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Expert 2K-FA Amplifier Review | Radioaficion Ham Radio

Expert 2K-FA Amplifier Review

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Expert 2K-FA Amplifier, 2000 watts, and SIX antenna outputs

It starts from the IK-FA's features but with much much more!
• Double the power output of the 1K-FA.
•The only solid state linear amplifier delivering this power on 50 Mhz.
• 6 selectable antennas.
• Continuous operation.

• Capable of driving an external set of band pass filters, for a perfect SO2R or multi station operation for Contests and DXpeditions.

Expert 2K-FA Amplifier, 2000 watts

• Automatic tuner remotable on the roof (option), you can automatically manage up to 6 antennas with just one coaxial cable feed.

Expert 2K-FA Amplifier, 2000 watts

• Advanced switching power supply with automating Power Factor Correction (according to the new EU's rules).

• Possibility to drive directly all tuneable antennas, such as the SteppIR.

Expert 2K-FA Amplifier, 2000 watts

• USB port for PC control and downloading upgrades.

• Dimensions: w38xh18xd42 cm. (connectors included)

• Weight: around 20 Kg.

Operational Description

The SPE Expert 2K-FA solid state linear amplifier is small, powerful and completely automatic, it provides a full legal power output and covers the radio amateur band range from 1.8 to 50 MHz,  All operating conditions (frequency, antenna and tuner) may be controlled from the transceiver.

The linear amplifier has two inputs (INPUT 1, INPUT 2) to which it is possible to connect two transceivers of any brand or type. These inputs are selected with the [INPUT] key or automatically.  It can manage up to six antennas (ANT 1, ANT 2, ANT 3, ANT 4, ANT 5, ANT 6 ).  The amplifier selects antennas automatically when they have been programmed.

The amplifier is composed of six push-pull of MRF151 G (mosfets) in class AB paralleled with a passive
combiner.

The modern transceivers have CAT control, thanks to this link the linear amplifier detects the operating
frequency of the transceiver and then automatically changes band, antenna and automatic tuner.

The power supply of the SPE Expert 2K-FA, unique in its category, is switching with a PFC (Power Factor Correction) that allows a drastic reduction of the harmonic components in the mains in accordance with IEC555-2.  It consists of two separate elements:

  • The first powers all the electronic circuits for command and control.
  • The second powers only the PA, its output voltages are 48 Vdc (MAX Pout), 35 Vdc (MID Pout), and 30 Vdc (LOW Pout).
  • The power supply meets also the followings rules:  UL60950-1, TUV EN60950-1, EN55022, EN61000-3-2,-3, EN61000-4-2,3,4,5,6,8,11; ENV50204, EN5502.


The amplifier has an automatic tuner that handles load mismatches up to 3:1  VSWR (2,5:1 for 50 MHz). A unique feature of this linear is that it not only measures the SWR after the matching, but also the SWR of the system antenna / cable, this allows to always evaluate the antenna system despite the matching and the power applied.


The amplifier contains a look-up table with the permitted amateur bands only (continuous coverage is inhibited, including CB band).  In the tuner management, antenna data and other working data are stored. Every band has a sub-band set, and for each of those, data related to the antenna and auto-ATU tuning is stored.

The CAT information and the frequency counter inside the linear detect the operating frequency and set the correct sub-band. Thanks to the stored data, the tuner and the antenna are automatically set correctly. Setting of the match data to write in the tables is performed automatically by pressing the [TUNE]  key, the system will then find the correct match for minimum SWR.


The SPE Expert 2K-FA has a sophisticated protection system that constantly controls the amplifier’s most important parameters.

These parameters are:

Temperature of the heatsink; max. / min. voltage on the PA; max. PA current; SWR; max voltage RF on the tuner; input power; power combiner balance. The protection system is effected in two different ways:

  • 1) Through hardware circuits to guarantee  minimum intervention time.
  • 2) Through software, with one of the two CPU’s, to guarantee the maximum precision.

The two results are always compared, every difference produces a protection trip and consequent alarm.

Several new features are provided:

  • Tuneable antennas control.
  • Setting up a separate receiving antenna.
  • Command of BPF external filters.
  • Remotable ATU (optz.).

Tuning Procedure

TUNER    (ATU)
The amplifier has an automatic tuner that handles load mismatches up to 3:1 VSWR (2.5:1 for 6 m).The amplifier contains a look-up table with all the permitted bands.  For tuner management, antenna data and other working data are stored. Every band has a sub-band set, and for each of those, data related to the antenna and auto-ATU tuning is stored. The CAT and the frequency counter detect the operating frequency and the correct   sub-band. Thanks to the stored data, the tuner and the antenna are automatically set correctly.

For every input there is a different table. If two exciters are connected at the same time, each exciter can have different configurations. It is possible to use the two different tables when the amplifier operates at two different locations. In fact it is possible to use the INPUT 1 at one and INPUT 2 on the other. In this way repeated reprogrammings are not needed  Furthermore, table driven management is useful to inhibit operation of the amplifier, for instance when an antenna for a particular band is not available.

All auto-tuner functions remain, on standby, whilst using the transceiver only. Setting of the match data to write to the tables is performed automatically by pressing the [TUNE]  key The system will then find the correct match for minimum SWR.

To achieve a better match than that achieved with the automatic tune routine (most unlikely) it is possible to set the tuning manually by using the keys [◄C], [C►], [◄L], [L►]. When manual tuning has been performed, it is possible to read the tuning value, the working frequency and the associated sub-band on the appropriate screen page. Both the types of tuning are always effected in “STANDBY“ state. Before beginning the matching process, the tuner measures the SWR of the system cable / antenna. if it is greater than 3.5:1, the procedure does not begin and an alarm is given. It is possible to bypass the tuner with a specific command, in order to use an external tuner.

NEVER USE THE INTERNAL TUNER WITH AN  EXTERNAL ONE, it could seriously damage the linear. IF YOU WANT USE AN EXTERNAL TUNER, BEFORE EXCLUDE THE INTERNAL ONE. The internal tuner may be excluded:

  • Totally.
  • For single band.
  • For single band only with a specific antenna.

It is always automatically excluded:
- With the only receiving antenna set  
- With tuneable antenna set.

Note: the tuner, like all analog circuits, introduces  a loss (0,8 dB max.) that may vary with tuning conditions.The power meter of the amplifier does not show this loss as the power is measured at the tuner input where the load resistance is always constant  (50 ohm).


Note: ATTENTION: When the amplifier is either in  “STANDBY” or “OPERATE” mode, always disable the automatic tuner in your transceiver.

Note: ATTENTION: As two different tables are used for INPUT1 and INPUT2, it  is necessary to make
separate matching, for the same antenna, depending on the used input.  Ignoring this caution could make the amplifier work for a long period with a high SWR and this practice could seriously damage the amplifier even if  the protection level is  a bit lower than the threshold.

SET ANTENNA.


Press [SET] and open the “ANTENNA“ menu page. Assign an appropriate antenna for the band concerned. If you don’t have an antenna for a band, input “N“. When all the antennas are programmed, exit and go back to STANDBY.


USE OF AUTOMATIC TUNER.


To complete the programming it is necessary to match the antennas to the  amplifier  by operating  “TUNE“. We recommend you to select each band (with available antenna) and then program the tuner for the sub-bands within which you will operate. Refer to the table in section 19 of this manual to select the appropriate sub-bands for your operating preferences. You are strongly advised to proceed with the utmost accuracy, not just match the current frequency, but all the sub-bands you are likely to use. Matching all the antennas on all bands available you will enjoy all the features of the automatic linear.


Progress as follows:

  • - Find the central frequency of the sub-band to tune in the table (refer to  section 19 of this manual) and set the transceiver to that frequency.
  • - Set your transceiver to transmit a continuous tone in RTTY or CW.
  • - Press and  hold the [TUNE] key for about one second.  The procedure for automatic tuning will start (you will hear the ATU relays operate)  and then it will stop when SWR is at a minimum. Sometimes it is possible to improve tuning by pressing the [TUNE] key  again.
  • - Repeat the previous steps for all bands and sub-bands you want.
  • - Repeat the previous steps for other antennas the same band after having selected it using the [ANT] key.


Note:   if the ALC link is not used, it is preferable to reduce the transceiver power to about 50 Watts during this operation.

It starts from the IK-FA's features but with much much more!
• Double the power output of the 1K-FA.

•The only solid state linear amplifier delivering this power on 50 Mhz.

• 6 selectable antennas.

• Continuous operation.

• Capable of driving an external set of band pass filters, for a perfect SO2R or multi station operation for Contests and DXpeditions.

• Automatic tuner remotable on the roof (option), you can automatically manage up to 6 antennas with just one coaxial cable feed.

• Advanced switching power supply with automating Power Factor Correction (according to the new EU's rules).

• Possibility to drive directly all tuneable antennas, such as the SteppIR.

• USB port for PC control and downloading upgrades.

• Dimensions: w38xh18xd42 cm. (connectors included)

• Weight: around 20 Kg.
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