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Simply moving the panels to the outside of the fence finally solved this problem.
So to guard against cows a fence was added. Now what could [possibly go wrong? Well, after some time the ar125 detectors started failing due to lack of power. Ok, so batteries donÕt last forever so those are changed out. Pretty soon, detectors failing again. Well, something must be wrong with the detectors. So the phone calls start to Mark. The solar panels are plenty big enough to power all this with extra capacity for cloudy days, etc. Finally mark asked, is the panel shaded at all. Solar panels are not one single cell but a series of many cells linked together...if one is shaded it brings down the voltage of the entire system and prevented it from ever being able to fully charge the batteries.
Apparently the expensive watertight cable just looks like black licroce to cattle, and so it didnÕt take long to chomp into this and kill the project.
Instead of bringing a ladder, bring a shovel and bury the box to make it less conspicuous to people and animals.
Another clever idea is to drill holes into your pelican case and install weatherproof fittings for all the cables so you can completely close the case and make it watertight.
Here is the cable coming down a 200Õ tower along the pulley cable similar to what weÕve seen before.
A problem with these long term deployments is what to do with the electronics. Leave them bundled where people or porcupines can get to them, sooner or later you are going to lose data. One solution is to stick the detector in a box 10Õ or so off the ground so that you have to bring a ladder out to service it.
So avoiding the problems associated with temporary towers. here is an example of a bombproof long term station with a steel post bolted to a concrete pier sticking out of the ground.
We have enough problems just keeping all these electronics running simultaneously--- so itÕs discourgings when you return to your station a month or two later to find total destruction. If your data is irreplacable, donÕt leave this equipment unattended any longer than you can afford to lose.
MET towers are temporary and will only be onsite for only about a year. You can bring your own tower and install it yourself in a couple of hours.
How about if we push it to the limit....letÕs take these bat detectors that were only ever intended for you to walk around with them in your hand in in one evening. Let's apply them to a problem the manufacturers had never dreamed of when these things were first built by running them months on end hundreds of feet in the air.
So here we have the microphone carraige, seen here rigged with an AR180 and an Anabat. A similar carraige mated with the pulley assembly about 150Õ or more off the ground on a met tower, and of course the nervous crew because they know if they screw this up and the tower must be lowered to fix something, someone is going to get a $10,000 bill.
An example of more long term solution ground based detectors but now with with solar added. Some detectors such as the ANABAT, AR125 and SM2 may require this kind of power addition where the D500x may be able to avoid this extra addition depending on your maintainance cycle.
A 2011 study at a Pennsylvania wind farm typifies expectations for these units and backs them up with unequivocal results.
2 D500x units, deployed 40m up a tower for 125 nights (which was 3,000 monitoring hours) and collected over 30,000 recordings with 100% up-time.
The other end of the battery connector is soldered to his batteries, taking no chance any connectors will get loose from being banged around in the wind or hoisting up the tower.
He made custom battery connectors to reduce cable breaking from repeated data checks.
Instead of just bending up the side of the ammo box to make a little roof like I suggested, he glued a PVC awning over the microphone area in hopes that there is less rain noise setting off false recordings.
HereÕs a another approach as we start transitioning into talking about power. Very simple...this is a D500x and an external battery all in a $20 steel ammo box.
When you pin the major manufacturers down and beat a confession out of them, they now admit that it is ok to point the microphone horizontally or down slightly without any other enclosure. So here is a simple mount for a D500x external microphone ready to be taped to a mist net pole or hoisted hundreds of feet into the air. This goes for the SM2 and AR125 microphones as well.
Alot of this recording thru a tube and off a reflector is adapted from ANABAT deployments. But When you shift to full spectrum recording thru these devices, your recordings are visably distorted. You have no hope of these distorted recordings being analyized successfully by automated IS software that is trained on near perfect voucher calls.
The simplest weatherproofing idea is adetector in a pelican box with battery, and hole cutout for the microphone. The microphone is not necessarily waterproof and detector is placed on the ground.
To make the microphone waterproof people have placed the microphone in tubes. Not only does this distort the sound when recording full spectrum, but here the microphone is actually pointing into the ground where we wouldnÕt expect bats anyway.
Reflector plates are popular and the idea is that the sound is reflected up into the microphone. This still distorts the full spectrum sound to a degree. If the plate it too small, too close to the microphone, or too steep of a reflection, you lose significant amplitude of sound...meaning these donÕt pick up nearly the number of passes that a plain microphone will. Some are mis-designed so that raindrops will hit the plate and splashback into the microphone.
Protective housing must shelter sophisticated (and expensive) electronics from wind, rain, condensation, and temperature extremes. Protection from vandalism should also be considered, especially when equipment is deployed on public land or in highly trafficked areas. The equipment also has to be deployed in an appropriate area (generally this means getting it high enough to intercept flying bats
Power considerations, especially for long-term monitoring need to be considered (for example, solar power, larger external batteries, direct current, etc.). File storage considerations, especially for the relatively large full-spectrum files collected by TE and DR units. (Remember, FD file sizes are 1-2 Kb whereas TE or DR files can be 1-2MB or more.) Finally, consider the ease of off-loading data for analysis and re-setting detectors for more monitoring.
Then, make sure that any time additional cabling is introduced to the unit to allow for extended power supplies, external storage devices, and on/off timers, that it is all connected properly and working appropriately so data is not lost due to one or more of the links in the chain failing.
When mounting microphones on vehicles, rig above roofs which will cause echos and away from engines which may introduce noise. Never place microphones on the ground or directly on rocks or cliff faces. Place microphones in edge habitat or small clearing, or travel corridors where you might intercept commuting bats as these types of calls are most diagnostic.
It is generally recommended that to minimize wind noise, point the microphone "downwind" of the prevailing wind...not into the wind or at 90¡ where you might inadvertantly set up a whistling noise that may add noise during recordings. Depending on the manufacturer, wind-driven rain may be driven into the microphone element. If the bat activity is expected to come from random directions to the station and no other protocol/considerations to follow, it would be best to point the microphone downwind to minimize equipment failure and unnecessary noise.
These are some examples of improvising in the field to improve sound quality. The detector is attached to a pole and extended away from rocks which will produce echos and distortion. Other microphones are placed on existing vegetation to "blend in" with the landscape rather than become a novel object of interest to passing bats.
Avoid recording with a detector placed directly on the ground. Simply elevating a detector one or two meters above ground can dramatically improve recording quality by reducing surface echoes, avoiding thermal layering, or near-ground air convection currents, all of which can distort ultrasound signals.
Place detectors out of a constricted flyway to record the best, routine search phase call samples.
Where possible, place detectors to blend in with (but above) vegetative clutter and pointed to listen out into open air space.
Conspicuous placement in a flyway, open meadow, or at the top of a tall mast may interfere with routine foraging activity at that site and will often result in many recorded sequences of short "inspection calls" from bats investigating the novel object in their path.
When bat detectors were created, inventors were simply trying to do one thing: listen to bats as you point the device in their direction; then perhaps make a recording so that you might look more closely at the sound with a computer.
These days people are using bat detectors for applications such as recording a year's worth of data hundreds of feet in the air and sitting through some of the harshest weather: wind and rain, sure. But also hurricanes, salt air, freezing temperatures, and baking temperatures.
Only the newest direct recording (DR) type detectors are starting to take weatherproofing into consideration, and generally end users still must come up with suitable their own solutions to suit their needs.
Bat Detector Placement,
Power and Weatherproofing
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