Why do I measure a short, (zero ohms), across the RF input on my Smartuner?
The RF input on all Smartuners is transformer coupled to sensing circuits. This is why you measure a DC short.
Is there isolation between the antenna ground and the DC ground on a Smartuner?
Yes. All of the Smartuner couplers use a capacitively coupled RF ground.
The PEP and CW are qualified at what ratings?
100 Watt PEP is equivalent to 30 Watts with 100% duty cycle of a continuous waveform. 100 Watts CW or Morse Code is equivalent to 40 Watts with 100% duty cycle of a continuous waveform.
What about marginal drive power to the coupler?
All SGC couplers have a minimum sensitivity of 3 watts; except the SG-239 which is 1.5 watts. These readings are for RMS peak power (double for peak minimum) and measured into a 50 ohm dummy load. Many users find stable conditions on CW or FM but not so stable conditions on SSB. This is due to minimum levels used on SSB which go over and under the minimum requirement. However, if your power level is marginal, the coupler may not initiate a tune.
What about VSWR sensitivity?
A more serious and common unstable problem occurs with some or most of the radios produced overseas for the amateur community. These radios have a highly sensitive VSWR protection (or too sensitive). The Icom IC-706 is a modern radio but shuts down almost to zero output for a slight VSWR occurrence. In some radios or high "Q" antennas, this will create an unstable condition, even at the 100 watt level and depending on the speech tone of the operator. Several easy ways to circumvent this problem are:
A. Speak louder and on a constant voice tone into the microphone and make sure that the radio is set for the maximum output.
B. Slightly readjust the VSWR protection adjustment in the radio.
C. Tune in CW or FM modes and then lock the coupler
Do I need RF beads and chokes?
RF beads and chokes should not be necessary in a good installation as they require an understanding of what is occurring and are very difficult to use efficiently. It is much easier to have a good and simple installation using a proper RF ground and avoid supposed existing grounds.
What sensing devices do Smartuners use?
They use six sensing devices:
3. Forward Power
4. Reflected Power
5. High or Low Impedance
Do Smartuners have the capability for full memory erasing?
This function is only available on the SG-237 & SG-239. On the other Smartuners, the memory address is erased and recorded with new data whenver the VSWR exceeds 2:1.
What happens if my Smartuner does not find a match?
Two things will happen:
1. The coupler will go into bypass mode (all tuning elements removed).
2. All LED's will blink until either RF is no longer sensed OR a new transmit frequency is detected.
Can I use a SGC Smartuner to tune a 50 ohm fed balanced style antenna?
Yes. SGC couplers can tune into any style HF antenna. Although primarily set up to work with end fed random length antennas (whips, longwire, loops, etc.), they can tune balanced dipole, beam, monobands, etc. To interface with a balanced antenna's impedance, you should install the coupler as close to the antenna as possible or when necessary use a 300-600 ohm ladder line lead for interconnecting.
Can a Smartuner tune a resonant antenna?
Yes. Smartuners can tune resonant antennas at resonant and outskirt points just like any random antenna length.
SGC Inc., Tel:
425-746-6310 Fax: 425-746-6384
Email: firstname.lastname@example.org SGC reserves the right to change specifications, release dates and price without notice.