[hpsdr] Alex Board XV Issue

[Bob Stricklin]

Hi Glen,

Not sure if your referring to a issue with software of hardware….

Is the issue you have on the original Alex or only on your new design?

Have you tested your board with a dedicated bus driver so you can activate each relay on the board?

Are,you testing with one of the SDR packages using setup?

Did you see the following note in Appendix A:

Note 1.) The RX 1 OUT switch also controls the default input
path for the normal receive function (that is, receiving from
the same antenna port as you are transmitting on.) In the event
that it is desired to receive through XV IN, RX 2 IN, or RX 1 IN,
then RX 1 OUT should be turned ON, so as to disconnect the
normal (default) receive path from the transmit antenna port.
If an external filter is to be placed in the normal receive
path, then both RX 1 OUT and RX 1 IN should be turned on,
and the filter connected between the RX 1 OUT and RX 1 IN
BNC connectors.

Is U3 bit 0 pin at 12V?

Since relay driver is open drain you should be able to activate the relay by grounding the U3 bit 0 output. If you have inadvertently connected 12V to this pin you will pull down your supply. You could use a small series resistor for this test.

The Alex schematics posted look correct.

Hope this helps you.

Bob, N5BRG







Message: 2
Date: Sun, 7 Jun 2015 10:11:18 -0400
From: "MDS Info" <info at mds-ham.com<mailto:info at mds-ham.com>>
To: "HPSDR" <hpsdr at lists.openhpsdr.org<mailto:hpsdr at lists.openhpsdr.org>>
Subject: [hpsdr] Alex board
Message-ID: <OLEMLLLENPOJJLABJGKJGENDLCAA.info at mds-ham.com<mailto:OLEMLLLENPOJJLABJGKJGENDLCAA.info at mds-ham.com>>
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Hello,

I have designed and built an Alex clone with all the Alex features on a
single board to match
the size of the Hermes.

On my checkout of the board, I noticed that XVTR RX relay is not activating.
Bit 0 of  U3 is high and never
goes low.  All the other relays work.

Is this a known problem?

All the HP, LP, antenna relays are functioning.

???

73's

Glen K4KV



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