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the TALC circuit results in 10 dB of speech compression with 0.1 mA final grid current The use of a linear master oscillator (LMO) provides linear and smooth tuning with 1 kHz calibration on all bands. Both VOX and PTT are built into the SB-100 as well as seini break-in operation for ( \\ ; a CM sidetone is also provided.

For operation at a fixed station, the 115 volt HP-23 AC power supply is available. For mobile installations, the HP-13 DC power supply and SB A-100-1 Mobile Mounting Kit will make things easy.

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Heat h kit 12A, 22 A, and 32A Single-Band

These new versions of ¿be SSB transceiver that opened up a whole new era in amateur radio have several interesting features, Heath has gone all out to give the radio amateur greater economy and better performance in their famous single-banders. Foremost among the new features of this series is the selectable upper or lower sideband.

In addition the microphone input and gain control, plus bias adjustments are now located on the front panel for ease in changing from fixed station to mobile operation. An added function switch position controls the optional 100 kHz crystal calibrator and the power connectors are now fully compatible with the Heath SB-series power supplies.

The receivers in these new units feature 1 mV sensitivity for 15 dB signal-plus-noise to noise ratio and 2,7 kHz selectivity. The modern crystal filter provides more than 45 dB of carrier and unwanted sideband suppression and the slow AVC action provides optimum SSB reception.

National NCX-5 Mark II

The National NCX-5 Mark II transceiver features 200 watts PEP on sideband, 200 watts C\\ and 100 watts AM on the popular ham bands from 3.5 to 30 MHz, The 1 kHz dial calibration is accomplished with a technique previously used only in the most expensive laboratory or military equipment— a digital readout in kHz on each amateur band with additional counter calibration to 100 Hz. The tuning rate of 10 kHz per knob revolution is identical on all bands and parallax is zero.

rhe NCX-5 is a double conversion unit with crystal controlled high frequency oscillators on each band and a linear solid state VFO. The use of a transistorized VFO eliminates many of the thermal instabilities of vacuum tubes and provides stability from a cold start which is equivelant to that of the best tube-type oscillators after warm-up,

The excellent selectivity characteristics of the NCX-5 are obtained through the use of an eight pole crystal lattice filter. This filter has a shape characteristic of 1.7:1 and 60 dB down the passband is only 4.76 kHz wade; at the 6 dB points the passband of 2.8 kHz uses a miliin Mini of spectrum consistent with pleasing voice quality; With the crystal filter and balanced modulator used in the NCX-5, the carrier suppression is 50 dB, the unwanted sideband suppression is 50 dB and third order distortion products are 30 dB down.

The N( :X-5 incorporates selectable sidebands tin all ham bands along with transceiver vernier tuning to permit 5 kHz tuning of t lie receiver independently from the transmitter. For DX operation, the optional VX-501 digital dial Vf O is available. The NCX-5 may be operated cither with VOX or PTT on both AM or SSB or w ith grid-block semi-hreak-in keying on CW. For AM operation a separate AM detector and AM carrier insertion is provided.

The National NCX-5 incorporates two rf stages in the receiver section for increased sensitivity and spurious signal rejection, and the fast attack, slow release AVC system provides smooth, clean SSB/CW reception without distortion, clicks, pops or thumps. For the deluxe installation, oiled walnut cabinets are available tor the NCX-5, tlie VX 501 external VFO and the NCX-A AC

power supply.

National 200 Transceiver

National 200

The new National 200 transceiver gives the radio amateur complete SSR, AM and C\Y coverage of 80 through 15 and 600 kHz between 28 5 and 29.1 MHz on ten meters at a very reasonable price. For complete cov^ erage of the 10 meter band two additional crystals may be obtained from the National Radio Company, This new transceiver features 200 watt PEP input on all bands. The fast attack, slow release AVC system works on all modes, SSB, CW and AM. For optimum performance, separate product detector and AM detection circuits are used.

To maintain high stability and the same tuning rate on all bands, a premixed crystal controlled front end arrangement is used. The selectivity obtained from the crystal lattice filter is excellent and results in a shape factor of 2.2:1 for high sideband suppression on transmit and rejection of ad jacent channel QRM on receive. The solid state balanced modulator used in the National 200 results in more than 50 db of carrier suppression. Thud order distortion products are suppressed more than 30 dB at full output and the unwanted sideband is suppressed 40 dB.

The extremely smooth tuning mechanism uses a 45:1 planetary and split gear drive; the dial is calibrated every 5 kHz. For AM and CW operation, the carrier is automatically inserted when switching to these modes. For maximum la Ik power on SSB and AM, an internal ALC circuit is pro vided; an external ALC input is available for use with higher power linear amplifiers,

Sideband Engineers

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