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--- member-projects:g4klx-23cms-eme [2025/03/29 18:07] – g4klx
+++ member-projects:g4klx-23cms-eme [2025/05/16 12:45] (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 May 2025 I had worked 165 unique stations off the moon (known as initials), in all continents, in 125 grids, and in 39 DXCC entities. I think I have worked around 15 US states.
 {{:member-projects:23cms-march-europe.png?200|}} {{:member-projects:23cms-march-na.png?200|}}
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 A potential problem is the results of WRC-23 which may have a huge impact on EME operation on 23cms, but at this time no-one knows for sure what it may be. In the extreme case I, and many others, may have to pack up on 23cms and look at getting going onto 13cms. This wouldn't be the most difficult change, the IC-905 can easily accommodate it, and the sequencer and relays would operate on 13cms without modification, but it would be an unwelcome termination of activity on 23cms, a band I have been active on since 1985.
+In order to hedge my bets, I have bought a 250W amplifier pallet for 13cms, and once built, and added a suitable dish feed and low noise amplifier, I should be able to be active on 13cms EME. I also bought a Pluto Plus as a suitable SDR for use on 13cms so I could keep using the QMAP program for spotting stations.
 {{:member-projects:img_3098.jpeg?200|}}