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Simple repeater
Posted: Thu Sep 30, 2004 10:25 am
by Goreks
Can some one help me , I want to build a simple repeater
I am gone to use a P210/HT800 as receiver and a mobile station
as transmitter maybe a Yaesu FT7800 (sorry it’s the only mobile a have at the moment )
can any body tell me how I should do the controller and how I get the right signals
on the HT:s COR/COS and audio and if I need to use audio transformer
73
SM1YCE
.
Posted: Sat Apr 29, 2006 2:13 am
by big-vito
Tjena
Looks as if you have had no luck in making the repeater?
Posted: Tue May 09, 2006 4:19 am
by AEC
If you have the schematics for both radios, then it's easy to locate the COS/COR for relay activation.
Use a meter to probe the 'ON' state of a point or points on the board that go high(+V) on squelch open, then you can take that point(if it is not loaded down doing this) and drive a NPN transistor or darlignton transistor for voltage amplification, to drive a relay to switch the other radio into transmit, you can use a small DPDT relay for COR and take one open connection and use that to drive another relay for switching transmit audio from an unloaded connection on the transmit radio.
You can also do a down and dirty cheap method of switching a transmitter 'ON' by feeding raw audio into a power FET and using that device to switch the radio into transmit while feeding (shaped) audio into the transmitter.
There's a lot more to it than this, but I think you get the picture, it's really not that difficult to make a simple repeater, it only takes time to get it working properly, and to make sure the transmitter is clean and the audio is clean as well, so you will need to tailor the audio on the transmitter to suit your ears as well as legalities for splatter and IMD products that your HT repeater may produce.
I myself would NEVER recommend using an HT as a transmitter, as you have NO heat sink capable of properly removing heat from the P.A, nor is the HT designed to be used in that manner for any long period of time.
Even a fan placed directly on the heatsink will not cool the P.A well enough to keep it operating safely very long.
Your best bet is to buy two mobiles and run the transmit side at the lowest power level it can operate, then add a repeater duty amplifier that's designed for this type of service.
You can buy a cheap CW ID module for around $70.00 U.S here, and they install in a short time with minimal soldering and can be programmed with a PC to set the time out delay, call sign, and probably a courtesy tone as well.
Not a bad deal really.
Posted: Thu May 11, 2006 3:27 am
by jwb8734
I personally used 2 GM300s with 16 pin connectors and it worked well.
You can use 2 SM50s or something with the 16 pin connector to easily make one. Good Luck
Posted: Thu May 11, 2006 6:38 pm
by AEC
Just about any mobile radio would be far better to use than any portable.
Even ham stuff........as long as you have tone decode and encode....CSQ is for 11 M walkie talkies....10-4 good buddy!
Even an old Azden PCS-2000 is infinitely better for use as a repeater than a hand held, not to mention it's easier to cool and scop out locations on the board.
Just add an old Comm-Spec TS-32 encoder/decoder board and you are all set to hook it up.
A quality GaAs FET preamp is a must on the receiver though, don't buy the junky Hamtronics crap though, you'll be sorry if you do.