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Reviews For: Alpha 4510 HF Digital Wattmeter

Category: SWR & Wattmeters & Dummy Loads

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Review Summary For : Alpha 4510 HF Digital Wattmeter
Reviews: 21MSRP: 745
Description:
1.8-30 MHz digital wattmeter that covers from 60mW to 3000 watts. Analog readings for forward, reverse and SWR with 4 digit readings for PEP, RMS and Delivered power.
Product is in production
More Info: http://www.alpharfsystems.com/
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00214.9
K6AER Rating: 2004-06-29
Incredible Lab Grade Instrument Time Owned: 0 to 3 months.
Lab Grade HF Wattmeter

I bought the 4510 Alpha wattmeter, serial number 0009, at Dayton. First some background; I am a microwave engineer and own a far amount of Hewlett Packard/Agilent test equipment. Having said that, I can attest to the fact that 99% of the watt meters on the market today are at best… wishful thinking. You know the types, each scale reminds you of a contest signal, all are 59 or above. The higher they read for a given wattage the better they make you feel. At least that what most marketing folks think. The Bird 43 and Coaxial Dynamics units are OK but leave much to be desired if you want accurate readings of low to high power SSB HF transmissions. A lab grade HF amateur wattmeter has been left to our imagination until now.

The 4510 is everything you could want in a lab grade HF wattmeter. Frequency is from 1.8 MHz to 30 MHz. Meter wattages are read in 5 dB levels from .3 watts to 3000 watts on the analog scale for FORWARD, REFLECTED and SWR. The digital scale reads in 4-seven segment LEDS the actual wattage for PEP, RMS and DELIVERED (Forward minus Reflected). The wattmeter has AUTO range where it selects the proper wattage scale for the analog meter. You can not over drive the meter for the microprocessor will limit the maximum meter deflection. The watt meter has a RS-232 output so you can display the meter readings on a computer. The computer driver for this program is included in the price. All that is needed is a straight RS-232 cable. The analog meter has a very bright blue/white LED’s lighting the meter face. If you don’t use the meter in a 2 minute period the meter goes into the sleep mode and only the ON LED is light. Upon any RF sensing the meter instantly comes to life, very cool.

About the circuitry. The Alpha 4510 has two microprocessors. One for frequency detection, RF sampling and A to D conversion on the RF board. The other for display, calibration and buss functions on the display board. The RF section is a strip line coupler that is compensated from an algorithm in the microprocessor that corrects for frequency, temperature and calibration variables. The wattmeter come with the best manual I have ever found on an amateur piece of equipment. It is in the same class as commercial Agilent/HP test equipment.

It this point you are wondering if the price is worth the $1100. Absolutely, no regrets what so ever. I tested the 4510 watt meter against my Agilent EPM-442 digital wattmeter and my HP8953E spectrum analyzer. In each test, on each band, we used a calibrated dummy load and tested the losses for the tap level and cable losses. Alpha specifies the accuracy to be +/-5% with typical accuracy of around 3%. I found the accuracy to be on average of 2.7 % for the bands tested between 160 and 10 metes. To give you an idea how close this is, on 20 meters the tested wattage for a CW or SSB peak reading was 1513 watts and the 4510 Alpha reading was 1545 watts. This was within the statistical accuracy of 2% as read on a $6000 digital watt meter and a $43,000 spectrum analyzer. Low power readings were just as accurate. Five watts, 100 watts or 2 KW it didn’t matter. The wattmeter will detect down to 60 mW. Perfect for calibrating QRP rigs.

Input DC voltage is 12 VDC from a switch mode external power supply that accepts from 100-240 VAC. The coax connections are direction sensing so you cannot connect the transmitter and antenna load to the wrong ports. The coax connectors can be changed from the outside from UHF (supplied) to “N” type. Weight is 9 lbs. So the cast aluminum case will not have the RG-213 moving it around. When the meter is turned off the meter movement has a DC shunt across it so vibration cannot damage the meter movement.

Bottom line is this wattmeter is high accurate, lab grade instrument that not only is the last word on your power output but serves as a bench mark for all other watt meters being produced to become. No more guessing if you amplifier has lost some of its dynamic range, you can see readings down to a watt on the 3000 watt scale. If you are a stickler for accuracy you got to get one of these watt meters.