Email-Korrespondenz mit Mario, IK0MOZ

29.01.2000

Hello, My name is mario and live in Rome, call sign IK0MOZ.
4 years ago arrived in my city a large quantity of Ex-DDR material
R130,R211,R107 of all tipes, R105, R155 and so on.. include with this set
it were also a large quantity of spare parts and accessories. Looking in
this very confused material I find many boxes with modules and parts of
SEG15 and 100. I write to a French friend and arrived to me wiring diagram
and modules P/N. with anly this info I built a complete SEG15 and with big
surprice is was running. For your couriosity I will send a pictures of this
set, with some parts and all internal wiring not original but it is
perfecly running.
73 de Mario - IK0MOZ

30.01.2000

Hi Mario,

thanks for your message, that's real ham radio as I like it!!! But I
didn't find any picture attached with your mail; so please send it
again.

If you allow, I would like to put your mail along with the picture(s)
and a german translation on my SEG web pages, because I think it's an
interesting story for all SEG fans.

Thanks again and 73 from Berlin,

Manfred, DL7AWL

30.1.2000

Hello Manfred, glad for your quick answer.
In the previous message was not attachements because not ready. Now you can
find them.
I want also include some more details about my Homemade SEG15.
For the first I am an user of ONLY ex-military radio sets. In my shack no
Jap set. I in my OM activity use only surplus rigs, specially of the
manpack type.
As said the story began around 5 years ago. In that period I never seen a
SEG15 only info coming from France and Netherland about the exixtence of
this very intersting set. Under my request received a picture and a block
diagramm, with the note "..fine set, same philosophy os British Sincall
30...". One year later in a surplus dealer of my city arrived a mountain of
strange sets coming from Germany. The goods were coming from an EX-DDR
warehouse and composed from all line of Russian sets, many with lettering
in German language, but also many original German sets (EKV receivers, UFT
manpack...). To complete hundreds boxes of spare parts of all kinds. I
remember a complete lab to repair EKV receivers with shelfs with thousands
of trais full of components.
Looking in this pile of parts I noted some carton box where it was in one
some shining cassettes a power module with variometer a key and in another
a series of small envelopes with parts like instruments, knobs, dials,
switches and so on. I take with me a pair of boxes and get home. Sent a fax
to France and in return by mail arrive to me a large block schematics with
all the part numbers of the modules and the witing to interconnect them. A
speedy check to the parts in my hands and realized that pratically I had
all series of major parts to assemble a SEG15. It was missing some
mechanical parts like the front panel, the external box, the harnes wires,
the potentiometers....
Back to the dealer looking better in the pile I find the silkscreened
panels, the box and other parts. In a side of the shop were also many sets
called FMB02 complete of maintenance cassette with inside hearphone, mike,
handset and key.
The project were ready to start.
1) First assemble the set homebrewing the interconnecting wires
2) Complete the set using FMB02 front parts.
In a two weekend work time I completed the work.
You can understand the moment that I applied the voltage to the set, but
with surprise and big satisfaction immediately heard on the hearphone noise
and then attaching a piece of wires LSB transmissions. After that I made a
transmission tests in LSB and CW with satisfactory reports specially in
modulation.
If you look at the pictures you can see the big work to assemble the rotary
switches and other wires, the tuning knob made using an EKV knob (No
original find), the front panel and the power supply made using parts of
the FMB02.
Now are around 5 years that this set is running. It has a problem that
seems to be a common problem for SEG15 that some time in A3J speaking the
PLL unlocks. This not happens in A2J. I spoke with a friend in Germany and
he said to me that this is a tipical problem of this set. Can I solve
this problem? what I have to do ?.
This is all
Attached you will find also the rule for a friendly competition among
surplus sets user. Please spread this info to other SEG friends and take
care that skeds are wellcommed and accepted.
73 de Mario - IK0MOZ

04.02.2000

Hi Mario,

thanks for the material about your "SEG 15 story", and please have a look
at my website where you will find it presented to the (german-speaking)
WWW community.

PLL unlock problem: Until now, I didn't hear anything about such a 
"typical" problem, so I can only guess around about possible reasons:

First of all, you should check the power supply of the synthesizer cassette
("Frequenzaufbereitung"). Is it stable and "hard" enough? Or are there short
voltage drops caused by modulation peaks? It could be a good idea to add
some more - distributed - blocking capacitors to the DC rails throughout
the set.

If those steps don't eliminate the problem, you should check whether it is
frequency dependent or not.

- If the problem increases towards one of the ends of the frequency range,
you could try some slight PLL/VCO adjustments in order to expand the lock
range or shift it into the right direction. For this, you will find some
hints in the context of the SEG 14 MHz range expansion.
Of course, that hints have to be adapted to your special situation.

- If the problem is NOT frequency dependent (and I feel that this is more
likely), it could be a grounding problem similar to the "bad modulation"
problem  regarded at my SEG website. It is an excellent example of big and
fatal effects caused by nothing but thoughtless ground wiring!
Maybe the nature of your problem is similar. Although I don't have any
experiences with SEG PLL unlock problems, I feel that you should pay
excessive attention to the ground conditions.

The best way to avoid dirty grounding side effects is to connect each
component separately to one central grounding point somewhere on the
chassis (instead of building a "daisy-chain" ground line or grounding
the components "randomly"...).

The same aspects apply to the positive DC lines, although these are less
critical.

As an experienced ham radio amateur, you probably already know such
things yourself. But for now, I don't have any other idea of what could
cause your unlock problem, so I hope that these "trivial" hints are
helpful.

73 from Manfred, DL7AWL