Antennae changeover relays - Revision history

G8GKQ: /* 146 and 70cms */

2018-12-06T16:44:31Z

146 and 70cms

2018-01-30T21:46:06Z

Tx / Rx sequencing: TROPIC

2017-09-19T19:33:36Z

1.3GHz (23cms) and above

2017-09-19T19:33:23Z

23cms and above

2017-09-19T19:32:07Z

146 and 70cms

2017-09-19T19:31:44Z

146 and 70cms

2017-09-19T19:31:12Z

146 and 70cms

2017-09-19T19:31:03Z

146 and 70cms

2017-09-19T19:27:43Z

Tx / Rx sequencing

2017-09-19T19:26:29Z

Transfer or 4 port relays

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 ==146 and 70cms==
-A good paper to read is Ian White's DG8 pre-amp article - http://www.ifwtech.co.uk/g3sek/vhfdx/dg8-preamp-v7.pdf - it's designed around 145 MHz but cover a lot of good practical engineering practice for pre-amps etc and does talk a little bit about the need for good relays.
+A good paper to read is Ian White's DG8 pre-amp article - http://www.ifwtech.co.uk/g3sek/vhfdx/dg8-preamp-v7.pdf - it's designed around 145 MHz but covers a lot of good practical engineering practice for pre-amps etc and does talk a little bit about the need for good relays.
 For 70 cm you can use reasonably cheap BNC relays and the Cx540 N type relay which are often available surplus.

← Older revision		Revision as of 21:46, 30 January 2018
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	[[File:Tx rx timing.JPG\|500px]]		[[File:Tx rx timing.JPG\|500px]]
		+
		+	The PIC controlled sequencer at [http://www.shortwaveradio.co.uk/tropic.htm shortwaveradio.co.uk called TROPIC] may well be a good choice. The kit is listed at £11.50.

	==Transfer or 4 port relays==		==Transfer or 4 port relays==

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 ==1.3GHz (23cms) and above==
-For the microwave bands (21.3Ghz and above) you need microwave relays. These come in many types but the most common are TNC, N or SMA. Good N-type relays (not the CX520s) tend to be expensive. SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.
+For the microwave bands (1.3Ghz and above) you need microwave relays. These come in many types but the most common are TNC, N or SMA. Good N-type relays (not the CX520s) tend to be expensive. SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.
 Typical SMA relays which are good up to 10GHz are shown below:

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 [[File:951 relay.JPG|200px]]
-==23cms and above==
+==1.3GHz (23cms) and above==
-For microwaves 23cm and down you need microwave relays. These come in many types but the most common are TNC, N or SMA. Good N-type relays (not the CX520s) tend to be expensive.
+For the microwave bands (21.3Ghz and above) you need microwave relays. These come in many types but the most common are TNC, N or SMA. Good N-type relays (not the CX520s) tend to be expensive. SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.
-Typical sma relays which are good up to 10GHz are shown below:
+Typical SMA relays which are good up to 10GHz are shown below:
 [[File:rsma-elay.PNG|200px]]
 [[File:sma-relay2.PNG|200px]]
 [[File:sma-relay3.PNG|200px]]
 ==Coil voltages==

← Older revision		Revision as of 19:32, 19 September 2017
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	[[File:amp relay.jpg\|200px]]		[[File:amp relay.jpg\|200px]]
−
−	~~SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.~~

	On the input you can use something like the RS951 relay and you can pick them up at rallys for a couple of quid!		On the input you can use something like the RS951 relay and you can pick them up at rallys for a couple of quid!

@@ Line 13: / Line 13: @@
 SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.
-On the input I would tend to use something like the RS951 and you can pick them up at rallys for a couple of quid!
+On the input you can use something like the RS951 relay and you can pick them up at rallys for a couple of quid!
 [[File:951 relay.JPG|200px]]

@@ Line 9: / Line 9: @@
 For 70 cm you can use reasonably cheap BNC relays and the Cx540 N type relay which are often available surplus.
-[[File:amp relay.jpg|400px]]
+[[File:amp relay.jpg|200px]]
 SMA relays are much more common for about £10 and up at a rally or microwave round table. It helps to know what you are looking for, RLC, Radiall, Teledyne etc.

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 Many circuits and pre-built designs are available including this simple single chip design by Ian Waters G3KKD published in CQ-TV 125.
-[[File:Tx rx timing.JPG|400px]]
+[[File:Tx rx timing.JPG|500px]]
 ==Transfer or 4 port relays==

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 ==Transfer or 4 port relays==
-A lot of surplus microwave relays are transfer relays - these can easily be recognised by having 4 connectors or ports.
+A lot of surplus microwave relays are transfer relays - these can easily be recognised by having 4 connectors or ports.  These are entirely suitable for use as 3 port change over relays and can actually be used to provide additional protection to your pre-amp by putting it in to a 50 ohm load on transmit.
 [[File:transfer relay.JPG|400px]]