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LVA Series

Magnetic Base Antennas

for Vehicles

LVA-16 magnetic antenna set

 

The LVA Series antennas are magnet-based whips, making them ideal for temporary installations on vehicles. They can be used with the new LL Series and the original LH Series Little L-PerRegister.jpg (2200 bytes)  Portable DF. They can also be used with the LA Series Aircraft DF mounted in a vehicle. (The LH and LA Series DFs are no longer in production.)

Antennas for one frequency band (121 MHz, for example), consist of two whips and bases with a connecting cable harness, molded diode switchbox, 10 feet of cable and a BNC connector to fit the receiver.

The antennas are placed on a vehicle aligned in one of two ways: front and back (fore aft) or left and right. When connected to the matching BNC jack on top of the LL series receiver (or on the single BNC jack on top of the LH series receiver), the L-Per meter will give directional information. Since the LL Series has a four position pointer, it will automatically give the appropriate indication. In the older style LH Series receiver, in the DF mode, the meter will show left-right indications if antennas are positioned left and right on the vehicle. If the antennas are oriented fore-aft, with the receiver in DF mode, meter indications to the left of center indicate a "fore" direction and deflections to the right indicate an "aft" direction to the transmitter.  Installation pictures.

We strongly recommend antennas be placed in the fore-aft configuration, which minimizes reflections and bearing information is more stable and easy to interpret. (If you orient your antennas left-right, you can drive right past the ELT/EPIRB and not know it for some time). The "fore" indication will allow you to continue toward the signal source and will switch to "aft" when you pass by it. Turn right or left to resolve left-right ambiguity

The LVA-10 is the single band antenna set used for tracking signals in the aircraft band (118-136 MHz, including 121.5).

If your DF is capable of receiving 243 MHz and you wish to track that frequency, the LVA-16 allows you that capability. It consists of the LVA-10 plus a single base and whip that has no cable connection. It is placed between the two "outboard" antennas connected with the cable. This extra antenna acts as a reflector to give a proper DF response on the higher frequency. It may be left off if you do not wish to track 243. However, this is NOT a "spare" antenna and nothing should be connected to it.

If you have an LVA-10 and wish to upgrade to an LVA-16, you can purchase the center whip and base separately.

The new LL Series Little L-PerRegister.jpg (2200 bytes)  has the capability of "four quadrant" DF on the LCD display. In order to give you left-right and fore-aft directional information at the same time, two sets of the LVA-10 antennas are used. One is placed in the fore-aft position and the other in the left-right position on the vehicle. Coax cable from the antenna pairs are plugged into the proper (marked) BNC connectors on top of the receiver. The display will now automatically show both a left-right and a fore-aft indication on the direction indicating bars. This is the LVA-100 LL.

If you wish to also track signals on 243 MHz, you add a center antenna in the middle, as before for the LVA-16.

This same system can be used on the older LH Series Little L-PersRegister.jpg (2200 bytes).   A second set of LVA-10 antennas is added to give four antennas: one pair mounted fore-aft and the second left-right. Since the LH Series units have only one BNC jack on the receiver, a small manual switchbox is provided (LASW-1) that plugs in to the antenna jack. This switchbox has two BNC connections on top and the coax from each pair of magnet antennas is plugged in to the appropriate jack, according to its alignment (fore-aft or left-right). The L-PerRegister.jpg (2200 bytes)  is run in the DF mode and the operator manually switches between the left-right and the fore-aft pair, with the meter indicating as explained above. This is the LVA-100 LH.

If you wish to also track signals on 243 MHz, you add a center antenna in the middle, as before for the LVA-16.

Complete  installation instructions are provided with each order.  They can also be downloaded as a PDF file, (4mb) and can be seen, with pictures under Antenna Installations.

Damage to the DF antenna system or to the receiver can result from placing a transmitting antenna too near them. This is true whether the DF receiver is turned on or not. The RF field from the transmitter will travel down the rods to the switchbox and destroy the switching diodes. This is not field repairable and antennas must be returned to the factory for repair, which normally costs $35 plus return shipping and handling. To be safe, separation should be 3 feet from a 5 watt transmitter in the same frequency range, 4.5 feet from 10 watts, 7 feet for 25 watts 10 feet for 40 watts, and 15 feet for 80 watts. If the frequency ranges are different, such as 121.5 for the DF and 150 MHz for the transmitter, half of the above distances should be used.

We recommend the antennas be taken off the car roof when not in use, as extended exposure to sun, fog and rain can cause the cable harness and plastic bases to become brittle and crack or allow corrosion from water entry.   If you want an "always ready" installation, consider the LFA series permanent mount antennas.   They are fully weatherproof.

 

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