[Lowfer] What kind of antenna ?

Thu Sep 8 15:59:00 EDT 2016

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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