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Determining Display Screen Sizes for Ham Shack Video Monitors

Jeff Wayne (K1YLV) on March 8, 2017
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Determining Display Screen Sizes for Ham Shack Video Monitors
By Jeff Wayne, K1YLV

How large should your flat panel display be? Today, we have more and more digital radios being sold that accept external video/data monitors to supplement the displays built into the radios. Some think that “Bigger is better”.

I have been in the audio visual industry for about 45 years. First as a school district’s Director of Media Services, and then in sales for several major AV system integration companies. We actually have a rationale for specifying display screen sizes, and you will probably be surprised to find out what is recommended and why.

Whether you need to add one or more video/data displays to your ham shack, or need a basic computer monitor, or TV for your entertainment room, as professionals, we begin conducting site surveys to determine several pieces of data including the following:

1. What is the maximum viewing distance from the video monitor or projection screen?
2. What is the minimum viewing distance (Front row)?

We use “Architects’ and Engineers’” specifications to determine an appropriate display image size. After that, if the customer wants to go large, we will sell him whatever he wishes to purchase.

Ergonomics and operator fatigue are critical when dealing with displays. Not only do you have to be able to see all of the data on the “Screen”, you should be able to do so without racking your head from side to side, and up and down. When I was a kid, many years ago, we would go to the movies for a Saturday matinee, and sit in the front row. When you were nine or ten, you could watch the cartoons and movies close to the screen, and still walk out of the theater without neck and back pain.

The screen size calculation has two standard numbers to consider and they depend on the content appearing on the screen. The formula is as follows: Screen Height = Distance from the screen to that last row of the room* DIVIDED BY 6**

Example: 12’ Max Viewing Distance = 2’ or 24” Display Screen Height 6
With a consumer LCD which has a 16:9 aspect ratio (Width-to-Height ratio), this would call for a 50” diagonal display for a 12’ maximum viewing distance.
*Last Row also means where your eyes will be when viewing the data at your equipment console.
**For small fonts or a display packed with data, use “6” as the divider. For general video viewing and large font content such as “PowerPoint”, you can use “8” as the divider for a smaller screen.

A second consideration is the minimum viewing distance that should be maintained. This is stated in the specifications as no less than twice the height of the display screen. If the display is too large, you will not be able to view all of the content without giving your neck fatiguing and possibly painful workout while tracking data all over the screen surface. I am composing this article on a notebook computer that has almost a 14” diagonal LCD screen. My eyes are approximately 24” away from it. The screen height is a little less than 7”. By formula, I am viewing the screen beyond the minimum recommended viewing distance of twice the screen height or 14”. I am OK.

Another ergonomic consideration is Angle of View. When viewing a video/data display, you should not have it positioned more than +/- 15o from the horizon. Have you ever visited a hospital’s emergency room and watched a TV (Which was usually on a channel that you hated) that was positioned high on a wall?

Watching a TV that is too high is difficult, especially over a long period of time. Your home TV should be mounted or placed within this range as well since you will be watching long programs and want to relax while doing so.

Basically, I have provided you with some guidelines that the “Industry” uses to size display screens appropriately. You do not have to follow these recommendations. They are starting points, and if you want a larger or smaller display, you can do whatever makes you happy.

If you want to scientifically select display monitors for your ham shack, use these guidelines and save yourself some money and a possible visit to a Chiropractor, especially after a long contest.

I am including a chart that I developed to simplify determining recommended display/projection screen sizes. I used the “6” factor that addresses small fonts and packed data displays. I hope that this will help you when adding video displays to your stations. The chart formats the formula to enable you to take the viewing distance and easily match up a display screen size.

Maximum Viewing Distance Chart for 16:9 Display Screens:

Note: Actual viewable screen sizes vary with manufacturer. Bezel widths and manufacturer’s true glass sizes vary, so please consider these calculations to be approximate. The Architects’ & Engineers’ formula of Screen Height x 6 = Maximum Viewing Distance was used, and is especially applicable for the display of smaller fonts, as used in spread sheets and AutoCAD.

Screen Diagonal		Screen Height		Max Viewing Distance
12”d				6.4”H				3.2’
16”d				8.5”H				4.25”
20”d				10.6”H				5.3”
26”d				12”H				6’
32”d				16”H				8’
40”d				19”H				9’6”
42”d				20”H				10’
46”d				22”H				11’
50”d				24”H				12’
60”d				29”H				14’6”
65”d				32”H				16’
70”d				34”H				17”
80”d				39”H				19’6”
90”d				44”H				22’
100”d				53”H				26.5’
120”d				63.6”H				31.8’

73,
Jeff Wayne, K1YLV
North Haven, CT

Member Comments:
This article has expired. No more comments may be added.
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by KJ4DGE on March 8, 2017 Mail this to a friend!
Nice article Jeff and good info. Thanks!
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by K0UA on March 8, 2017 Mail this to a friend!
Thanks for the info Jeff. Much better article than we have been getting lately.. Thumbsup.
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by W1NK on March 8, 2017 Mail this to a friend!
Jeff,

First off, great article with info I'm going to apply not only to my shack monitor but also to the monitors at my office's front desk. This is info that will be useful for my patients as well. You see ... I'm a Chiropractor!

Secondly, Jeff, I don't know if you remember me, but you and my Uncle Frank, WA1YID, got my brother Tom and I interested in amateur radio 40 years ago. For the benefit of those reading, Jeff was kind enough to let Tom and I, both newly minted Novices, operate the station he managed at a local high school. We had no gear at the time, so it was a real treat using a Swan 700cx (at Novice power levels, of course) and antennas we could only dream of at the time (high dipole and a TH6).

Thanks for the article and for dusting off those memories from 1977.

Frank Vesci, W1NK

(My apologies for the brief departure from the topic!)
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K1YLV on March 8, 2017 Mail this to a friend!
Hi Frank, It is great hearing from you. I was happy to help two new enthusiastic young hams. Wow! Time flies when you are having fun.... Thank you for your kind response to my article and for letting me know that you are still on the air. 73, Jeff
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K9MHZ on March 8, 2017 Mail this to a friend!
I think they should put 4K curved screens in the new SDRs. HDMI inputs as well, so when the 75-meter phone crowd loses their propagation, they can just start up Talladega Nights and watch Ricky Bobby again.
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by KA4KOE on March 8, 2017 Mail this to a friend!
I was taught screen vertical size was equal to most distant viewer divided by 8 when I took ICIA classes in Fairfax, VA. Have they revised this rule of thumb?
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by VK4FFAB on March 8, 2017 Mail this to a friend!
I cannot follow this, its not in metric ;)
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by N0YG on March 8, 2017 Mail this to a friend!
Very good information, NOW I know why I got a neck ache when I use to have a 53" about 2 feet from my computer. WOW was I a Dumb A$$, lol. Anyway now I use a 27" computer monitor and it works fine. I still have the 53" in the closet and the 65" in the living room. lol
Thanks Again for the info.
n0yg Robert
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by AC7CW on March 8, 2017 Mail this to a friend!
Thank you for info Jeff. Is an IPS panel much better for what we hams do?
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by W6CAW on March 8, 2017 Mail this to a friend!
All of a sudden my 27" monitor seems small. 100"? WOW!
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K1YLV on March 9, 2017 Mail this to a friend!
Thank you for your comments related to your ICIA class. You may have missed the second part of the Architects' & Engineers' formula. Using a factor of 8 is appropriate for general video and content from programs such as PowerPoint. When you have to view small fonts such as those on spread sheets and detail on more packed screens, such as that which is presented by some SDR radios, the formula calls for the use of 6 as the factor to provide a more effective view of the data.

Ultimately, these rules are only guidelines and the end user is the ultimate judge of what works best.

73,

Jeff, K1YLV
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by KI3N on March 9, 2017 Mail this to a friend!
My determining factors were budget and weight. I mainly work a lot of digital modes and am a police dept communications officer by profession so I am used to (and maybe crave) multiple monitors. With that in mind I purchased several 24" size widescreen monitors on sale over the last few years and found a great deal at a hamfest on several smaller 20" monitors. I found a well-rated stand for them online and mounted everything firmly to the desk. The mount sits forward enough so that the smaller screens are readable in their native format. My monitor desk sits 90 degrees from my radio desk, so everything is still close at hand.
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K1YLV on March 9, 2017 Mail this to a friend!
I am planning to write a follow-up article related to the care and feeding of LCDs soon. There is a lot of information about them that most people do not know.

The irony of the LCD size situation is that most LCDs that are 32" diagonal or larger are Consumer grade. I have to check, but I was advised by a manufacturer's rep that Consumer TVs are built with the expectation of a 4 hour/day duty cycle. There are LCDs rated Commercial Grade for digital signage that have 24x7x365 duty cycles with multi-year onsite replacement warranties.

There are many LCDs that are smaller than 32"d and are more affordable and rated for office use. They cost less than the larger Consumer LCDs and have 12 hour/day duty cycles.

Thank you. 73, Jeff, K1YLV
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by KA4KOE on March 9, 2017 Mail this to a friend!
Its been almost 10 years since I designed any AV, so I'm a bit rusty.
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K6CRC on March 9, 2017 Mail this to a friend!
A useful and relevant article. Lots recently that were not!
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by VE7JMR on March 9, 2017 Mail this to a friend!
I am unclear why this article does not factor in screen resolution? The figures provided seem to indicate a NTSC (optimistically 720x480) screen resolution era, not 16:9 HD (1920x1080) or UHD (3840x2160) technology.

A 16:9 aspect ratio 12" diagonal screen with a resolution of 1024x600 would be 98 dots per inch and have an maximum viewing distance of about 36".

A 120", 16:9, 3840x2160 display would be 37dpi and have a maximum viewing distance of 96", 8', not 31'8"! This same 120" screen with a resolution of 1920x1080 would have a maximum viewing distance of 180" or 15'.

Any further away from than these maximum viewing distances and the human eye cannot resolve the detail of the display.

The required resolution for a 16:9 120" screen viewed at 31'8" would be 900x506 pixels; 9 dots per inch.

Put another way, a 65" UHD (3840x2160) screen best viewed from about 50' away. The same 65" screen at 1920x1080 maximum distance is 100'.

https://en.wikipedia.org/wiki/Visual_acuity
"The maximum angular resolution of the human eye at a distance of 1 km is typically 30 to 60 cm. This gives an angular resolution of between 0.02 and 0.03 degrees, which is roughly 1.2–1.8 arc minutes per line pair, which implies a pixel spacing of 0.6–0.9 arc minutes.[15][16] 6/6 vision is defined as the ability to resolve two points of light separated by a visual angle of one minute of arc, or about 320–286 pixels per inch for a display on a device held 25 to 30 cm from the eye."

Optimal display viewing angle is 30° to 40°.

Assumptions:
Desired viewing angle is 35°
Viewing distance is 3'
Screen resolution is 1920x1080
Therefore:
Optimal diagonal screen size for the above: 26"
Screen dot pitch: 85 dots per inch
Maximum distance to appreciate 85dpi is ~40' (Pretty close to 36' the intended viewing distance.)


 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by VE7JMR on March 9, 2017 Mail this to a friend!
Correction to the previous post:

"Put another way, a 65" UHD (3840x2160) screen is best viewed from about 50" away."
 
IPS vs TN LCD displays  
by VE7JMR on March 9, 2017 Mail this to a friend!
IPS = Better colour fidelity, better viewing angle, lower frame rate (60 to 72Hz), more expensive
TN = Lower colour fidelity, lesser viewing angle, higher frame rate(e.g. 144Hz frame rate video gaming), lower cost

TN is cheaper, IPS looks better. For amateur radio applications IPS would not add any value other than perhaps being an overall better quality image (especially colour reproduction). Many IPS monitors will have a better quality black and a more even back-light level than TN monitors; these attributes are beneficial for applications such as photo and video editing. (Note that an even back-light level is more an attribute of attention to detail for a more expensive IPS monitor, not an attribute of either IPS or TN technology.)
 
Calculation for screen size  
by VE7JMR on March 9, 2017 Mail this to a friend!
https://en.wikipedia.org/wiki/Optimum_HDTV_viewing_distance#Human_visual_system_limitation
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by K1YLV on March 10, 2017 Mail this to a friend!
Thank you for your detailed analysis of various resolutions of displays and content. You can save yourself a lot of work and anguish with this topic. While resolution and eyesight will always be elements of viewing displays, it is the size of the font or graphic that is the determining factor. If we display a 10 point font on a screen that can be viewed at a maximum distance of 10', doubling or quadrupling the lines of resolution on the same screen size is still going to produce a 10 point font and that does not mean that you can double or quadruple your viewing distance. An eye doctor's eye chart is black dense ink on a white background. That is extremely high resolution. With your theory, it would seem that no matter how bad your eyesight is, everyone should be able to read the complete chart because of its high resolution. Thank you for reading the article and for taking the time to submit such a well thought out theory. 73, Jeff, K1YLV
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by WD9IDV on March 10, 2017 Mail this to a friend!
When I am in the market for a new desktop monitor I set my budget, lets say $300. I then hire a consultant to figure out optimal angles, resolution, pixel densities, etc. I then hire an electrical engineer to figure out all the necessary logistics to install the monitor. I then hire a union laborer unpacking specialist to the unboxing. As my engineer and consultant watch my union labor relations specialist remove the monitor from the box, my unboxing video review professional makes an unboxing video for YouTube.

Costs: Monitor $300.
Consultants $7500.

Total Costs: $7800.
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by N8EMR on March 10, 2017 Mail this to a friend!
You forgot to factor in the AGE of the ham and how crappy his eye sight is.. -:)
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by VE7JMR on March 10, 2017 Mail this to a friend!
Glad to contribute to the topic.

With the availability of UHD (4K) displays, perhaps the point is that when selecting a display, make sure to understand the content requirements and viewing distance.

Don't get caught up investing in screen resolution that cannot be seen from the normal viewing position. (Assuming normal or nominally corrected vision.)
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by NW0LF on March 17, 2017 Mail this to a friend!
I have 2 24" monitors on my shack desk.
 
RE: Determining Display Screen Sizes for Ham Shack Video Mon  
by GM1FLQ on March 26, 2017 Mail this to a friend!

.......not enough, you need at least 12 x 36" monitors to qualify as a progressive ham today.
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by KC9AAE on March 30, 2017 Mail this to a friend!
I've found that I really enjoy a resolution of 2560x1440, which is my main display, the other is 1920x1080.
 
Determining Display Screen Sizes for Ham Shack Video Monitor  
by AB1DQ on April 12, 2017 Mail this to a friend!
Bigger is better.
 
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