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