Wednesday, August 27, 2014

Vacations in Rhodes, Greece

It was about time. After almost 4 months of non-stop working and trying to understand the huge amount of source code written in C and assembly i decided to go for 6 days and visit my friends in Rhodes. Rhodes is an island located in the eastern Aegean Sea in Greece,. It is a quite big island in terms of land area and population, with a population of 110000 permanent residents. In the summer the population explodes due to tourism. In mid of August at the highest peak of the season it is expected that around 30000 people are going to use the airport.

Back to our topic: vacations. One of the things i like more in Rhodes is the dark skies. At least if you are living outside of the city center the night skies are quite dark for the observation: light pollution is class 4 or 5. After the sunset the temperature comes down and allows relaxing observation of night sky.
Looking at the stars during summer with my telescope (Astromaster 70AZ). In the island of Rhodes.
Looking at the stars during summer with my telescope (Astromaster 70AZ).
The second thing i like most is the beaches. In many cases, just outside from the city, in less than 15' travel time, you can find beautiful beaches without a lot of noise and people. On the downside, you have to take everything with you from home or hotel. There is nothing around. One of these beaches is Afantou beach.
One random picture from the beaches of Rhodes.
One random picture from the beaches of Rhodes.

Time to sign out...

Saturday, August 9, 2014

Celestron travelscope 70 + T2 mount + Nikon D3200

The T2 mount is finally here. I was able to use it with my Celestron Travel Scope. The T2 mount took almost 40 to receive it from China. I replaced the eyepiece and removed the mirror prism, and suddenly I had a lens 400mm. Of course, the quality is much worse than the actual lenses, and I will need a lot of post-processing, but the price I paid it was less than 100 euro.
Nikon D3200 attached to the Celestron travelscope 70 using a T2 Mount.
Nikon D3200 attached to the Celestron travel scope 70 using a T2 Mount.

Here is my first impression: I need a good tripod. Even the light wind I had on 4th floor makes the images blurred. The tripod I way too cheap for this work, and the exposure more than 5 seconds does not forgive. Anyway I also did some daylight tests, here are my results:

View from my camera with 55mm.
View using the travel scope.
Here is one plane, note that I had to increase the ISO due to darkness.
My next target was the second most bright object in the sky: the moon. Again the quality was not the best, and I think it is because of the bad tripod. Here is the picture:
Shoot of the moon using the travel scope 70 and the Nikon dSLR.
The shoot of the moon using the travel scope 70 and the Nikon dSLR.

Overall I will say that is a good opportunity to take nice pictures during the day and night. However, you will have to buy a good tripod to be able to have long exposures. Moreover, the quality of the glass is not the best: there is fringe distortion. Again it is an ultra cheap solution that provides acceptable performance. Getting some star photos is my next goal.

Thursday, August 7, 2014

Applications using RTL-SDR: a revisit after two years

Two years have been passed from my last serious exploration using a cheap RTL TV receiver. I still remember my self trying to found a connector from the Canadian antenna to European type connector. I couldn't find my  Lifeview LV5T Deluxe usb that i bought last time, so i bought a new one, this time a HAMA DVB-T based on the FC0013. The reception is similar with my old lifeview stick, however a noticed worse performance when going over 800 MHz. The time has come again to see if something changed in the field of applications that support the RTL receivers.

Last weeks i have used four different applications, so here is my opinion and some screenshots:

1. SDR# (SDRSharp)

One of my favorites when i 'm using windows. The newest version has been improved considerably from the last time i used it. The application was open source, but unfortunately the programmer switched to closed source, but it is still free to download.



2. HDSDR 

This was the first SDR application i have ever used. I remember two years ago the performance of the application was really bad. In the next release things got better, but still it was far away from SDR#. My experience even trying simple FM radio channels is still bad. Limited options about the bandwidth.



3. SDR-RADIO.COM V2

I tried this application from curiosity. It suppose to be the most complex from all others.  The problem is not in the complexity of the application, but in the bad GUI design, compared with the other applications. It is not bad choice, but the interface need improvement.




4. GQRX

This is totally open source. It is fast, but looks simpler compared with the other applications. I would expect smoother controls from what is now. It is a pain in the back if you want to compile it in old version of the Ubuntu, due to dependencies in the GNU radio.


Overall i will choose SDR#. It has the best interface and it is one of the fastest available. SDR-RADIO V2 is not bad, but needs some work on the GUI. Avoid using HDSDR, it is still limited when using RTL based chips, although the author has improved the performance. GQRX is simple and fast in Linux and it is available in the repositories if you are using Ubuntu 14.04 LTS.

Sunday, August 3, 2014

A trip to kaloi limenes (south of Crete)

Recently i visited south of Crete to take a taste of the beautiful beaches. The waters on the area were the clearest i have seen in Crete. The trip going from Heraklion to kaloi limenes takes around 1 hour and half. It i will be better to start early and take as much water you can. The sun is really strong on the summer and then temperature is probably higher than anything you have felt.

Map with the trip from Heraklion to kaloi limenes (good ports)
Here is the route we used. Unfortunately the route is not easy especially in the last part.

Here are some photos from the trip:

View of inner Crete.
View of inner Crete.
Here is the top view of the beach. Note the oil storage and terminal facility, located on the small island of Aghios Pavlos ("Saint Paul") at the port's entrance. Despite the industrial appearance the beach i exceptionally clean.

View of the beach of kaloi limenes south of Crete. Note the oil storage.
View of the beach. Note the oil storage.

View of the beach south of the Crete, kaloi limenes in Greece.
View of the Beach. Few people only and mostly locals.

View from the road of the beach kaloi limenes south of Crete, Greece. The area is perfect for organized and non-organized camping.
View from the road. The area is perfect for organized and non-organized camping.

Sunset on the way back to Heraklion. Another 1,5 hours  driving back!
Sunset on the way back to Heraklion. Another 1,5 hours  driving back!