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

Limita de jos

Rareori patrulez pe anunturi de echipamente Second Hand, mai ales de cand am ocazia sa dau nasul cu ele si mai ales, prin ele...
Dar azi mi-a trimis un amic un link, insotit de un text ce mi-a starnit curiozitatea.
Ma uit si nu imi vine sa cred! Oare atat sa priceapa cel care vine sau incearca sa gaseasca niste prosti care sa ii cumpere Baofengul inscriptionat cu ICOM?
Dar, oare ICOM, ce parere are?

Va las sa va delectati:

Anuntul este aici: http://www.radioamator.ro/mp/read.php?m=85746&a=1

Singura mea dilema este legata nu de functia de dual receive (care nu inseamna ca receptioneaza simultan doua frecvente) si nici de cei 10W (PMPO, pentru cunoscatori...) ci daca, atunci cand il voi intalni in frecventa il voi trata ca o statie pirat sau nu. Caci, cineva care vinde asa ceva, inseamna ca, ori e prost de bubuie si nu a luat un examen de radioamator, ori ne ia de prosti, caz in care replica nu poate fi trimisa pe frecvente caci ar incalca Regulamentul!

Sa le trimit si astora de la ICOM poza? Chiar daca au vazut multe, asta cred ca o sa ia premiu!

LATER EDIT:

Am gresit! Nu este Baofeng ci Tyt!
Am gasit si "cum se face", la colegii radioamatori din Bulgaria:

CUM SA ITI FACI UN ICOM.