EME174 Series Amplifier Kits

EME174-HF Amplifier

Fully Constructed EME174-HF Kit

PLEASE NOTE: That this Product has been discontinued

Please Note: that all information including pictures on this web page are copyright to Mini-Kits and must not be used on any other web site, or reproduced in any publication.

The Mini-Kits EME174 PC Board has been designed for constructing simple filters and Broadband Amplifiers. Kit part numbers are suffixed with the amplifier gain in dB. The EME174-HF10 is a 10dB gain version. The amplifier uses a combination of loss less and shunt feedback providing a wide bandwidth from around 250kHz to over 120MHz. The amplifier is designed to be terminated into 50ohm loads for stability, and has a gain peak in the UHF region. The 20dB gain version has high frequency roll off to prevent parasitic oscillation when the amplifier is un terminated. Both amplifiers can either be used for receive or transmitter gain stages, and have an excellent OPIP2 of +47dBm, and OPIP3 of +67dBm which is good for strong signal handling and low distortion. The noise figure is around 3.5dB which is ideal for HF to low band VHF use. The maximum output power for the 10dB gain version was measured as +27dBm @ 1dB compression.

EME174-HF10 Kit Notes:

Basic 54MHz Low Pass Filter Kit
The EME174-HF10 amplifier has been designed as a building block that can be used in either a high performance receiver or transmitter design. The amplifier design uses a combination of loss less and shunt feedback providing a wide bandwidth from around 125kHz to over 400MHz. The amplifier has a peak gain of 13dB at 275MHz so a suitable low pass filter should be used to limit the high frequency response. The amplifier is biased for 150mA and has low inter modulation distortion important for strong signal handling in receivers, and a clean output when used in transmitters.
EME174-HF10-1

The above graph shows the low frequency performance up to 5MHz.

EME174-HF10-2

The above graph shows the gain up to 150MHz

EME174-HF10-3

The above graph shows the input return loss

EME174-HF10-4

The above graph shows the output return loss

EME174-HF20 Kit Notes:

Basic 54MHz Low Pass Filter Kit
The EME174-HF20 amplifier has been designed as a building block that can be used in either a high performance receiver or transmitter design. The amplifier design uses a combination of loss less and shunt feedback providing a wide -3dB gain bandwidth from around 200kHz to 120MHz. The amplifier is biased for 150mA and has low inter modulation distortion important for strong signal handling in receivers, and a clean output when used in transmitters.
EME174-HF20-1

The above graph shows the low frequency performance up to 5MHz.

EME174-HF10-2

The above graph shows the gain up to 150MHz

EME174-HF20-3

The above graph shows the input return loss

EME174-HF20-4

The above graph shows the output return loss

Mounting Into a Die cast Enclosure:

OPTIONAL HFA-HW HARDWARE KIT

1 x ENCL03 Hammond 1550Q Enclosure
4 x PP-M3x6-NB M3x6mm Pan Philips Screw
4 x CS-M3x6-ZS M3x6mm Countersunk Screw
4 x PS-M2.5x6-ZS M2.5x6mm Pan Slot Screw
2 x EYE-M3-A M3 Solder Eyelet Lug

1 x EYE-M5-A M5 Solder Eyelet Lug

1 x FT1500 Feedthrough Capacitor 1500pF
4 x N-M2.5-ZS M2.5 ZS Nut
4 x SPA-M3x8-A M3x8mm Spacer
4 x WSP-M3-NS M3 Shake proof Washer
2 x WCS-M2.5-NB M2.5 Shake proof Washer

Mounting Procedure:

  • Construct the PC board as per the Kit notes but DO NOT fit the SMA35 sockets to the board.
  • Put the PC board into the enclosure and mark through the 4 holes in the PC board to the bottom of the enclosure using a fine felt tip pen.
  • Centre punch and drill 4 x M3 holes in the bottom of the enclosure, then countersink the 4 holes on the outer of the enclosure to suit the 4x M3x6mm countersunk bolts.
  • Mount the 4 x M3x8mm spacers using the 4 counter sunk bolts to the enclosure.
  • Carefully mark and drill two 4mm holes for the SMA connectors in the die cast enclosure as shown in the picture above.
  • Fit the two SMA sockets to the enclosure, and mark the mounting holes using a fine felt tip pen. Centre punch and drill these out using a 2.5mm drill bit to suit the mounting of the SMA connectors.
  • Place the PC board into the enclosure and bolt to the M3x8mm spacers using the 4x M3x6mm bolts and M3 washers.
  • Fit the SMA connectors to the enclosure using the M2.5x6mm bolts washers and Nuts. A M3 solder lug is used on each of the SMA connectors to connect to the PC board top ground plane.
  • Connect some tin plated wire between the strip lines on the board to the centre pins of the two SMA connectors.
  • Drill a suitable hole to fit the FT1500 feedthrough capacitor, and mount it the M5 eyelet
  • This concludes the construction of the complete boxed Kit which can now be tested.

 

Kit Changes and Modifications

EME174 Amplifier Kits

1/ Please note that these Amplifiers require 50ohm loads on both the input and output for stability. These amplifiers are not recommended to be used as antenna amplifiers unless the antenna is a good 50ohm load.

2/ The 100pF capacitor on the collector of the BFG235 should not be fitted on the 10dB amplifier version.

This and all subsequent pages © to Mini-Kits 1999 - 2017, All rights reserved