laste change: July 2009


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CTN-520 remake

fits for:

  • C-220
  • C-228
  • C-520
  • C-528
  • C-620
  • C-628

  • + same size
  • + same functions
  • + better DDS-signal
  • + sold to many countries world wide, e.g. greece, austalia, europe, asia with great feed back

you can order 24h a day in our online-shop.

Manual for installing CTN-520

How to install your CTN-520 remake
file: PDF
size: about 0,5MB

technical details

Parameter CTN-520 remake CTN-520 original Remarks
CTCSS-frequencies 38 frequencies (67,0 - 250,3Hz) 38 frequencies (67,0 - 250,3Hz)
rated voltage input RX 130mVpp @ 700Hz deviation 130mVpp @ 700Hz deviation signal from rf-generator
rated voltage input µPC RX 4,00Vpp not available signal from rf-generator
signal threshold unit RX 30mVpp 40mVpp signal from rf-generator
response time RX 140ms - 300ms 110ms - 353ms
deviation VHF TX 700Hz @ Uout=0,6Vpp (P2) 700Hz @ Uout=0,6Vpp (R801) trimmer in center position
deviation UHF TX 700Hz bei Uout=0,6Vpp (P1) 700Hz bei Uout=0,6Vpp (R802) trimmer in center position
current consumption 5V DC TX / RX 1,90mA 2,04mA

procedure of development

  • there are still several thousand of those portables on air
  • the origin unit is sold out since a long time
  • at the mid of 2008 Klaus, DL8NAT began to start the development
  • the hardest step was to develope a high-quality-decoder for CTCSS
  • CTCSS is pretty narrow to human voice and very low-frequent
  • it took Klaus several months to develope, aprove and to optimize soft- and hardware
  • march 2009 - the first measurement on a prototype
  • Edition 7.xx - quick frequencie changing causes trouble
  • Version 8.00 - optimum function
  • 27. June 2009: first pre-series are being tested
  • mid of July 2009: serial manufacting starts...

Feedback / References

Jürgen, DG4KF wrote at 10.07.2009

"Vielen Dank für die Übersendung der Artikel.
Das Nachbau Modul funktioniert hervorragend.
Das ist doch schon mal was für ein so altes Gerät
noch Erweiterungs-Zubehör zu bekommen..."
Mustafa, TA1AL from Istanbul wrote on 18.07.2009

"I received the TONE UNIT yesterday and I check it
on my Standard C528. I opened with your tone unit
all vhf and uhf repaiters in Istanbul.
Your tone unit worked very fine.
Congratulation well done.

frequently asked questions

I have a (working) Standard C520 and I am interesting in a sub-tone module in order to be able to activate repeaters.
Is your CTCSS - CTN-520 REMAKE ok for this purpose?
Is it a "Plug & Play" module or it needs regulations to do? (I don't have rf instruments in my lab).
Thank you in advance for your answer.
Paolo IK8... 08.08.2010

Hi Paolo,

many thanks for mail and your request.
The CTN-520 is made for the C-520 and the C-528.
It is a plug and play unit so you won't have do regulations.
Just put the CTN-520 into your STANDARD and it is ready for qso in CTCSS-Mode.

you can order 24h a day in our online-shop.