Receiver and references about radio astronomy

http://www.stargazing.net/david/radio/receivers.html

My first APRS Packet on ISS

Today I've sent and repeated my first APRS Packet through the International Space Station ISS.

The aprs path was ARISS.
Equipment:

TH-D7  many years old
Wimo sota Log Periodic Antenna
Power about 3 watt


During the pass I've "READ" a lot of other stations from all over Europe.
Being from Suedtirol, Dolomity Mountains, my message was Italy Dolomiti.

So the belove screenshot is like a qsl for me.
You can seen on the balloon that i was repeated by RS0ISS :

 This the raw string

2015-07-12 08:34:33 CEST: IN3AQK-7>TV3U01,RS0ISS*,qAR,LA3QMA-SG:`'(<0x1f>l <0x1c>./>ITALY DOLOMITI

www.aprs.fi

http://www.ariss.net/

 

 

 

 

 

IN3AQK-246 antenna 144 Mhz, 70Mhz, 50Mhz multifunction sota - Field Radio Dipole

On my mountain activations I normally need a lightweight hamradio equipment.
The problem is that I'm not an athlete and doing a climb of 800 to 1000 meters, in Dolomiti mountains, above 2000 meters is not simple if you are not fit.

I do both HF and VHF activations but I prefer to use the altitude to try VHF and above qso.

I need a simple and re-configurable antenna able to work on 2 meters, 4 meters and 6 meters with a minimum effort, an antenna that could be used in vertical, horizontal polarization, in linear or inverted V configuration.

As you know the dipole a nearly no gain but it's surely better than the standard whip of a yaesu 817

I decided to built a strange dipole based on two 1,4 meters telescopic whips.
The dipole could be used atop a fiberglass rod.

The name is IN3AQK-246  ... the numbers are the bands :-)

Some photos are better than 1000 words

IN3AQK-246 antenna

Antenna parameters at 50.100

Front view, the ferrite beads are used as a RF cocke

Really simple!!

SWR diagram in 2 meters band

144 Mhz configuration

Two new test instruments in my shack

Two new test instruments are now ready on my shack:

I've built them from a kit of components.

• IZ1PMX VNA vector network analyzer  from 2 Mhz to 180Mhz
• Multifunction tester, very cheap.

IZ1PMX  Vna

Is a Vector Network Analyzer, based on a projetc of Alfredo IZ1PMX

It's based on a Atmel Processor ATmega  and a AD9951 DDS.

The instrument has a frequency range from 2Mhz to 180Mhz but test has been done to 250 Mhz.

It's a really cheap kit, has a good price to performace ratio

The reference site is:

http://www.qrpitalia.it/

Here you could find also a QRP HF transceiver

IZ1PMX VNA 2-180 mhz

Multifunction Tester

I needed an Electrolytic ESR meter so searching on internet ad blogs I found this little an very very cheap instrument base on an Atmel atMega processor.

The funny is that this instrument reads completely automatically also:

• Capacity
• Inductance
• Resistance
• Electrolytic ESR

Detect and give information's about:

• Diodes
• Transistors
• Fet 
• Mosfet
• Tirystors

It's a really useful instrument especially when a component has to be tested or it's of unknown type.

The gear is electrically simple, all the operations are done by the microcontroller and the software.

It can be found on some online cinese shops.

Multifunction tester

A tribute to UO-11

In just six months time engineers at the University of Surrey developed, built and launched on 01-03-1984 UoSAT-2 as a piggyback payload aboard a U.S. Thor-Delta rocket carrying the LANDSAT-D earth observation satellite from Vandenberg Air Force base in the orbit.

With 70 kg was UoSAT-2, the first satellite with advanced digital “store-and-forward (email)”


UO-11 is not operative but sometimes, when it's on sunlight it begin to transmit the telemetry on 145.826 Mhz.


Here it's possible to see the update status of this satellite along many others:


Oscar satellite status


This is a audio recording that I've personally made of the UO-11 telemetry sound:


UO-11 sound on soundcloud

The Fredbox

I really like this post and the idea to build a Fredbox in the future:

http://www.vk2zay.net/article/123

So this post only a memo on the site that speak about it.

ISS SSTV transmissions

I've get it...yess

QIKcom-1 APRS Satellite

 A fresh info from Bob, WB4aPR




APRS Satellite operators:

http://aprs.org/qikcom-1.html


We are delivering our next APRS satellite (QIKcom-1) next week and it will
have a mission life of maybe 6 months.



It is a very quick reaction short fuse opportunity so we are simply going
to fly an APRS digipeater (TinyTrack4) supporting the three digipeater
aliases of ARISS, APRSAT and WIDEn-N but it will operate at 4 Watts RF
power and be easily heard on any HT..



It has no other CPU on board and so it flies with only the fixed settings
set before launch.



But we do have an A/B switch which can be used to switch between two bank
settings.

I just cannot think of any neat must-do ideas for how to use the other bank
settings.



The host spacecraft has plenty of power, so there is no need for low power
options… (they can simply turn us off if needed).  Telemetry is a boring
Volts, current, and two internal temps.  The settings in bank 0 are now:



DIGIPEATER:  ON

ALIASES:          ARISS, APRSAT, WIDEn-N

BTEXT:              USNA-W3ADO APRS Satellite every 2 minutes

TELEMETRY:   every 1 minute.



I just cannot think of any use for a separate bank settings?



If you have ideas of how to use the A/B settings let me know.



Bob, WB4aPR

Mobilinkd TNC2 on Ubuntu Linux

First step let Ubuntu to see the modem

My bluetooth usb adapter is an old emtec one, Ubuntu 14.04 does recognize it immediately after plug-in in the usb port.

Then I've switched on Mobilinkd TNC2, the blue led started to flash.

The first problem is that the enclosed Ubuntu bluetooth manager does not works with a Bluetooth serial module of the Mobilinkd TNC.

As I try to configure it with the bluetooth manager it request to set a random password on the modem that is not possible.

So install the blueman bluetooth manager:

sudo apt-get install blueman.

Now start blueman and magically it's possible to pair the Mobilinkd TNC and see it as a rf serial /def/rfcomm0

Try to see if the modem is accessible from the serial port with a terminal, like moserial.

The serial port speed should be 115200.

For example in moserial I saw:

== BeRTOS AVR/Mobilinkd TNC2
== Version 2.0.1.571
== Voltage: 4026mV
== Starting.

Second step AX.25 settings

First install the necessary AX.25 packages:


# sudo apt-get install ax25-tools# sudo apt-get install ax25-apps

Then, configure your AX.25 ports to allow you to access the TNC.

sudo vi  /etc/ax25/axports:

# /etc/ax25/axports

#

# The format of this file is:

#

# name callsign speed paclen window description

#

packet0     IN3AQK-9         115200  255    2      144.900 MHz (1200 bps) Packet

Pay attention no empty lines are allowed!

Then connect the AX.25 packet0 port to the tnc with the command:

sudo kissattach /dev/rfcomm0 packet0 10.0.1.1

The result is:

AX.25 port packet0 bound to device ax0

With ifconfig you could see a new ax25 port with the ip 10.0.1.1

Then it's time to call for example:

axcall packet0  IR3DG


Now its, possible to point Xastir to the just created port packet0

To be continued

APRS on QRP Portable

In addition to having a strong passion in QRP activity, especially in portable, have always been passionate about economic digital technology, Such as packet radio, APRS and TNC, NO D-Star, NO DMR.

In the 90s my packet radio station  and packet radio satellite gears has been continuously on for years, it was my internet at zero cost.

During my QRP HF portable activities, I had the necessity to have a wireless data communication system, not based on cellular technology.
Also because often where I go there is no cellular coverage while the packet-aprs system works.

In addition as software developer work I have developed wireless tracking systems, very similar to APRS.

I have used for some time the tinitrack4, both as aprs and kiss modem.
It works fine, but had some problems, such as:

Too sensibile to the RF emitted by the transmitter
Too many connectors
External power supply.
Casino to connect to Android.

Last Monday I stumbled on this project:

http://www.mobilinkd.com/

http://store.mobilinkd.com/

Bought immediately and arrived yesterday with DHL.


It is a packet radio kiss modem.
In practice it means that it is a stupid modem, not a real or TNC APRS one.
 
Therefore it requires an external system such as Android.

The modem is very small, it attaches directly behind RTX handheld with a rubber band.

It has an internal lithium battery that allows 48 hours of work.

Beautiful thing is that the serial port is bluetooth and then zero cables except the one with the RTX.

The system do NOT works with iOS systems, because they do not have support of Serial over Bluetooth.

It interfaces seamlessly with APRSDroid and BTTerm for Android, but it also goes with APRS clients and  Terminals for Windows and Linux.

The configuration is done in 5 minutes with a simple program for Android or Windows.

This system can be seen on www.aprs.fi, I can indicate on which frequency are QRV on HF during my activations.

Can I send sota spots , read the cluster and even send an email.


The modem is the little box behind the wouxung

APRS data on my tablet over bluetooth 

Sota Omini di Pietra 2000 metri I/AA-307

Oggi ho fatto una bella attivazione Sota alla cima Omini di Pietra 2000 metri I/AA-307

Aggiornamento, pare che ora la cima non sia più valida come referenza Sota

50 collegamenti circa in 20 Metri, quando mi hanno spottato su sota.uk si è creato un pileup che ho fatto fatica a gestire.

Particolarità dell'attivazione:

Sono uscito con stilo mfj da 5 metri e compressore di dinamica fukamateur.de.

Risultati eccellenti, entrambe le soluzioni sono state vincenti

Ciao e 73 de IN3AQK

Qui sotto qualche foto.

Come vedete sono circondato dagli omini di pietra

Gli omini di Pietra

The Shack of IN3AQK

The equipment

73 de IN3AQK