Hi ... 447.575 MHz - 11.2 MHz (Intermediate Frequency) = 436.575 MHz (output of the receiver multiplier injection chain) divided by 3 = 145.45833 MHz. Try high side injection ... that frequency will come out to 152.925 ... Neil - WA6KLA
----- Original Message ----- From: Nate Duehr <[EMAIL PROTECTED]> Date: Monday, November 27, 2006 11:54 am Subject: [Repeater-Builder] spur from UHF MASTR II mobile - link radio > Hi guys, > > Built a link radio out of a MASTR II mobile a while back. 444.575 > TX, > 447.575 RX. > > It is NOT duplexed and the RX section turns off during TX, just a > normal > MASTR II mobile setup. The only modification done was to by-pass > the PA > and run the exciter output over to the Low-Pass Filter board in > the PA > section directly -- didn't need much power to make this link work > with a > 6 or 7 element yagi mounted outside, pointed at the repeater it's > linking into. > > After having the link installed in my basement for a few days, I > realized that it's throwing a fairly strong dead carrier on VHF at > 145.460 or thereabouts, but ONLY when it's sitting idle in > Receive. > When the radio is transmitting the carrier generated by the > receiver > disappears. > > It's not strong enough to receive it further than about one house > away > on an HT down the street, and I don't hear it one block over, but > there > in the house... permanent carrier on 145.46. (Unfortunately this > is the > output frequency of one of our club repeaters that's over 40 miles > and > behind a ridge from my house, and the repeater "loses" completely > to the > carrier coming from the link radio in the basement.) > > I attempted to figure out the mix math to see if that would be a > "normal" thing to see when using that particular UHF RX frequency, > but > I'm honestly not very good at that. I figured I'd post and see if > any > of the list's gurus might have an explanation of why it might be > doing > this. Any thoughts? > > I might (just to see what happens) stuff the crystals in another > MASTR > II, tune it up, and see if the same thing happens, but if this > could be > explained mathematically, that would be more "interesting". > > Hmm, what other info might you need... ahh... thinking back, the > crystals might not have been ordered with high-side injection... > I'd > have to look at the ICM packing sheet, and it's at home. > > Nate WY0X > > > > > > Yahoo! Groups Links > > > >
