There are some options.... http://www.repeater-builder.com/hamtronics/ta-51pl_mod.html This modification was originally written to allow PL to be transmitted at industry standard levels. Using this modification, with a suitable varactor, will provide full voice deviation of 5 kHz. This works well on a TA451 because of the multiplication factor of 36. This modification converts the transmitter from PM to FM. You'll need to pre-emphasize and limit in software. This gives the best sounding audio from an older Hamtronics exciter. Use only on ham bands - modification is not commercial use accepted. http://www.repeater-builder.com/hamtronics/ta-51altaudio.html Similar to what Robert mentioned, and should be fine as long as you are limiting without pre-emphasis in software. Use only on ham bands - modification is not commercial use accepted. http://www.repeater-builder.com/hamtronics/pdf/COR-3.pdf Look at the circuitry associated with Q1 and Q2. Kevin On 3/8/2014 11:37 AM, Robert A. Poff WB3AWJ wrote:
I would think that it should switch 100ma with no problem. Make sure you put a diode across the relay coil (band toward + volts) to suppress back emf when the relay releases.
As to the Hamtronics exciter....
I had to use one (TA451) on a local club UHF repeater that I redid as an Allstar node. That repeater always had sounded horrible before. And to no surprise, with the Allstar node it sounded absolutely RANCID. I needed to bypass all the mic processing and the really nasty clipper, and inject the transmitter audio downstream just after the splatter filter, and essentially directly into the phase modulator. Through an isolation resistor (somewhere around 4.7K if I remember correctly).
Now it sounds as smooth as my Mastr II / Allstar repeaters do.
------------------------------------------------------------------------ *From: *"Bryan Fields" <Bryan@bryanfields.net> *To: *"app rpt-users" <app_rpt-users@ohnosec.org> *Sent: *Friday, March 7, 2014 5:44:12 PM *Subject: *[App_rpt-users] RTCM PTT circuit
I'm interfacing the RTCM with a hamtronics exciter and will be using a small relay to key it.
Can it sink 100 ma to ground for the relay or do I need a driver transistor?
-- Bryan Fields
727-409-1194 - Voice 727-214-2508 - Fax http://bryanfields.net