|
MYTHOS MY4000Q, QUAD OBSERVATION SYSTEM
COPY
WHAT OUR EXPERTS SAY...
A small sticker on the back of the Mythos MY4000Q 12-inch
monochrome monitor proclaims it was made in February 1998, that's as maybe, but
by the looks of it, some of the circuitry inside the case it was designed back
in 1978... Even the rounded metal case looks as though it belongs to another
era. Nevertheless the package is reasonably well specified, the monitor
features a quad display, and the basic outfit includes one low light black and
white camera, a 60-foot pre-terminated cable and mounting hardware. Each
line-powered camera has a built-in microphone and speaker, for two-way intercom
operation with the monitor. Optional sensors or motion detectors can be plugged
into the back of each camera. Mythos also market colour quad and switcher
systems plus a wide range of cameras, housings and ancillaries.
The MY400Q monitor has two display modes, quad or auto, the
latter being a sequenced output from each camera with variable dwell time of
between 1 to 18 seconds. The quad display is in real-time (i.e.,
non-multiplexed), so there's no movement lag.
Front panel layout and the cosmetics are reasonably
conventional. From left to right the controls are: intercom push to talk (PTT),
quad/auto mode switching, cameras 1 to 4 selectors and alarm enable/disable.
Next to that there is bank of four presets for setting volume, dwell time,
contrast and brightness and on the far right there's the mains on/off switch.
On the back panel there are four mini DIN sockets, one for each camera, two
recessed presets for vertical and horizontal hold, video and audio input and
output sockets for connection to a VCR and a pair of connections for activating
an alarm or VCR recording. Additionally there's a single BNC connector for the
video output connection for a slave monitor. A small speaker is located behind
a grille on the left side and the intercom microphone is mounted immediately
above the PTT button.
Build quality on the monitor is rather average. The metal
case on our sample wasn't particularly well finished with spot welds showing
through, it wasn't a very good fit either. As we have already mentioned, the
monitor electronics are quite frankly a bit of a mess. Accessibility is poor and
there are wires all over the place; it looks like a serviceperson's worst
nightmare. By way of contrast the quad display board, bolted to the side of the
case is a model of up to date design practice, it is neatly laid out with only
the bare minimum of interconnections. It's as if they came from two completely
different factories, which they almost certainly did! Whilst we're on the
subject, there's more evidence of slipshod design. The mains cable is held in
place by a crude looking metal stirrup, but the most worrying aspect is the
positioning of the mains on/off switch. It is so close to the CRT that live
cables are actually trapped between the switch terminals and the metal
anti-implosion shield around the outside edge of the picture tube. It is just
asking for trouble!
The construction of the cameras is much more encouraging.
They're housed in sturdy extruded alloy housings that look reasonably tough and
well able to withstand the rigours of life in a domestic, commercial or
industrial environment. They're reasonably compact too, measuring 58 x 58 x
117mm. Weather protection is minimal; there are open ventilation grilles on the
sides so they're not really suitable for use in damp or dusty conditions. A
mounting bracket with a threaded collar can be attached to the top or bottom of
the case.
Each standard MCC500 cameras is fitted with an 8mm F1.4
fixed-iris, CS mount lens. Behind that there's a 1/3-inch CCD image sensor (512
x 582 pixels) with a stated low light sensitivity of 0.5 lux and a resolution
of 380 lines. Just above the lens is a small hole for the forward-facing
electret microphone; a tiny 1-inch loudspeaker is mounted on the left side of
the case. There is only one external adjustment on the camera and that is focus;
all other camera presets are internal and not accessible to users or
installers. Exposure is fully automatic, using a variable-speed electronic
shutter, that operates over a range of 1/50th to 1/10,000th
second. On the rear of the camera there are two sockets, one is for the connection
to the monitor, carrying line 12-volt DC power, video, two-way audio and alarm
signalling. The other, also a 6-pin mini DIN, is for an external alarm sensor.
Mythos can supply a range of compatible devices, including PIR and door
contacts.
Inside the camera there are two PCBs, the one at the front
is a purpose-designed module, supporting the CCD image sensor, the second one,
which fits between a pair of rails in the sides of the case, handles video
processing, power regulation, audio and alarm functions.
OPERATION
The instruction book supplied with the outfit spends the
first four pages dealing with safety warnings. It makes interesting reading;
there is more than half a page covering the do's and don't of erecting an
outside TV antenna and safely handling wheeled carts… The rest of the book
covers the system basics in a fairly undemanding manner, there's even a small
diagram showing which direction to turn a screwdriver in order to tighten a
screw. On the other hand it lacks potentially more useful information,
regarding the positioning or alignment of cameras.
Fortunately installation couldn't be much simpler -- it
easily qualifies as a DIY system. Each camera is supplied with a universal
mounting bracket, suitable for attaching to wall or ceilings; the outfit also
includes screws and a quantity of adhesive cable tidies. Camera back focus is
factory-set, manual adjustment is possible. The monitor set-up is equally
straightforward; apart from picture, sound and camera dwell settings, there's
very little else to do.
Once the system is up and running cameras can be chosen individually
from the bank of front-panel selector buttons, the display can sequenced, or presented
as a quad display, whatever appears on the screen is also present on the slave
monitor and VCR video outputs. If an alarm is used in conjunction with any of
the cameras the sequencer switches automatically to the camera input concerned
and stays with it for around 50 seconds, before resuming sequencing. The output
on the back panel of the monitor can be used to trigger an external alarm or activate
a time-lapse VCR to switch to real time mode, for the duration of the alarm
activation.
PERFORMANCE
The monitor display is sharp with negligible noise and plenty
of detail. Picture geometry and focus are both good. The claimed 800-lines at
the centre of the screen is a tad optimistic but it's not too far short and is
in any case far in excess of the capabilities of the cameras. The MCC 500
sample cameras supplied with out test system managed a very creditable 350 plus
lines. The images were crisply focused to the edges of the display area, despite
what looks like fairly low-cost optics. The picture has a wide dynamic range
when lit by good natural light. Low light sensitivity is as advertised and the
camera can produce a useable image in very poor conditions. We managed to make
out numberplates at up to ten metres, using only available street lighting.
It's not all good news though. We discovered that the
camera's auto exposure system is quite lively and uses quite coarse changes in
shutter speed to compensate for varying lighting levels. This becomes clearly evident
on contrasty scenes where there is a strong light or bright patch. Every so often the camera appears to have
trouble making up its mind, and ends up rapidly switching between two shutter speeds,
causing the image to flash. Admittedly it doesn't happen very often but it is
entirely possible that scenes lit by daylight, or mixed lighting, will at some
point during the day cause the exposure system to 'hunt'. Extra care needs to
be taken where windows or skylights are within the picture area. Apart from
that, the exposure system copes quite well with gradual changes in lighting
levels.
Although the four camera inputs are not synchronised there's
only minor picture disturbance at the switching point, fine tuning the vertical
hold preset minimises instability to just one or two frames. The quad display
is very stable and the lack of multiplex 'jitter' reduces the nuisance of
motion artefacts.
The audio facilities work quite well. The camera microphone
has good forward sensitivity and will pick up normal speech, in quiet
surroundings, up to five metres from the front of the camera. Not surprisingly
the tiny speakers inside the camera are not very loud, so it can be difficult
for the operators to make themselves heard, especially in noisy surroundings.
OVERALL ASSESSMENT
Despite our misgivings about the design and construction of
the monitor/switcher it works well so we'll give Mythos the benefit of the
doubt and hope that the rat's nest of cables around the monitor driver printed
circuit board will withstand the test of time. We gave our sample a few good
thumps and the picture remained rock-steady. We're less enthusiastic about the
routing of the mains cable, the position of the on/off switch and its proximity
to the picture tube; we feel this is something that could require attention,
urgently.
Performance is generally good. The cameras produce a clean, steady
image under a wide range of conditions, though bear in mind what we've said
about the exposure system and the pulsating picture. Although we're fairly
happy with the basic specification a few extra features wouldn't have gone
amiss, even if it meant a small increase to the price. Some sort of alarm
indication would be useful, as would camera idents and a clock display, especially
when the system is used with an ordinary VCR.
The Mythos system is a bit of a mixed bag, but if you can
live with the rough edges it is worth considering alongside the similarly
specified opposition, for undemanding small-scale multi-camera applications.
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 ?
---end---
Ó
R.Maybury 1998 0506
| 
