[Lowfer] Analog VS SDR LF comparison

[K2ORS]

Doug,
   What frequency range did you get with the custom ARR preamp?
tnx & 73 Warren

----- Original Message ----- 
From: "Douglas D. Williams" <kb4oer at gmail.com>
To: "Discussion of the Lowfer (US, European, &amp, UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Tuesday, October 09, 2012 6:37 PM
Subject: Re: [Lowfer] Analog VS SDR LF comparison


> Minor update.
>
> The KIWA splitter, being a passive unit, introduces a 6dB attenuation to
> both output ports. Is this a problem? Most likely not, given the band 
> noise
> at VLF/LF, and the gain at the output of the Clifton Labs Z1501D active
> antenna.
>
> Regardless of that logic, I decided to obtain and introduce into the 
> entire
> system a 20 dB preamp, and for that purpose I chose a special order model
> by Advanced Receiver Research (our own Jay Rusgrove):
>
> http://www.advancedreceiver.com/
>
> Since that will likely produce a signal level that will drive the
> input Winradio SDR input into clipping, I managed to bid and win on eBay a
> 50 ohm, 0-50 dB step attenuator (1 dB steps) by JFW Industries, INC.
>
> My plan is to place the 20 dB preamp after the 500 kHz low pass filter,
> then to the step attenuator, then the KIWA splitter, then etc. etc.
>
> It will likely be a haywire mess on my workbench, with all the patch
> cords, and I am happy with that.
>
> -Doug KB4OER
>
>
>
>
>
>
>
>
>
> On Sat, Oct 6, 2012 at 4:17 PM, Douglas D. Williams 
> <kb4oer at gmail.com>wrote:
>
>> Well, as I mentioned to this group a few weeks ago, I planned to do a
>> series of comparisons between an analog receiver and an SDR at VLF/LF
>> frequencies, using the same antenna.
>>
>> In order to receive the same signal simultaneously on both receivers with
>> the same antenna, I would need some sort of "splitter". KIWA Electronics
>> manufactures two models:
>>
>> http://www.kiwa.com/LFCombiner
>>
>> Neither one completely covered the frequency range I am interested in,
>> which is 5kHz to 500+kHz, so I commissioned a "special order" model, 
>> which
>> I received today. BTW, I would like to take this opportunity to thank 
>> Craig
>> Seigenthaler at KIWA for his help in this. In addition to the custom
>> splitter/combiner, I own one of their 500kHz low pass filters, and can
>> recommend their products without reservation. They are built like a 
>> Sherman
>> tank.
>>
>> The antenna that will be used in this comparison is a custom Clifton
>> Laboratories Z1501D active whip, located about 50' from my house with the
>> base up 20' from ground. The "custom" part is I asked Jack at Clifton 
>> Labs
>> to lower the bottom range of the active antenna from 20kHz to below 8kHz,
>> which he did with flying colors (all the way to about 3kHz).
>>
>> The setup is as follows:
>>
>> Output from the Clifton Labs indoor DC coupler goes first to the KIWA
>> 500kHz low pass filter, then to the KIWA splitter. Output "A" goes to an
>> AMRAD LF converter custom built by Todd Roberts with an OCXO for 
>> stability,
>> then to an Icom R75 with the OCXO option, as well as a 500Hz and a 250Hz
>> crystal filter. Output "B" goes directly into a Winradio Excalibur Pro
>> G33DDC receiver.
>>
>> At first, I was going to run two instances of Argo on the same PC, one 
>> for
>> each receiver, but I ultimately decided to connect the two receivers into
>> two separate PCs.
>>
>
>
>
>>  *[SNIP]*
>>
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