[Lowfer] SIW in EN90xn & some antenna & filter measurements, one correction...

[Michael Sapp]

Garry & All:  One correction......

    ".....at night those total rx power levels drop by about a third, but 
are still
fairly high.:"

        I should have said "those voltage levels drop by about a third."

       Which is closer to being 10dB lower in total rx input power levels at 
night.....

        73,  Mike wa3tts

----- Original Message ----- 
From: "Michael Sapp" <wa3tts at verizon.net>
To: <k3siw at sbcglobal.net>; "Discussion of the Lowfer (US, European, & 
UK) and MedFer bands" <lowfer at mailman.qth.net>
Sent: Wednesday, December 10, 2014 2:37 PM
Subject: Re: [Lowfer] SIW in EN90xn & some antenna & filter measurements


> Garry: OK, thanks for the reminder on 630m wspr. I've been testing the new 
> 300kHz LPF here and it is like 25~30 dB down at 475.7 kHz so I was not 
> running a second receiver at 630M.
> Guess I'll go back to WSPR2 tonite on 630m with my 500kHz filter and run 
> more 300kHz LPF tests in daylight when all the local AM BC stations are at 
> full power.
>
> Total uVs on the EWE to the NE are 150,000uV and 45,000uV (@50 ohms) to 
> the SW with no LPF's in line during daylight. Levels do drop considerably 
> at sunset when many of the
> local AM BCs reduce power (I have measureed something like 40,000uV and 
> 12,000uV range at night).
>
> Daylight antenna rx power levels drop to 2,100uV SW and 6,500 uV NE with 
> my 500kHz LPF and 200uV to SW and 300uV to NE with the new
> 300 kHz LPF as measured with an Boonton CA-91 RF voltmeter, about 15 
> minutes prior to this e-mail....
>
> With 20dB of gain from the W1VD design 2N5109 preamp, that provides 20,000 
> to 30,000uV of total LF amplified signal level after the 300kHz LPF. A 3dB 
> pad on the mixer input lowers the total rx signal level to the 10,000 to 
> 15,000 uV, which is -27 to -24.5 dbm range.  Having 47 to 50dB of dynamic 
> range head room with a level 23 mixer sure helps to provide intermod-free 
> performance below 300kHz....
>
> For example, with the 500kHz filter and 6,500uV of total daytime LF/MF 
> signal, the 20 dB 2N5109 preamp ups that total rx power level to 650,000uV 
> and the 3dB pad before the mixer reduces total rx power to 325,000uV, 
> which is slightly more than +3dBm total signal level the mixer is seeing 
> in daylight receive conditions.  One can appreciate the need for an LF/MF 
> optimized  +17 or +23 dBm level mixer with many nearby AM BC 
> stations.....at night those total rx power levels drop by about a third, 
> but are still fairly high.
>
> Compared to the cost of college tuition these days, finding that old 
> Boonton CA-91 on ebay for $50 and putting it to use sure has been a 
> worthwhile educational investment....
>
> 73, Mike wa3tts
>
>
>
>
>
>
> ----- Original Message ----- 
> From: "Garry Hess" <k3siw at sbcglobal.net>
> To: "lowfer list" <lowfer at mailman.qth.net>
> Sent: Wednesday, December 10, 2014 12:35 PM
> Subject: Re: [Lowfer] SIW in EN90xn
>
>
>> Thanks for another nice capture Mike. Hopefully the noise will die down 
>> one of these nights. 474.2 kHz WSPR activity has been low and nothing 
>> other than MP has been copied on 137 kHz. The lowfer watering hole does 
>> have a handful of stations but more would be nice. The forecast for 
>> Saturday here is quite mild so may finally get a chance to work on the 
>> lowfer SIW slash code.
>> -- 
>> 73, Garry, K3SIW, EN52ta, Elgin, IL
>> ______________________________________________________________
>> Lowfer mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/lowfer
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Lowfer at mailman.qth.net
>> Post must be less than 50KB total for message plus attachment!
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>
> ______________________________________________________________
> Lowfer mailing list
> Home: http://mailman.qth.net/mailman/listinfo/lowfer
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Lowfer at mailman.qth.net
> Post must be less than 50KB total for message plus attachment!
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html