[OFARC] Vagaries of FT8

[Mark]

I have the same problem sometimes.  A lot of these guys are just chasing DX
and they just don't like me.  

 

From: ofarc-bounces at mailman.qth.net [mailto:ofarc-bounces at mailman.qth.net]
On Behalf Of Ralph (home)
Sent: Sunday, August 18, 2019 8:52 PM
To: OFARC
Subject: [OFARC] Vagaries of FT8

 

Last Tuesday I have a brief discussion with Mark about settings for FT8 to
get the best signal out.

I have tried all the suggestions, with no improvement in QSOs made.

So, I started looking deeper.

 

The other evening, I finally had a chance to start running some tests of FT8
propagation from my QTH.

I gauged the quality and reach of my signal using this web page

It shows who heard you where, and how strong you signal was at their
location.

 

https://pskreporter.info/pskmap.html

 

 

I hope the notes below give you some ideas that will help your efforts on
the various digital modes.

 

Ralph

KE5HDF

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My antennas are 20M/40M dipole with common feed point (wire running N-S)
about 30 ft up

80M inverted V + tuner to get 30M  (on N side of house, apex at 30 ft)

 

TEST 1

Used the same power level on 20M, 30M, and 40M

Try for QSOs for about 5 minutes on a single band

Immediately Look at reception reports for my call on that band in last 15
minutes

 

20M showed lots of reception reports with good coverage east and west, with
some successes to SW, SE, and NE - GOOD!

 

40M had very few reception reports anywhere - SWR is 2+, at same height as
the 20M - ANTENNA problem (too low?, need to re-tune it?, maybe move it?)

 

30M showed  many reports to NW through NE. nothing to the South - SWR 1.2
using a tuner with the 80M V, antenna working well but too close to the
house (blocking signals)

 

Signal strength reports normally show my signal weaker than the other guy by
several dB

I expected this because of the low antenna height and using dipole rather
than a beam antenna.

Plus.. You don't know how much power the other guy is running

 

TEST 2

Same set up - single band . 20M

But look for changes in signal reach PLUS reception reports near the station
I am trying to contact

 

Results.

20 M reached to New Zealand on one occasion, South America lots of times,
Spain several times

30 seconds later, my signal went only as far as New Mexico (that is one
transmit/receive cycle)

 

On several cycles, my signal was reported by the station I was trying to
reach (Argentina, Spain, Wash. State)  but they never replied to me

 

Repeat for 40M 

SWR was back down to 1.7

Signal reports were good to NW and NE, some to South

Signal reception reports Similar results as for 20M

 

Conclusions re: FT8 & settings

The approaching Grey line seemed to have minimal impact on signal distance

Rapid changes in signal path likely due to ionospheric conditions

My station is good

antennas are good

software control settings good

 

40M Antenna:

I recalled the first evening was rainy, today was dry.

Probably had capacitive loading by the water collecting on the tree at one
end of my antenna throwing off my 40M SWR.  (20M wire does not reach the
tree)

 

Possible explanation for poor QSO rate - during the grid chase last year, I
did a LOT of contacts.  Maybe the other guys just lot looking for our grid.
too may hams in Houston area to be a "special" contact.

 

Changes to make:

try to move my 80M V to the giant magnolia tree (50 ft tall) at my back
fence instead of my TV antenna mast secured to the house (capacitive loading
again)

Or 

or maybe buy out my 2 neighbors so I can do a better 80M antenna????

OR

Just keep more beer handy, don't sweat it, enjoy the ride

 

 

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