Specifications

SMARTUNER MANUAL 37

SGC Inc. SGC Building, 13737 S.E. 26th St. Bellevue, WA. 98005 USA

E-Mail: sgc@sgcworld.com Web Site: www.sgcworld.com

Next, the SSB transmitter should be adjusted to the lowest desired frequency, and the

test as outlined above should be repeated. The SMARTUNER should immediately sense

the mismatch and switch to the tune mode to retune the antenna system. Since the

algorithm must search through more possible values of L and C to find an appropriate

combination at the lower frequencies, the tune cycle may take longer. A few spoken

words should achieve an “all tuned” indication. The SMARTUNER installation and

tune-up are considered complete if the above tests have been successfully performed.

The SMARTUNER will probably not be supplied from SGC with memory data

appropriate to your installation, and the memory feature may not seem impressive at

first. Allow the SMARTUNER to “learn” your antenna’s requirements by proceeding

from frequency to frequency and allowing the normal tune-up to occur. As the

SMARTUNER computer memorizes more and more frequencies, you should then be

able to return to a previously tuned frequency and find that the coupler immediately

responds “ALL TUNED,” even before the first word is completed.

The memory system is capable of storing hundreds of individual frequency/relay

combinations, mostly in the lower operating frequencies, providing better memory

resolution at lower frequencies where antenna systems are inherently narrow band.

Usually, only one or two memory positions are needed to provide satisfactory coverage

at higher frequency bands.

6.6 Do-It-Yourself Light-Bulb Dummy Load

Any time that a transmitter is used, it must be outputting into a load. A load is anything

that the output power can be pumped into. If the transmitter is operated without any

sort of load connected, the final amplifier stage could become severely damaged. The

problem is that you should never test a transmitter on the air for the first time, if you

are unsure about how to operate it, and if you are unsure whether it is working

properly. You could create harmful interference to other stations.

To test transmitters without actually operating into an antenna, dummy loads were

created. A dummy load is a load that will dissipate the energy from the transmitter

instead of emanating it into the ionosphere. Nearly all commercial dummy loads are

large oil-filled cans. These dummy loads change the transmitted energy into heat, which

is absorbed by the oil. Because different transmitters output different amounts of

power, different sizes of dummy loads must be used. Dummy loads for typical amateur

powers (under 500 watts) are relatively inexpensive and are readily available.

Unfortunately, when you use a can-type dummy load, you can't see "what's happening"

with your transmitter. In this case, you can use a light-bulb dummy load to test your

transmitter. Here, the light bulb is directly connected to the output of the transmitter

and it dissipates the RF energy as light. The light bulb dummy load is more useful than