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The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Bob Here are the 'signal only' plots for winter and summer ... http://www.w1vd.com/WWVBwintersummersig.jpg . Apparently not much difference at 60 kHz ... other than hours of daylight. SNR plots probably more relavent for the test under discussion. [...] Content analysis details: (-0.5 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [76.96.62.16 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (jrusgrove[at]comcast.net) -0.0 SPF_PASS SPF: sender matches SPF record -0.5 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 8460b2e1d76e3c88160000ac97456bac Subject: Re: LF: Coast to Coast on 74kHz ground wave ? Content-Type: multipart/alternative; boundary="----=_NextPart_000_0007_01CF0809.E0B219D0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_20_30,HTML_MESSAGE, NO_REAL_NAME autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false This is a multi-part message in MIME format. ------=_NextPart_000_0007_01CF0809.E0B219D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Bob Here are the 'signal only' plots for winter and summer ... http://www.w1vd.com/WWVBwintersummersig.jpg . Apparently not much difference at 60 kHz ... other than hours of daylight. SNR plots probably more relavent for the test under discussion. Jay W1VD WD2XNS WE2XGR/2 WG2XRS/2 ----- Original Message ----- From: Bob Raide To: rsgb_lf_group@blacksheep.org Sent: Thursday, January 02, 2014 9:39 PM Subject: RE: LF: Coast to Coast on 74kHz ground wave ? Jay; The only actual way to determine if it's field strength is of course to take field strength measurements. Frozen ground makes the biggest conductivity change. And to what depth of ground is frozen as well effects the field intensity. The lower the freq also tremendously effects groundwave coverage regardless of the conductivity. That is also included in part 73-74 of the Commission's rules. Each of the 10 kHz channels is shown. All AM broadcasters, of course want to get the lowest freq that can be found for their allocation. Distances reached are shown for each broadcast 10 kHz channel in the rules as well over a given conductivity path. BTW; The 60 kHz WWVB is a direction array to better cover the US proper. ------------------------------------------------------------------------------ From: jrusgrove@comcast.net To: rsgb_lf_group@blacksheep.org Date: Thu, 2 Jan 2014 21:16:07 -0500 Subject: Re: LF: Coast to Coast on 74kHz ground wave ? Laurence, Bob I cherry picked the winter and summer SNR levels of WWVB at different US locations ... see http://www.w1vd.com/WWVB20wintersummer.jpg . The daytime path from Boulder to Cutler ME is about 7 dB better SNR in the winter and fairly flat from 1600 - 2000Z. The daytime path from Boulder to San Diego is a bit more 'peaky' with best SNR at about 1800 Z but is only a few dB better in winter vs. summer. While this doesn't shed a lot of light on what to expect coast to coast it does confirm the advantage of wintertime conditions at 60 kHz. I don't have information as to whether the SNR differences are due to changes in ground conductivity, lower background noise, or some combination of both. Jay W1VD WD2XNS WE2XGR/2 WG2XRS/2 ----- Original Message ----- From: Bob Raide To: rsgb_lf_group@blacksheep.org Sent: Thursday, January 02, 2014 8:09 PM Subject: RE: LF: Coast to Coast on 74kHz ground wave ? Laurence; It would be easy to determine coverage of radio signals of longer wavelengths using the soil map. However, the "soil map" is only an estimate and changes DRASTICALLY from season to season. When the ground freezes the conductivity in my area goes from about a 3 [soil map shows I'm in 4] to over 12-14 and the colder it gets the higher it goes! I have been and still am in the broadcast business building my first AM station licensed to Penn Yan NY in 1980. Transmitter site just west of where I am sitting right now. I found 850 kHz fit here perfectly for a KW daytimer. My consulting engineer Harold Munn in Michigan said "no so fast". You see, measurements takes precedence over the soil map. It happens that I was up against the Cornell University 870 5KW station and clearance was somewhat close but signals did not overlap. I rented a calibrated field set [FIM41] and took the measurements in March. Broadcast engineers and communications attorneys want to see cold weather measurements not those taken in 100 degree July heat! My council tendered my app along with my measurements. This measurement program was not to end here! Before it was over with Cornell's engineers and council 3 sets of measurements were taken and finally joint measurements were agreed upon in October of the following year! I have since built or modified and owned 4 other AMs-all requiring measurements to show the allocations or modifications fit for one reason or another. Needless to say for an attempt at west coast groundwave I would also look at as close to 68 kHz as I could find clear! Lower the freq the further the groundwave per meter of signal strength. This is why I made the statement that a signal must be put on the air to determine coverage! I would only attempt such a feat as hitting the west coast groundwave in dead cold frozen ground of Winter!!! Frozen ground is cheating a bit and engineers taking measurements would never agree to such measurements unless they could be averaged with mid summer measurements and the average taken for the allocation. The soil map? In the world of broadcast engineering "don't mean stink". ---------------------------------------------------------------------------- From: hellozerohellozero@hotmail.com To: rsgb_lf_group@blacksheep.org Date: Thu, 2 Jan 2014 15:20:00 -0900 Subject: LF: Coast to Coast on 74kHz ground wave ? Hi Chaps - I saw the discussion on the modes and losses and wanted to add a bit - When looking at WWVB 60Khz (close to 74?) contours for daytime I notice more of a Vertical peanut shape in the fiedlstrength favoring North South, with highest losses over Mountaineous terrain and likely the lowest ground conductivity, say between 0.5 and 2 milliseimens - something we see (in general) afforded by ground to the West of Ft Collins (especially NW) and to the Eastern mountain ranges, and its not too Bright on most bearings from here in Alaska as we have a lot of the pointy high snow covered thingies up here too. I see they plonked WWVB there due to having local high Alkalinity of the soil - high conductance. Whether given the height of the mountains even at 60kHz we loose a bit more than flat Earth Id say a whopping Yes, that and some of the oddities that ground waves going over glaciers can have all add up to further attenuation. Have a looksee at http://www.fcc.gov/encyclopedia/m3-map-effective-ground-conductivity-united-states-wall-sized-map-am-broadcast-stations If I look at how /4 gets up here - it would in reality have to be a fairly high angle reflection, as Im close in to the Chugach and Talkeetna Mountains and those mountain ranges extends hundered of miles on the /4 bearing. - I see no signal at all (ok I wasnt using OPds) and even with a reasonable antennae and good s/n its a sky wave opening only - well, at any reasonably power that we can generate. Whereas he was strong in CA last night he was only just detectable up here - though I blame the Auroral ovaly stuff too for that. Interestingly enough and with the limited amount of data - if Bob was to generate another 3dB he would have probably been visisble at dot 60 every night to date over the 5000Kms path or so , ie a lot less variation on a day to day than I see at 137. On groundwave on 137 I did some reasonable tests and with my 3W ERP (ish) in the main loop on a quiet iono day in Autumn maintaining a CW just read level of some 1000Kms down to Corpus Christi from the OKie/Kansas Border and but out West was considerably poorer - we had poor conductivity to the West of us for a while.... I saw with interest on the NIST web site the scalloped nature of signal reception at night at 60KHz at some times of the night. http://tf.nist.gov/images/radiostations/wwvb-large/0800utc.jpg Cheers from a soggy snowyish Anchorage. ------=_NextPart_000_0007_01CF0809.E0B219D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Bob
 
Here are the 'signal only' plots for = winter and=20 summer ... http://www.w1vd.com/= WWVBwintersummersig.jpg .
 
Apparently not much difference at = 60 kHz ...=20 other than hours of daylight. SNR plots probably more relavent for = the test=20 under discussion.
 
Jay W1VD  WD2XNS  = WE2XGR/2 =20 WG2XRS/2
 
 
----- Original Message -----
From:=20 Bob = Raide=20
Sent: Thursday, January 02, = 2014 9:39=20 PM
Subject: RE: LF: Coast to Coast = on 74kHz=20 ground wave ?

Jay;
The only actual way to determine if it's field = strength=20 is of course to take field strength measurements.  Frozen ground = makes=20 the biggest conductivity change.  And to what depth of ground is = frozen=20 as well effects the field intensity.  
The lower the freq = also=20 tremendously effects groundwave coverage regardless of the = conductivity. =20 That is also included in part 73-74 of the Commission's = rules.  Each=20 of the 10 kHz channels is shown.  All AM broadcasters, of course = want to=20 get the lowest freq that can be found for their=20 allocation. 
 Distances reached are shown for = each=20 broadcast 10 kHz channel in the rules as well over a given=20 conductivity path.
BTW;
The 60 kHz WWVB is a direction array to = better=20 cover the US proper.   
From: jrusgrove@comcast.net
To: = rsgb_lf_group@blacksheep.org
Date: Thu,=20 2 Jan 2014 21:16:07 -0500
Subject: Re: LF: Coast to Coast on 74kHz = ground=20 wave ?

Laurence, Bob
 
I cherry picked the winter and summer = SNR levels=20 of WWVB at different US locations ...  see
 
http://www.w1vd.com/WWVB20wintersummer.jpg .=20
 
The daytime path from = Boulder to Cutler=20 ME is about 7 dB better SNR in the winter and fairly flat from 1600 - = 2000Z.=20 The daytime path from Boulder to San Diego is a bit more 'peaky' with = best SNR=20 at about 1800 Z but is only a few dB better in winter vs. summer.=20
 
While this doesn't shed a lot of = light=20 on what to expect coast to coast it does confirm the advantage of = wintertime conditions at 60 kHz. I don't have information as = to whether=20 the SNR differences are due to changes in ground conductivity, lower=20 background noise, or some combination of both. 
 
Jay W1VD  WD2XNS  = WE2XGR/2 =20 WG2XRS/2  
-----=20 Original Message -----
From:=20 Bob Raide=20
To:=20 rsgb_lf_group@blacksheep.org= =20 Sent:=20 Thursday, January 02, 2014 8:09 PM Subject:=20 RE: LF: Coast to Coast on 74kHz ground wave ?

Laurence;
It would be easy to determine coverage = of radio=20 signals of longer wavelengths using the soil map.  = However,=20 the "soil map" is only an estimate and changes DRASTICALLY = from=20 season to season.  When the ground freezes the conductivity in = my area=20 goes from about a 3 [soil map shows I'm in 4] to over 12-14 and the = colder=20 it gets the higher it goes!  I have been and still am in=20 the broadcast business building my first AM station = licensed to=20 Penn Yan NY in 1980.  Transmitter site just west = of where I=20 am sitting right now.  I found 850 kHz fit here perfectly for a = KW=20 daytimer.  My consulting engineer Harold=20 Munn in Michigan said "no so fast".  You see, = measurements=20 takes precedence over the soil map.  It happens that = I was up=20 against the Cornell University 870 5KW station and clearance = was=20 somewhat close but signals did not overlap.  I rented a = calibrated=20 field set [FIM41] and took the measurements in March.  = Broadcast=20 engineers and communications attorneys want to see cold weather = measurements=20 not those taken in 100 degree July heat!  My council = tendered my=20 app along with my measurements.  This measurement program was = not to=20 end here!  Before it was over with Cornell's engineers and = council 3=20 sets of measurements were taken and finally joint measurements were=20 agreed upon in October of the following year!
I have since = built or=20 modified and owned 4 other AMs-all requiring measurements = to show=20 the allocations or modifications fit for one reason or=20 another.
Needless to say for an attempt at west coast groundwave = I would=20 also look at as close to 68 kHz as I could find clear! Lower = the freq=20 the further the groundwave per meter of signal strength.
This is = why I=20 made the statement that a signal must be put on the air to = determine=20 coverage!  I would only attempt such a feat as hitting the west = coast=20 groundwave in dead cold frozen ground of Winter!!!  Frozen = ground is=20 cheating a bit and engineers taking measurements would never agree = to such=20 measurements unless they could be averaged with mid summer = measurements and=20 the average taken for the allocation. 
The soil map?  = In the=20 world of broadcast engineering "don't mean stink".
 
From: hellozerohellozero@hotmail.com
To:=20 rsgb_lf_group@blacksheep.org
Date: Thu, 2 Jan 2014 15:20:00=20 -0900
Subject: LF: Coast to Coast on 74kHz ground wave ?

Hi Chaps - I saw the discussion on the modes and = losses=20 and wanted to add a bit -
 
When looking at WWVB = 60Khz =20 (close to 74?) contours for daytime I notice more of a Vertical = peanut shape=20 in the fiedlstrength favoring North South, with highest losses over=20 Mountaineous terrain and likely the lowest ground conductivity, say = between=20 0.5 and 2 milliseimens - something we see (in general) afforded by = ground to=20 the West of Ft Collins (especially NW) and to the Eastern mountain = ranges,=20 and its not too Bright on most bearings from here in Alaska as we = have a lot=20 of the pointy high snow covered thingies up here too.  I see = they=20 plonked WWVB there due to having local high Alkalinity of the soil - = high=20 conductance.
 
 Whether given the height of the = mountains=20 even at 60kHz we loose a bit more than flat Earth Id say a whopping = Yes,=20 that and some of the oddities that ground waves going over glaciers = can have=20 all add up to further attenuation.
 
Have a looksee at http://www.fcc.gov/encyclopedia/m3-map-effective-ground-c= onductivity-united-states-wall-sized-map-am-broadcast-stations
&nb= sp;
If=20 I look at how /4 gets up here - it would in reality have to be a = fairly high=20 angle reflection, as Im close in to the Chugach and Talkeetna = Mountains and=20 those mountain ranges extends hundered of miles on the=20 /4 bearing. - I see no signal at all (ok I wasnt using = OPds) and=20 even with a reasonable antennae and good s/n its a sky wave = opening=20 only - well, at any reasonably power that we can generate. Whereas = he was=20 strong in CA last night he was only just detectable up here - though = I blame=20 the Auroral ovaly stuff too for that.
 
Interestingly = enough and=20 with the limited amount of data - if Bob was to generate another 3dB = he=20 would have probably been visisble at dot 60 every night to date over = the=20 5000Kms path or so , ie a lot less variation on a day to day than I = see at=20 137.
 
On groundwave on 137 I did some reasonable tests = and with=20 my 3W ERP (ish) in the main loop on a quiet iono day in Autumn = maintaining a=20 CW just read level of some 1000Kms down to Corpus Christi from the=20 OKie/Kansas Border and  but out West  was considerably = poorer - we=20 had poor conductivity to the West of us for a = while....
 
I saw=20 with interest on the NIST web site the scalloped nature of signal = reception=20 at night  at 60KHz at some times of the night.
 
http://tf.nist.gov/images/radiostations/wwvb-large/0800ut= c.jpg
 
Cheers=20 from a soggy snowyish=20 = Anchorage.
 
 
 
 
<= /BLOCKQUOTE>
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