Message-ID: <009701c975b9$52783920$0301a8c0@mal769a60aa920>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <003301c9759e$c21f3f00$0301a8c0@mal769a60aa920> <7665659012654DCE89B4DD1FC8228550@JimPC>
Date: Tue, 13 Jan 2009 19:58:36 -0000
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Subject: LF: Re: Re: Antenna Diversity
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Yes Jim
I have all of this in mind, but I am not too concerned about the detail at 
present, just trying to observe the sig quality for qso purposes. I would 
like to try it some time on the TR path. The best method of course is one RX 
and both antennas fed to it via a mixer and each antenna input calibrated 
and equalised. Ideally each antenna should have a separation of 1 wavelength 
at least, but that is difficult considering the freq and space reqd.
I have seen this done on HF and it is vy impressive.
There are other ways if one had the time.
73 and tnx ur observations de 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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