Message-ID: <00c901c97676$02397bf0$0301a8c0@mal769a60aa920>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <003301c9759e$c21f3f00$0301a8c0@mal769a60aa920> <7665659012654DCE89B4DD1FC8228550@JimPC>
Date: Wed, 14 Jan 2009 18:29:16 -0000
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Subject: LF: Re: Re: Antenna Diversity
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Jim
Today I have dismantled the 190m loop and erected another 1/4 wave inv L for 
500 and testing at present. First observations indicate more noise but 
signal is still strong in spite of noise.ie sig over noise still good.
DI2AG qrp beacon has noticeable fade, it shows that qrp definitely suffers 
more fade than qro beacons like DI2AM, virtually no fade noticeable.
73 mal/g3kev

----- Original Message ----- 
From: "James Moritz" <james.moritz@btopenworld.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, January 13, 2009 6:37 PM
Subject: LF: Re: Antenna Diversity


> Dear Mal, LF Group,
>
> That is an interesting experiment - It would be interesting to know how 
> far
> apart the loops are to result in different fading patterns.
>
> I would be very wary in interpreting the results from two totally 
> different
> types of receiver - The SLM has essentially a fixed gain, while I see the
> IC-746 has a DSP "back end" with complex AGC loops acting on both analogue
> and digital parts. I guess the AGC in the IC746 is never totally disabled 
> in
> order to prevent overloading of the A/D converter. So that may explain why
> loop "B" has a more constant apparent output level. One check would be to
> swap over the antennas between receivers, and see what difference that 
> made.
> I suppose it would not be too difficult to have, say, a relay that 
> switched
> the same RX input between the two antennas, perhaps every 10 or 20s or so,
> with an attenuator pad to get the signal levels roughly equal. That way ,
> the comparison could be made with a single receiver.
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
> ----- Original Message ----- 
> From: "mal hamilton" <g3kevmal@talktalk.net>
> To: "rsgb" <rsgb_lf_group@blacksheep.org>
> Sent: Tuesday, January 13, 2009 4:48 PM
> Subject: LF: Antenna Diversity
>
>
> LF/MF
> I am experimenting at present with antenna (space diversity) using two
> loops...
>
>


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