DG7YBN / 432 MHz EME Station
  Last Update Jan. 1st 2018




.......


On this website I give a little overview on my 432 MHZ EME efforts. The setting is ... I do not intend to take a
serious amount of cash and buy me a super station but rather see how to get along with sensibly chosen componets
and a fine line up of either self made or second hand equipment that needs a hand. Which is probably close to self
building then. Because one at least has to understand what is to be repaired. Neither do I have endless antenna
space nor time for my amateur radio hobby.

Current array: Single GTV 70-19m, 17.8 dBi Low Noise Yagi

EME? ... is sending a radio signal from earth to the moon, using it as a reflector, so that another station can
receive than signal down on earth. Earth -> Moon -> Earth = EME. Hence the enourmous distance of 2 x 384,400 km
the signal has to travel there is a path loss of 250 dB roughly and a time delay of 2 seconds.


Image: © Dr. Tanja Kurzenknabe





Station



• Antenna: 1 x GTV 70-19m
• CCTV camera for manual moon tracking, see tube in H-frame
• Coax Relay: Relcomm RDL SR012
• LNA: TGN Technology Prototype of 2018 "True Low Noise" series 2 Stage, 0.34 dB NF at 32 dB of gain
• Coax for TXing: 22 m of 5/8 inch Flexwell, DIN 7/16 connectors plus jumper cables
• PA: GS35b in DJ3FI coaxial cavity
• TRX: Kenwood TS-811e

NC1I received on 2017-01-01 with best -8 dB with this setup





Easy QSO with my single 4.2 m boom Yagi and modest output power








Old Array 4 x 20 ele. DL6WU by Konni Antennen, modified balun

This is a 4 x 20 ele. DL6WU design sold as 'F20' by Co. Konni-Antennen, electrical length just under 6 wl. (4.1 m) with
modified Balun and D1 by DG7YBN. With the experience gained in recent years I removed the poor PCB and low quality
coax balun and replaced that by a balun made from RG142 PTFE with direct connections. Looking up this DL6WU design
in the 432 MHz VE7BQH G/T table click we find it not being bad at all.
What is sensitive is the way the dipole box and balun was produced by Konni-Antennnen in the early 80ths.

See the old and new balun

 

A length of 2.00 m of RG213mil with even 30 years old N-connectors leades from each DE to a 1/4 wave splitter made from
brass + copper (UKW-Berichte? / looks like the ones sold by WiMo). Patch coax from splitter to coax relay is approx. 1.3 m
of H100. To overcome the stiffness problem of the H100 I arranged a wide bow around the elev. axis of the rotor.


TRX



I am using an ordinary Yeasu FT-736R. No extras fitted, no modification done.
Frequency stability is alright as long as I start it up about 15 minutes before I want do start operation.
The RX is quite deaf on 70 cm, I am thinking about building a second stage high IP Preamp and bandpass filter
to follow the mast mounted LNA.


Coax Relay and LNA



The mast switch box holds a RelComm RDL SR012 (insertion loss .02 dB / port isolation > 90 dB @ 432 MHz) and a
directly connected tgn-technology ULNA 3013 EME that came with a measurement protocol stating an NF of .28 dB.
For details on that switchbox click here.

From here to shack I use separate RX and TX coaxes. RX is approx 28 m of RG213, TX is 24 m
of 5/8 Flexwell with 7/16 connectors patched with a 0.5 m of RG213 from its 7/16 to N and to get it into the switch
box properly. A larger switch box with 3 x 7/16 coax relay suitable for direct connection and splitter with 7/16
bushing is planned. An Andrews Heliax 5/8 patch coax is waiting already


Elevation & Moon Tracking



Rotor is a common Yaesu G-5500 combination. Moon tracking is by hand. I have a 2.4 GHz link camera installed in
a plastic drain tube with cross lines made from flower binding wire. That gives me an additional noise floor when
on of 1 dB approx. and works find with the HPBW (12 degr. approx.) of that bay with one well known big disadvantage:
Even though IR sensitive moon is 'gone' when behind heavy clouds ... , not to mention daylight .. hi ..


Power Amplifier



This is a GS35b PA cavity design (produce of DJ3FI). Due to the high Q of that anode cavity its 'low power'
amplification gain is in excess of 13.5 dB so that the driving power of my FT736R lets me almost explore legal limit
power here ( > 600 W). Which is way enough for the N-connectors up on the pole.

An LDMOS driver might follow when a bigger switch box is mounted with an all 7/16 connectors coax relay.

Coax Feedlines 7/16 Connectors



TX; 5/8 in Flexwell and 1/2 in Andrews patch coax with 7/16 connectors in shack
(connectors gifted by Oliver, DL2ARD of DL0GTH es Helmut, DG9YIH of DF0MU tnx!)






Sun Noise




With the EME Calc by Dough, VK3UM my RX-System as described above should give a sun noise of 10.5 dB @ sfi = 146✶.
I measure 9..10 dB in my quite noisy location.

(✶) sfi is a measure for solar flux (density) at 10.7 cm or 2.8 GHz. This number is of limited use for quantifying
the actual flux on 432 or 144 MHz. In smart programs like the VK3UM EME Calculator solar flux numbers for a span of frequencies
are gathered and lined up with an algorithm to derive relatively good calculated numbers for the amateur bands.

In my article: Notes on VHF/UHF Antenna G/T, Dubus 2/2012 & Dubus Technik XII
I show that in explicite way with sfi vs. frequency charts added.

From common sfi as F10.7 for 3.4 GHz to sfi F70cm?

Open the VK3UM EME Calc and press the "Get IPS Data" button

now press "Current IPS Flux Data"

and read out for 144 or 432 MHz.

In the sample we find an sfi, F10.7 = 68 and an sfi, F70 cm = 31.
That sfi = 31 now is the correct number for our 432 MHz with respect to all derivations by time delay
between you measurment and the last measurments by the IPS and the interpolation in the EME Calc program.






RX wise



First 'SWL' activies with old array of 4 x 20 ele. DL6WU by Konni Antennen with overhauled balun and dipole box

.. even with crude soundcard in/output rates ...

• 2014-04-12: Received NC1I as special call W1AW/1 (48 rear mounted 15 ele. Yagis + QRO) with up to -6 dB and very clear speaker copy
  Link to .wav sound page click , mind that this NOT through a narrow CW filter but full SSB 2.7 kHz audio
  Here is a link to OK1TEH's 432 MHz EME Stations gallery click



• 2014-04-12: Received HB9Q (15.3 m dish + 2kW PA) with -12 .. -10 dB in bad moon position with beam scratching house roof
  Here is a link to OK1TEH's 432 MHz EME Stations gallery click



• 2014-11-07: Received OK1DFC, Zdenek (10 m dish + 1.5kW PA) with -14 .. -11 dB



• ARRL EME Contest, Nov. 8/9th 2014: Received quick QSO between HB9Q (10 m dish + 1.5kW PA) and UA3PTW (20 x 15 ele. mod. DJ9BV)



• ARRL EME Contest, Nov. 8/9th 2014: Received DL7APV CQing (16 x 13wl DJ9BV) with up to -7 dB



• ARRL EME Contest, Nov. 8/9th 2014: Received SM2A CQing (4 x 32 ele. - 13wl)



• ARRL EME Contest, Nov. 8/9th 2014: and a little pile up calling JE1TNL - UT5DL (8 x 7.7 wl DJ9BV, 600 W ?)










73, Hartmut, DG7YBN



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