Frequently Asked Questions: Bat Detectors

  1. Pettersson Elektronik sells various accessories such as cables, headphones and batteries. Do I have to purchase such items from Pettersson Elektronik or can I use other types?
  2. Is there a "High Frequency" output on the D230/240x bat detector?
  3. Can I use a mono recorder to record from my bat detector?
  4. What are the differences between Time Expansion and Frequency Division bat detectors?
  5. How do I set up the D240X to make automatic recordings?
  6. Can I use external batteries with the D100/D200 series detectors?
  7. Is it possible to use recorded heterodyne signals for sound analysis?
  8. My D500X loses time and date settings, what can I do?
  9. What type of CF cards should I use with the D500X and D1000X?
  10. The battery indicator on my D500X/D1000X detector shows that the battery is ok, but the detector shuts down in a little while.
  11. Should I format and/or "prepare" the CF cards to be used with the D500X?

Answers

1. Pettersson Elektronik sells various accessories such as cables, headphones and batteries. Do I have to purchase such items from Pettersson Elektronik or can I use other types?

Most standard accessories can be used with Pettersson bat detectors. As long as you follow the recommendations given in the Operating Instructions of the bat detector, you can equally well purchase accessories in your local electronics store.

2. Is there a "High Frequency" output on the D230/240x bat detector?

A "high frequency" output gives the original, unaltered signal. Such an output is used to record the high frequency sound on a device capable of recording high frequencies (a computer with high-speed sound card or a high-speed recorder). The D200 detector has a high frequency output available all the time, while the other D2xx detectors don't. However, pushing the Comment button will feed the original, high frequency signal from the microphone to one of the two output channels on the D230/240x detector. So, as long as you push this button, you have the high frequency signal available for recording.

3. Can I use a mono recorder to record from my bat detector?

The "Tape" output of the D100/D200/D230/240x bat detector has a two-channel (stereo) jack. In order to use a mono recorder, you need a special "stereo-to-mono" cable that connects the channel from which you want to record to a mono (2-pole) plug that fits in the recorder.

The D940/980 uses "phono" jacks on the Tape output, hence a mono cable is all it takes to connect it to a mono recorder.

If you have a stereo recorder, you should use a two-channel (stereo) cable. The D500X and D1000X have built-in recorders so there is no need to connect an external recorder.

4. What are the differences between Time Expansion and Frequency Division bat detectors?

Time Expansion (TE) and Frequency Division (FD) detectors are both "broadband" detectors. This means they will make the entire ultrasonic range audible all the time (in contrast to a Heterodyne detector, which is sensitive only to a limited range of frequencies at each time). There are, however, several important differences between the two types.

A FD detector transforms the ultrasonic calls in real time, i.e. the calls are heard through the detector at the same time they were emitted by the bat. A TE detector first stores a portion of the ultrasonic signal in its digital memory and then replays it at a slower speed, i.e. it is does not transform the calls in real time. The delay depends on the actual storage time, and if this is very short (up to around 100 msec), the replay is also made fairly quickly and the detector gives an "almost real time" response.

Since the TE detector actually stores the original signal (which is then stretched out in time), the output of such a detector provides the same information as the original signal. Hence, it is possible to make any type of analysis and obtain useful and accurate results. This includes spectral analysis of all types (e.g. spectrogram/sonagram). A FD detector counts the number of cycles of the ultrasonic signal and generates an output cycle (pulse) for each N input cycles, where N is often 10. This effectively divides the frequency by N. Obviously, an FD detector is only capable of tracking one frequency (harmonic) at each time. Usually (but not always!), this is the fundamental frequency. Consequently, it is not possible to perform any harmonic analysis from an FD signal. To do this, TE signals should be used.

TE detectors have a number of other advantages over FD detectors. For instance, the former are more sensitive and offer the user better possibilities to aurally analyze the transformed calls.

To conclude, if you require a broadband bat detector, a TE detector is usually the best choice. However, if the limited storage time of the TE detector is a problem and/or you need a real time response, a FD detector should be chosen. As an alternative to a TE detector, direct high-speed recording of the ultrasonic calls can also be made with the D500X and D1000X detectors. In that case there is virtually no limit on the recording length (storage time).

5. How do I set up the D240X to make automatic recordings?

See description »

6. Can I use external batteries with the D100/D200 series detectors?

Answer: Yes. The easiest way is to make an “adapter” that fits on the regular 9 V battery connector of the detector and connect the external battery through the adapter. The “adapter” can be made of a standard 9 V battery connector with leads:

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The external battery is connected to the leads of this connector with the positive terminal to the black lead and the negative terminal to the red lead. Please note that this is opposite to the common standard and this is because the battery connector is used in the opposite direction in this case (to supply current rather than to receive). Before connecting an external battery to the detector using the above adapter, you should carefully verify that the polarity at the battery connector is the same as that of a 9 V battery, e.g. using a multimeter. Reversing the polarity may cause permanent damage to the detector.

7. Is it possible to use recorded heterodyne signals for sound analysis?

No, heterodyne signals are not well suited for analysis. The main reason for this is that the frequency of the output signal from a heterodyne detector depends on the setting of the frequency control (the tuned frequency), so it will vary depending on the setting. 

8. My D500X loses time and date settings, what can I do?

The D500X has a small back-up battery built in, which keeps the real-time clock running when the detector is not run from its regular batteries. If the D500X loses the time and date, the back-up battery is empty and should be replaced. The way this is done, depends on the version of the D500X. Early units require that the unit is disassembled while on more recent units, the back-up battery can be accessed after removing only the front panel (the one with the CF card slots). Please contact Pettersson Elektronik for more information about this.

A temporary solution is to avoid turning the D500X off with the INT/EXT power switch (use the 1/0 switch on the keyboard instead). Then the real-time clock will be powered from the main batteries instead.

9. What type of CF cards should I use with the D500X and D1000X?

Sandisk Ultra/Ultra II or Sandisk Extreme/Extreme III CF cards are recommended. Sizes up to 32 GB have been tested.

10. The battery indicator on my D500X/D1000X detector shows that the battery is ok, but the detector shuts down in a little while.

The battery indicator shows the battery voltage, not the remaining battery life time. Especially if an external battery with a higher nominal voltage is used, the battery voltage may be high enough to make all segments of the battery indicator turn on even if the battery is far from fully charged. Checking the condition of external batteries with a battery tester will provide a better indication of the battery status.

The current D500X firmware version shows the actual voltage in Volt, rather than a bar indicator. This gives a better measure of the battery condition.

11. Should I format and/or "prepare" the CF cards to be used with the D500X?

D500X version 1 firmware required the CF cards to be formatted and then "prepared" with the D500X Utility program. The preparation step has been eliminated in version 2 firmware, so from version 2 and on, the CF cards should only be formatted in Windows (as FAT32), not "prepared". Consequently, the preparation command has been removed from the current version of the D500X Utility program.