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Low End Gear And Research Equipment


hiflier

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SWWASAS

I did get a dedicated microphone but they are very costly to have one as good as the recorders built in ones comparing specs of one against the other.      I simply mounted the discrete microphone on another aluminum rod similar to the recorder mounting.    But then you have the microphone cord and power supply to deal with.   With the cord, the microphones own battery,  the need to keep the cord from blowing around and producing noise,    complexity increases along with potential failure rate due to another battery and set of connectors.         The only advantage to a dedicated microphone is to place the dish and microphone some distance from where you and the recorder are.    That way you could turn on the recorder as needed or change SD Cards or batteries,  when needed without going to the dish.    I have not done so but one dish user reports that he puts the dish in a separate tent to have it hidden yet able to record.         I assume that you know that digital recorders are capable of having different fidelity depending on what sample rate is selected.     The higher the sample rate the higher the fidelity, and the shorter period of time that can be recorded on a given SD card.    I use a moderate rate that gives good fidelity and several hours of recording time on the SD card.     As I recall the sample rate is 40K htz.       As the Sierra Sounds people found out,    if they had available a digital recorder which had not been developed at that time,  their recordings would be even more remarkable and yield much more data.    Don't use an analogue recorder to save bucks.  

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NorthWind

On the "squirrel baffle" plans, I like the idea of having an FM transmitter so a person can sit some distance away from the dish / recorder setup and still be able to listen on a battery powered FM radio. Even from the cab of a heated vehicle. I imagine one can get or build a transmitter with even more broadcast distance range. 

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hiflier

Some wireless systems can go 300 ft. (Sennheiser has one that claims 400 ft.) but range is typically a line-of-sight issue. There are a lot of different brands and models and some will reject outside interference better than others. Things are improving in that regard as the UHF frequency spectrum is continually getting tweaked better for broadcasting. I've seen units for as little as $100 to over $1,000 but one would still have to invest in a recorder to patch into a receiver unit. A lapel mic, like one wears on TV interviews, would be my choice for better ease of mounting as well as weight. It's also probably not a good idea to get different components from different manufacturers as there could be compatibility issues which could reduce performance or make the system not work at all.  

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Interesting about the FM transmitter. It never crossed my mind. Great thinking.

 

I've been reading more about parabolic shape and the math behind it. At what distance do I have the recorder or microphone from the bottom of the parabolic dish. I finally found what I was looking for:


https://www.analyzemath.com/parabola/focus-of-parabola-calculator.html

 

So, if I was looking at this 18" squirrel baffle from Home Depot with a 3" depth the focal point of the mic would be 6.75". Contrast that with a real parabolic dish (22") from Wildtronics that is 6" deep. That equates to a focal point of only 5.04". This calculation is confirmed by looking at the microphone in this video by Wildtronics and you can see the mic is below the level of the rim.

 

https://www.youtube.com/watch?v=LKOaumJGC48

 

https://www.wildtronics.com/store.html#!/All-Purpose-Parabolic-Parts/c/11897290/offset=0&sort=normal

 

Hope this helps so you'll know exactly what distance to put the mic/recorder from the base of the parabolic dish.

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NorthWind

When I go to make one, I think I will just line it with a thin strip of mylar taped down from rim to to base hole, then just use a laser pointer on the mylar to find where the focal point is, as was alluded to above. Then just remove the mylar. I hate math and while I am decent at it, I avoid it if I can. Too many bad memories of evil math teachers in my youth.

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hiflier

I would use a flashlight, Northwind. because you have to be looking into the mylar to do what your saying. So I think for your eyes sake a flashlight might b safer than a laser pointer? You'll end up with the same result.

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SWWASAS

Rather than get into the math.   Like has been mentioned the best way to determine the focal point is a flashlight or laser pointer.    You could actually use a singe bulb overhead light in a darkened room.      You want a point source that you can move across the dish from rim to rim.     Have something like a dowel sticking strait out of the dish and just mark where the light hits the stick.      Light perpendicular to the rim of the dish should strike the same place on the dowel as you move across the dish side to side.       Some umbrellas may be near parabolic and since they are so large some minor deviation from true parabolic may not make much difference.    The only problem is that the sound will vibrate the umbrella,   rob some energy and not all will be reflected to the dish.     I would bet a squirrel baffle is not parabolic.    Another source a dish would be an old satellite antenna.   Dish or Direct would work but be sort of heavy since they are made of steel.   I bet if you look around your neighborhood there may be several no longer used on roofs.     Wax one,  lay up a couple of layers of fiberglass cloth using the dish as a female mold, let it cure,   then pry it loose to have a fairly large and light weight fiberglass dish.     It does not need to be metal to reflect sound.  

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SWWASAS
On 12/30/2019 at 4:49 PM, wiiawiwb said:

SWWASAS

On 12/30/2019 at 4:49 PM, wiiawiwb said:

SWWASAS - where did you find a threaded aluminum rod that fit perfectly into your recorder?

I have a tap and die set and threaded the rod myself.    The recorder has a camera mount female thread.     You could simply get a bolt that fits the recorder threaded fitting    I think it is 1/4 course thread.   and epoxy glue the bolt to the rod.      Amazon has all kinds of photographic camera mounting adapters that could be used too.     I do not know how often I go into my local hardware and farm supply place and wander around looking for something to make some project work.     They expect everyone to ask for something for a particular use.     I just tell them I have a project and am looking for parts to make it work.   Sometimes you have to be very creative.          

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gigantor
On 1/3/2020 at 3:26 PM, hiflier said:

 

 

Honeywell Impact Sport Bolt Sound Amplification Electronic Earmuff $89.95

 

earmuffs.PNG

  • Slimline Earcup Design - Sleek, extremely low profile earcup design with cut-out allows for full clearance of firearm stock.
  • External Audio Input - Equipped with an external AUX jack cord that allows you to connect to any MP3 player or scanner.
  • One Volume Control - Single knob control for on/off and volume.
  • Convenient Storage - Compact folding design for convenient storage.
  • Easy Height Adjustment - Padded headband adjusts for a secure, non-slip fit.
  • Contemporary Style - Deluxe padded black leatherette headband with black earcups.
  • Air Flow Control Technology (AFC) - Allows you to hear normal conversation which occurs at low frequencies but delivers protection at the high frequencies.
  • Sound Amplification - Ambient sound is amplified safely to 82dB to deliver superior directional sound quality in stereo.
  • Automatic Noise-Blocking Protection - Amplification automatically shuts off at 82dB, attenuating hazardous impulse and continuous noise.
  • Digital Sound Compression - Five times sound amplification enhancing low level frequencies. Ideal for indoor shooting, outdoor and hunting for amplification of sound while reducing harmful noise from impulse sounds such as gun fire.
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BlackRockBigfoot
On 1/3/2020 at 3:26 PM, hiflier said:

I told ya!

 

The sound amplification is pretty decent on my pair.  The front facing microphones allow you to really hone in on a sound's direction.

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hiflier
Posted (edited)

Been sort of testing these things out. The sound amplification is impressive. The fit is firm but not tight. And the ear cups are hinged so that they fold/rotate to nest inside of the headband. BRB, you mind reader you! I was just typing about the directional capabilities of the mics. Tomorrow I'm going to try them on reversed with the mics toward the back. I'm thinking eyes front, ears behind. It may not make a difference but I'll try anything. The idea here with getting them is to help take some of the time pressure off the thermal at camp. Plus, I probably won't have a dog on my next trip out so these might be the next best thing for early sound detection. I usually just keep an eye on my dog for advanced notification. I have been wanting a pair for a couple of decades but was always leery of damaging my ears with a sudden loud sound. These are perfect as a guard against that. And even though the first half millisecond before they kick in can come in loud at least it should be brief enough to help deter any hearing damage.

 

These are part of a camp set up I have envisioned. I can hang out outside with these on and read or do whatever until I hear something. Then the thermal will come out. I'll have a trail cam watching the camp as well as having a NV device with optional IR capability if I wish to use it. I had also been looking at parabolic dishes and thought these would help simplify things in that department. and be directional as well. I've looked into whether or not I can record from them because of the enhanced volume level but I think that unless I jam a small recorder between the ear cups I'm kind of out of luck there. Worth testing though just to see.........or in this case, hear. I also like that they have an auto shut off after four hours. It will remind me to climb into the camper and get some sleep LOL.

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MIB

Despite actually being able to hear better, wearing headphones in camp at night causes one of the most naked and exposed feelings you'll likely ever experience.    I don't like it, don't like it a bit.

 

MIB

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