Gemini HF-1K




This program provides remote support for the Gemini HF-1K amplifier from Linear Amp UK. This software supports Windows 7 and higher, so Windows XP is not supported. The kit is signed - check for a signing certificate from Ltd.

Download links are at the bottom of this page.

The connection between your computer and the amplifier is ethernet, the Gemini 1K's IP address is configured from the front panel.

For normal use the software is designed to be intuitive - you will normally only use the Band/Antenna options. Although the band changes by detecting the input frequency from your transmitter, you can also change the band without having to transmit. Similarly select the antenna - A, B or C. The antenna selection is saved for each band.


You must know the IP address of the Gemini 1K amplifier, this is shown in the front panel's network options window. The default port is 9100. When you know the IP address select Connect from the Home tab in the ribbon bar. Enter the address and press Connect, you should then see a display similar to above in the Introduction.


Select Settings from the Home tab in the ribbon bar.


Select either a preset colour scheme or change the colours as desired.


Other options such as brighness, beep settings.


Added August 20th, available in release 1.0.2. The software uses OmniRig from Afreet Software, Inc. to connect this software to your radio via a serial cable or in the case of Flex / ANAN / SDR a virtual serial cable. The radio is regularly polled for changes in frequency, when a different band is selected on the radio the amplifier band is automatically selected without the need to transmit.

Select Tracking from the Options panel in the ribbon bar.


Selecting Tracking options displays the OmniRig configuration window. the important fields are: Rig type (usually written on the front panel of your radio, also found in the handbook), serial port to use and the polling interval.


Speech Support

Version 1.0.5 introduces speech support for users with visual impairment.

  • When enabled, messages such as errors, trips are always spoken, as are band and antenna changes.
  • Changing the antenna automatically sets the antenna as the default for the current band.
  • To enable: Ribbon bar, Options, Display, Speech Support.
  • For a list of the latest command set select Speech Commands.


Ketstroke Command
Ctrl+'A' Select antenna A
Ctrl+'B' Select antenna B
Ctrl+'C' Select antenna C
Ctrl+'D' Clear trip
Ctrl+'1' Select band 1.8 MHz
Ctrl+'2' Select band 3.5 MHz
Ctrl+'3' Select band 5 MHz
Ctrl+'4' Select band 7 MHz
Ctrl+'5' Select band 10 MHz
Ctrl+'6' Select band 14 MHz
Ctrl+'7' Select band 18 MHz
Ctrl+'8' Select band 21 MHz
Ctrl+'9' Select band 24 MHz
Ctrl+'0' Select band 28 MHz
Ctrl+'X' Select band 50 MHz
Ctrl+'O' Toggle speech support
Ctrl+'P' Report peak power
Ctrl+'S' Report status
Ctrl+'W' Report SWR
Ctrl+'T' Report temperature
Alt+'R' Switch mode to Run
Alt+'S' Switch mode to Standby





Firmware Upload

Firmware is loaded into the amplifier by using FTP. The FTP code is a slightly modified version of FTP Client Class from

  • Power the amplifier on while pressing the small PROG button on the rear of the amplifier.
  • Note: Do not connect to the amplifer.
  • Select Firmware Upload from the Options tab in the ribbon bar.

In the Firmware Upload window click Upload and enter:

  • Amplifier IP address, port 21. (To see the address assigned to the amplifier's FTP server click Set Network on the front panel.)
  • Username=none, Password=none (currently the username and password are not used)
  • Select the firmware to be loaded (a .HEX file)
  • Press Upload to strat the Upload.

A full upload takes typically 90 seconds, the progress is shown in the main window.

Connecting to
220 Service ready for new user.
331 User name okay, need password.
230 User logged in, proceed.
200 Command okay.
215 Chrysalis Embedded FTP
Uploading E:\Open\Gemini1K\Firmware\GEMINIV2WBController_2_08_17_04_22.hex
Sending 481 KB
200 Command okay.
200 Command okay.
150 File status okay; about to open data connection.
100 KB, 200 KB, 300 KB, 400 KB, 481 KB

When the transfer finishes the amplifier will automatically restart.


Do not change the FTP server addres and/or port, these must be left exactly as shown below.



Remote Software


Version 1.0.6, November 26th 2019 [link].


Version 1.0.5, August 9th 2019 [link]
Version 1.0.3, September7th 2018 [link]
Version 1.0.2, September 4th 2018 [link]
Version 1.0.1, August 10th 2018 [link]


Amplifier Firmware

Note: firmware releases are cumulative, the most recent download contains all fixes and enhancements.

Version 1.20b, Decmber 7th 2019 [link].


Change Log

1.20b Corrects for vswr display errors in some hardware versions of the amplifiers

1.06 resolves issue of band re-selection error sometimes occurring on SSB on 24/28MHz

1.05 minor changes to internal timings when changing bands and antennas to correct occasional false trip errors.

1.03 fixes issue where changing from some bands which involved an antenna change at the same time sometimes caused a high VSWR Trip. Adds amplifier name to DHCP record. Fix for out of band errors when doing two tone tests on some bands.