Re: Troposcatter & ducting

Keith Morehouse
 

I do.  Until 6 years ago, I was able to take advantage of it.

I recall a bad cold wave around Thanksgiving one year, when the Great Lakes were still warm and ice free.  A duct set up over the lakes and up the St Lawrence valley that allowed me to work K1WHS in Maine on 2, 222 & 432, along with VE2's from EN52 - well over 800 miles.  And, 2M QSOs all the way to VE1.  On 432, I was using a single 9WL yagi at 40' and 200W.

I also had a 'everyday' range of close to 400 miles on 2M troposcatter with a 5WL yagi at 75'.  Well set-up rovers could be worked out to 300-350 miles on 6 & 2M.  That's actually not too much different from what I see here in DM58.  Unfortunately, many local rovers are just not set up for longer haul stuff like they were in the upper Midwest.  They mostly have a 'work local' attitude.  You would never see serious rovers in IL, WI or MN counting on loops for 6 or 2.  The easily worked 6M rovers ran full size antennas, even if it was just a dipole or beam driven element.  It made a huge difference.

-W9RM

Keith Morehouse
via MotoG


On Fri, Sep 13, 2019, 3:35 PM Steve London <n2ic@...> wrote:
Last week, there were several -days- of 2 meter propagation between Mississippi
and Ontario/Western NY, to the west of Dorian. Eat your heart out.

73,
Steve, N2IC

On 09/13/2019 03:29 PM, Keith Morehouse wrote:
> A random observation...
>
> There is troposcatter and then there is tropospheric ducting, which is what most
> VHF+ ops from east of the continental divide (and some west coasters) are
> familiar with, when 2M and above 'opens' over paths exceeding 3-400 miles.
>
> While troposcatter is a useable propagating mode most anywhere and accountable
> for a good majority of those 300 mile Q's on 10M and above, tropo ducting is
> another animal altogether and rarely appears in areas of drastically variable
> terrain like central and western Colorado.  The temperature inversions that
> often (always ??) cause ducting to occur are usually at low enough elevations
> that they are blocked by high terrain.  Plus, inversions go hand in hand with
> atmospheric moisture content, something hard to come by in the dry southwest. 
> My current humidity here in DM58 is 15%, which actually is high for this time of
> year.
>
> -W9RM
>
> Keith Morehouse
> via MotoG
>
> On Fri, Sep 13, 2019, 3:08 PM James Duffey <JamesDuffey@...
> <mailto:JamesDuffey@...>> wrote:
>
>     I was referring to the Olathe-Amarillo path. Tropo losses rise steeply
>     beyond 300 miles. Six and two are not too different with respect to the plot
>     below. Meteor scatter starts to overcome tropo at about 350 miles, depending
>     on station capability. WSJT-X helps, but at those distances MSK144 is
>     probably better than FT8 or FT4 for that path. Typical modest station
>     capability on 2M is about 200dB, less on 6M roughly by the difference in
>     antenna gains.
>
>     The difference in large part is due to the height of the scattering media;
>     for troposatter it is about 35,000 ft or below, for meteor scatter is it 60
>     miles or so. - Duffey
>
>
>     James Duffey KK6MC
>     Cedar Crest NM
>
>      > On Sep 13, 2019, at 13:42, Steve London <n2ic@...
>     <mailto:n2ic@...>> wrote:
>      >
>      > Albuquerque-to-Amarillo: 269 miles. Once you get over the Sandia's, it's
>     a mostly downhill-to-flat path.
>      >
>      > Olathe-to-Amarillo: 410 miles.
>      >
>      > For reference, My QTH in DM52XT to Santa Fe is 240 miles. Can work W7QQ
>     on 6 and 2.
>      >
>      > 73,
>      > Steve, N2IC
>      >
>      >> On 09/13/2019 10:29 AM, Arne N7KA wrote:
>      >> I am  hearing him and decoding.
>      >> Arne N7KA
>      >>> On September 13, 2019 at 10:20 AM Ed <n5jeh@...
>     <mailto:n5jeh@...>> wrote:
>      >>>
>      >>> MSK  144 would work better for that distance with no other propagation
>     to help. Just MHO
>      >>>
>      >>> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for
>     Windows 10
>      >>>
>      >>> *ED  N5JEH   DM65RD *
>      >>>
>      >>> *From: *Arne N7KA <mailto:N7KA@... <mailto:N7KA@...>>
>      >>> *Sent: *Friday, September 13, 2019 8:52 AM
>      >>> *To: *NMVHF <mailto:nmvhf@groups.io <mailto:nmvhf@groups.io>>
>      >>> *Subject: *[nmvhf] DM95
>      >>>
>      >>> I copied N5KS on 6M FT8 yesterday with good sigs -8 to -14.  I am
>     trying to work him for new 6M grid and sent him  an email about looking this
>     way and into Olathe during the contest this weeked.   He is in Amarillo.
>     N5EPA might have a good chance, possibly W7QQ.
>      >>>
>      >>> Arne N7KA
>      >>>
>      >
>      >
>      >
>
>
>
>



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