[Lowfer] What kind of antenna ?

Michael Sapp wa3tts at verizon.net
Thu Sep 8 17:15:56 EDT 2016 

Doug: RRR, You can thank K8RZ, James Davey was the person who brought them 
to my attention....

Mike tts

----- Original Message ----- 
From: "Douglas Williams" <williamsdoug1966 at gmail.com>
To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" 
<lowfer at mailman.qth.net>
Sent: Thursday, September 08, 2016 4:49 PM
Subject: Re: [Lowfer] What kind of antenna ?


> Those look interesting. I'll have a look. Thanks, Mike.
>
>
>
> On Thu, Sep 8, 2016 at 4:08 PM, Michael Sapp <wa3tts at verizon.net> wrote:
>
>> Doug: Watch the SM5BSZ "sensors" youtube videos on LF noise and antennas
>> when you have the time. They are very worthwhile....
>>
>> https://www.youtube.com/watch?v=C65u7Pmz7a0
>>
>> 73 Mike wa3tts
>>
>> ----- Original Message ----- From: "Douglas Williams" <
>> williamsdoug1966 at gmail.com>
>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <
>> lowfer at mailman.qth.net>
>> Sent: Thursday, September 08, 2016 3:59 PM
>>
>> Subject: Re: [Lowfer] What kind of antenna ?
>>
>>
>> Agreed. That would be highly improbable. Worked for me, though.
>>>
>>> On Thu, Sep 8, 2016 at 3:55 PM, Michael Sapp <wa3tts at verizon.net> wrote:
>>>
>>> Doug: OK, Not likely everyone has the same noise environment or ground
>>>> conductivity....
>>>>
>>>> Mike tts
>>>>
>>>> ----- Original Message ----- From: "Douglas Williams" <
>>>> williamsdoug1966 at gmail.com>
>>>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" <
>>>> lowfer at mailman.qth.net>
>>>> Sent: Thursday, September 08, 2016 3:36 PM
>>>>
>>>> Subject: Re: [Lowfer] What kind of antenna ?
>>>>
>>>>
>>>> Here are two interesting screenshots I took comparing the difference in
>>>> VLF
>>>>
>>>>> noise between having the DC coupler for my active antenna grounded at
>>>>> the
>>>>> station end VS leaving it ungrounded. In both screenshots, the active
>>>>> whip
>>>>> antenna is grounded at the base, which is about 50' from the house. In
>>>>> my
>>>>> situation, it is far better to leave the coupler "floating".
>>>>>
>>>>> https://dl.dropboxusercontent.com/u/33457409/z1203grounded.JPG
>>>>>
>>>>> https://dl.dropboxusercontent.com/u/33457409/z1203%20ungrounded.JPG
>>>>>
>>>>> D.
>>>>>
>>>>>
>>>>>
>>>>> On Thu, Sep 8, 2016 at 3:12 PM, Michael Sapp <wa3tts at verizon.net>
>>>>> wrote:
>>>>>
>>>>> That would be my HF vertical and the local noise level is 30~40 dB
>>>>> higher
>>>>>
>>>>>> on it compared to the ground isolated EWEs...
>>>>>>
>>>>>> Mike tts
>>>>>>
>>>>>> ----- Original Message ----- From: "Douglas Williams" <
>>>>>> williamsdoug1966 at gmail.com>
>>>>>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer bands" 
>>>>>> <
>>>>>> lowfer at mailman.qth.net>
>>>>>> Sent: Thursday, September 08, 2016 2:49 PM
>>>>>> Subject: Re: [Lowfer] What kind of antenna ?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Have you tried just throwing a wire out the window and using that?
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> JOKE! ;-)  That's an interesting system. I'll have to study it some
>>>>>>> more
>>>>>>> and read up on EWEs.
>>>>>>>
>>>>>>> On Thu, Sep 8, 2016 at 1:55 PM, Michael Sapp <wa3tts at verizon.net>
>>>>>>> wrote:
>>>>>>>
>>>>>>> Doug: Essentially orthogonal EWEs
>>>>>>>
>>>>>>>
>>>>>>>> https://www.dropbox.com/s/xw0flkh343xhamg/LFMFEWE.JPG?dl=0
>>>>>>>>
>>>>>>>> https://www.dropbox.com/s/5ygrqqv624c73y7/ewegnd.JPG?dl=0
>>>>>>>>
>>>>>>>> https://www.dropbox.com/s/x0hu6b30w9gu694/feedsys.jpg?dl=0
>>>>>>>>
>>>>>>>> A couple brief notes...
>>>>>>>>
>>>>>>>>    The ground return wires between each end of the EWE antenna
>>>>>>>> improves
>>>>>>>> ground resistance stability and is essential for being able to 
>>>>>>>> switch
>>>>>>>> antenna directions from the shack position by swapping rx input and
>>>>>>>> termination resistor. For the same reason the 10:1 transformers at
>>>>>>>> the
>>>>>>>> antenna require a common ground or the receive direction will not
>>>>>>>> switch
>>>>>>>> by
>>>>>>>> swapping the rx input and termination resistor.
>>>>>>>>
>>>>>>>>    The background noise improved noticeably when I added the
>>>>>>>> mid-point
>>>>>>>> ground on the feed lines. The two feed lines to the isolation
>>>>>>>> transformer
>>>>>>>> in the shack have their outer jackets tied together at the 
>>>>>>>> isolation
>>>>>>>> transformer input. That noticeably lowered AM BC surface wave 
>>>>>>>> energy
>>>>>>>> as
>>>>>>>> measured with an O-scope. With those parallel feed lines having the
>>>>>>>> outer
>>>>>>>> jackets of the coax separate I was able to measure a few hundred
>>>>>>>> millivolts
>>>>>>>> of AM BC energy between them at the isolation transformer input.
>>>>>>>>
>>>>>>>>    The background noise improved when I added the perimeter ground
>>>>>>>> wire
>>>>>>>> around the square area defined by the orthogonal EWEs.
>>>>>>>>
>>>>>>>>    Cleaning and oiling the ground connections a few times a year
>>>>>>>> seems
>>>>>>>> to
>>>>>>>> be worthwhile for maintaining antenna performance. I do the sealing
>>>>>>>> current
>>>>>>>> treatment once a week or so to keep the loop resistance low for 
>>>>>>>> each
>>>>>>>> feed
>>>>>>>> line run...(the emf blasts away the thin oxide on the F connector 
>>>>>>>> and
>>>>>>>> antenna switch contact surfaces )
>>>>>>>>
>>>>>>>>   Sorry if TMI ~:) Mike wa3tts
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> ----- Original Message ----- From: "Douglas Williams" <
>>>>>>>> williamsdoug1966 at gmail.com>
>>>>>>>> To: "Discussion of the Lowfer (US, European, & UK) and MedFer 
>>>>>>>> bands"
>>>>>>>> <
>>>>>>>> lowfer at mailman.qth.net>
>>>>>>>> Sent: Thursday, September 08, 2016 12:14 PM
>>>>>>>> Subject: Re: [Lowfer] MM lowfer beacon update
>>>>>>>>
>>>>>>>>
>>>>>>>> What kind of antenna are you using, Mike?
>>>>>>>>
>>>>>>>>
>>>>>>>> On Thu, Sep 8, 2016 at 10:10 AM, Michael Sapp <wa3tts at verizon.net>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>> Garry: I heard CFH on 76.2 last night but nothing from XND.  Noise
>>>>>>>>> level
>>>>>>>>>
>>>>>>>>> was about constant S6 from a local source when I checked this AM
>>>>>>>>>
>>>>>>>>>> daylight.
>>>>>>>>>> Not much chance of hearing XND through that kind of noise wall...
>>>>>>>>>> now
>>>>>>>>>> and
>>>>>>>>>> then the local noise turns off and I have S1 or so noise level 
>>>>>>>>>> when
>>>>>>>>>> no
>>>>>>>>>> lightning static is around, but even that lower background noise
>>>>>>>>>> seems
>>>>>>>>>> like
>>>>>>>>>> an order of magnitude higher than what I have on 137 kHz. I did 
>>>>>>>>>> the
>>>>>>>>>> AC
>>>>>>>>>> voltage measurement on the speaker output the other day on 75 kHz
>>>>>>>>>> with
>>>>>>>>>> a
>>>>>>>>>> trusted analog meter with the ALC off and pretty much confirmed
>>>>>>>>>> that
>>>>>>>>>> 10
>>>>>>>>>> dB
>>>>>>>>>> "by ear" perceived noise difference between 75 kHz and 137 kHz.
>>>>>>>>>> Seems
>>>>>>>>>> like
>>>>>>>>>> I have broadband noise sources 10~15 kHz wide either side of 37
>>>>>>>>>> kHz,
>>>>>>>>>> 60kHz, and 75 kHz....  This noise source or sources is coming in 
>>>>>>>>>> on
>>>>>>>>>> the
>>>>>>>>>> antenna as my converter is dead quiet with no antenna signal 
>>>>>>>>>> input.
>>>>>>>>>> My
>>>>>>>>>> common mode coaxial chokes are around 12mH or so, perhaps not
>>>>>>>>>> enough
>>>>>>>>>> to
>>>>>>>>>> suppress much VLF energy. The noise level is much lower on the NW
>>>>>>>>>> direction
>>>>>>>>>> versus SW but still too high for weak signal detection.  I added 
>>>>>>>>>> a
>>>>>>>>>> 2
>>>>>>>>>> x
>>>>>>>>>> 3
>>>>>>>>>> ft
>>>>>>>>>> aluminum earth capacitor plate at the feed line midpoint ground 
>>>>>>>>>> but
>>>>>>>>>> that
>>>>>>>>>> did not help much. I suppose I should be grateful with being able
>>>>>>>>>> to
>>>>>>>>>> hear
>>>>>>>>>> reasonably well on 137, 185, 485 kHz and most of the LW BC and 
>>>>>>>>>> NDB
>>>>>>>>>> bands...but it would be nice the solve the VLF noise issue...
>>>>>>>>>>
>>>>>>>>>> I did not check for MM or WM overnight, I'll have to give that
>>>>>>>>>> another
>>>>>>>>>> shot some evening when the QRN is low...
>>>>>>>>>>
>>>>>>>>>> 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: Thursday, September 08, 2016 9:08 AM
>>>>>>>>>> Subject: Re: [Lowfer] MM lowfer beacon update
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Garry, Thanks for the capture and report. I just looked at a
>>>>>>>>>> weather
>>>>>>>>>>
>>>>>>>>>> forecast, and maybe the storms will stay North of here.  It is
>>>>>>>>>> fairly
>>>>>>>>>>
>>>>>>>>>> dry
>>>>>>>>>>> here, so some rain would be welcome.
>>>>>>>>>>>
>>>>>>>>>>> I have removed the "umbrella" style tophat/guywire that I used
>>>>>>>>>>> last
>>>>>>>>>>> winter on the vertical, and put back to the Marconi style 
>>>>>>>>>>> flattop
>>>>>>>>>>> which
>>>>>>>>>>> is
>>>>>>>>>>> supported by taller trees. I am thinking the top 3rd of the
>>>>>>>>>>> vertical
>>>>>>>>>>> was
>>>>>>>>>>> shielded too much with the droopy umbrella wires. I am not sure 
>>>>>>>>>>> if
>>>>>>>>>>> my
>>>>>>>>>>> new
>>>>>>>>>>> supports will survive the winter winds. Time will tell.
>>>>>>>>>>>
>>>>>>>>>>> In the next week or so I will move WM to the vertical, and get 
>>>>>>>>>>> it
>>>>>>>>>>> back
>>>>>>>>>>> to
>>>>>>>>>>> normal operation.
>>>>>>>>>>>
>>>>>>>>>>> 73   de   N8OOU - Mike Meek
>>>>>>>>>>>
>>>>>>>>>>> On 09/08/2016 07:13 AM, Garry wrote:
>>>>>>>>>>>
>>>>>>>>>>> Mike, noticeable boost in SNR for lowfer MM this morning here so
>>>>>>>>>>> the
>>>>>>>>>>>
>>>>>>>>>>> higher power is showing up at more than just your local 
>>>>>>>>>>> receiver.
>>>>>>>>>>>
>>>>>>>>>>>> The
>>>>>>>>>>>> higher power particularly helps since storms are all around. 
>>>>>>>>>>>> See
>>>>>>>>>>>> no
>>>>>>>>>>>> sign
>>>>>>>>>>>> of WM so far.
>>>>>>>>>>>>
>>>>>>>>>>>> Got a late start looking for WH2XND on 75 kHz WSPR-2 but 
>>>>>>>>>>>> because
>>>>>>>>>>>> of
>>>>>>>>>>>> storm racket that probably didn't matter much. Had to depend on
>>>>>>>>>>>> the
>>>>>>>>>>>> usual near-sunrise enhancement to get a few, minimal SNR 
>>>>>>>>>>>> decodes.
>>>>>>>>>>>> Interestingly, found wideband source CKN on 76.2 kHz from BC
>>>>>>>>>>>> active.
>>>>>>>>>>>> Don't see that one too often. Usually CFH is running on 73.6 
>>>>>>>>>>>> kHz
>>>>>>>>>>>> from
>>>>>>>>>>>> NS
>>>>>>>>>>>> but it's been off the air for quite awhile now. Neither one
>>>>>>>>>>>> bothers
>>>>>>>>>>>> reception of WH2XHR, at least not here.
>>>>>>>>>>>>
>>>>>>>>>>>> 73, Garry, K3SIW, EN52ta, Elgin, IL
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>>
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