SG-237 SMARTUNER™ INSTALLATION MANUAL
1 S G -237 Smartuner™ Manual SG-237 Specifications HF Frequency Range: Power Input Range: Input Impedance Range: VSWR (Typical): DC Input Requirement: Average Input Current: Initial Tune Time: Retune from Memory: Memory Bins: Tuning Combinations: Antenna Length (>3.3 MHz): Antenna Length (<3.3 MHz): Installation: Operating Temperature: Case: Cable: Dimensions: 1.8-60 MHz 3-100 W (PEP) 40 W CW Max (40% duty cycle) 45-55 Ohms Less than 1.4:1 +13.8 VDC (nominal) 300 mA Less than 2 sec.
2 S G -237 Smartuner™ Manual The SG-237 is supplied in a waterproof case, on a mounting plate with pre-drilled holes. It is ideal for any mobile or base-station installation. RF and DC power is supplied to the unit through the same bundled cable (9 feet supplied). The cable includes the RG-58 coax for the RF connection to the transceiver, two wires for DC and ground, and two wires for optional accessories. (See Section 5 for more details on the Smartlock™).
3 S G -237 Smartuner™ Manual hand, SGC antenna couplers are not limited in their impedance ranges and will tune all types of antennas, including end fed wires and whips. For the most efficient operation possible, install your SGC coupler as close to the feedpoint of your antenna as physical limitations allow. See section 4.0 for examples of ideal configurations. More information, including details of several real installations and technical notes can be found on our website. 3.
4 S G -237 Smartuner™ Manual 4.0 Five Golden Rules of HF Installation These rules apply to all types of stations, including base, mobile, airborne and marine. They are very important for planning and installing your HF system, if you want to achieve good communications. 1. Install transceiver as close to operation site and power supply system as possible (whether an external power supply or battery system). 2. The antenna must be installed in an open space and as far as possible from your operating point.
5 S G -237 Smartuner™ Manual This manual is produced as a guideline for the SG-237 antenna coupler. Performance and results may very and SGC does not warrant any installation or any result. This manual is subject to change without notice. Selected Antenna Configurations Automobiles: RVs or trailers provide an excellent base to install effective low cost antennas, and end feed or loop antennas can be used.
6 S G -237 Smartuner™ Manual Flagpole: If a flagpole is made of PVC pipe, it is easy to tape a large gauge wire to the inside of the pipe and use a good counterpoise. Typical flagpoles are 25 to 35 feet in height, which offers excellent performance on all bands. Note the ground radials that are necessary with any long wire or vertical antenna.
7 S G -237 Smartuner™ Manual Insulated Backstay: The coupler must be placed as close as possible to the base of the backstay antenna. Connect the RF ground terminal to all the metal parts or structure of the boat. Triangular Loop Antenna: This antenna for sailboats is designed to operate in a groundless environment and still provide high performance. This type of installation will require only one insulation point on the bottom backstay and an electrical connection on top of the mast and the stay.
8 S G -237 Smartuner™ Manual Long Wire Antenna: These perform well on fishing vessels and are very efficient because antenna lengths of 50 feet or more can be installed without any difficulties. If vessel is not of a metal structure 3 radial wires as long as possible can be connected to the coupler and spread on the lower bottom part of the vessel. Ladder feed Antenna: These may be used if necessary, however, installation of the coupler directly at the antenna is preferred for higher efficiency.
9 S G -237 Smartuner™ Manual “V” Antennas: Both “V” and inverted “V” antennas are convenient for limited space installation and increase of directivity. 5.0 Optional Smartlock The Smartlock allows the operator to have additional controls over the SG-237. It is not required for normal operation. 5.1 Tune, Tune Lock/Reset The ‘Tuned’ (Green LED): This LED lights when the coupler has successfully tuned.
10 S G -237 Smartuner™ Manual Reset: Pushing the red reset button allows the coupler to be reset, if the toggle switch is in the normal position. This is preferred over turning the input power off an on. 5.2 Smartlock Notes The Tune Lock function is in most cases unneeded. Inadvertent retuning is a rare occurrence. Re-tuning may occur when the environment or antenna system has changed (as in with mobile operation being used while in motion).
11 S G -237 Smartuner™ Manual 6.0 Troubleshooting SGC has a knowledgeable staff that can assist you with several common issues you may encounter with your coupler, however, we suggest you follow these steps before contacting us. 1. Check all of your connections and cables. The most common fault with an SGC coupler is insufficient RF grounding. Many users underestimate the importance of this, and as a result, compromise their station’s performance.
12 S G -237 Smartuner™ Manual Before building or using the light-bulb dummy load, remember that these models typically don’t dissipate the transmitter’s output as well as an oilcan dummy load. The result is that weak RF will ‘leak’ out; we have heard a few stories of amateurs who were heard around town while operating their transmitters into a light-bulb dummy load. If you use this system, make sure that you test the equipment on a clear, harmless frequency.
13 S G -237 Smartuner™ Manual 6.2 B.I.T.E.* LED Descriptions *Built-In Test Equipment: Utilizing these LEDs to troubleshoot your Smartuner requires opening the coupler case and observing the LEDs located on the PCB. Please note that doing so will break the factory seal and may compromise the weatherproofing of your unit. If your unit is still under warranty, it is recommended that you call SGC before opening the cover. TND This LED will light when the turner has found an acceptable match.
