by Idiom Press

The elite-class SSB transmit speech processor that your high-performance station's been missing.

RF clipping is simply the most effective way to increase the average power of your SSB signal.  LogiKlipper works by converting your audio to SSB at an IF of 125 kHz, amplifying the signal, and then clipping it.  This results in a signal with higher average power, but also with harmonics.  Since the clipping is done at 125 kHz, the harmonics are at 250 kHz and higher, and are easily filtered out.  (If the clipping were done at audio frequencies some harmonics would be inside the filter passband, which would result in unacceptable distortion.)  The signal is then downconverted and demodulated back to audio to be sent to your rig.  The result is clean, splatter-free audio that sounds louder on the other end.

But my rig has compression built in.  Why do I need the LogiKlipper?  Compression works by adjusting the gain as you speak.  It cranks up the gain after the signal has been quiet for a while, such as between words; then when the signal gets loud, the gain is turned back down.  Compression is certainly better than no audio processing, but it can be tricky to adjust the mic gain, and it lends itself to splatter problems.  The problem is that the compression is always trying to guess what the signal level will be, based on what the level was a short while ago.  Sometimes the compression doesn't provide enough boost, and your signal is unintelligible on the other end.  Sometimes the compression provides too much boost, overdriving the transmitter.  How many times have you heard someone splattering up and down the band, or heard every background noise in someone else's shack over the air?  The LogiKlipper on the other hand is easy to adjust, and will be more effective than the compression in your rig.  You'll be able to complete the sked under difficult conditions, or be heard by more people in the net, or hold your contest run frequency better, or snag the really rare DX in the monster pileup.

ARRL members may be interested to download a QST article by Harold G. Collins, W6JES, from 1969 that shows exactly why RF clipping beats compression.  LINK

Designed by Dave Haupt W8NF, the LogiKlipper has been optimized to give the best possible performance:

• Unprecedented front-end dynamic range: up to 60dB above the onset of clipping.
• Custom-designed active filtering overcomes the limitations imposed by using “stock” ceramic or crystal filters, resulting in much less IMD in the clipping process.  The result is a much cleaner, less muddy sound than that of other RF clippers on the market.
• Switching-mode mixers used in SSB modulator/demodulator overcome the inherent IMD in active mixers.
• A fast-responding downward-expanding-style noise gate provides superior background noise reduction, keeping shack noise out of your transmitted signal.
• A beefy audiophile-grade output circuit can drive long cables and capacitive loads with ease.

The LogiKlipper was designed to work with just about any microphone, driving just about any rig.  The LogiKlipper can be configured for common microphones with round eight-pin Foster plugs by merely resetting jumpers (no soldering required!), and the up and down buttons still work.  The universal output cable with round eight-pin Foster plugs is included.  The LogiKlipper also works with vintage crystal microphones. 

The LogiKlipper also can drive just about any SSB rig, whether modern or vintage tube-type.

The LogiKlipper is simple to adjust for proper operation: just talk into the microphone as you usually do, and adjust the front-panel mic gain control until the peaks go to half scale on the LED bargraph, which is 0 dB on the scale.

The LogiKlipper has three modes:

• MILD gives you a full-bodied sound, great for ragchewing, yet still increases average SSB power by as much as 6dB. (10 dB of clipping)
• PUNCH gives you a dominating, somewhat processed sound, great for running a frequency or being net control. (20 dB of clipping)
• PENETRATE adds a high frequency boost, which sounds shrill, but is that last ounce of effort you need when you really, absolutely, MUST get that QSO NOW, before the island DXpedition goes off the air. (20 dB of clipping)

WARNING: raising the average power of a SSB signal, as the LogiKlipper does, also raises the duty cycle, which demands more from transmitters and amplifiers.  The design of the station must take the higher duty cycle into consideration.  Idiom Press is not responsible for damage to station equipment as a consequence of the higher duty cycle.

Connections and Cables

The LogiKlipper offers three input jacks: an eight-pin round jack on the front panel, a 3.5mm (1/8") phone jack on the front panel, and a rear-panel 3.5mm (1/8") phone jack.  There are two output jacks on the rear panel: a round eight-pin Foster jack for the included universal output cable, and a 3.5mm (1/8") phone jack.

For users with microphones that have eight-pin round Foster plugs, the microphone plugs into the front panel, and the included universal output cable goes from the LogiKlipper to the radio.  The LogiKlipper can be easily reconfigured for different brands of microphones and radios.

The LogiKlipper's power jack takes a barrel-style power plug with a 2.5mm inner diameter and 5.5mm outer diameter.  A power cable is included with the unit.

Specifications

Specification	Metric	US
Weight	0.63 kg	1 lb 6 oz
Length, including knobs and connectors	19 cm	7 1/2"
Width	13 cm	5 1/4"
Height, including feet	6 cm	2 1/4"
Maximum current draw	200 mA	200 mA