During my lunch time pause I sometimes do some qrp qso.
I'm trying to costantly improve my qrp setup and to optimize the deployment time.
At the moment I use a Hoxin HV-10 antenna that I'm able to setup in 5 minutes
The rig is a ft-817 and the tuner is an sg239 that I can't use a home.
I' also made a PC Headset to Ft817 adapter.
Questa è stata un'attivazione lampo con la precisa intenzione di attivare la cima senza ricercare il punteggio.
Normalmente vado in montagna con la mia dolce compagna e posso dedicare sulle cime circa un ora di tempo. Cerco quindi di ottimizzare al massimo il tempo e di fare il minimo necessario di collegamenti, tanto come punteggio non posso competere con nessuno.
Questa volta mi sono portato sia una hb9cv per le vhf che una verticale multibanda autocostruita per le hf. Come accaduto le altre volte in VHF, in assenza di contest in pratica non si fanno collegamenti, infatti ho fatto solo un qso su 145500 in fm con un radioamatore di Trento. La prossima volta mi porterò una jpole di cavo, tanto per risparmiare peso.
Ho quindi installato l'antenna per le HF e qui subito in trenta minuti sono riuscito a fare 4 collegamenti. In aria c'erano tantissime stazioni che attivavano dei fari marittimi e quindi non ho avuto grosse difficoltà.
La mia oretta a disposizione è passata ed una nuvola ha tolto d'improvviso il sole, ha cominciato a fare freddino e quindi siamo ripartiti.
The Fuchs Antenna was introduced by Arwed Fuchs, an Austrian Radio Amateur in 1928.
It was used as a high efficiency single band half-wave endfed antenna by many radio amateurs over a long period, but it was more or less forgotten when most radio amateurs started using coax-fed dipoles.
In 2000, Frank, DL7AQT, did lots of experiments with the Fuchs, and was happy to end up with a multiband version for portable use.
QRPproject sell an obtmized version of the tuner in a kit, it is based on Franks’ design with
some small modifications we made because the variable used by Frank is no longer available.
The antenna is a monoband endfeed half wave dipole. The length of the antenna should be a λ/2 or a multiple of it.
For 3.5 MHz you need about 41 m. But you can match these wire length with Frank's development also on all others bands between 10 and 80 m!
The length of about 41 m is a good compromise. With the Fuchs circuit it is possible to use these 41 m wire on all bands between 10 and 80 m.
The alternative is 21 meters of wire for the bands from 10 meters to 40 meters
Having all the necessary parts on my junkbox I've assemble my version the only different parts is the variable capacitor, mine has a maximum value of 160 pf.
First tests are really encouraging, I was able to tune a 10 meters radial laid on the floor from 80 to 15 meters.
Attivazione del monte Roen di domenica 4 agosto In concomitanza con l'Alpe Adria VHF.
Per tutta l'attivazione ho operato con 2,5 watt circa dato che avevo delle batterie al litio da 11 volt.
Dall'abitato di Amblar in Val di Non ho raggiunto in automobile Malga Roen. Dalla Malga Roen per il sentiero 500 ho raggiunto la vetta del monte Roen in circa 60 minuti. Il caldo alle 0800 era già tanto e questo non presagiva niente di buono.
Alle 0940 ho iniziato a trasmettere ed ho incontrato subito stazioni con 50 di progressivo, più di un qso al minuto.
Come al solito mi si è presentata la solita barriera degli Appennini, oltre non sono riuscito ad andare. Massimo qrb poco oltre i 300 KM.
Alle 1330 esauriti tutti i qso possibili e dato il caldo torrido, vento nullo e solo cocente sono tornato a casa. Abbastanza soddisfatto ma devo migliorare il qrb.
The ultimate QRSS Transmitter Kit is a new version of the original Ultimate QRSS kit. This new version comes with a pre-assembled AD9850 DDS module, and plug-in low pass filter modules which are also available separately for any band. The kit can transmit on any frequency from audio (500Hz) to over 40MHz, and changing bands is a matter of plugging in the appropriate low pass filter kit to attenuate unwanted harmonic output. I've just completed the kit and put in on air, these are some photos:
Kit from above with DDS and LPF Filter
The kit during a transmission, note the coin over the dds, to add some thermic dissipation and mass
I've found that the problem was a Fake!! C2078 transistor that I've bought on internet.
Today I received new ones bought from Eleflow and now I have, in cw, 2 watts on 20 meters and 4watts on 40 meters.
Unfortunately I have a lot of un-sopressed carrier on LSB, about 1 watt!!.
I've tried lovering r62 but the carrier is still there.
I must re-study alle the schematics to find the problem.
Someone have suggestions?
These are the pics of my sota style activation on Matatz (2179) on Passiria Valley, near Bolzano.
The climbing last about 2:30 hours with a height to climb of 680 meters from the parking.
This was a sota style activation but unfortunately not a real sota as the reference does non exists as the moment.
I've done 3 qso on 28 mhz and 3 qso on 14 mhz
The equipment was:
Ft817
zm-2 antenna tuner
home made whip antenna based on a fishroad, with a base tuning coil and a 2,5 meters radiator
Last year I've received a dual band (20 meters and 40 meter) qrp transceiver named TJ2A partially assembled.
The transceiver kit is made from www.youkits.com and distributed mainly on Ebay.
I've just build a TJ2A in the past without problem, mine worked well from the beginning.
The ham in this video is me with my original TJ2A
Due to a misunderstand with a Ham I've changed my working TJ2A with this partially completed.
This is another, bad history.
This TJ2A was half completed and I tried to complete it. Soon I've found that the transceiver was badly assembled with a lot of mistakes as, trace cutted, bad solders, inverted LM386, components swapped and so on.
I must say that at that moment I was really disappointed because instead of a working TJ2A I had received un-repairable one.
After a lot of investigations I've corrected nearly all the problems, now the TJ2A receives but it does not transmit with the correct power. The expected power is, from the specifications about 3-4 watt, but at the moment I obtain only half a watt!!
Now I'm really frustrated because i feel that the solution is near but I'm not able to fix this last section.
On the picture the part of the schematics where is located the PA.
I've checked and re-checked all the fundamental parts and all seems at the correct position with the correct value, bu the power is still low.
On this guide of Pa1ap I've found his measured values and they seems near in value of the mine:
On the 40 meters band I have:
R60 80 mV pep
R65 1400 mV pep
C92 800 mV pep
ANT 4 V pep
The only anomaly that I've found is that at C92 I've a voltage less that the voltage at R65.
I'm not really sure if Q14 is used as an amplifier or as a buffer.
Unfortunately the Pa1ap guide does not report the values at c92 so I've not a reference value.
I've checked Q14 and it's working in my opinion.
To obtain 4 watt at the antenna I must have nearly 40Volts on 50 ohm at the antenna.
So the voltage level must rise from 80 mV pep at the input of Q12 to 40 Volt to the antenna.
Pin 1 is the KEY pin, it's pulled low by the tuner to tell the radio to start transmitting.
Pin 2 is the START pin to/from the microprocessor. Under normal circumstances the START pin is pulled high when a remote tuner is attached to tell the radio that the tuner is present. When you press 'TUNE' the radio pulls the pin low telling the tuner to start the matching sequence.
A 10k resistor, connected to the 3 pin is enough tell the ic 706 that a fake tuner is present
Pin 3 is POWER rated for 1 amp max and switches on and off with the radio.
My quadcopter first flight, with APM 2,5 ardupilot and rctimer components.
Unfortunately the second flight was not as funny as the first one.
After about 2-3 minutes of fligth the copper went down directly into a small river.
Three ESC are broken and a lot of N-Mosfet where blown up. The cause is under investigation but at the moment I've no idea on how to prevent the problem.
The ESC's were flashed with a SimonK firmware, I'm not sure that this could be the problem.
So I had to buy four new ESC from another shop and of different type.
Back soon here with flights with the new configuration, "The show must go on"
