[Lowfer] What kind of antenna ?

Thu Sep 8 16:49:08 EDT 2016

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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