ATTENTION: The current draw from a 12V DC supply is around 220mA. If you leave the voltage regulator as is on the PCB it will run very hot! You can use a small heatsink or relocate the voltage regulator on a box wall for nice and cool operation.

Fig. 3. VLF gain response

Fig. 1. Gain curve from 1 MHZ to 60 MHZ

Push-pull 2x Gali-74+ Pre-Amp (LNA) for HF Receivers



  • 2 x GALI-74+ in push-pull for great IMD2 & IMD3 performance


  • IN/OUT Relay


  • DC through coax (Bias-Tee)


  • 10 KHZ - 60 MHZ suggested frequency range



Steve, AA7U,  was kind enough to point out that my photo with the voltage regulator bolted on the PCB is misleading. Actually the voltage regulator runs hot and needs either a small heatsink or removed from the PCB and attached on a box wall or any metal surface. For some buyers asking me to place this preamp inside a box, I fix it just under the PCB, under its silkscreen position. He also noticed the input impedance was not correct. In the schematic diagram first released I swapped the transformers winding information of my other project "DXer's LNA" with 4x GALi74+ preamp. The schematic is now corrected.  Frank, also measured second and third order output intercept point (OIP2 and OIP3) and together he measured NF at 10 MHz with the HP 8970B noise figure meter:  +24.59 dB gain, NF 3.36 dB

IMD results for this preamp, using my two-tone IMD test set:

SV1AFN dual GALI-74 preamp, 12.5V, 230 mA. 3/4 Mc test tones, set for 0 dBm at output of preamp:

1Mc +70.6 dBm OIP2

7Mc +69.3 dBm OIP2

2Mc +40.5 dBm OIP3

5Mc +40.7 dBm OIP3

  • The input transformer is wound with 4 turns for the primary winding and 6 turns for the secondary.
  • The output transformer's primary has 4 bifilar turns (or 8 turns center tapped) and the secondary 6 turns.
  • The two inductors are identical and are wound with 18 turns.

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Fig. 4. Wideband gain curve. See the transformers limitations.

DIY KIT:

Factory soldered PCB with all SMD components, relays and connectors. The buyer winds the transformers, the inductors and solder them in place.          EUR 49.00

A completely built & tested Module is at EUR 59.00 without  VAT 24% with EUR 11.99 shipping from Greece (EU). 

The 24% VAT is only applicable to individual buyers from the EU countries.

The shipping is with Registered Mail with tracking info. It usually takes about 2-3 days for Europe and 8-10 days for USA/Canada.

​Add all the items you need into your cart and pay easily with Paypal.

The shipping cost is EUR 3.99 for total value under EUR 9.99, EUR 7.99 for total value under 49.99, EUR 11.99  for total items value under 99.99, EUR 15.99 for total value under 199.99 and free for total value grater than EUR 200.00. The shipping is with registered mail with tracking info, except for the lowest scale of EUR 3.99, and delivers to USA, Australia in about a week to 12 days max, or less than a week for Europe. 

Special arrangement for shipping with DHL or other courier service is also available. Please email us.

Fig. 2. Reverse gain (isolation)

This company is registerd with the Greek Tax office and VAT. 

The business details are:

Grammatikos Katsouris

SV1AFN.com

Sole Proprietorship

127 Artakis str, Athens, 17124 GREECE

VAT no. EL 042237030

Chamber Reg. No 171467

Bank Account: 

National Bank of Greece, BIC ETHNGRAA

IBAN: GR6701101910000019100189455

Account Holder: Grammatikos Katsouris

Our shop is on-line, there is no physical shop to visit.

DUNS number: 524163138