Hi Bob! Long time, since I spoke to you. On the CXB station there is a transmit disable input on station connector J2-5. (comes from TTRC P2900-4) A low applied there will inhibit all transmit activity. I did this on my 440 machine with just a simple DTMF board to comply with the remote knockdown requirement. This way, I could continue using the internal controller. (better sounding audio, than any external controller, in my opinion)
By the way, I have a Ballantine 3440A RF millivoltmeter. I aquired the meter, and the complete RF probe kit, for it off ebay. The meter was $50, and the big suprise was the RF probe kit. I got it for $30, and it was basically brand new. Ballantine lists this probe kit for $900+! Was my lucky day! Gary KB7TRP --- In [email protected], "Bob M." <[EMAIL PROTECTED]> wrote: > > Boonton makes some nice instruments. Just make sure > the RF probe comes with it (they plug in and are often > not included), and that the unit is guaranteed to be > working. You don't need to measure the exact > amplitude, you only need to detect the peak and dips > as you tune the filter coils. > > The stations can be set up to repeat, do CW ID, and > even time out, if programmed correctly. On/off control > is the primary item you'll need to provide from the > outside world, and I don't think there was an easy way > to do it (i.e. they didn't just give you a signal you > could ground to disable the transmitter). I found it > was just easier to do everything with an external > controller, and this gave me the ability to put in an > audio delay module at the same time. However, I will > say that the interfacing is not as simple as plugging > something in and running with it; significant > technical prowess would be required to do the job > successfully. My station was a CXB that programs with > a PC and RSS, so changing parameters is a whole lot > easier. > > Bob M. > ====== > --- Mathew Quaife <[EMAIL PROTECTED]> wrote: > > > The unit that I got is the Boontoon RF > > Millivoltmeter Model 92E. Looks like it should > > cover what I need it to do. Thanks for the help, > > when it gets here, I am certain I will have more > > questions until this repeater is up and fucntional, > > and then comes the fun of tying in an outbord > > controller for the unit. Thanks. > > > > Mathew > > > > > > "Bob M." <[EMAIL PROTECTED]> wrote: > > There will be some loss in the filter (maybe 0.5dB > > per > > section), and about 30dB loss when using the tuning > > probe. If you're feeding in 223mV (0dBm), you would > > probably measure -30dBm using the RF voltmeter > > connected to the tuning probe, when the filter is > > fully peaked. This is around 7mV. However, even when > > the coil is mis-tuned, you'll still get some > > indication with the proper meter. It'll be harder to > > see with a spectrum analyzer because of its low > > impedance input. > > > > I use an old HP3406A sampling (RF) voltmeter. They > > show up on eBay once in a while, but you can't get > > parts for them any more, so if it doesn't work, it's > > difficult to repair unless a common part has failed. > > > > Mike (ILQ) please contact me. > > > > Bob M. > > ====== > > --- Mathew Quaife wrote: > > > > > Hi Mike, did a little research and found one in > > > Chicago. I knew about the SM, just never thought > > of > > > one being outside the SM. So should have one here > > > in a few days, and then get back to working on the > > > repeater. > > > > > > Mathew > > > > > > > > > Mike Morris wrote: > > > At 05:13 AM 11/13/05, you wrote: > > > > > > >Sitting here looking at the tune up procedure for > > > the filter, it tells me > > > >to insert a rf millivoltmeter probe into J18 and > > > insert a 225 mV signal > > > >into the the output of the post filter. I did > > this, > > > and get nothing on > > > >the meter at all. > > > > > > It takes a LOT of level to force a signal past a > > > detuned filter. > > > > > > >Now I'm not sure if there is a difference between > > > my RS Volt-Ohm meter and > > > >an RF millivoltmeter. > > > > > > Your RS VOM does have an AC mode, but I'd be > > > surprised > > > if it responds to frequencies above 100khz. If it > > > responds to > > > 447MHZ RF at all, I'd be very, very surprised... > > > > > > An RF millivoltmeter is just that - a meter that > > > reads at RF > > > frequencies down to the millivolt (and frequently > > > microvolt) > > > levels. > > > > > > If you think about it a service monitor and a > > > spectrum analyzer > > > both have the function as RF millivoltmeters... > > when > > > you measure > > > receiver sensitivity you are injecting a low level > > > RF signal into the > > > receiver, and the RF millivolt / microvolt meter > > > section is reading > > > the result. > > > > > > Mike WA6ILQ > > > > > __________________________________ > Yahoo! Mail - PC Magazine Editors' Choice 2005 > http://mail.yahoo.com > 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/
