[TowerTalk] TowerTalk Digest, Vol 210, Issue 9
Wilson Lamb
infomet at embarqmail.com
Tue Jun 9 12:38:35 EDT 2020
Wasn't there an article in QST that expounded on the limited reality of NVIS.
As pointed out, most of us are NVIS on 40 and down anyway.
WL
----- towertalk-request at contesting.com wrote:
> Send TowerTalk mailing list submissions to
> towertalk at contesting.com
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://lists.contesting.com/mailman/listinfo/towertalk
> or, via email, send a message with subject or body 'help' to
> towertalk-request at contesting.com
>
> You can reach the person managing the list at
> towertalk-owner at contesting.com
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of TowerTalk digest..."
>
>
> Today's Topics:
>
> 1. NVIS (not exactly towers, but HF) (jimlux)
> 2. Re: NVIS (not exactly towers, but HF) (John Simmons)
> 3. Re: NVIS (not exactly towers, but HF) (jimlux)
> 4. Re: NVIS (not exactly towers, but HF) (Rob Atkinson)
> 5. Re: NVIS (not exactly towers, but HF) (jimlux)
> 6. Re: NVIS (not exactly towers, but HF) (Gene Smar)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Mon, 8 Jun 2020 11:02:53 -0700
> From: jimlux <jimlux at earthlink.net>
> To: towertalk <towertalk at contesting.com>
> Subject: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID: <68dc58ff-8aad-9e26-a6ff-61c1df21b2bc at earthlink.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> I guess if you have a tower, you're not so interested in NVIS <grin>
> Interesting paper (behind IEEE paywall unfortunately) in this month's
> Antennas and Propagation Magazine. The authors have a series of papers
> over the past few years of interest, looking at various performance factors.
>
>
> P. J. Coetzee and W. P. du Plessis, "Performance Limiters of
> Near-Vertical-Incidence Skywave Propagation: A Scientific Approach," in
> IEEE Antennas and Propagation Magazine, vol. 62, no. 3, pp. 39-44, June
> 2020, doi: 10.1109/MAP.2019.2943313.
>
>
> Abstract:
> Near-vertical-incidence skywave (NVIS) propagation is defined as
> providing continuous coverage from nearly 0 km (just beyond the line of
> sight) to a couple hundred kilometers from the transmitter with no skip
> or dead zones. NVIS communications are especially effective during
> disaster-relief operations when infrastructure is severely damaged. The
> ability to accurately determine the performance limiters of NVIS
> propagation can help in the planning of high-frequency (HF) (3-30 MHz)
> emergency communication links. In the literature, widely varying radial
> distances (from as few as 50 to up to 160 or even 320 km) for the
> coverage attainable by NVIS propagation have been reported. It is very
> difficult to plan an NVIS link for homeland security or disaster relief
> when the published guidelines vary to such a degree. In this study, a
> scientific approach was utilized to determine the NVIS performance
> limiters for varying solar conditions, times of day, and geophysical
> locations.
>
>
> ------------------------------
>
> Message: 2
> Date: Mon, 8 Jun 2020 18:14:35 -0500
> From: John Simmons <jasimmons at pinewooddata.com>
> Cc: towertalk <towertalk at contesting.com>
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID: <3cc24071-eec0-9417-8e70-0055051b4285 at pinewooddata.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> $33 for the 5 page article. I'd like to read it but I'm not sure there
> would be enough unique info to justify the price.
>
> Perusing the IEEE website I wasn't able to find the cost for individuals
> to become a member.
>
> -de John NI0K
>
> jimlux wrote on 6/8/2020 1:02 PM:
> > I guess if you have a tower, you're not so interested in NVIS <grin>
> > Interesting paper (behind IEEE paywall unfortunately) in this month's
> > Antennas and Propagation Magazine.? The authors have a series of
> > papers over the past few years of interest, looking at various
> > performance factors.
> >
> >
> > P. J. Coetzee and W. P. du Plessis, "Performance Limiters of
> > Near-Vertical-Incidence Skywave Propagation: A Scientific Approach,"
> > in IEEE Antennas and Propagation Magazine, vol. 62, no. 3, pp. 39-44,
> > June 2020, doi: 10.1109/MAP.2019.2943313.
> >
> >
> > Abstract:
> > Near-vertical-incidence skywave (NVIS) propagation is defined as
> > providing continuous coverage from nearly 0 km (just beyond the line
> > of sight) to a couple hundred kilometers from the transmitter with no
> > skip or dead zones. NVIS communications are especially effective
> > during disaster-relief operations when infrastructure is severely
> > damaged. The ability to accurately determine the performance limiters
> > of NVIS propagation can help in the planning of high-frequency (HF)
> > (3-30 MHz) emergency communication links. In the literature, widely
> > varying radial distances (from as few as 50 to up to 160 or even 320
> > km) for the coverage attainable by NVIS propagation have been
> > reported. It is very difficult to plan an NVIS link for homeland
> > security or disaster relief when the published guidelines vary to such
> > a degree. In this study, a scientific approach was utilized to
> > determine the NVIS performance limiters for varying solar conditions,
> > times of day, and geophysical locations.
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk at contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> Message: 3
> Date: Mon, 8 Jun 2020 17:04:43 -0700
> From: jimlux <jimlux at earthlink.net>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID: <7014f85c-9072-7d85-94a0-b6ebc6e0d2ce at earthlink.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> On 6/8/20 4:14 PM, John Simmons wrote:
> > $33 for the 5 page article. I'd like to read it but I'm not sure there
> > would be enough unique info to justify the price.
> >
> > Perusing the IEEE website I wasn't able to find the cost for individuals
> > to become a member.
>
> Fairly pricey - $100 ish/year - although they have a deal now for half
> price (and then they'll tag you for the full amount)
>
> and then you need to get a digital library subscription (3
> downloads/month rolling over for up to 12 months) which is $20/month.
> There's a higher price option too.
>
> It's not cheap.
>
> If you're a student, it's substantially cheaper - I don't know how long
> you can be a student member, and what the qualifications are.
>
>
> If you make your living doing it, you either get the access through your
> work, or you justify it as part of "doing business".
>
>
>
> ------------------------------
>
> Message: 4
> Date: Tue, 9 Jun 2020 09:39:09 -0500
> From: Rob Atkinson <ranchorobbo at gmail.com>
> To: towertalk <towertalk at contesting.com>
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID:
> <CALWD7Z4u+0Hhs1PyMnc7VOmCDou=xxkdGddQaEDtC5VjUwvMDw at mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> I didn't see anything in the abstract that made me want to read it as
> far as ham radio is concerned. A number of hams over the past years
> have cited military work with cloud burners as a justification for
> their usefulness in ham radio. I don't contest a horizontal antenna
> that has its highest field intensity straight up, but I do contest the
> argument for ridiculously low hanging antennas because that's what
> other services do. There are several differences between ham and
> other services that have to do with power limits, frequency
> exclusivity, transmission modes, battle conditions, and radiation
> efficiency.
>
> 73
> Rob
> K5UJ
>
>
> ------------------------------
>
> Message: 5
> Date: Tue, 9 Jun 2020 08:05:04 -0700
> From: jimlux <jimlux at earthlink.net>
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID: <c562b6b1-91f7-3be8-968c-fb9358b0bc1f at earthlink.net>
> Content-Type: text/plain; charset=utf-8; format=flowed
>
> On 6/9/20 7:39 AM, Rob Atkinson wrote:
> > I didn't see anything in the abstract that made me want to read it as
> > far as ham radio is concerned. A number of hams over the past years
> > have cited military work with cloud burners as a justification for
> > their usefulness in ham radio. I don't contest a horizontal antenna
> > that has its highest field intensity straight up, but I do contest the
> > argument for ridiculously low hanging antennas because that's what
> > other services do. There are several differences between ham and
> > other services that have to do with power limits, frequency
> > exclusivity, transmission modes, battle conditions, and radiation
> > efficiency.
>
>
>
> what's interesting in the article isn't so much the NVIS stuff, but the
> modeling approach. They're doing some ionospheric ray tracing using
> ionosonde measurements. For what it's worth, the antennas they are
> using are at 0.2 wavelength, which isn't one of those knee high wires.
> At frequencies from 4-11 MHz it seems.
>
> They're using Coleman's ray tracing approach
> 21] C. J. Coleman, ?Point-to-point ionospheric ray tracing by a direct
> variational method,? Radio Sci., vol. 46, no. 5, pp. 1?7, 2011.
> Here's a report on it
> https://apps.dtic.mil/dtic/tr/fulltext/u2/a271058.pdf
>
> These days, there's a lot more real-time ionosonde data available - it's
> sort of the next step beyond NCDXF beacons or various reverse beacon
> networks.
>
>
> Of particular interest is a paper I want to track down
>
> [17] P. J. Coetzee, ?A technique to determine the electromagnetic
> properties of soil using moisture content,? South Afr. J. Sci., vol.
> 110, no. 5/6, pp. 1?4, 2014.
>
>
>
> ------------------------------
>
> Message: 6
> Date: Tue, 9 Jun 2020 11:59:01 -0400
> From: "Gene Smar" <ersmar at verizon.net>
> To: <towertalk at contesting.com>
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
> Message-ID: <008901d63e76$e51bb670$af532350$@verizon.net>
> Content-Type: text/plain; charset="UTF-8"
>
> TT:
>
> Regarding ridiculously low dipoles and NVIS operation, they really do work after a fashion. In addition to towers, I collect military radios and am a member of the Military Radio Collectors' Association http://www.mrca.ar88.net/ . We meet on the air several times a week on HF. We also attend an annual gathering of the membership (predominantly east coast) each September in Gilbert, PA, in the Pocono Mountains. Here we actually use our shorter-range 51 MHz FM radios as well as our backpack HF rigs that the US Special Forces used in 'nam. Several of our members have told hair-raising stories about their use of these packs in the field.
>
> To make a potentially long story mercifully shorter, we set up my NVIS crossed inverted Vee antenna (75M and 60M wires) in a mountain valley 20 miles north of our base camp at Gilbert. We operated a 50 W HF rig on 75 M USB and base heard us Lima Charlie. (Loud and clear.) We then disassembled the Vees and held the 75 M wires taut at chest height and base was still able to copy us; a station in upstate New York also copied us LC. The SpecOps guys among us told us that's how they used to deploy their skyhooks when they had no time to string the wires between trees.
>
>
> 73 de
> Gene Smar AD3F
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of jimlux
> Sent: Tuesday, June 09, 2020 11:05 AM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] NVIS (not exactly towers, but HF)
>
> On 6/9/20 7:39 AM, Rob Atkinson wrote:
> > I didn't see anything in the abstract that made me want to read it as
> > far as ham radio is concerned. A number of hams over the past years
> > have cited military work with cloud burners as a justification for
> > their usefulness in ham radio. I don't contest a horizontal antenna
> > that has its highest field intensity straight up, but I do contest the
> > argument for ridiculously low hanging antennas because that's what
> > other services do. There are several differences between ham and
> > other services that have to do with power limits, frequency
> > exclusivity, transmission modes, battle conditions, and radiation
> > efficiency.
>
>
>
> what's interesting in the article isn't so much the NVIS stuff, but the modeling approach. They're doing some ionospheric ray tracing using ionosonde measurements. For what it's worth, the antennas they are using are at 0.2 wavelength, which isn't one of those knee high wires.
> At frequencies from 4-11 MHz it seems.
>
> They're using Coleman's ray tracing approach 21] C. J. Coleman, ?Point-to-point ionospheric ray tracing by a direct variational method,? Radio Sci., vol. 46, no. 5, pp. 1?7, 2011.
> Here's a report on it
> https://apps.dtic.mil/dtic/tr/fulltext/u2/a271058.pdf
>
> These days, there's a lot more real-time ionosonde data available - it's sort of the next step beyond NCDXF beacons or various reverse beacon networks.
>
>
> Of particular interest is a paper I want to track down
>
> [17] P. J. Coetzee, ?A technique to determine the electromagnetic properties of soil using moisture content,? South Afr. J. Sci., vol.
> 110, no. 5/6, pp. 1?4, 2014.
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>
> ------------------------------
>
> End of TowerTalk Digest, Vol 210, Issue 9
> *****************************************
More information about the TowerTalk
mailing list