[hpsdr] Diversity experience.

[Kjell Karlsen]

Hi Robin and Gerhard.

I am using a 84 meter long loop for RX1 (and TX) and a W3DZZ for RX2. They  
are at 90 deg. to each other. Normally the loop picks up less noise (The  
W3DZZ has 1 dB more noise than the loop, at least on 3,7 MHz.)

I can swap the two antennas and get the same results but I have to use the  
loop as Reference Source in the Phasing Control panel. If I use the W3DZZ  
as reference Source, the noise attenuation is not more than 12 dB or so.  
When using the loop as reference the attenuation is >20 dB. So the antenna  
having the lowest noise should be used as Reference source.

73, Kjell




På Sat, 14 Nov 2015 08:57:24 +0100, skrev Robin Davies  
<rdavies6 at yahoo.co.uk>:

> Hi Kjell
>
> I've just managed to find myself a second Mercury card to experiment  
> with diversity receive....as in my small, noise ridden QTH in suburban  
> London I'm hoping it might help me remove some of the interference that  
> plagues me. My guess is that having a second antenna that has stronger  
> reception of the noise signal helps the nulling process...and I wondered  
> what sort of antenna's you were using....anything special for the second  
> antenna? I'm thinking of an active antenna...as they seem pretty very  
> good at picking up local noise.
>
> I'm still hankering after an Apollo board to accompany my Hermes...and I  
> was wondering if you felt anyone would ever get there in terms of  
> producing a board for sale?
>
> 73
>
> Robin Davies
> G7VKQ
>
>
> On 13-Nov-2015, at 10:16 PM, Kjell Karlsen wrote:
>
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi all.
>>
>> I have lately experienced how efficient the diversity is to eliminate  
>> local noise. One month I got some very high noise on 80 meter that I  
>> have located it to come from the ADSL line into my house. So far I have  
>> not been able to get rid of it but when using Diversity, I am able to  
>> suppress the noise >15 dB so that I can read stations that are totally  
>> unreadable.
>>
>> But if I change the frequency up and down, even only 50 Hz, the noise  
>> reduction is lost. But if I activate CTUNE, the diversity noise  
>> reduction is kept even if I move to a totally different frequency. I  
>> have not seen this mentioned before but I may have missed it.
>>
>> I am really impressed of the diversity. It is quite unbelievable how  
>> efficient is really is!
>>
>> 73, Kjell
>>
>>
>>
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>
>


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