Author Archives: mario

Marconi Memorial Contest 2013

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We did not have enough operators for a DM7A operation from uphill. I did not want to skip the contest completely and therefore i did the Marconi Memorial 2013 for 6 hours on sunday from Triebenberg JO61XA. The setup was somewhat unsual. I used a portabel setup consisting of my FT-857D and a HL-200V/50 and a 11ele Tonna. I had to power the station from my 1kW gererator.
Before i was a bit sceptical about the capabilities of the setup because the FT-857D is definitively not made for VHF contest operation. But since i have a narrow CW filter and the station densitiy was quite low i was lucky and faced absolutely no overdrive of the RX and almost no QRM by closeby stations.
In the end i had a total of 120QSO with about 36500 points.

One of the first qso was the ODX with IK5ZWU/6 who had a surprisingly strong signal for about 830km distance. MNI TNX Walter !

Paddle, keyer interface, FT857, audio recorder, HL-200, rotator control

Paddle, keyer interface, FT857, audio recorder, HL-200, rotator control

KBS from Sofia in DRM/AM Simulcast

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The korean national service KBS is currently testing DRM-AM simulcast. This means the same service is transmitted side by side on co channels. One channel contains the service broadcasted in DRM mode, the next channel contains the same service via AM. This gives the opportunity for some nice comparisons between DRM and AM stability and audio quality. Find two audio snippeds below.
The transmissions will be every evening from 19UTC to 20UTC on 5875kHz (DRM) and 5885kHz (AM) – source www.drm.org

The screenshot shows a part of the radio band yesterday evening. Unfortunately the conditions to Sofia had been really poor. You can see the both signals of KBS and some much stronger signals from other broadcasters.
Obviously the DRM signal was suffering from sideband lobes falling into the DRM spectrum limiting the SNR because at the end when the modulation was already switched off the DRM SNR increased rapidly.

KBS_DRM_Simulcast_test

Voice audio snipped – first DRM, then switching to AM

Music audio snipped – first DRM, then switching to AM

The DRM audio was transmitted in AAC+ Mono with 18kBit/s. It gives a rather nice sound compared to other DRM broadcasts that can be received at the moment.

DUR activity 2013 October

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After 2 month of inactivity from my side another trial with 3 bands. I had 23/13/9cm with my 1.5m dish.
Meanwhile i integrated the 5W PA for 9cm. This time Murphy tried to do its very best.
I had to tear down the antenna 3 times in between. First i had troubles to find the correct lengths of the ropes for the mast.
When testing the transverters i experienced 9cm was not switching to TX. During my mast trouble i accidently disconnected the 9cm power cable at the mast unit.
After that operation was going relatively smooth. This time i was heard very well by the others on 9cm. But i experienced that my RX seems to be really poor. I always gave much better reports than i got. I did not check the sensitivity so far. Everything you dont check will not work ;)
In the end i had 17 QSO on 23cm, 9 QSO on 13cm, 5 QSO on 9cm.
ODX on 23cm was HA5UA/p. Thanks for the patience during that weak signal QSO.
Next steps with improving my setup will be a new rotator control. The original KR600 controler has some issues and i somethimes do not get correct heading. 23cm would need to be mounted to the mast. Unfortunately i dont think that i can get the mast up then. It would be too heavy.

setup during october 2013 DUR activity in JO61XA

setup during october 2013 DUR activity in JO61XA

Back with new URL…

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The blog was off for some days because of vacation. After returning i noticed that dyndns completely discontinued the free service even for old accounts and since i did not want to pay 25$ to go back to ath.cx i decided to move to no-ip. Now the new URL will stay dh5ym.hopto.org as long as possible.

July DUR Contest

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This morning i tried my dish as 3-band station from jo61xa. Low participation and strange conditions. No chance with ok2uyz and ha8mv but a nice qso to om. This time new was 9cm but not yet with pa. Therefore only 1 qso with DL4DTU.
Now sitting in the sun with ice and coffee ;)
image

image

DUR Contest May & WebSDR

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This time DUR contest together with Steffen DJ5AM.
QRV on 23cm, 13cm, 10GHz, partly 24GHz.
Not very much DX on 23cm this time but some nice 10GHz QSO with the station of Steffen.
I made a short video receiving my 23cm signal with the WebSDR located at my home QTH.

DUR Contest May 2013 - receiving myself on my 23cm websdr
Watch this video on YouTube.

The WebSDR is a test and receives 23cm & as well as 10GHz using 2x RTLSDR USB sticks.
PA3FWM kindly added support for these types of USB receiver sticks which makes it very easy to setup WebSDR receivers for the bands between 24MHz and 1700MHz. One is connected to a crystal stabilized sat LNB which makes the receiver for the narrow band section of the 10GHz ham band.

As long as the receiver is online you can find it here:
http://dh5ym.hopto.org:8901

The following pictures show my 23/13cm equipment after then end of the DUR test ready to go home and the 10GHz and 24GHz station of Steffen, DJ5AM.

DCIM100MEDIA

DCIM100MEDIA