairly consistent across the different power levels but once into the 1000 watt scale there was some variance.
Modulation - Worked in a fashion identical to the Astatic 600. Should be good enough to give most CBer's a general idea of their modulation levels.
WORKMAN P5000 SUMMARY
GRADE = D
The talkback monitoring function of this meter works fairly well (AM only) and that's really the high point of the meter. While it offers the same functions, lights, and features as the Astatic 600, and its accuracy and function are almost identical, the workmanship of the knobs, the lack of the power adapter, and the missing knob on the back leave me to believe that the quality on these units is lower than the Astatic 600.
One of the main reasons I chose to use such similar meters in this review was to see if there was any "real" difference between these two and the final verdict is yes. The difference is in the quality of the knobs - if I narrowed my choice down to between these two meters the Astatic 600 would get the nod.
Now maybe it's a bit strange to compare two three-window meters against a single window meter but I thought in this $85-$130 price range it would interesting to see if there was any difference in dropping the extra $20 and buying the more expensive meter.
The Dosy meter measures SWR, Wattage, and modulation just like the first two meters but it only has one window which means the readings aren't simulatanous and it requires switching between functions. This meter is advertised as being made in the USA while the other two don't state where they are made (China most likely).
The Dosy meter does have a lighted display and it comes with a 12 plug for the back and comes with a wal wart to power the meter. If you intend to use it mobile you'll have to fashion your own plug to wire in the vehicle.
Looking at the left side of the meter the first knob is the SWR calibration knob. Just below that is a RMS/PEAK switch which allows you to switch between average wattage readings and peak wattage readings. Next is a switch to flip between a 2000/4000 scale (this is in addition to another knob that selects your wattage level). In the middle is the Modulation / SET (modcalibration) switch. The small knob located along the bottom is to adjust the volume of the monitoring levels for the phone (headphone jack). The last switch is the modulation SSB/AM switch to be set depending on the mode of operation for which you are checking modulation.
The most important knob on the meter is the mode selector. This knob allows you to set the wattage level for reading output on the meter (example: if you have a radio with 100 watts output you'd want to use the 200 watt setting on the knob). The knob also has options for SWR (to check your SWR levels), SWR SET (to calibrate your meter before checking SWR), and MOD (to check your modulation level).
The meter light on/off switch is just to the left of the mode knob and says "Lite" next to it.
At the back of the meter you'll see your input jacks and the power input plug.
The Dosy did come with a set of headphones so that you can monitor your tx audio (basically talkback) through the meter. The headphones themselves were of very low quality and I actually threw them out and plugged in my ipod headphones which worked much better.
SWR - The SWR meter worked well on the Dosy and gave the expected readings for SWR matching up with my MFJ-259B's readings.
Wattage - The Dosy was the most accurate of the three meters. On the 20 and 200 watt scales it did show the AM carrier at 1 watt higher than the actual output but when measuring peak output the Dosy was much more accurate than I expected. It was only 10% off on peak readings in the 20/200 watt scales when inputing 50 watts or less. When running over 100 watts peak in the 200/2000 watt scales the AM peak readings were within a 10% margin of error but the SSB peak readings margin of error increased to 15% meter.
Modulation - The modulation measurement on this meter is easier to read than the other two and seemed to function better (the needle swing was more consistent).
DOSY TC-4001 P SUMMARY
GRADE = B-
The Dosy meters are well made (in the USA) and show a higher level of workmanship than the other two we reviewed. It's not an active peak reading meter and so we weren't surprised by the slight margins of error in the peak readings, but nonetheless for the price range this meter still gives a fairly accurate picture of SWR, Wattage, and Modulation.
The knobs have a much better feel than the other meters and while it doesn't have the three-window simultanous display I found the larger size meter face was much easier to read and the movement was easier to follow.
It's more expensive than the other two by at least $20-30 but around the $90-120 price range I'd choose this meter over the other two for my personal shack. If you're looking for even more performance from your meter there are some active peak reading meters in the $160+ price range. So if you can afford to spend a bit more cash on a meter those might also be an option.
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