Portable HF antenna setup

Well, the winter is coming (at least when I peek to the calendar) so it's time to make the antennas for portable HF.
I am using an ICOM IC-703+ with the ICOM backpack and a vertical Racal antenna. But this is not enough for me so I planned to experiment with an End Fed antenna.
I contemplated the End Fed Half Wave antenna with a high ratio UnUn but the tests I did on my lab didn't convince me. I also find the lenght of the EFHW not suitable for what I expect from a portable setup. It's simply to lenghty to use it on various setups, mainly to keep it at the necessary height from the ground.
So, the next choice for a multiband wire antenna is also some sort of End Fed but the one that can be fed with a 9:1 UnUn, an aperiodic one.
On the internet there are several places where you cand found a suitable lenght for the wire.
As I am not interested on 160m band from portable, I choose the 13.5 m as the best for me.
I quickly made a 9:1 Unbalanced to Unbalanced broadband transformer and a 1:1 choke Balun made from a piece of RG316 teflon coax on a FT-120-43 toroid core. This consist of 4+4 turns on the ferrite core.
I prepared two pieces of RG58 coax cable. One of 10m and the second one of 5m.
I can use the choke balun to make a counterpoise from the 5 or from the 10m of coax cable. If the conditions permit, I cand put a real counterpoise directly on the 9:1 BalUn and use the entire lenght of the cable with a UHF Female-female adapter without the choke balun. Or even to use the choke balun right at the transceiver's output.
So, I believe this setup let me experiment in the field with the best setup from various ones.
I will revisit this post after the Christmas holiday.
Merry Christmas!

 I forgot, this is a small Z-Match made with polyvaricons. This is to be used with 450 Ohm ladder line and simmetrical dipoles.

Codificarea condensatoarelor SMD (I)

Acum ceva vreme, cineva m-a intrebat cum citeste valoarea unui condensator SMD marcat.

Atentie, majoritatea condensatoarelor ceramice SMD NU sunt marcate, valoarea lor urmand a fi citita cu un capacimetru si un ESR metru, dupa caz.

 

De cele mai multe ori, condensatoarele SMD ceramice sunt marcate cu un cod care consta in doua simboluri, o litera si o cifra. 

In unele cazuri, exista si o a treia litera, marcata inaintea celor doua. Aceasta codifica producatorul insa este rareori utilizata.

Cele doua simboluri esentiale sunt ultimele doua, cum spuneam, o litera urmata de o cifra.

Litera reprezinta mantisa valorii, exprimata in pF, iar cifra reprezinta exponentul,  exprimat ca 10ⁿ .

De exemplu, un capacitor marcat S3 va avea valoarea de 4.7nF (4.7 x 10³ pf) iar un condensator marcat cu A2 va avea valoarea de 100 pF (1.0 x 10² pF).

Uneori, combinatia de litere si cifre poate fi citita in mod gresit, de aceea, notatiile care prezinta ambiguitate au o linie DEASUPRA marcajului, asigurandu-se astfel citirea corecta a valorii condensatorului.

Simplu, da?

Litera	Mantisa	Litera	Mantisa	Litera	Mantisa	Litera	Mantisa
A	1.0	J	2.2	S	4.7	a	2.5
B	1.1	K	2.4	T	5.1	b	3.5
C	1.2	L	2.7	U	5.6	d	4.0
D	1.3	M	3.0	V	6.2	e	4.5
E	1.5	N	3.3	W	6.8	f	5.0
F	1.6	P	3.6	X	7.5	m	6.0
G	1.8	Q	3.9	Y	8.2	n	7.0
H	2.0	R	4.3	Z	9.1	t	8.0
						y	9.0

 73 de Adrian YO3HJV

Home Alone Ham...

Its a (stupid) tradition here to have at the beginning of December "Home Alone" at TV.
So, I choose not to watch to because I do have a lot to do!
I recently (re) finished my HF backpack kit and I am looking forward for my new LiFe battery to get rid of the heavy SLA one!
Basically, it's an ICOM IC-703. Yeah, the one that I trade a TS480 SAT for!
After it had some problems due to an idiot (me) who put a FT2000 to tune directly to the input of the ICOM, I managed to make it again like new! I had to change the pre-driver and the little uPC which attack the pre-driver and some SMD inductances and after just a few minutes of QSO one of the final transistors gave up but now, everything it's OK.

I even want to make a small external Z-match to be able to tune balanced antennas like G5RV but I gave a second chance to the wonderfull internal ATU and made just an external matcher for the Racal foldable vertical whip which I often use on portable HF.

No, the schematics is not on public domain because I had a hard time fine tuning it, but if anyone need to have a diagram, I will send it via e-mail. An antenna analyser is a must!
In a few words, that box change the sign of the imaginary part of the antenna impedance, make it easyer for the internal antena tuner. 

After I repair and realigned the radio, it was the perfect time to finally made the handset and the headset I dreamt a lot!
Studying the service manual, I found that I have audio output on the microphone RJ45. The only problem is that I must put a dumb 3.5 mm jack into the external speaker to mute the radio and have the audio only on the handset. But this is not a real problem, right?

About the title, well, I was home alone today!

I let you with the pictures and feel free to ask for details!

73 de Adrian, YO3HJV