Stabo 933/934 prs cb.
#21

Hello Henning, yes you are correct.

Ok, capacitors arrived very fast indeed so the first order of business was to release the suspect component from the board. Quite fiddly as its a through hole component but double sided with those little "vias" that join each side.
Using a very small tip and a desolder pump (not ideal, I need a proper desoldering station) I released it.
A quick check with the multimeter showed it was shorted.
I actually took it apart and after unwinding about 4 turns the short disappeared.
The new component went it easily and was soldered in position.
After clipping the front panel back on and checking nothing was amiss, like trapped wires etc, I held my breath as the power went on.
Neednt have worried, I had a fully operational display and best of all no smoke! Smile
Ive had a closer look at the diagram since and found another electrolytic thats even more critical than the failed item.
Its located on the 13.8volt feed directly from the switch and is again connected between the ground and power line, so if that ever shorts out its possibly going to destroy part of the pcb and let out lots of expensive magic smoke, so that capacitor will get changed along with all the others before I dare apply power again.
Heres a couple of pictures inside the radio, I didnt get a chance to assemble the antenna today unfortunately.

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[Bild: wxcfbMW.jpg]


The diagram shows the capacitor that failed on the left arrow, followed by the choke that heated up, then over on the right the voltage regulator and finally the capacitor thats connected to 13.8volts that might do some nasty damage if it ever goes the same way as the other one.

[Bild: C6s1klj.jpg]

Failed item.

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Replaced item.

[Bild: mn2BJRD.jpg]

And it works!

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#22

Does anyone know how to find out what the individual codes are for these radios?

The manual states that its possible to selectively call a particular radio by its code but so far ive not found the code to do so... ?
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#23

Hello,

the code has to be negotiated between the users before starting the conversation.

In Switzerland the Code "00000" was used as the CQ-Call-Code (Common Call-Code for all users)

There was a manufacturer offering a code cracking tool to identify the code of a private conversation with 00001 and 99999.



Hallo,

Der Code musste zwischen den Funkfreunden vor dem QSO verabredet werden.

In der Schweiz wurde der Code "00000" als CQ-Code (Allgemeiner Anruf) genutzt.

Es gab wohl ein Gerät, was unbekannte Codes (00001-99999) knacken und anzeigen konnte. Näheres weiß ich nicht.


73 & 55 (Gruss)
Henning Gajek
CB: Bad Dürkheim 23 / Bravo Delta 23 / 13HN23
QRV seit 1977
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#24

Thanks Peter, concerns duly noted. There are still users on 934 in england however, most are using yagis with horizontal polarisation which as you know impacts far less on the vertically polarised signals of the celltowers.

Thanks for the reply Henning.
As far as the manual goes it seems that the radios have their own unique identifaction codes, such as 45321 (5 digits) which when input into the radio means your/my radio will call with that code only to connect with the radio that has that code.
As far as I can see its a selective calling system but I cant see how you can actually aquire the codes from any other radio unless it identifies itself first...

The 00000 cq code does work however as Ive tried it on the other stabo and both do talk to each other and select their own channels as per the manual.
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#25

I did a little experimenting the other night.

With the delta connected to the co linear on Ch20 my noise floor here is around 3 bars, sometimes momentarily goes to 5 but most generally on 3.
Ch40 is usually 1 to 2 bars so much quieter.
The co-linear antennas fed by a length of westflex103 so I decided to see what would happen using a length of RG8 to connect inline.
I found a big drop off in received signal for only around 8 feet of RG8 and it shows just how sensitive things are at this frequency.

So if youre going to put an antenna its imperative to use the proper cable or else youre just killing the signal strength.
PL259 are no good you have to use N types.
It surprised me to see such a short length do so much damage actually!

Having aquired a decent swr meter for the job I tested out the co-linear.
Currently it is reading at around 1.5:1. swr.
Straight out of the box its pretty well on the money.

The yagi took a bit of messing to get the coax onto as its like trying to fit an angry snake onto the end of the N connector, the cables very stiff indeed.
Eventually after getting the yagi to sit and behave itself I found that the swr was 1.2:1.
Im very happy with that.
Swinging it around I could isolate the local noise sources from the towers on the band so at least I now can point it away from them to listen for potential voice traffic.

I will definitely fit the yagi to a tripod and take it to the hills and see what I can hear from afar...if anything! Smile
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#26

Hallo / Hello,

QRZ-934 schrieb



Da das Cybernet-Delta (= 934 MHz-Funkgerät) mit dem Co-Linear auf UK-Ch20 verbunden ist, beträgt mein Rauschpegel hier etwa 3 Balken, manchmal geht er kurzzeitig auf 5, aber im Allgemeinen auf 3.
Ch40 ist normalerweise 1 bis 2 Balken so viel leiser.
Die kolinearen Antennen werden von einer Länge von "Westflex103" gespeist, daher beschloss ich, zu sehen, was bei einer Länge von RG8 für die Inline-Verbindung passieren würde.
Ich fand einen großen Abfall des empfangenen Signals bei nur etwa 8 Fuß (ca. 2,40m) RG8 und das zeigt, wie empfindlich die Dinge bei dieser Frequenz sind.

Wenn Sie also eine Antenne einsetzen wollen, ist es unbedingt notwendig, das richtige Kabel zu verwenden, sonst töten Sie nur die Signalstärke.
PL259-Stecker sind nicht gut, Sie müssen N-Typen verwenden.
Es hat mich überrascht, dass eine so kurze Länge tatsächlich so viel Schaden anrichtet!

Nachdem ich mir ein gutes Schwingungsmessgerät für diese Aufgabe angeschafft hatte, testete ich das kolinear.
Zur Zeit beträgt die Anzeige etwa 1,5:1. swr.
Direkt aus der Schachtel heraus ist es ziemlich gut auf dem Geld.

Die Yagi musste ein wenig verwirrt werden, um den Koax anzuschließen, da es so aussieht, als ob man versucht hätte, eine wütende Schlange auf das Ende des N-Steckers zu setzen, wobei die Kabel in der Tat sehr steif sind.
Nachdem ich die Yagi schließlich dazu gebracht hatte, sich zu setzen und sich zu benehmen, stellte ich fest, dass der Swr 1,2:1 war.
Damit bin ich sehr zufrieden.
Durch das Herumschwenken konnte ich die lokalen Geräuschquellen von den Türmen auf dem Band isolieren, so dass ich es zumindest jetzt von ihnen wegzeigen kann, um auf möglichen Sprachverkehr zu lauschen.

Ich werde die Yagi auf jeden Fall auf ein Stativ montieren und sie in die Hügel mitnehmen und sehen, was ich aus der Ferne höre... wenn überhaupt! smiley


Ja 900 MHz ist eine ziemlich schwierige Frequenz. Deswegen glaubten damals auch viele, dass CB-Funk auf 900 MHz der "Tod" des CB-Funks gewesen wäre und waren dagegen.

Viele CB-Hersteller waren dagegen, weil sie schnell gemerkt haben, dass man eine gewisse Qualität braucht, damit es funktioniert.

In der Schweiz hat sich gezeigt, dass es doch geht :-)

Mobiltelefone mit GSM-Standard auf 900 MHz haben gezeigt, dass es doch geht und heute funkt die 5G-Technik bereits auf 3500 MHz (3,5 GHz)

english version:



Yes, indeed. 900 MHz is a little bit complicated to handle with.

Therefore many CBers believed that CB-Radio on 900 MHz would be the death of CB because of poor distance-range and were against it.

Many CB-Importers/Manufacturers were against it, as they knew, you need a minimum kind of quality to keep it working.

In Switzerland the CBers of SCBO-Organisation showed, that it works

Mobile GSM phones on 900 MHz show it, too.

Today 5G is using 3,500 MHz Frequency which is much more higher than 900.


73 & 55 (Gruss)
Henning Gajek
CB: Bad Dürkheim 23 / Bravo Delta 23 / 13HN23
QRV seit 1977
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