Bti Lk

BTI LK-2000 is a single tube, grounded grid linear amplifier built to really take it and loafs along at the full legal input This amplifier is offered in two styles—the floor model console, or the two-unit table top model with a separate power supply. Either model is convertible into the other with a few available conversion parts.

The amplifier tube is the quick-heatiiig Eimac 3-1000Z which has a full 1000 watts plate dissipation and replacement cost of only seventy-eight dollars. More than ade quute cooling is provided by using the recommended air cooled socket and chimney along with a very quiet blower. A unique after coolii'g feature has been incorporated in the BTI LK-2000 which keeps the blower running from 60 to 90 seconds after the amplifier is turned off.

The solid state power supply is built around a husky 40 pound plate transformer; computer grade capacitors provide 30 uF of output capacitance, the combination of a solid state power supply and quick-heat -tube permit almost instant on and off—no warm-up waiting is required. For filament power to the 3-100QZ, a separate filament transformer is mounted in the rf section.

Drive to the 3-1000Z is applied through low-Q broad band tuned input circuits; not over 100 watts of drive is required for lull, power operation. The LK-2000 performs quite well with only 50 watts of drive and under these condition provides 1500 watts PEP input- Although the cathode input circuits are tuned for amateur band phone operation, they may be retuned by the user for operation at other frequencies with the instructions furnished.

A pi-L output circuit is used to match {he plate to the antenna; the pi-L is preferred over the simple pi circuit because of its improved harmonic attenuation. To assure maximum shielding, all cabinet joints of the rf section are alumi-gokl processed.

The ALC circuitry used in the BTI LK-2000 provides many distinct advantages; when adjusted according to the instruction manual, the ALC will prevent distortion from overdriving in either the amplifier or the exciter. It allows much freedom in mouth-to-mike distance while maintaining the same full output. Even when you get a little excited and shout, the ALC instantly adjusts the level to prevent distortion.

Either 115 or 230 volts is required for the power supply. An overload relay in the plate current circuit turns off the main power relay when plate current exceeds one ampere. An accessory dummy load is available which will take the full output of the transmitter for several minutes during tune up, A control knob on the front panel of the amplifier switches from the antenna to the dummy load; a thermal switch in the load will automatically turn oil the amplifier if the load reaches it maximum rated temperature.

erator from accidentally coming in contact with the high voltage dc which is present in both compartments.

Collins Linear Amplifiers

Collins 30L-1

i fie Collins 30L-1 linear amplifier is rated at 1000 watts PEP 011 SSB and 1000 watts average on CW 011 all bands; it may be easily driven to its fulled rated input by any 70 to 100 watt exciters. This unit is completely sell contained and designed for table top use.

Although the 30L-1 was designed specifically for SSB and CW service on the amateur bands from 3.5 to 30 MHz, provisions are made for general coverage use too. I he ALC voltage from the 30L-1 linear is fed back to the exciter, providing maximum talking power without overdriving and distortion, In combination with rf inverse feedback, the ALC circuit provides more average power with a sharper sounding signal

The 30L-1 uses four 811A triodes in the grounded grid configuration. Since the 811A's are instantly heated, there is no delay in warm-up.

In addition to indicating plate current and plate voltage, the pane^ meter is connected into a special comparator circuit. In the "tune" position, the amplifier is optimum-ly tuned when the tuning and loading controls are adjusted to zero the meter.

For safety, both the rf and power supply compartment covers operate safety interlock switches. Cover removal closes these switches and shorts the high voltage to ground. This arrangement protects the op

Collins 30S-1

rhe Collins 30S-1 requires only 70 to ¡00 watts of driving power to provide the full legal input of 1000 watts (average) on SSB and 1 kW on CW transmissions. This amplifier is completely self-contained and uses the commercially popular 4CX1000A as a grounded grid linear amplifier.

All the controls for operating the 30S-1 are conveniently located on the front panel permitting i:asl and efficient band changes. With the simple push of a button you can switch from (he 100 wait power level of your exciter to the full kilowatt output of the 30S-1.

To assure maximum talking power and minimum distortion, the ALC voltage from the 30S-1 is fed back to the exciter. This, incombination with rf inverse feedback, provides a very clean and sharp signal. Correct tuning and loading are indicated by a zero reading on a full scale multimeter; the loading control and PA tuning control are simply adjusted to obtain zero meter indication.

Drake L-4

There's nothing halfway about the Drake L-4 linear amplifier; this unit is built for continuous duty at full capacity. The rating of 2000 watts PEP on SSB and 1000 watts on CW, AM or RTTY is ensured; the massive plate transformer, heavy duty tank components and voluminous cooling system make continuous operation at these ratings possible.

The power amplifier uses two 3-400Z or SI63 zero bias triodes in a class B grounded grid circuit. These two tubes have a total plate dissipation of 800 watts and their rugged construction will withstand a lot of abuse. For minimum distortion, higher efficiency and a constant 50 ohm input impedance, the cathodes of the 3-400Zs are matched with broadband tuned input circuits.

Any exciter that will deliver 100 watts PEP 3SB and 75 watts on CW will drive t he L-4 to the maximum legal input power. In the grounded grid configuration, most o! the driving power is added to the output power. The use of a transmitting AGC circuit controls the exciter gain to allow a higher audio level without peak clipping. In addition, rf feedback is used to decrease distortion to better than 35 dB and tends to equalize tube characteristics from tube to tube.

Galaxy 2000

The unique new design of the Galaxy 2000 permits the use of ten parallel 6HF5 tubes to deliver high efficiency, even on ten meters» Ln fact, the power output on all bands is guaranteed to be at least 1200 watts PEP. Chese tubes are easily obtainable and their total replacement cost makes them very attractive for linear amplifier use- In the Galaxy 2000 the GHFos operate well within the manufacturer's voltage, current and temperature specifications.

The Galaxy 2000 operates in class ABi and delivers a very clean and stable signal. The amplifier incorporates both voltage and current monitoring, with an FCC specified time constant meter, as well as a tune position which monitors the rf output of the amplifier. The automatic linearity system (ALS) circuit used in the Galaxy 2000 provides automatic comparison of the input-output waveform, and acts on this information to maintain exact waveform duplication with best linearity.

The Galaxy 2000 features a compact table top design with built-in antenna changeover relay, heavy duty solid state power supply, and reduced power input in the tune-up position. Any exciter in the 100 to 200 watt class will drive the amplifier to full rated input and only a single ground of the operating contro circuit is required for operation.

Galaxy 1000 Linear Amplifier

Gonset GSB 201

Exceptionally compact—only 8 high,

12ir wide and 17" decp-the GSB-20I

lends itself readily to table-top mounting. Finished in blending light greys, it presents a handsome, clean-cut appearance.

The Gonset GSB linear amplifier provides 10 dB gain on the 80, 40, 20, 15, and 10 meter bands with maximum input power of 2000 watts PEP on SSB, ' 000 watts CW or 400 watts AM. It will operate with nearly am SSB exciter, homebrew or commercial; 100 watts PEP drive will provide the maximum of 1000 watts PEP output. The GSB 201 incorporates a number of desirable operating features which include the use of four low cost SllA tubes in stable, grounded grid circuitry. The power supply uses mod ern silicon rectifiers and an antenna changeover relay is built in. A panel switch permits preliminary tuning to be done at low power levels, thereby reducing interference. j!ie plate current meter is switchable from the front panel to indicate plate current or relative power output.

Amplifier Hxl

The Hammarlund HXL-1 1500 watt PEP linear amplifier provides an excellent match to lower powered SSB exciters and provides 1500 watts PEP on SSB, E 000 watts on

CW and 250 watts in AM service. This efficient linear uses a pair of 572A/13 triodes in a bands witching arrangement that covers all the ham bands from 80 through 10 meters. This amplifier features an internal power supply, built-in antenna changeover relay, pi net output circuit and a multipurpose meter which has been provided with a built-in circuit that even provides a linearity test.

Antenna Changeover Relay

interested in a kilowatt mobile? How about a small table top linear? The Heath-kit HA-14 KW Kompact may be just what you're looking for. This miniscule little box will provide up to 1000 watts PEP on all bands from 80 through 10, yet is only 3 inches high, a little over a foot wide and ten inches deep. It is small enough to be mounted under the dash of nearly any car with plenty of room to spare-room enough in most cars to allow it to be stacked with your transceiver, providing a complete un-der-the-dash mobile kilowatt station.

Two 572-B/T-160-Ls operating in parallel in the final provide a clean signal with third order distortion products 30 dB down at 1000 watts PEP input. A built-in SWR meter and antenna changeover relay acid to the operating convenience* In addition, the broad band input circuits on each band require no tuning. Also, provisions for remotely controlling the power supply used with the KW Kompact should appeal particularly to the mobile operator,

Heath kit SB-200

The Heathkit SB-200 desk-top linear amplifier is a complete self-contained unit that provides 1200 watts PEP input on SSB and 1000 watts on CW. This unit has its own built-in power supply and any exciter with 100 watts PEP output will provide adequate drive. Two heavy-duty 572-B/T-160-L final amplifier tubes provide an extremely clean signal with minimum distortion.

For maximum efficiency and low distortion, prefeiined cathode input circuits are used. These, along with ALC within the SB-200 and provision for external use of the automatic level control result in a relatively constant audio output under varying conditions. The amplifier is completely shielded for TVI protection and stability and a built-in SWR meter and antenna changeover relay provide the maximum in operating convenience.

The conservatively rated power supply uses silicon diodes for maximum reliability and is circuit breaker protected (no fuses to worry about). In addition, this supply may be operated from either 115 or 230 volts ac, 50/60 Hz.

Amper 400z
Henry 2-K

The Henry 2-K linear amplifier uses two rugged 3-400Z grounded grid triodes which were espec ial I y designed f or zero-bias linear operation. These tubes provide 800 watts of plate dissipation and the full legal limit in all modes—2000 watts PEP on SSB and 1000 watts on CW, AM, and FSK,

The Henry 2000 wait linears are available in two models» the console model 2K-2 and the desk model 2KD-2 which has an external power supply. If you have your own power supply, the rf deck is available separately as the 2KR-2. The power supply used in these units is a heavy duty 2500 volt de supply which is rated very conservatively, A choke input filter provides very good regulation and the solid state rectifiers insure year-in, year-out reliability.

For greatest efficiency and maximum attenuation of unwanted signals the pi-L plate circuit uses a silver plated tank coit The band switch is a rugged unit with 20 ampere contacts and solid straight-through linkage, In addition, heavy duty bronze gears are used to drive the tuning capacitors. An aluminum cabinet eliminates any magnetic resonances and double rf shielding minimizes harmonic radiation, hi fact, the second harmonic is more than 60 dB down from the full rated input.

To obtain maximum drive and maintain linearity, a resonant cathode-pi input circuil is used. The special plug-in design permits operation on any frequency from 3.5 to 30 MHz. The built-in SWR meter and rf output meter simplifies tuning up while allowing ihe operator to monitor the performance of his antenna.

In addition to the 2K line of linear amplifiers, Henry has just announced the new 4-K 'Commercial unit [he 4-K employs the 5CX1500A power pentode which is designed for superior linearity. This tube provides a full 4000 watts PEP input on SSB with efficiencies in the range of 60<?.

The Hunter Bandit 2000B linear amplifier is designed for operation with SSB transceivers providing 100 watts PEP output. However, the output of the exciter may be substantially higher without harming the linear amplifier. This means that most modern SSB transceivers are compatible with the Bandit.

Four UE572B triodes are used in the power amplifier; these tubes provide 2000 watts PEP input on SS14. There is no warm-up period required because the filaments of these tubes are instant heating and the solid state high voltage power supply provides instant power. When the linear is turned off, the exciter is connected directly to the antenna through the internal antenna change-over relay.

A separate adjustable rf output meter is included in the output circuit of the 2000B, This meter permits the operator to adjust the measuring circuit to accommodate different feed line impedances and to adjust Sensitivity on all bands, t his meter is particularly interesting in that it follows the modulation envelope much like a VU meter and provides an excellent modulation moni-

1967 Ham Radios

National NCL-2000

The National NCL-2000 covers all the amateur bands from 80 through 10 meters and includes a husky built-in 115/230 volt AC power supply. The full key down power on CW, AM and RTTY is 1000 watts, with 2000 watts PEP on SSB for the full legal limit. The two 8122 ceramic tubes used in the final were designed specifically for single sideband service and provide 800 watts of plate dissipation to assure conservative operation, The output of the NCL-2000 is very clean with the third and fifth order distortion products down 30 or 45 dB respectively; in addition, hum and noise are more than 40 dB down and the full rated input The use of grid regulated class AB$ operation results in high efficiency and linearity along with easy tune-up and low drive requirements; the NCL-2000 may be driven to full rated input with any exciter delivering 20 to 200 watts PEP, The NC\ 200 is protected against overload and the operator against electrical shock with the built-in safety devices. In addition to fuses, time delay and plate current overload relays, a plate power fid interlock and automatic high voltage shorting bar are included.

Sideband Engineers

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  • ruby
    Where is that thun control located on a Henry 2 K 3 hf amplifier?
    4 years ago
  • adalberto lucciano
    Does the bti lk2000 require an antenna changeover relay?
    4 months ago

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