Download the MSR2000 to external controller text from my http://www.radiowrench.com/sonic page. It mentions what I feel is a great/better location for your controller audio connections.
cheers skipp > "Army Curtis - AE5P" <[EMAIL PROTECTED]> wrote: > No. The output of the controller goes to the Squelch-Gate card, and > through the several stages of audio amplification there before going > on to the exciter. Since that was the way Motorola designed it, it > seemed like the best way to keep it. > > Cheers, > > Army > > --- In [email protected], "skipp025" <[EMAIL PROTECTED]> > wrote: > > Your driving the transmitter directly from > > your repeater controller..? ... using the > > back plane method? > > > > Sounds like your repeater controller tx output > > doesn't have enough drive power (capacity) to > > directly drive the tx channel element IDC > > (channel element modulator circuit). > > > > Cheers, > > > > skipp > > www.radiowrench.com > > > > > > > "Army Curtis" <[EMAIL PROTECTED]> wrote: > > > Well gang, I have a real interesting problem for you that's > about to > > > drive me nuts. > > > > > > I have a MSR-2000 repeater that I'm putting into the 2M ham band. > > This > > > is one of the radios removed from service by the Ontario > Provincial > > > Police, so it is a Canadian Motorola VHF low split, originally > > > transmitting at 141.xxx. > > > > > > Following the suggestions on the Repeater-Builder web site, I > have > > > converted it to a ham style controller (CAT-700). The radio tunes > > up per > > > the book, with all meter readings very nominal, and it makes full > > power > > > (100 watts) easily. > > > > > > Here's the issue... it will not deviate the transmitter more than > > about > > > 2.7 KHz using a 1 KHz tone before it starts severely distorting. > The > > > problem appears to be in the exciter, which is a TLD9241A. There > is > > a > > > sticker on the exciter shelf that says 0.260 volts = 5 KHz > > deviation. > > > Anytime I put more than about 0.140 volts into the exciter, it > > starts to > > > distort. I am using an IFR-1200S to send and receive the 1KHz > tone, > > and > > > I'm looking at the wave form of the transmitted signal on the > > 1200S. I > > > have verified the 1200S is clean by looking at its output on > another > > > service monitor, and it is very clean to beyond 6 KHz deviation. > I > > have > > > looked at the audio going into the exciter on a scope, and it is > > very > > > clean to up around 0.400 volts, so I would say that the receiver, > > > controller audio, and transmit audio up to the exciter input is > not > > the > > > problem. > > > > > > I tried changing the exciter to another identical board, same > > problem. I > > > changed the channel element to a known good element, same > problem. I > > > have changed the audio input transistor on the exciter board > (Q501), > > > same problem. I have tried to adjust the IDC on the channel > element. > > > While it does change the deviation, it has no effect on the > > distortion. > > > > > > Here is some additional info I just ran down to the shop to > check. > > > Sending a 5 KHz deviation at 1 KHz signal into the IFR1200S from > > another > > > service monitor shows no distortion, so no problem there. > Putting an > > > audio generator right on the audio input to the exciter shows the > > same > > > issue, but here is where it gets interesting. Changing the audio > > > frequency, I am seeing a definite pre-emphasis network somewhere > in > > the > > > exciter, as a tone of 1 KHz gives about 2.7 KHz deviation, but a > > tone of > > > 3.2 KHz gives right at 5 KHz deviation, with NO distortion. > > > > > > So, here's my question. I always thought you set deviation on an > FM > > > transmitter using a 1 KHz tone, setting a maximum deviation of > > about 4.5 > > > KHz. I can see with this exciter that doing that will result in > much > > > more than 5 KHz deviation at frequencies above 1 KHz. Yet the > > Motorola > > > book calls for setting the deviation to 5 KHz using a 1 KHz > tone. > > > > > > What am I missing here? > > > > > > Army - AE5P > > > Nacogdoches, the oldest town in Texas Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
