[Lowfer] WM in EN90xn, SIW still way up from normal

Sun Dec 7 16:35:06 EST 2014

Mike - TTS;

Thanks for the later captures and filter info.  I can only praise the 
Propagation Gods for looking favorably upon us today.  In looking at the 
captures, while Wm is consistently weaker than SIW, we seem to be 
tracking together in the peaks and fades.

Mike - OOU

73   de   N8OOU - Mike Meek

On 12/07/2014 10:34 AM, Michael Sapp wrote:
> Mike & All: Still receiving light traces of WM here in daylight and SIW
> continues way above average as I usually require QRSS60 for
>
> a reasonable daylight copy of SIW....
>
> https://www.dropbox.com/s/ehtgg2owa0gy8g2/capt00029.jpg?dl=0
>
>
> No cover on the 300kHz filter as it is still in progress. I used mold
> chokes on the center two inductors (vs T61-50 inductors on the outer two
> inductors ) and the low Q was
> evident when I did a performance test from 50kHz to 1 Mhz with my signal
> gen and RF voltmeter... I should have those two molded inductors
> replaced this evening or the next day with appropriate T61 core
> inductors.  My isolation xfmr is wrapped in foam and then a mu-metal
> shield. Not sure if shielding 1/2 inch leads to the BNC connectors would
> help much --- I suppose a mag shield in the form of a steel plated
> outlet box would not hurt. The in-shack transmission line chokes are in
> a mag shield box with ground-isolated BNCs....remainder of my converter
> is modular in aluminum Bud boxes
>
> Here are the remainder of the early thru mid - morning captures...
>
> https://www.dropbox.com/s/idvvjtm14ue9cy0/capt00018.jpg?dl=0
>
> https://www.dropbox.com/s/fzfns9txi9jj2tr/capt00019.jpg?dl=0
>
> https://www.dropbox.com/s/c38sixwqtb9ydci/capt00020.jpg?dl=0
>
> https://www.dropbox.com/s/mi83vvwor6fw3ne/capt00021.jpg?dl=0
>
> https://www.dropbox.com/s/5ja959eh5d687cf/capt00022.jpg?dl=0
>
> https://www.dropbox.com/s/8zkaiiwbn5ab1em/capt00023.jpg?dl=0
>
> https://www.dropbox.com/s/cxa56wqaljpz638/capt00024.jpg?dl=0
>
>
> Isotemp LO & RAY6 converter....
>
> https://www.dropbox.com/s/k7qg6t6s7wsq84n/IMG_4145.JPG?dl=0
>
> (Isotemp 3.0MHz OCXO, Mini Circuits RAY6 DBM (10kHz>50MHz RF IN, level
> 23), W1VD 2N5109 LF design preamp, & single-ended Norton 2N5109 as the
> +23dBm LO driver at 3MHz)....
>
> 73, Mike wa3tts
>
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> ----- Original Message ----- From: "N8OOU" <n8oou at meekfarm.us>
> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands"
> <lowfer at mailman.qth.net>
> Sent: Sunday, December 07, 2014 7:07 AM
> Subject: Re: [Lowfer] WM in EN90xn
>
>
>> Mike - TTS,
>>
>> Thanks for that great capture. I would say that it is the result of
>> mother nature, and your filters.
>>
>> I tested some changes in the Wm Helix Box yesterday which took the
>> beacon up and down during the day. I experimented with different
>> wiring configurations by adding in a re-wound AM BCB ferrite rod as an
>> adjustable inductor.
>>
>> My results ended up being net losses, so I restored the Box to my
>> original configuration.  I am back to the same operating parameters I
>> have been using for the past couple weeks.
>>
>> I am curious to know if you have the filters open just for the pix, or
>> will they be open all the time?
>>
>> When I first got the "ham-it-up" converter I experimented for 3 or 4
>> weeks trying different things to be happier with it's performance.
>> Most of the work was putting various filters on it's input. That did
>> bring the performance level up to something acceptable, but killed the
>> concept of it being a "wide band" receiver.
>>
>> Mike - OOU
>>
>> 73   de   N8OOU - Mike Meek
>>
>> On 12/07/2014 03:58 AM, Michael Sapp wrote:
>>> Mike & All:  Best capture here yet of WM and at QRSS30 nornal this
>>> time....
>>>
>>> https://www.dropbox.com/s/9b1cd6nipf4jt3h/wmq30.jpg?dl=0
>>>
>>>
>>>      Not sure if how much of the above capture is band enhancement,
>>> as I built a new 9th-order Butterworh 300kHz LPF this evening and
>>> have it in line.  I am noticing a lower background noise level at the
>>> watering hole and at 137kHz. Seems like the MF~LF converter has more
>>> head room with
>>> more LPF roll off in the AMBC band...
>>>
>>>     https://www.dropbox.com/s/r1ile71ugrqergn/IMG_4143.JPG?dl=0
>>>
>>>
>>>      A few days ago I started experimenting with adding a few roll
>>> off caps to my 75>50 Ohm isolation transformer. The
>>> 50 ohm side is about 600uH and I found that switching 10nF and 22nF
>>> caps across the 50 ohm secondary did a reasonable
>>> job off reducing my AMBC overload (the LF EWE has relatively high
>>> signal levels from the local BC 50KW stations ) that remained
>>> with my existing 500kHz LPF.
>>>
>>>   Of course, an impedance matched solution is preferred, so I went to
>>> the AADE program and toyed around with various LPF designs until I
>>> found one I liked....
>>>
>>>     I'll find out soon enough if the LPF is helping the converter
>>> performance or if we just had good LF band condx this AM.....73 Mike
>>> wa3tts
>>>
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