Finding Tropo Enhancement in a Place That Doesn't Have Tropo - 10/20 Update

Hello everyone,

When I retired last June I moved to the Highlands of Arizona, a community known as Prescott (pronounced "preskit" rhymes with "biscuit"), grid square DM34un. I was excited to start over again on 2-Meter VUCC (#237 4/1988), but understood that this one would be more challenging.

I set up an antenna to monitor the FM broadcast band to help me find potential 2-Meter Es and Meteor scatter paths in the future. To my surprise, on a few occasions I would pick up FM broadcast stations from Tuscon, 175 miles away. So something is enhancing it. I asked for volunteers and luckily Ron Herring, W7HD just north and west of Tuscon volunteered to operate 2-Meter PropNET and see if we could capture each other.

Ron is running 25 watts into a Diamond X50 vertical @ 50 feet and I am running 10-15 watts into a 4-Element F9FT Tonna Yagi @ 25 feet. On occasions I switched to a Cushcraft Ringo Ranger II without the radials (base at 18 feet).

Here are our results for the week-ending 10/18:

Weather was not very cooperative this week.
They were a few low pressure disturbances that passed through the area.

Tx Call	Tx Grid	Rx Call	Rx Grid	Distance (km)	Band	Path Score	Freq Δ	IMD	UTC Time
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-092	60%	2014-10-18 14:47:20
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-093	80%	2014-10-18 12:57:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-094	-07	2014-10-18 12:37:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-115	99%	2014-10-18 11:57:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-097	-08	2014-10-18 11:27:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	50%	-121	99%	2014-10-18 10:17:20
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-120	40%	2014-10-18 10:07:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-116	80%	2014-10-18 09:17:21
KA5DWI	DM34UN	W7HD	DM42JI	265	2 meters	17%	+296	60%	2014-10-18 08:55:29
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	67%	-119	40%	2014-10-18 08:27:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	67%	-119	50%	2014-10-18 08:07:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	50%	-119	60%	2014-10-18 07:57:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-122	80%	2014-10-18 07:37:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-122	-14	2014-10-18 07:17:21
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-103	80%	2014-10-17 12:37:22
KA5DWI	DM34UN	W7HD	DM42JI	265	2 meters	17%	+184	80%	2014-10-17 11:25:45
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-109	40%	2014-10-17 11:17:23
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-109	-14	2014-10-17 10:17:22
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-113	-04	2014-10-17 08:57:12
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-115	+00	2014-10-17 07:37:12
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	67%	-121	80%	2014-10-17 06:07:12
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	50%	-124	60%	2014-10-17 05:47:13
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-124	90%	2014-10-17 05:37:13
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-126	-03	2014-10-17 05:27:12
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-124	40%	2014-10-17 04:17:13
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	50%	-088	80%	2014-10-16 11:27:15
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	33%	-083	-06	2014-10-16 11:17:15
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-086	+00	2014-10-16 10:47:15
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-113	-16	2014-10-16 06:37:14
W7HD	DM42JI	KA5DWI	DM34UN	265	2 meters	17%	-069	80%	2014-10-14 06:17:19
KA5DWI	DM34UN	W7HD	DM42JI	265	2 meters	17%	-282	40%	2014-10-12 14:03:07

Several times I saw Ron's signal on the waterfall, but the software failed to sync with it. All captures this week was using the Yagi.

What Provides the Enhancement.

My Station

A Yaesu FT290R driving a THP 30 watt Amp, Janel QSA5 MosFET preamp into a rebuilt Tonna F9FT 4-Element Yagi.  All of the equipment is 32 years old!  Ron's W7HD signal is being captured in the pic.

Path 

I am located in Prescott Valley. Verde Valley and Black Canyon are to my Southeast. Phoenix is located in a valley and continues as San Tan Valley towards Tucson. 

There are very few obstructions between us.

The vertical line marks to the direction to W7HD from my QTH. As noted, it is straight down the valley. Only one mountain is in the downward view and it is low on my horizon. 

The view to my station (KA5DWI) from Ron's QTH is noted by the vertical line. He has no obstructions to my QTH

Weather Conditions Promoting an Opportunity

Week-Ending 10/11/14
First Captures

NWS Radar Mosaic Afternoon of 10/07/14.
Tropical Storm Simon was entering the Gulf of California. 

As it approached, the counter-clockwise wind from the low pushed warm air along the eastern border of the valleys. The false echoes (light blue) shows the inversion in the valleys. This provides the conditions for ducting of VHF signals.

Second Opportunity

The next opportunity was a surprise on 10/10.  The line of very strong thunderstorms formed in the northern Chino Valley. The storms produced hail and started to break up once the sun set.

Once the storms died out, the air cleared, the atmosphere stabilized, and winds were fairly light.

Upper air winds were also light. That is odd for Thunderstorm formation.  The storms had tremendous uplift as observed at my QTH. The result was hail. 

Upper-Air Soundings-Flagstaff AZ the following morning.
Line on left: Dewpoint
Line on right:Air Temperature
Vertical Axis: Height
An inversion occurs when both measurement lines go in opposite directions.
Inversion at: 3,100 m, 5,100 m, & 10,000 m.

No strong inversions over Tucson, but small ones at 1,500 m and 2,500 m.

Third Opportunity

Still wedged between two surface low pressure troughs, little to no wind on the surface. Notice the heat island temperature in Phoenix are 10-20 degrees warmer than the surrounding areas..

Upper level winds are light over Arizona.

High pressure is centered over Arizona at mid-levels.

There are three inversions over Flagstaff.
4,700 m, 6,700 m, & 10,000 m.

Over Tucson, there are well-defined inversions at 1,500 m and 4,700 m.

Week-Ending 10/18/14 Opportunity

The NWS Radar Mosiac show once again good temperature inversions in the valleys.

Arizona is located this day between 2 surface lines of low pressure (trough and warm front).

Very little to no surface winds provide good radiation cooling

In the Upper Air, Arizona is located on the backside (left) of high pressure centers. Winds again are light. 

 

At both Flagstaff and Tucson there are at least 2 levels of temperature inversions.
Air-Temperature increases, Dew Point rapidly decreases

Summary
Tropospheric enhancement and ducting of VHF signals are a matter of having temperature inversions at levels visible to your RF path. The opportunities are there more than you think. Once identified, it is a matter of having someone on the other end.

I hope this can guide you in experiencing the joys of working VHF/UHF weak signal.

73s
Art Jackson KA5DWI/7 DM34un

4-Year Analysis Spring/Summer Es Propagation from PropNET

The following charts and data are based on 10-Meter PropNET and Non-PropNET PSK31 captures of North American PropNET participants from April 25 through August 15 2010 - 2013.

A specific formula was used to distinguish Sporadic Es propagation from F2 or Trans-Equatorial propagation. Only PropNET participant data from North America and Hawaii was used in the study. Any questionable data was removed to the best of my ability.

This information is for the use Amateur Radio public.  Please reference PropNET Studies as the source.

Narrative will be added as time permits.

Enjoy.  This stuff is fascinating and I believe it answers many questions about Sporadic Es propagation from year to year.

SOLAR CONDITIONS:
After one of the longest lulls in the Solar cycle ever recorded, the sun finally started to get more active in 2011. Unfortunately the increased activity in Solar Flux peaked in 2012.  Many look for a second peak in 2013-14.

Once the 2012 Es season ended, solar flux hit levels approaching 180.  By the spring of 2012 it had begun a decline.

On the other hand, the actual number of sunspots has not declined that much.

The number of new sunspot regions have actually grown year to year since 2010.

Despite the growth in new regions, these do not last very long.
Their ability to produce intense flares has been impeded.

Solar activity actually has a steady increase since 2010.  Due to mistiming of the solar poles, there has been a less extreme rise in solar flux. New sunspot regions form, create instability but do not produce the high MUF to support F2 propagation.

Es ACTIVITY BY DAY:

In 4 years, North American PropNET participants captured almost 300,000 packets from other members or non-participants transmitting specific algorithms. 

These are the average daily captures by day six weeks prior to and after the Summer Solstice. The trend line produced by the data shows that peak activity occurs at or near the solstice.

The overall trend was highly affected by the volumes of 2010 and 2011.

2010 - The last year of low solar activity.

2011 - Solar activity picks up.  The season had a lull early, and then became active toward the latter half.

2012 - Solar activity has peaked.  What activity there is occurs in the first half with a large lull during the solstice period.

2013 - Solar activity remained high. The trend line was almost a duplicate of 2012.

Activity has drastically deceased since 2010.

The number of open hours each season has declined, but at a slower level.

Es ACTIVITY BY HOUR:

As has been seen in most years, Es activity has a dual-peaked diurnal.  In 2010, it was a morning peak.  As solar activity increased, it became afternoon active.

11:00 UTC represents sunrise on the East Coast of North America.  Activity peaks 2 hours prior to noon in the center of the continent and again 2 hours before the sun begins to set.

When solar activity was low, the morning hours are most active. As solar activity increases, it shifts to afternoon.

This chart is based on an equal percentage breakdown.  The highest hourly percentage of day occurred late afternoon when solar activity was its highest.

As solar activity increased, active hours of Es declined.

As the season begins if an hour opens, intensity increases until the solstice and steadily declines afterward. 

This chart shows that once solar activity increases, intensity drops of at beginning and end of the season.

As noted on the chart, low solar activity has a great influence.

F2 and Trans-Equitorial:

As solar activity rises so does TEP open.  This was very prevalent in the last 3 years.

Population Changes in 4 Years:

PropNET captures were about 5 times greater than Non-PropNET captures.

Changes in the mixture of PropNET to Non-PropNET changes since 2010 have occurred, but are very slight overall.  For the past two seasons, PropNET to Non-PropNET are at 80% to 20%. The only real changes that were noticeable were around year 2011 and were no more than 5%.

 The decline became more extreme after 2011

 Non-PropNET declines more evenly in 4 years.

 The mix of Non-PropNET to PropNET does not change much.

The overall decrease since 2010 for PropNET captures is about 3.5% greater than Non-PropNET..

Comparing North To South:

I wondered if what happens in the southern half of the continent is different than the northern half.  I split the continent at the grid squares FMx7, EMx7, DMx7 and CMx7 to the north and measured the data by hour by year.  To my surprise there is little difference, other than there is more activity in the south.

There are more active southern participants in PropNET.

When the totals are broken down by percentage of day, the north sees more Noon activity, the south sees more sunrise and sunset activity.  Not much difference, but a little more noticeable the last couple of years.

More Directional Comparisons:

So how does Es propagation differ by direction.  Once again consistant North to South, East to West.  Only Northeast to Southwest, Northwest to Southeast show any differences. 

 There are little differences in these directions.

Most activity is to the North.

 Only Eastward conditions are more volumes found.

Northeast and Southwest show morning activity.
Northwest and Southeast show afternoon and evening activity.

EARLY CONCLUSIONS:
As was expected, solar activity has a profound affect on Es propagation after the minimum has occurred. The peak should occur by the winter.  It will be interesting to see how these numbers change the next few years.  I think it will be on the way up.

More analysis to come...............

73s
Art Jackson KA5DWI