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Uniden R4 vs. Uniden R8: What’s The Difference & Which One Should You Buy?


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Uniden R4 vs. Uniden R8: Quick Take

The Uniden R4 is the upgraded version of the popular R3, whereas the R8 is the updated version of the trusty R7. Both the R4 and R8 are built on new platforms, giving them an advantage in terms of range and available features when compared to the older R3 and R7. As far as which one you should go with, here is what we recommend.

  • When it comes to price: The Uniden R4 is our choice. As of this writing, it retails for about $400 on Amazon. If you are new to radar detectors, the R4 is easy to use and will give you plenty of advance notice when a radar source is nearby.
  • When it comes to features: The R8 is the better option with its directional alert arrows and more expansive OLED display. As of this writing, it retails for about $700 on Amazon.

Let’s take a closer look at each radar detector.

Uniden R4: The Perfect “Grab & Go” Unit

Uniden R4 in Alert Display Style #1
Uniden R4 in Alert Display 1

The Uniden R4 sits alongside units from Escort, Cobra, Radenso, and K40 in my collection of radar detectors. While my Escorts are nice with all the Bluetooth features, sometimes I don’t need all that “stuff” when I drive. My goal was to find a “grab and go” radar detector for quick trips around Detroit with decent range and good false alert filtering for a reasonable price.   

At first, I sought out two inexpensive Cobra units but was only satisfied with one and developed a love/hate relationship with the other. Since ordering my R4, I haven’t used my Cobra radar detectors all that much. Here is a link to my full review of the Uniden R4, but allow me to summarize some of the high points. 

Radar & Laser Protection

The Uniden R4 will alert you to X, K, and Ka radar bands and laser (LiDAR) guns. While you will have the occasional K band false with the R4, the new Auto Mute Memory feature will sometimes jump in to save them.

With its Auto Sensitivity mode, the R4 is a great “set it and forget it” radar detector. Auto Sensitivity mode is speed-dependent, automatically switching back and forth between City and Highway modes at a pre-set speed via the settings menu. The faster or slower you travel determines whether the R4 is in City or Highway mode, but you don’t have to touch the unit either way.

You can experiment with the K and Ka filters in the settings menu, including a segmentation filter. Since Ka is most common here in Michigan, I have my R4 set to narrow segmentation. In narrow segmentation, the R4 scans only for U.S.-spec guns versus the entire Ka frequency range (or wide segmentation). Since the R4 is not watching the full Ka frequency range, it has a quicker response time.

The R4 can also detect POP transmissions, MRCD, MRCT, RT3, and RT4 (RT3 and RT4 being the separate frequency ranges of Gatso radar). This means the Uniden R4 will alert you to a wide variety of radar sources, from patrol cars and speed traps to traffic cameras and other photo enforcement devices. When warning you of an upcoming red light or speed camera, the R4 will show traffic light or camera icons and the corresponding distance (in feet) to the alert. 

All Threat Feature

The R4 will simultaneously detect up to four radar bands and show each of them visually through the All Threat feature in the settings menu. The strongest signal is designated as the priority, showing front and center on the OLED display. Any other signals appear on the left side of the screen and resemble a little digital chart. Below this digital chart is the type of radar band, followed by signal strength bars that ascend vertically the closer you get to the source.

The default setting for the All Threat feature is off, but turning it on will give you more situational awareness. Since the R4 does not have directional alert arrows like the R8, having the All Threat engaged will give you an idea of everything happening in the immediate area.

Memory Quota

The R4’s updated platform supports a feature called Memory Quota, something the R8 will also have. Memory Quota lets you set the individual number of Mute Memory and Mark Locations. In total, the R4 can save up to 2,000 points between the two, but you can allocate that one way or another in 50-point increments.

For example, I have my Mute Memory set at the maximum of 1,750 allotments, meaning I have 250 for Marked Locations. I tend to encounter more Mute Memory locations here in Detroit, so I want the highest allotment possible. However, I could drop that allotment for Mute Memory in 50-point increments if I need more room for Marked Locations.

Driving With The Uniden R4

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I appreciate my R4 when traveling on main thoroughfares like Novi Road, Telegraph Road, and I-696 here in the Detroit metro. These areas are heavily patrolled between the local Sheriff’s Deputies and Michigan State Police, and the amount of traffic combined with the layout of these roads makes it hard to see law enforcement.

While you will come into contact with the occasional K band false, the R4’s range is hard to beat. Here in Michigan, law enforcement has a contract with DBA Stalker Radar & Video, so we see a good combination of constant-on and instant-on Ka band, which the R4 alerts to. Since Ka is the most common radar band in use today, the Uniden R4 is a good pick if you are shopping for a reliable radar detector but don’t want to spend the money on an R8.

If you are on a stricter budget than what the R4 allows, look at the Uniden R3 instead. Although the R4 is technically the replacement, Uniden still offers the R3 as a value option (it’s about $100 less than the R4 at the time of this writing). Although the older R3 won’t have as many features, it’s still a fantastic “grab and go” radar detector with accurate, long-range detection.     

Uniden R8: The Radar Detector for Diehards

Uniden R8 in Alert Display 2.
Uniden R8 in Alert Display 2.

The Uniden R8 and R4 are close in terms of performance and features. For example, both have the Auto Mute Memory feature, Auto Sensitivity mode, and the Memory Quota option. However, the R8 offers a larger OLED display, directional alert arrows, and longer range detection. 

When it comes to the Uniden R4 vs. Uniden R8 discussion, there are two ways to look at it. If you are more pragmatic and just want a little peace of mind for your daily drive, the R4 is absolutely the better choice. However, if you are an enthusiast who loves cool gadgets, then the R8 will be worth every penny.       

Here is a link to my full review of the R8, but allow me to summarize some of the high points. 

Radar & Laser Protection

The Uniden R8 will alert you to X, K, and Ka radar bands and laser (LiDAR) guns. Like the R4, the Uniden R8 has a City and Highway mode. In City mode, X and K band sensitivity is reduced to prevent false alerts, while Ka bands stay at full sensitivity. In Highway mode, all bands move to full sensitivity for the most reaction time on the open road. 

You can optimize the R8’s sensitivity levels through the Advanced mode and adjust the Rear Balance in the settings menu. Like the R4, the R8 also has an Auto Sensitivity mode. 

Directional Alert Arrows

This is one primary differentiator between the R4 and the R8. The R8’s larger platform houses two radar horns – one front-facing horn and one rear-facing horn – to enable the arrows. When you receive an alert, the R8 will flash an arrow on the OLED display to let you know which direction the threat is coming from (front, rear, or side).

You can set the R8 to announce the type and frequency of any radar bands you encounter via the settings menu. If you do, the R8 will also announce the direction of the radar source as it displays the arrow.

Driving With The Uniden R8

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The main question is whether or not directional alert arrows are worth the price jump between the R4 and R8. That depends on a couple of different factors.

If you live in a smaller town, the Uniden R4 is enough. While the directional alert arrows are nice, you probably don’t need to spend the money on an R8. Where I grew up in rural Iowa, the local officers always “hid” in the same spots, like the Bomgaars parking lot or by the ballfields as you came into town. If you live in an area like this, save the money and go with the R4.

However, the directional alert arrows are helpful for me in metro Detroit, where my daily commute is much more involved than when I was living in Iowa in high school. If you don’t mind spending the money, the R8 will give you the most situational awareness with the least amount of effort. This is what I appreciate most about the R8. With the directional alert arrows, voice notifications, Gatso detection, and All Threat feature, I always have a good idea of what’s happening around me.

Uniden R4 vs. Uniden R8 Verdict

  • Performance & Value Combo: The Uniden R4 is our pick, retailing for about $400 on Amazon. The Auto Sensitivity mode makes the R4 easy to use no matter where you live. And if you are new to radar detectors and looking to purchase your first one, the R4 is a great choice.
  • Features & Functionality Combo: The R8 seals the deal because it offers all the bells and whistles. As of this writing, the R8 retails for about $700 on Amazon, but if you are a radar detector enthusiast, the R8 is a must-have.   

For additional insight, browse through the Radar Detector forum, which has an entire discussion section dedicated to Uniden radar detectors. There are tons of people on there (myself included) who can help you make the best decision.

Carl Anthony is Managing Editor of Automoblog and a member of the Midwest Automotive Media Association and the Society of Automotive Historians. He serves on the board of directors for the Ally Jolie Baldwin Foundation, is a past president of Detroit Working Writers, and a loyal Detroit Lions fan.