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--- member-projects:g4klx-23cms-eme [2025/03/29 17:47] – g4klx
+++ member-projects:g4klx-23cms-eme [2025/04/14 15:33] (current) – g4klx
@@ Line 50: / Line 50: @@
 I had hoped to buy a G4DDK preamplifier which are state of the art, but Sam has stopped making them. I therefore sourced a WD5AGO preamp which promised to have similar performance, typically a noise figure of between 0.2 and 0.3 dB and a nice high gain from a two stage design. I also bought an old DB6NT preamplifier from the G4BEL SK estate which has a noise figure of around 0.7 dB as a standby.
+{{:member-projects:wd5ago.jpg?200|}}
+At the dish end this pre-amplifier is fed through an isolating relay, which switches the pre-amplifier over to a dummy load on transmit to protect it. This relay is energised on receive rather than on transmit to give fail-safe operation.
 ** The Dish Rotator **
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 Hyperflex 5 co-ax is used for most of the RF interlinks, including from the pre-amplifier back to the shack, and a length of Ecoflex 15 to carry the transmit RF from the shack to the dish feed. A Bird 43 Thruline using a 500E element is used for measuring RF output and checking that the return loss is acceptable.
-At the dish feed end the pre-amplifier is mounted next to another co-ax relay which provides isolation on transmit to ensure that the pre-amplifier isn't damaged. A small dummy load is used to terminate the pre-amplifier in transmit mode. The equipment at the dish feed is protected by a supermarket carrier bag!
+The equipment at the dish feed is protected from rain by a supermarket carrier bag!
 All RF relays are powered in receive mode to ensure that a loss of power puts everything into a safe mode and doesn't have any transmit RF going into the pre-amplifier for example.
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 Feedback on operation is done via the [[https://logger.hb9q.ch/|HB9Q EME Logger]]. Other EME software is available, most notably from [[https://www.vk5dj.com/doug.html|VK3UM]] (SK).
+** Connecting it All Up **
+Due to the complexity of the system, it is better to show the connections between the various parts by type. These are: RF Connections, Sequencer Control, and Software Links. I do not claim any originality in the way my system is connected, but it probably reflects many others. I know that the sequencer control is very close to that used by Dave G0LBK although the hardware used is substantially different.
+{{:member-projects:eme_rf_connections.png?200|}} {{:member-projects:eme_sequencer_control.png?200|}} {{:member-projects:eme_software_links.png?200|}}
 ** The Results **
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 {{:member-projects:img_2344.jpeg?200|}}
-By the next night I had replaced the pre-amplifier with the lower noise one, and proceeded to work a total of 65 unique stations in my first week of operation with my compromised system. For the next period of operation I had replaced the dish feed with my Septum Feed and slowly increased my power to 300W or so. By March 2025 I had worked 133 unique stations off the moon (known as initials), in all continents, in 102 grids, and in 37 DXCC entities. I think I have worked 15 US states.
+By the next night I had replaced the pre-amplifier with the lower noise one, and proceeded to work a total of 65 unique stations in my first week of operation with my compromised system. For the next period of operation I had replaced the dish feed with my Septum Feed and slowly increased my power to 300W or so. By April 2025 I had worked 154 unique stations off the moon (known as initials), in all continents, in 115 grids, and in 39 DXCC entities. I think I have worked 15 US states.
+{{:member-projects:23cms-march-europe.png?200|}} {{:member-projects:23cms-march-na.png?200|}}
 WSJT-X incorporates an Echo mode which transmits short pulses and detects the echo, and I can usually see returns of around -19dB (in a 3kHz bandwidth) which is more than enough to be able to work myself, if that were possible. Indeed I have worked many people running systems similar or smaller than mine. The smallest station that I have worked is G0HIK with two 33 element yagis, OE3JPC who uses two 56 element yagis is also regularly worked when the path loss is low.