MFJ MFJ-821B Vhf Power Swr Wattmeter Field Meter MFJ-812B 144-220 Swr/wattmeter

( Brand: Mfj ), ( Manufacturer Part Number: MFJ-821B ), ( Compatible Brand: Universal ), ( Type: Wattmeter ), ( Unit Type: Unit ), ( Band: Vhf ), ( To Fit: Ham Radio Transceiver ), ( Country Of Origin: United States )

Review MFJ Vhf Mhz Power Swr/wattmeter Field Strength Meter

The **MFJ-821B** and **MFJ-812B** are versatile, high-performance VHF/UHF power and SWR meters designed for amateur radio operators, field day enthusiasts, and professional communicators who demand precision, durability, and ease of use in both stationary and mobile environments. These field meters are engineered to provide real-time measurements of transmitted power, reflected power, and standing wave ratio (SWR) across the 144 220 MHz frequency range, making them indispensable tools for optimizing antenna performance, troubleshooting transmission issues, and ensuring efficient power delivery. The **MFJ-821B** builds upon the reliability of its predecessor, the **MFJ-812B**, by incorporating enhanced features such as a more robust construction, improved accuracy, and a user-friendly interface with backlit displays for clarity in low-light conditions. Both models utilize a high-quality directional coupler to measure forward and reflected power with exceptional sensitivity, ensuring accurate readings even at low power levels, while their rugged, all-metal construction protects sensitive components from environmental factors like dust, moisture, and mechanical stress. Ideal for portable operations, these meters feature a compact yet sturdy design with a built-in handle for easy transport, making them perfect for field day setups, emergency communications, or on-the-go testing. The **MFJ-821B** further distinguishes itself with a wider frequency range and a more precise measurement system, catering to users who require higher performance in competitive or professional settings. Whether you're calibrating an antenna system, monitoring power output during a contest, or diagnosing SWR mismatches in a mobile setup, these meters deliver the accuracy and reliability needed to maintain optimal signal integrity. With their intuitive controls, durable build, and comprehensive functionality, the **MFJ-821B** and **MFJ-812B** remain trusted companions for radio enthusiasts seeking dependable performance in every operating scenario.

The MFJ-821B and MFJ-812B are popular VHF/UHF field meters designed to measure SWR, power, and other RF parameters. Below is a detailed breakdown of their pros and cons, followed by a concluding recommendation.

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### **MFJ-821B (VHF/UHF Field Strength Meter with SWR/Power Metering)**

1. **Versatile Functionality** Combines a field strength meter, SWR meter, and power meter in one unit, making it useful for both field testing and antenna tuning.

2. **Wide Frequency Range** Covers 144 440 MHz (VHF/UHF), suitable for amateur radio bands like 2m, 6m, and 10m.

3. **Field Strength Measurement** Allows for signal strength analysis, useful for DXing, repeater checks, and interference detection.

4. **SWR and Power Measurement** Accurate readings for antenna tuning and transmitter output checks.

5. **Portable and Rugged** Compact design with a durable build, ideal for field use.

6. **Backlit Display** Improves readability in low-light conditions.

7. **USB Interface** Can log data for later analysis, though software support may be limited.

8. **Affordable** Generally priced lower than dedicated field strength meters from other brands.

1. **Limited Frequency Coverage** Does not cover HF bands (below 144 MHz), restricting its use to VHF/UHF only.

2. **Accuracy Concerns** Some users report discrepancies in power/SWR readings compared to more expensive meters, especially at higher power levels.

3. **No Built-in Antenna Analyzer** While it measures SWR, it lacks the detailed impedance analysis of a dedicated antenna analyzer.

4. **Software Dependence** The USB logging feature requires compatible software, which may not be actively updated.

5. **No Bluetooth/Wi-Fi** Relies on USB for data transfer, which can be cumbersome for real-time monitoring.

6. **Durability Issues (Reported)** Some users mention plastic components may wear out over time with frequent use.

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### **MFJ-812B (VHF/UHF SWR/Power Meter)**

1. **Simpler Design** Focuses primarily on SWR and power measurement without the field strength meter, making it more straightforward for antenna tuning.

2. **Reliable for Basic Use** Works well for checking SWR and forward/reverse power, which is essential for safe transmitter operation.

3. **Budget-Friendly** One of the most affordable SWR/power meters in its frequency range.

4. **Compact and Portable** Easy to carry in a field kit or vehicle.

5. **Good for Beginners** Ideal for operators who need a no-frills meter for basic antenna work.

1. **No Field Strength Metering** Lacks the signal strength analysis feature of the 821B, limiting its use for DXing or interference checks.

2. **Less Versatile** Not suitable for advanced RF analysis or logging.

3. **Potential Calibration Drift** Like many budget meters, accuracy may degrade over time without recalibration.

4. **No USB Logging** Cannot store or transfer data electronically.

5. **Limited Frequency Range** Same as the 821B (144 440 MHz), so not useful for HF operations.

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### **Comparison Summary**

Feature MFJ-821B MFJ-812B

----------------------- ----------------------------------- -----------------------------------

**Primary Use** Field strength SWR/power SWR/power only

**Frequency Range** 144 440 MHz 144 440 MHz

**Field Strength** Yes No

**Data Logging** USB (limited software support) No

**Price** Mid-range Budget

**Best For** Operators needing signal analysis Basic antenna tuning

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### **Conclusion and Recommendation**

The **MFJ-821B** is the better choice if you need a **multi-functional meter** for both **SWR/power measurement and field strength analysis**. It s ideal for:

- DXers who want to check signal strength.

- Repeater users who need to monitor interference.

- Operators who want a single device for antenna tuning and RF analysis.

However, if you **only need SWR and power measurement** and want a **simpler, more affordable option**, the **MFJ-812B** is sufficient. It s a solid choice for:

- Beginners who don t need field strength readings.

- Operators who prioritize cost over additional features.

- Those who already have a separate field strength meter.

- **Buy the MFJ-821B** if you want versatility and field strength capabilities.

- **Buy the MFJ-812B** if you only need basic SWR/power metering and want to save money.

For **HF operations**, neither meter is suitable consider a dedicated antenna analyzer (e.g., MFJ-259 or Rigol DS1054Z) or a more advanced field strength meter like the **MFJ-993C** if you need broader coverage.

If accuracy is critical, you may also consider higher-end meters like the **Narda SRD-100** or **Bird 43** for better precision, but they come at a significantly higher cost.

Details:

MFJ-812B VHF 144-220 MHz Power SWR/Wattmeter Field Strength Meter. Good condition.

part #: mfj-812b prices

• $30.00-$40.00

specifications hamamateuradio:

• brand: Mfj
• mpn: Mfj-821b
• compatible brand: Universal
• type: Wattmeter
• unit type: Unit
• band: Vhf
• to fit: Ham Radio Transceiver
• country of origin: United States

returns hamamateuradio:

• method: Money back
• time: 60 Days
• policy: Returns Accepted
• paid by: Buyer

seller hamamateuradio:

• city: Indianapolis, Indiana
• # reviews: 861
• rating: 98.2%

general hamamateuradio:

• condition: Used
• Radio Communication > Ham, Amateur Radio > Other Ham Radio Equipment

offer hamamateuradio:

• quantity: 1
• sold: 0
• options: Ship-to-home
• started: March 13, 2026
• availability: In Stock

shipping hamamateuradio:

• cost: $0.00
• carrier: USPS
• class: Standard
• transit: 5-11 Days
• type: Calculated
• service: USPS Ground Advantage

payments hamamateuradio:

• credit card: Mastercard
• other
• wallet: Paypal

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