[OpenTRV-dev] TX failure with second board

Mon Mar 18 10:42:22 GMT 2013


Yes, I do fully understand the opacity of the art and had not thought of that of the plastic.

The way that I have had it set up was a run directly parallel to and a few mm from the edge of the board, parallel to a similar length (power) conductor, and indeed inside a black plastic case.

So several negative points for style there.

So, go on, gimme a wild guess.

I think I'll replace the antenna with ~87mm and have it protrude from the box as early as possible.

Bruno: I think this shows that your antenna routing point for the case is very much on the money, so we definitely should allow the option of bringing the antenna straight out through the case perpendicular (sideways, parallel to the mounting surface I guess, unless Mike cringes again) in instances where aesthetics are not critical.



On 18 Mar 2013, at 10:31, Mike Stirling wrote:

> ----------------original message-----------------
> From: "Damon Hart-Davis" EMAIL ADDRESS HIDDEN
> To: "Mike Stirling" EMAIL ADDRESS HIDDEN
> CC: "Damon Hart-Davis" EMAIL ADDRESS HIDDEN , "Closed list for developer discussions" EMAIL ADDRESS HIDDEN
> Date: Mon, 18 Mar 2013 10:08:57 +0000
> -------------------------------------------------
>> Hi Mike (and list),
>> The transmission problems that I was having with the second soldered-up board
>> appear to be, given this morning's (and unintended overnight!) experiments, a
>> mixture of timing jitter and antenna issues.
>> What is the likely ERP loss from my crappy 75mm antenna, running parallel to the
>> board edge and in its plane, compared to an 87mm perpendicular? Hand-waving
>> estimate is all that I'm after, eg 3dB/x2.
> Shrug; it's a black art remember! Is there some separation between the board and the antenna's parallel run, or are they directly adjacent. If the latter then that would probably reduce ERP drastically. Is it in an enclosure? Black plastic is often quite opaque to RF due it often being coloured with carbon.
> --

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