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

[Michael Sapp]

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















----- 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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