Post on 02-May-2018
transcript
EME DXpedition 2014 to OH0 –
Aland Isles, testing new High
Precision Inclinometer
EME Meeting 2015 in Örebro
Monika and Michael
aka: the M&M-team
Why a new inclinometer??
• The home made pendulum-type inclinometers based on MAB 25 absolute encoders suffer from friction in bearing and high inertial mass, resulting in hysteresis and swinging
• The actual tracking resolution with the well-known OE5JFL controller could hardly be pushed to 0.2 degrees
• US-Digital inclinometer A2-T also shows a lot of overswing, no alternative
• Tracking with solid 1.8 m dish on 10 G had to be manual in reality (as experienced with TK/DL1YMK)
• Consequently: any better solution available???
What is ideally needed?
• Specifications….resolution equal or better than 0.1
degrees
• Ideally no friction (hystresis), no swinging, direct
response to change of position
• Fully compatible with a MAB25/28 on a JFL-controller ->
Synchronous Serial Interface, SSI
• Data protocol not too far from MAB25
• Sealed housing for protection against WX impact (wind
swing)
• Is there a suitable commercial solution available??
The answer is: YESSS,
but…
• The solution was found after intensive web
search:
• A micro-electro-mechanical system (MEMS)-
based 2-axis inclinometer, produced by Posital-
Fraba, an American/German jv company for
industrial sensor technology
• MEMS structure sizes typically between 1 and
100 µm, subsequently low masses involved
• BUT: price around 450,- €
This is what you pay for…
• 0-360° 1-axis configuration
• 13 bit resolution = 0.04° (MAB25: 12 bit)
• 0.14° accuracy/linearity
• Active linearization and temperature compensation
• Hermetically sealed UV-resistant PBT-housing, encapsulated with PUR duromer
• SSI differential data output protocol, RS422 data line drivers
• Programmable counting direction
• Operating voltage 5 – 30 V DC
• M12 connector for cabling
source: Posital
Next Step: Expert check…
• I contacted Hannes and asked, if the Posital incl. could eventually be incorporated in the controller system
• Hannes checked details like data telegrams etc. and found some stepping stones (update timing, etc.), but finally judged it could possibly be done….
• A test inclinometer was purchased and sent to Hannes to experiment with
• Hannes adopted the firmware and also made hardware adoptions on the interface board (biasing) over Xmas 2013
• I copied the hardware corrections on my controller and tested the system on the bench…found some bugs ;-)
Beta testing results JFL/YMK
• The supply voltage of 5 volts for the Posital incl. was too low, especially with long runs of data cable
• The splitter board had to be modified for a 12 V/ 5V supply
• Up to 30 m CAT6 cable gave stable readings
• Long runs (50m needed at SA6BUN) of CAT7 cable caused the data output stages and the 7805 to oscillate intermittandly because of diverted ground potential between controller & splitter board, causing high current start-up situation with erroneous readings
A genuine OE5JFL drawing
Quote Hannes:
„…I made a
minor alterations
to the splitter
board…“
Essentially
splitting of VDD
in 5 V and 12 V
for encoders
Modified splitter board
Proven additional changes
on splitter board
• 2 x 100 nf from input/output of 7805 to ground
essential for preventing oscillations
• ‚Sharpening‘ of CLK pulses for MAB25 by pull-
down resistor 560 ohms to GND on splitter
board
• 100 µF on 12V Vdd of inclinometer
• Improving GND situation by connecting shielding
of CAT RJ45 and sockets; GND wire in 50 m
AWG26 has ca. 6 ohms line resistance
Weak points on CAT cabling
Mods on interface board
Few piggy-back resistors for
modified biasing of data input stages
Useful hints and kinks
• The Posital inclinometer can be obtained through a German distributor under:
aracke@hera-automatisierung.de
• Exact inclinometer type needed:
ACS-1-S102-VE2-PM
• Firmware V7.6 Inkl obtainable on Hannes‘ website
Burn-in test for inclinometer
during OH0-trip
• With a 1.8 m dish and moderate power on 6
and 3 cm a precise tracking, preferably
down to 0.1° is needed
• The new inclinometer enabled a „switch on
& forget“ tracking situation, once the system
was calibrated with moon noise on 3cm
• Absolutely no pumping observed, always
spot-on, using PWM-control
EME DXpedition 2014 to
OH0 – Aland Isles, photos
and a report from the site
EME Meeting 2015 in Örebro
Monika and Michael
aka: the M&M-team
Decision for the Aland Isles
• Due to other projets in 2014 we decided
very late to make another EME –CWonly-
DXpedition
• As we have enjoyed very much the 2009
EME-DXpedition to Aland Isles - on 70, 23,
13 and 9 cm -, our choice was again the
Aland Isles, but this time only on 6 and 3 cm
with the „small“ 1.8 m dish – so more
holidays and sightseeing, less „pressure“ to
make a lot of QSOs
Searching for QTH
• We had to search for a suitable QTH very short termed – so we made compromises regarding our aim “no trees around the holiday house“, because Aland is very forested – which was not the best situation for a suitable moon window
QTH on
the east
coast of
Lumpar-
land
Ferry from
Sweden
After arrival in the night..
• The house was very romantic with a fantastic view over the sea – but completly „packed“ in trees
• 2nd problem: the surronding was uneven, so no real good place for a dish
Dish position
• We decided to build up the dish in a rock scree, which took us hours for equalizing the uneven ground with the help of stones – but in the end it worked……
„Shack“ I
• The house was
very small with
only one bigger
table for dining
– so the
equipment was
placed on a
couch table
standing on an
additional bed
„Shack“ II
• The morse key was UNDER the table – note: pretty inventive in the absence of enough space ON the table….
• No place for the 2nd OP, but this time it was not necessary because of the MEMS inclinometer – the tracking worked automatically
Moon windows I
• This time
my duty
was to
estimate,
„when do
we have a
moon-
window??“
• The moon
declination
was pretty
low…
First moon
window to JA
2nd and
much longer
moon
window to
Europe
Moon windows II
• A 3rd moon window to US, but this was not enough to work K2YUH – he needed higher moon elevation -but we managed to work W5LUA (who is more to the West….)
Moon windows
• So these were our primitive calculations according the experiences in the first days to estimate, „when we do have a moon window?“ between the trees and to announce it in time;
• in the last days this was only at nighttime, so we sleept a few hours in between, hi
Installation of Inclinometer
• Duck tape fixes
almost everything…
• Inclinometer attached
to the counterpoise
arm by screws…not
everything is that
much provisional as it
looks at first sight
Set Up on 6cm
• It was the first time,
that we tried to work
6 cm with the „small“
dish
• We used - in parts -
the equipment from
the big dish - with a
few improvements -,
but we had no time to
test it at home
• So we ran full risk, as
usual 6 cm PA 10 GHz Transverter/PA
Feed on 6 cm
• The feed is the old
round septum feed
by WD5AGO
• Isolation is @ 27 dB
• Return loss around
24/25 dB TX/RX-
ports
• The 1st LNA behind
the feed is put in a
waste bin foil to
protect it against the
usual rain
Improvements on 6 cm
• Compared to Jersey and Corsica the CS/G was widely improved by:
• A 2nd LNA with 0.7 dB NF in transverter (the first LNA has 0.5 dB) and
• A fingerfilter between both LNAs
• ½“ Cellflex cable from LNA to transverter
6 cm set up
• The PA for 6 cm was built
in a plastic box to put it
just behind the dish (6NT
make 115 W out)
• We were able to hear our
own echoes at every time
with 100 W in feed
• It was somewhat
surprising, as all forecast
programs said, this would
NOT be possible…
Improvised Waterproofing…
• SM-powersupply for 3
cm trvtr and 6cm
GaAS-PA close to
dish
• 13.8 V at 60 A
• Please note:
accessory….found on
any M&M DXpedition
dish pictures
Feed on 10 GHz
• Linear vertically pol. round wg feed (LX1DB)
• Attached to wg switch
• NF-selected WG-LNA by 6NT
• Selected flexible WR90 wg runs, 2 x 75 cm, -0.45 dB on 44 W out from trvtr
• 100 cm Sucoflex 104 between wg LNA and 2nd coaxial LNA in trvter behind dish
• CS/G 5.8 dB
• Very little obscuring of dish!!!
10 Ghz set up
• Even more minimalist
compared to 6 cm
• Why than make templated
contacts rather than real
QSO‘s in CW ???
• SDR-IQ is a great help to
find signals a bit off-
frequency
• Little need to spend
valuable moon window,
discussing about mutual
Doppler….I WILL see you
10.450 GHz for JA-friends
• Toshi, JA4BLC, was
very interested to
work OH0 on 3 cm
• Donated one of his
10450/10368 MHz
converters
Results on 6 and 3 cm
• 3 cm: LX1DB OK1KIR PA7JB PA0BAT OZ1LPR (1.8 m/44W) G3WDG JA4BLC OK1CA F1PYR JA1WQF JA6CZD DL7YC SM6CKU SP6JLW
• 6 cm: OK1KIR OK1CA G3WDG PA0BAT SM6CKU ES5PC UA3PTW W5LUA JA6CZD JA4BLC DL7YC G3LTF PA7JB LX1DB OH2DG SM6FHZ JA1WQF
In total 14 initials on 3cm and
17 initials on 6 cm, many of
them country – and continent
- firsts from OH0 on both
bands.
JA from OH0
• Our JA friends were
very enthusiatic
about their success
and published a
few weeks later 2
pages in their „CQ
Ham Radio“ about
our OH0-
DXpedition
Conclusions
• QTH was far from ideal
• Nevertheless, it was possible to give several stations OH0 as initial and country first (if the stations were quick enough…)
• We had more fun than in the last years, because it was a very relaxed EME-DXpedition with a lot of sightseeing, which we‘ll perhaps repeat to other countries (so only with the small dish) ???
• During breakfast time we brought OH0 on 2m MS (750W / 0.5 dB NF / 9 ele 6WU) on the air, surprisingly for a few hams, who wondered in the KST- chat, who the hell OH0/SA6BUN was….
2 m MS
• It was a very simple set up with the help of a parasol stand, which we relocated just a bit…
• In one of the stormy nights (the dish did not move a cm) the antenna broke down on the roof, but we repaired it as usual (with duck tape )
Happy in the end….
Thank you
very much
for your
attention,
CU off the
moon
some
time…
de M&M