July 2002 product reviews

flected power and SWR simultaneously.
stances you’ll be concerned with average test gear you’ll ever own is your watt- power, leaving it up to you to “ask” for do an adequate job in this department.
the output of your transceiver and adjust a calibration knob. Other wattmeters dis- at 2, 14, 28, 50 and, for those meters with it accordingly. A wattmeter can alert you play only forward or reflected power— curacy tests were conducted at 5, 100 and power at a particular point. With the for- reading. That is, they can display power levels that are present at extremely brief wattmeter to calculate feed line loss—just SSB signal that can have a relatively low compare the power at the input of the feed average power, but include numerous bursts of higher peak power that exist for are not laboratory-grade meters. Al- ers include wattmeters, but these are tied meters: active and passive. The active brated ARRL Lab equipment, it isn’t fair stalled. In contrast, a stand-alone wattme- wattmeters sample peak power levels elec- to expect the same level of performance.
If you require extreme accuracy, you have nient when you’re trying to troubleshoot take a measurement at the feedpoint of an can tolerate reasonable accuracy; you guess, active wattmeters provide the most don’t need to split hairs at tiny fractions accurate peak-power readings. In most in- DIAMOND SX-200
DIAMOND SX-200
stacked scales and a single meter movement lighted, but you have to supply an external12-V power source (Diamond includes the 200 you have to use the front-panel switches to jump between forward power, reflectedpower and SWR functions as necessary. The SX-200 is a passive peak-reading meter with a switch to select either average or peak- power modes. To measure SWR, you mustfirst calibrate the SX-200 in the calibrate control, then switch to the SWR mode. TheSX-200 specifies a frequency range of 1.8 desktop meter, the SX-200 measures 6 × 2 one of the heftier meters of the bunch.
quite good in our Lab tests, but the for-ward power accuracy could have beenbetter. From a user standpoint, we foundthe need to frequently change switch set-tings a little cumbersome. The meter isruggedly built, however, with a sleek, at-tractive appearance.
Manufacturer: Diamond Antenna, 435 tel 760-744-0900; www.rfparts.com/
diamond/. $99.95.
DIAMOND SX-20C
button selects average or peak power dis- × 35/16 × 33/4 inches) designed to be as gedly built as the Diamond SX-200. In plays. The frequency range of the“hands off” as possible. The SX-20C is intended for mobile use, but it works just housed in a 41/2 × 31/4 × 31/4-inch alumi- Manufacturer: Diamond Antenna, 435 num case. The display is illuminated and, other (the so-called “cross needle meter” 92069; tel 760-744-0900; www.rfparts.
com/diamond/. $89.95.
12-V dc “wall wart” supply to power the PALSTAR WM150
DIAMOND SX-20C
Frequency Range: 3.5-150 MHzPower Range(s): 30/300 WPEP Measurement: None Actual Forward Power (Average only)Frequency (MHz) From July 2002 QST ARRL
PALSTAR WM150
Palstar states that the meter is not specifi- Frequency Range: 1.8-150 MHzPower Range(s): 300/3000 W cally designed for accuracy above 50 MHz.
45356; 937-773-6255; www.palstarinc.
com/. $89.95.
DAIWA CN-101L
the cross-needle meter design more than20 years ago, and it has been showing up 101L is a desktop meter with three switch selectable power levels: 15, 150 and 1500W. The frequency range is 1.8 to 150 was 1.7:1 (2.5:1 indicated onmeter), possibly affecting unit requires more than 5 Wfor proper operation.
requiring external power isused. “Passive” indicates a peak envelope power (PEP). The CN-101L isn’t well designed for peak powermeasurement, and the manual says asmuch (see the note in the data table).
pany, 60 9th Floor, TOC Building, 22-17-7 chome, Nishi-Gotanda Shinagawa-ku,Tokyo, Japan. Available from several US DAIWA CN-101L
dealers. Typical street price $94.75.
DAIWA CN-410M
Power Range(s): 15/150/1500 WPEP Measurement: Passive† that also features Daiwa’s famous cross- pleasant experience in the shack as well.
The CN-410M is designed for operation (peak or average). The CN-410M comeswith a mobile mounting bracket. Accord- 3 W, but this aspect of its performancewas not tested.
CN-410M has been discontinued. How-ever, this meter is still quite popular at hamfest fleamarkets and on-line auctions.
*According to the CN-101L manual, “For monitoring PEP, a condensor is placed into detector circuit. This function can not hold peak envelope power.” but we noticed that its accuracy declined at †For PEP monitoring, “Active” indicates that a circuit requiring external power is used.
the high end of its range. Also, on 2 meters, “Passive” indicates a circuit that requires only RF.
‡Amplifiers for 6 meters or 2 meters were not available at the time of testing.
a significant figure at this frequency.
From July 2002 QST ARRL
MFJ ENTERPRISES MFJ-860
Frequency Range: 1.8-54 MHzPower Range(s): 30/300 WPEP Measurement: None Actual Forward Power (Average/Peak)Frequency (MHz) DAIWA CN-410M
Actual Forward Power (Average only)Frequency (MHz) Note
*SWR on input was 2:1 at 100 W on 144 MHz, so test was not
dealers. Typical street price $98.75.
and at 5 × 31/2 × 5 inches it is the largest VECTRONICS PM-30
meter tested for this review. A Lexan face varied considerably according to thepower level and frequency. SWR accu-racy was fair.
Manufacturer: Vectronics, 300 Indus- trial Park Rd, Starkville, MS 39759;
800-363-2922; www.vectronics.com/.
VECTRONICS PM-30
Frequency Range: 1.8-60 MHzPower Range(s): 300/3000 W MFJ ENTERPRISES MFJ-860
wattmeter in this group. At about 41/2 × 31/2 × 21/2 inches, it is also among the smallest. It sports the convenient cross- readings. In fact, the only switch on the two power ranges: 30 and 300 W. TheMFJ-860 is average-reading only. The was surprisingly accurate. Its insertionloss was also acceptable and well within related to the small size of the meter dis-play itself. It can be difficult to read un- †For PEP monitoring, “Active” indicates that a circuit requiring external power is used.
“Passive” indicates a circuit that requires only RF.
‡Amplifiers for 6 meters or 2 meters were not available at the time of testing.
674-1800; www.mfjenterprises.com/.
$44.95.
From July 2002 QST ARRL

Source: http://ham.srsab.se/test/wattmeter.pdf