HFU HF Underground
General Category => General Radio Discussion => Topic started by: Fansome on July 01, 2010, 1449 UTC
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> To: udxf@yahoogroups.com
> From: tmjva@verizon.net
> Date: Thu, 1 Jul 2010 09:04:39 -0400
> Subject: [UDXF] Apple Hires Antenna Engineers.
>
> For those of you who have been commiserating over baluns, here may be a
> job for you:
>
> +------------------------------------------------------------+
> | Apple Hires Antenna Engineers. Really.
> | from the you're-holding-it-wrong dept.
> | posted by CmdrTaco on Wednesday June 30, @10:16 (Cellphones)
> |
> https://apple.slashdot.org/story/10/06/30/130205/Apple-Hires-Antenna-Engineers-Really
> +------------------------------------------------------------+
>
> kangsterizer writes "Sometimes, news items are just about a good laugh.
> You may or may not like Apple, but the way it has been handling its
> antenna issue has been like a small tech soap opera — Steve Jobs, the
> CEO, saying 'not to hold the phone that way,' rumors of software issues,
> and the latest but most crunchy part, since the antenna issue has been
> widely discovered, on 23 June, several 'antenna engineer' positions opened
> up at Apple. Seems someone got fired: - Antenna engineer job position 1,
> [1]Antenna engineer job position 2, [2]Antenna engineer job position 3." I
> just figure they did all their testing in California, where AT&T dropping
> calls is as common as $4 coffees.
>
> Discuss this story at:
> http://apple.slashdot.org/comments.pl?sid=10/06/30/130205
>
> Links:
> 0.
> http://jobs.apple.com/index.ajs?BID=1&method=mExternal.showJob&RID=55852&CurrentPage=1
> 1.
> http://jobs.apple.com/index.ajs?BID=1&method=mExternal.showJob&RID=55849&CurrentPage=1
> 2.
> http://jobs.apple.com/index.ajs?BID=1&method=mExternal.showJob&RID=55854&CurrentPage=1
>
>
> --
> Tracy Johnson
> Ye olde telnet games at 198.212.189.111
> BT
>
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You know, this may not be related to 'antenna' deficiencies at all, it may be a multi-path/co-channel interference induced problem ...
Not having not researched the complaint, the 'induced drop call effect' could be being induced by weakening the intended signal from the presently serving cell site ... and any operating co-channel (same channel) cell sites could be received as a stronger signal ... the result eventually being: a dropped call!
SNR (Signal/Noise ratio) drops below a certain level and - the switch (or the phone) 'releases' (Ericsson term) the call.
All this could be media hoopla based on the published results a classical 'case sample of 1 (one)' experiment ...
We see this 'muti-path' phenom every day on HF - especially in the situation of 'selective fading' where the fade 'takes out' the carrier say and the broadcast sounds like DSB-supressed carrier ... that's mutli-path distortion as created by two (or more) paths in the ionosphere (or maybe the combo of groundwave and skywave interference in the case of AM radio where the two 'meet' and is referred to as the 'fading wall')
Groundwave, unless the earth/soil conductivity is changing, would not cause fading. More likely that
a weak skywave is 'phasing' against the groundwave and you end up with fading.
The D layer in the ionosphere is not completely absorptive during the day, and so will allow some
signal to reflect. At night the D layer goes away, so at night, it stops absorbing AM broadcast
wavelength radio waves.
When the sun comes back out, the D layer is recreated.
One can experience a "fading wall" at night driving to or away from an AM station at 150 to 200 miles
or so, depending on conditions. I have experienced this several times driving into Dallas and observing
WBAP 820.
Get close enough and no fading; out further and the fading starts as the ground wave is at times
canceled and then alternately reinforced by the skywave signal.