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RE: LF: OP65 late start for tonight-73 dial as usual...

To: <[email protected]>
Subject: RE: LF: OP65 late start for tonight-73 dial as usual...
From: "hvanesce" <[email protected]>
Date: Fri, 13 Dec 2013 04:03:39 -0700
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Graham and Bob,

 

Attached plot shows loss over land or water at 74 kHz and (with some imagination) 136 kHz; probably best taken with a grain of salt, although the plot is associated with J. R. Wait’s analytic solution for field strength vs. distance, frequency and attenuation factor. Next message will contain a plot generated from Wait’s solution using the attached attenuation factors.  

 

73,

 

Jim AA5BW

 

From: [email protected] [mailto:[email protected]] On Behalf Of Graham
Sent: Thursday, December 12, 2013 2:46 PM
To: [email protected]
Subject: Re: LF: OP65 late start for tonight-73 dial as usual...

 

 

Definitely   strange  propagation   on   75K ! 

 

Thats  6000kmt  3 hours   with  'no'   QSB ? other than  a  rise and  fall  ,  the  gaps  are  most likely  qrm  dropping the  decode  level  , to  under the  -44 point   

 

 

 

 

These  2  decodes  , even  with the  4/5  db  scale  misalignment , puts the  signal    ~ 10 dB  over the  previous  max  and  round   15  dB  over the  first  decode  level    .band appeared to  be  closed  down ... by what  ?? .  double  take  though  ?   how  is  the  s/n  level  computed ?  Opera  is the  average  over the  time  line  , in this  case , 65 mins

 

0230  -28   0.4    0.074615    0   WG2XRS/4               30
0245  -28   0.4    0.074615    0   <WG2XRS/4>    FN12LQ   30

 

 

So how  ? its the  same  Ae  as  136 , but  path losses  ( over  water  ?)  seem to  be  much  less  that  136  ?

73-G,

 

 

 

 

From: hvanesce

Sent: Wednesday, December 11, 2013 10:34 PM

Subject: RE: LF: OP65 late start for tonight-73 dial as usual...

 

Bob, Graham, Hartmut, Henny, all,

 

It’s interesting to see these recurrences of Hartmut’s grabber showing stronger signals than grabbers closer to Bob (such as Henny’s grabber), at later times in the dark cycle.

 

I second (third?) the motion that skip/multimode-interference is a likely contributor, especially considering the number of months over which this characteristic has been observed.

 

Has anyone seen long-distance Hollingsworth plots for frequencies near 74kHz? I attached a Hollingsworth plot for 24kHz that supports the concept, but I have had little success finding such plots for LF [Davies (1990/2008) suggests that there isn’t much data of this sort for long-range LF]. I have a copyrighted plot from Bracewell (1951) that shows (at 85kHz) Hollingsworth-type signal strength cycles of ~6dB over range intervals of ~ 100km near 1Mm, and an analytical study by Johler and Berry (1964) showing (at 100kHz) Hollingsworth cycles out to 1.5Mm. These would seem to be qualitatively supportive of the skip/multimode explanation of signals stronger/later at Hartmut’s grabber, compared to grabbers closer to Bob (such as Henny’s grabber), but the east-RX/west-RX signal strength inversions observed in the 73kHz-band experiments by this group sometimes seem much larger than the ~6dB values in the two LF (85kHz and 100kHz) references that I have found.

 

Congratulations to all on the 74.5kHz Opera results!

 

73,

 

Jim AA5BW

 

 

 

 

From: [email protected] [mailto:[email protected]] On Behalf Of Graham
Sent: Wednesday, December 11, 2013 10:10 AM
To: [email protected]
Subject: Re: LF: OP65 late start for tonight-73 dial as usual...

 

Bob

 

We need  the  local  decodes  from Wolf , they have the  fade pattern  plotted  out , the  web linked  plots  have the  fade %  but  not the  distribution

Op is  giving a  calibrated   precision  s/n  level   average  along  the  time  line , so  what your getting  is accurate  propagation data , you  can  recover it from the  psk-map  data base with a  web  sql   search , or  keep  the  Opera  software  running  on a  web linked  PC and  any  band  activity  will  be  listed 

 

The total  lack  of  signal in the Uk is not  expected !  but  last  night , you  could  of  dropped  to   10% power , which  , considering  the  wavelength , from the  same Ae  , starts  to  point to better  prop  than 136 ?  odd  ,  the  path  would  support  OP16  at  that  level  as well at  full  power !

 

73-G,

 

 

From: Bob Raide

Sent: Wednesday, December 11, 2013 3:48 PM

Subject: RE: LF: OP65 late start for tonight-73 dial as usual...

 

G;
Take a look at Henny's capture and see earlier signal.  Compare with Hartmut's capture that shows more signal later.  All in all the band was good but varies as to when it peaks in a given area.
Hartmut and Henny and a few others have hot antennas and receivers.  Hartmut uses a directional ant.  Do some write-ups on these hot-shot blokes and there equipment.  They have very serious 73 band equipment that really "cuts the mustard". Bob
 


From: [email protected]
To: [email protected]
Date: Wed, 11 Dec 2013 14:49:37 +0000
Subject: Re: LF: OP65 late start for tonight-73 dial as usual...

This  new  fangled  75KHz stuff  , Gary , its going  strait  over  our  heads  .... 

 

G,

 

Sent: Wednesday, December 11, 2013 2:10 PM

Subject: Re: LF: OP65 late start for tonight-73 dial as usual...

 

Oooopps !!

>>The Alan, G3NYK & original.......

Sorry, typo :-
Should be :- Alan, G3NYK & original......

73, de Gary - G4WGT
                            
MF-LF-VLF Grabber : http://myweb.tiscali.co.uk/wgtaylor/grabber2.html
Web : http://myweb.tiscali.co.uk/wgtaylor/index.html
 
.

On 11/12/2013 13:29, Gary - G4WGT wrote:

Graham, Bob.

I  agree, skip looks likely or something similar.
I have not had a glimpse of any of Bob's or Dex's signals & as you know I was first to set up a 24/7 grabber for 74kHz.

The Alan, G3NYK & original UK 73kHz chaps should be able to help here with a reason !

73, de Gary - G4WGT
                            
MF-LF-VLF Grabber : http://myweb.tiscali.co.uk/wgtaylor/grabber2.html
Web : http://myweb.tiscali.co.uk/wgtaylor/index.html
 
.

On 11/12/2013 11:33, Graham wrote:

Bob

 

3 LF Guys in the  UK still  no  show , but  Wolf  , up to  -35 dB , looks like the  hat trick  , 3  in a  row .. -35 is a  significant  signal  , at that  level  OP16 would  decode ,  g4wgt/g0ktn/g8huh   all have  good  LF set ups ,   -35  is 9 dB  over the  op65  level ...

 

Skip distance ?  , where  is  Alan  when you  need  him  hihi

 

73, G,

 

 

 

 

-36

OPERA

0.073

11/12/2013 02:22

WG4XRS

FN12LQ

DL-SWL

JO52HP

-35

OPERA

0.073

11/12/2013 03:27

WG4XRS

FN12LQ

DL-SWL

JO52HP

-41

OPERA

0.073

11/12/2013 04:33

WG4XRS

FN12LQ

DL-SWL

JO52HP

 

 

Txmtr

Rcvr

Band

Mode

Distance

Time (UTC)

WG4XRS

DL-SWL

4000m

OPERA

3880 miles

04:33:32

WG4XRS

K3SIW-2

4000m

OPERA

580 miles

06:44:56

WG4XRS

K3SIW-1

4000m

OPERA

580 miles

06:44:58

WG4XRS

W3NF

4000m

OPERA

233 miles

02:22:06

G0KTN

G0KTN

4000m

OPERA

0 kms

08:09:46

G8HUH

G8HUH

4000m

OPERA

0 kms

08:09:09

KU7Z

KU7Z

4000m

OPERA

0 miles

08:00:48

G4WGT

G4WGT

4000m

OPERA

0 kms

10:48:35

W3NF

W3NF

4000m

OPERA

0 miles

02:16:28

K3SIW

K3SIW

4000m

OPERA

0 miles

21:07:23

WG4XRS

WG4XRS

4000m

OPERA

0 miles

06:54:11

VE7BDQ

VE7BDQ

4000m

OPERA

0 kms

09:09:11

K3SIW-1

K3SIW-1

4000m

OPERA

0 miles

08:34:59

K3SIW-2

K3SIW-2

4000m

OPERA

0 miles

09:14:57

 

 

 

From: Bob Raide

Sent: Tuesday, December 10, 2013 11:52 PM

Subject: LF: OP65 late start for tonight-73 dial as usual...

 

OP/OPDS65 tonight as promised and WSPR 15 tomorrow night.  Thanks to W1VD and group for decodes to get me dialed in-should be interesting tomorrow night for first time on WSPR 15 on 73 band full night-73-Bob WG2XRS/4 [WG4XRS] NY

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Attachment: Attenuation vs Frequency - CommSystemsCh2.pdf
Description: Adobe PDF document

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