[Lowfer] What kind of antenna ?

Michael Sapp wa3tts at verizon.net
Thu Sep 8 15:12:24 EDT 2016 

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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