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Sunday, May 18, 2008

Building for 80, Listening to 17, Ragchewing on 20

Just a quick Sunday morning report from Rome: With my 20 meter DSB rig finally tamed, I've been trying to decide which band to build for next. Italian hams just got access to more of 40 meters (now 7.0 -- 7.2 vice 7.1 MHz) so for a while I was thinking of 40. But 40 is pretty quiet at 5 am here, while there ARE stations operating on 80 at that time. So I'm building for 80. Actually I am rehabilitating a DSB rig that I built in London for 40. This morning I changed the coil in the VFO and have it percolating nicely from 3.55 -- 3.8 MHz.

I've been having a great time on 20 DSB. We have a local roundtable in Rome each night at 2030 local. I0YR, IK0JNI, IKOJMH, and I0ZY are all regulars. Very FB. Yesterday afternoon I worked Renato IZ1MJU up in Torino. He too was running a homebrew station. It is rare to have an HB-HB qso, especially on phone.

Right now I am tuned to my old stomping ground on 17 meters, listening to my old friend Chris, SM0OWX. I'll have to get that 17 meter rig going...

I should have another SolderSmoke podcast next weekend. I've added some stuff to the blog page: Check out the slide shows (2 of them) and the Dilbert Knack animations.

73 from Rome.

Saturday, May 17, 2008

LB Cebik, WN4RNL, and the "Ham Spirit"

As all of you probably know, LB Cebik, esteemed antenna expert and mentor, recently passed away. This morning I happened to find his entry on the wonderful "Novice History" web site:
http://www.novice.bappy.com/index.html

Note what LB says about "the ham spirit."

L.B. Cebik, W4RNL (WN4RNL, 1954)
I was licensed in 1954 as both a Novice and a Tech, since
then you could take both exams in one session and
privileges were separate. (W1APS/WN1APS)I got on
the air for the first time with a ham a couple of blocks away,
an fine old timer.

However, I got key fright half way through. My dad,
James S. (Jim) Cebik, came to my rescue and finished
the contact, although he had not touched a key in
over 20 years.

Jim Cebik had been 1ATG and later W1BUK in the late
1920s and early 1930s (and wrote a few articles on
his experiments). He gave up amateur radio
when he married in the depression years. Relative
parts costs were high, and family came first. In fact,
he rarely mentioned amateur radio, and my
entry was independent via some high school
comrads and a cousin. But he had not forgotten
his CW or key skills and saved me from
embarrassment on that first day. I returned the favor
by renewing his interest in amateur radio
and about 1964, he was relicensed and obtained
his old W1BUK call, which he used for very many
years. He died in 2002 in his high 90s.

So my Dad was a part of my Novice beginning
in amateur radio, and I strove to send CW with
a straight key so that one could not tell it from
a keyer.

He remains a strong part of my effort. He noted
that the ham spirit is to give, if needed, the shirt
off one's back to a fellow ham and to expect--not
its return--but rather that it be passed on to the
next ham who needs it.
That is the spirit of my web site.

My Novice days were a joy, and I have been
pleased to carry my father's amateur radio days
into everything that I do.

Hope this is useful.
-73-
LB, W4RNL

Friday, May 16, 2008

QST 1924 -- THE AMATEUR BUILDER

A few episodes back I was talking about the old QST articles in which amateurs were extolled to focus more on efficiency and technincal quality, and less on high power and brute force. Wes, W7ZOI was kind enough to send me some of these articles. Here is the header for one of them.

Thursday, May 15, 2008

FB QRP Homebrew From India

I always liked the descriptions of the ingenious homebrew stations used by Indian radio amateurs. This morning I came across VU2LID's site and found this:

A typical Indian QRP station will use a modified AM broadcast (BC) receiver, for the receiving part. The transmitter will usually have a final RF power amplifier using BD139 (or some power MOSFET like IRF530), driven by a Variable Frequency Oscillator (VFO) and chain of buffer/driver amplifiers (2-3 stage). Most of the stations use Amplitude Modulation (AM). Commonly available medium power Hi-Fi audio amplifier modiles using integrated circuits (like the TBA810), driving a modulation transformer forms the AM modulator part.


The above drawing was done by OM Bhasi, VU2UCY (SK)

Tuesday, May 13, 2008

From Sicily: An SSB Transceiver using only 5 tubes!


It's 5:30 am. I'm in the shack with a cup of coffee. The only sounds are birdsongs from the window and an Italian 80 meter SSB QSO from my Drake 2-B. Life is good.

And it got better when I found the rig pictured above. It is the work of Andrea IW9HJV and Johnny IW9ARO, two obvious victims of "The Knack" from Sicily.

It is a beautiful 20 meter SSB transceiver. And it uses just 5 tubes. While it doesn't have the bi-directionality of the BITX-20 (you can't really do that with tubes) it does share the BITX-20's simplicity and elegance of design.

The web site of Andrea and Johnny is another work of art. Check it out!
http://www.webalice.it/hotwater/RTX5x20.htm
Bravo Andrea! Bravo Johnny! Bravissimo!

Calibrating my W7ZOI/W7PUA Power Meter

In the course of testing my 20 meter DSB rig, I discovered that the chart I prepared for my
W7ZOI / W7PUA power meter had some problems. In my first effort to get some calibration points, I used a simple diode and cap peak reading signal probe to measure voltage across 50 ohms, but I may have neglected to convert from peak to RMS before calculating the power. That would certainly mess up the chart!
This morning I used my old Heathkit SG-8 signal generator and my HAMEG (20 Mhz) 'scope to get a couple of points for my graph of the response curve (line) for my meter.
I drew the new line, then used my trusty HW-8 at 1 watt to see if my chart was accurate. It was right on the money!
I look forward to happily measuring milliwatts with this very FB piece of test gear. See the June 2001 issue of QST for more details. Thanks to Wes and Bob for the great project. And thanks to Thomas in Norway for sending me the AD8307 chip.

Monday, May 12, 2008

Farhan on Schematic Drawing Software

I'm really in the dark ages on this subject -- I usually just draw something by hand and then scan it. Others (like JF1OZL) have good results with this technique. I don't. So I was glad to see this suggestion from Farhan on software that can be used to draw professional-looking schematics:

"i have used something called schemat.zip available freely on the
internet. it consists of a bitmap file with all the symbols that we
use in ham radio. i open it in ms paint, start a new copy of ms paint
and start selecting the symbols from the first ms paint window and
pasting it into the fresh ms paint window. Remember to UNSELECT
OPTIONS->DRAW OPAQUE. Sorry for the caps, but it is important. You can
use the line tool to draw the 'wires' connecting individual
components. holding the shift key down while drawing lines forces the
lines to come out perfectly horizontal or vertical."

Thanks Farhan!
Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column