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My G5RV Special

After a couple of years I completely rebuilt my HF antenna. Based on the same principle of the old one, the new antenna is a dual polarization model. It’s a G5RV wich is possible to “drive” also in vertical polarization. It works from 6 to 160 meters band and the vertical polarization is recommended on the lower band of 160m.

To get more info try to see the next video where I present my antenna (english subtitles):

 

SSTV contatcs via Es’Hail 2 / QO100 satellite

I finally managed to be active again on the QO 100 satellite. After some tests and SSB QSO’s I tried RTTY and than also some SSTV transmission.

Considering that currently my signal at the transponder input is not very strong, I never thought I would be able to make 2way QSOs even in SSTV!

Below are some nice images exchanged with Greg SQ6ILB from Poland. Stability and synchronism are excellent both in reception and transmission.

 SQ1ILB SSTV QSO WhatsApp Image 2020-08-31 at 17.48.01(2)  WhatsApp Image 2020-08-31 at 17.48.01
2.4 GHz Uplink converter


This is the box with the converter 430/2400 Mhz disciplined by external GPSDO and the booster before the final destination on the roof.

Baofeng UV-5R plus – Defective antenna

I don’t use this cheap handheld often, on the contrary, I rarely use it.
Anyway, I prepared it for the holiday trip, to hear some local Hams and have FM chat.
Once I got there I turned on the small radio and with great surprise I could not hook up any repeater, even the FM broadcast band was quiet or with very low signals. Then, moving the antenna, I realized that this had something wrong.
So I spent the holidays between the pool and the sea leaving the radio in a drawer.
Once at home I dismantled the antenna and with (little) surprise I found that the isolation capacitor had a broken lead.

Considering the low price of the radio this was not a surprise.

To open the antenna just remove the ring nut around the connector and with a small screwdriver widen the rubber that encloses the antenna. Slowly unscrew the connector counterclockwise until the antenna comes out completely. A piece of heat shrink tubing is placed around the capacitor to avoid short circuits.

ant1

 

So quickly I replaced the 3 pF capacitor with a new one.

Before putting the cap back on, I did tests that confirmed that the antenna was working perfectly!

ant2

It is not a big problem to solve but perhaps it could often happen if the antenna were to hit or bend due to a sudden movement.

Useful support for cheap sdr receivers

Since we had the possibility to use the cheap RTL-SDR receivers for amateur radio purposes, I encountered some problem on how was possible to place them in my radio station. Usually fix them directly in the PC USB socket is not an easy way, often the PC is far from the antenna cable inlet and we need to use other long pig-tails to connect the receiver to the antenna.  Also the use of longer USB cable so to put the receiver somewhere on the radio desk is not a convenient way, sometime this cable doesn’t support the fast USB transmission not allowing the passage of data. But the biggest problem is precisely where to “lay” the receiver, it is light and small but for this reason it is difficult to manage with its two cables. I solved all this using a simple USB 3.0 female data extention. I got it as a partner company gadget but you can find them on the Internet at various prices. It is very solid, heavy and has non-slip feet. Here follow a couple of photos.

SDR RTL support The USB 3.0 cabling

APA 1/2 ora di scienza intervista l’Ing. Jader Monari sullo SKA in Australia

WhatsApp Image 2020-05-01 at 20.42.53

QO-100 SSTV receptions

20200212_1910_DL9DAC Frank JO31QI

20200212_2013_DL3RTL BERLIN JO62QL

20200214_1446_DL8II Juergen

20200309_1908_Alain F6IKY QTH JN26OP

KGSTV

20200309_1914_Alain F6IKY QTH JN26OP

20200212_1919_DL9DAC Frank JO31QI 20200212_1938_db8tf

20200212_1927_db8tf

CLASSIC SSTV MMST software

Hist31 Hist29 Hist28 Hist27
Hist26 Hist25 Hist24 Hist23
Hist22 Hist21 Hist19 Hist18
Hist17 Hist16 Hist15 Hist4
Hist14 Hist13 Hist12 Hist3
Hist11 Hist10 Hist9 Hist6
Hist5

QO-100 Satellite: receiving with the condo dish! (Hotbird 13E)

In the first period of my test with QO-100 Satellite, I tried to receive it with a 80 cm dish using a PLL LNB. To “discipline” and get a stable signal I used the SDR Console software option for this satellite. It works very fine and I didn’t need any other correction to get good and stable signals, also for SSTV. After purchasing the converter from DX Patrol I begun to test transmission, first with an homemade 20 turns helix, then with a D-Link 14db panel.

I was only capable to do CW QSO, my signal was very weak also with 8 Watt amplifier. So I decided to use the 80 cm dish to transmit and try something new with an existing dish on the roof: it was the 100 cm condo dish for satellite digital channels.

I didn’t know what the distance of the second LNB should be, after some internet research I prepared an aluminum corner bracket with a long slot that allowed me a wide range of movement.

IMG_20200221_115504

The aluminium bracket with the two LNBs

 

IMG_20200221_115426

The front of the 100cm dish

Once the bracket was installed I turned on my receiver which I controlled via smartphone and Team Viewer .

With small steps I moved the LNB along the bracket looking for the point where the beacon signal was highest.

After few minute, and about 18 cm far from main LNB, I found the peak. Some other adjustment for the best signal, now I receive the begin beacon at about -60 dbm with a noise floor of about -95 dbm.

It’s not bad at all!

Now I can use the 80 cm dish for the uplink, I made some QSOs with significantly higher received signals in CW and with very clear and strong audio in SSB.

Other tests will follow.

IMG_20200221_115404

IMG_20200218_104639

The 80 cm dish for the uplink

 

Sat

3rd of September strong thunderstorm

In the afternoon of the 3rd of September, a strong storm broke down in central Italy with very violent electrical events. Tens of thousands of lightning strikes the peninsular skies while our meteor scatter station at the APA Latina observatory was active. At that time the GRAVES transmitter was not in operation (perhaps due to maintenance) and, although the frequency does not lend itself to good lightning reception, thousands of very strong electrical discharges have been captured by the system. Here a short video of that moment related to the captured lightning.

fulmini

Interactive ISS 3D simulation pass over Italy on August 7th 2019

Images taken from Heavens Above

2019_08_07_19_33_44_Visualizzazione_ISS_interattiva_3D 2019_08_07_19_34_15_Visualizzazione_ISS_interattiva_3D 2019_08_07_19_35_25_Visualizzazione_ISS_interattiva_3D 2019_08_07_19_35_53_Visualizzazione_ISS_interattiva_3D 2019_08_07_19_36_30_Window 2019_08_07_19_37_42_Visualizzazione_ISS_interattiva_3D 2019_08_07_19_38_26_Window

 

Meteor scatter radio system is operational again

Meteor scatter radio system is operational again.
Radio receiver was changed, now We are using an RSP1A SDR receiver (https://www.sdrplay.com/rsp1a/).
Also the 30 db preamplifier has been removed, we are testing if the internal LNA of the SDR is good enough for our purposes.