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JVC TM-H140PN COLOUR MONITOR

 

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WHAT OUR EXPERTS SAY...

There is a widely held belief within the CCTV and surveillance community that video monitors are much of a muchness. Whilst it is true they all look pretty much alike, and basically do the same job, there is often a world of difference between the best and worst examples, both in terms of performance and reliability and that's without bringing cost into the equation. The trouble is, from the outside, and without specialist equipment it is quite difficult to judge things like picture quality, but the real problem is that a poorly designed monitor can actually reduce the amount of detail contained in video image, without the end user or operator even realising it!

 

It mainly comes down to resolution, measured in horizontal lines (not to be confused with vertical scng lines), which determines a video monitor's ability to display fine detail. Most general-purpose models can resolve between 400 and 500 lines, the same ballpark as the majority of mid-range and general-purpose CCTV cameras, which is all well and good, but clearly loss of detail will occur when a low-end monitor is used with a system that includes any high performance cameras.

 

This is the market that JVC is addressing with the TM-H140PN and its recently launched stablemates. This particular model has a 14-inch (36cm) colour display with the kind of resolving power that relatively few cameras can match or exceed. The stated resolution is in the order of 750-lines, and that is well above the industry norm and approaching the kind of performance of specialist monitors. The display tube is a 90-degree deflection type, which has rounded corners and a slightly curved faceplate (compared with the current crop of flat-screen TVs and PC monitors), more about the consequences of that in a moment.

 

The rest of the specification is uncontroversial; the chassis is dual system and can handle PAL and NTSC signals. It has two switchable video and audio input channels, Channel A is composite video only, Channel B is composite and Y/C (S-Video), with the Y/C input taking precedence. Most picture parameters can be adjusted using a set of on-screen displays and it has two simple remote control options, for switching input channels and aspect ratio (normal 4:3 or 16:9 widescreen). The mono sound system comprises a 1-watt amplifier driving an 8cm speaker mounted on the right side of the case.

 

Inside the case there are two main printed circuit boards, quite large by current standards. The one in the base contains the power supply, scanning and EHT circuitry whilst the one on the right side is responsible for video and audio processing. Both appear to be made to a very high standard and the general quality of construction is very good.

 

From the outside it all looks relatively normal, it is housed on a two-tone metal-clad cabinet with ABS plastic front screen surround. On the back panel there is an impressive-looking bank of input and output sockets, and a socket for the mains cable. The AV sockets are clearly labelled, from the top to bottom they are: Channel A composite input and loop-through (BNC), Channel B composite and S-Video input and loop through (BNC and mini DIN), Channel A and Channel B audio in/out (phono), remote channel and aspect ratio switching (phono). 

 

SETUP AND OPERATION

Moving around to the front there is a row of buttons beneath the screen, from right to left they are Phase (hue adjustment on NTSC signals), Chroma, Brightness, Contrast, Menu, Volume/Select up/down, Under Scan, A & B input select and Power on/off. Pressing the Chroma, Brightness or Contrast buttons brigs up a simple bargraph display on the screen and the level is adjusted using the volume up/down buttons. Under Scan reduces the size of the image by around 10%, allowing the edges of the picture, which may otherwise be obscured by the screen surround, to be seen.

 

There are two menu displays, the first one appears after pressing the Menu button and this has four selectable items: sharpness, colour temperature, colour system and aspect ratio, the function is chosen using the phase and chroma buttons and changes made with the volume up/down buttons. The second menu is called up buy pressing Phase and Menu together and this displays a Service menu. This covers horizontal and vertical position, white balance (individual RGB settings), control lock, status display, and remote control on/off. Holding down the Phase and Menu buttons when switching on displays the option to return the monitor to its factory defaults.

 

PERFORMANCE

The monitor's ability to resolve up to 750-lines is not in doubt, images look clean and sharp, colours are natural looking and accurate on the default settings. Bot6h contrast and brightness required adjustment though, the latter having a surprisingly narrow range with comparatively little headroom to spare at high brightness levels. In general performance is very good, however, the tube faceplate does tend to pick up a fair number of reflections from overhead and desk lighting and sunlit windows. This is partially to do with the curvature of the faceplate and any anti-reflective coatings if it has any not doing an especially good job. In the scheme of things it is a relatively minor nuisance, but installers it's worth installers giving a little more thought than usual to location and lighting.

 

Monitor manufacturers appear to treat sound almost as an afterthought and the TM-H140 doesn't set any new benchmarks. There's sufficient volume provided the side-mounted speaker grille isn't obstructed and it's fine for speech and incidental sounds.

 

OVERALL ASSESSMENT

Proving convincingly that all monitors are not created equal the TM-H140 is well suited to demanding applications where no compromises can be made over quality and performance, and if you factor in the price, it is actually quite good value!

 

 

 

PRODUCT ASSESSMENT

Design and design features                      ****

Circuitry and components                ****

Ease of installation and wiring            *****

Range and variety of functions            ****

Accompanying instructions              ***                            

Technical advice and backup            ??    

Value for money                         *****                      

 

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R. Maybury 2001 2303

 


 

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