Useful information:

UHF EQUIPMENT:

UHF equipment is the "top of the range" covert surveillance equipment. It is crystal controlled so the frequency does not "jump" or change slightly when in use. This means that you do not have to be there to monitor your recordings. The frequencies of the transmitters are tuned directly to the channels of the receivers so you simply switch on the transmitter and select the appropriate channel on the receiver. You can then monitor the conversation yourself or connect a voice-activated tape recorder to the receiver and leave the equipment on standby. The recorder will then automatically record whenever the receiver picks up sound. UHF means "Ultra High Frequency". All our UHF transmitters are tuned in the region of 400mhz. This means that you will not pick up any interference from radio stations, airlines, police radios etc. As a result, the quality you get is crystal clear. If you want to use two UHF transmitters make sure you ask for one on channel A and one on channel B when ordering. That means you can use them both in the same area and just switch the receiver to either channel A or B depending on which transmitter you want to listen to.

RANGE: The range of each transmitter varies depending on how it is powered and the size of the antenna. The ranges listed on the website of all transmitters is "line of sight" only. Obviously this range will be shortened by obstructions between the transmitter and receiver. e.g. walls etc. A realistic range for the miniature room transmitter is between 100 to 200 meters, depending on the number of obstructions. Mains powered transmitters should give you approx 80 to 100 meters. The calculator, pen and phone should also give you 80 to 100 meters approx.

VHF EQUIPMENT (AIRBAND):

Vhf equipment transmits on frequencies between 110mhz and 125mhz. It is above the frequency of radio stations but in the same frequency range as airlines, cabs etc. This means that you may receive interference when listening to your transmitter, especially if you are in a built-up area or near an airport. There is also a possibility of the frequency moving slightly so you may need to readjust your receiver. This is not a problem if you are monitoring the conversation but if you have left the equipment on standby with a voice activated recorder you may not pick up clear conversation. Most VHF transmitters can be retuned to FM, which will allow you to pick them up with an FM radio. This will not harm the transmitter but it is not recommended, as you are then more likely to get interference from radio stations. The range may also be affected. You also have to be careful when retuning transmitters as the coil involved can break if it is overturned. We will happily do the retuning for you at no extra cost. You can use several transmitters with one receiver though the transmitters would need to be on different frequencies and you would need to manually retune the receiver to each transmitter each time you wanted to listen to each transmitter.

RANGE: The ranges vary depending on the area they are used in and the number of obstructions between the transmitter and receiver. Built-up areas will have more obstructions and are also more likely to have transmissions from cabs etc. to cause interferences. The miniature air band transmitter should give you a range of 100 to 200 meters while the mains adaptor will give you 80 to 100 meters.

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