On Thu, 18 Dec 2008, kb5vjy wrote: > After months of waiting, I have been issued a repeater pair of 147.255 > for a long range 2m repeater that will be installed. This is my first > 2m repeater, but I do have 3 70cm repeaters (all Mastr II's)..
> I have a Mastr II Station 100w Cont. Duty PA for the project... I > still have to order the xtals. I will run a PL as needed on 127.3. > The controller will be a CAT (version unsure of) > I have a 2000' broadcast tower with a platform at 1300' and another > at 1000'. There is a DB 224 mounted under the 1300' and one under > the 1000' platform with a section of 7/8 feedline running from the > top platform and the bottom platform. There is a full rack size NEMA > 12 enclosure on the 1300' platform. After Feb '09 there will be NO > VHF transmitting equipment on this tower at all. The closest > transmitter is 6 miles away. > > What I would like to do, is mount the radio in the enclosure at the > top platform. Use the top DB 224 for the Receive antenna, and the > 1000' DB 224 for the Transmit antenna. What are the problems that I > will run into with this situation, and should I look for some type of > filter for the receiver. I do plan on putting an APRS Digi at 1300' > as well moving one of my 70cm repeaters to the same platform some > time early next year. First, congradulations on securing the site. This is often the most difficult part of the process. Second, the adventure is just beginning. Running split antennas with 300 ft of vertical seperation... The charts seem to indicate that you'll have enough seperation, but I'd still recommend a pair of cans for simple filtration. You never know when a helicopter is going to be nearby, for example. ;-) I hope your run from 1000 to 1300 ft is with 7/8ths inch heliax. I'd also recommend that you use 2C ICOMs for the repeater; it's going to be seeing more temperature extremes than most repeaters will. Not everyone is lucky enough to be in an air-conditioned space. -- Kris Kirby, KE4AHR <[email protected]> But remember, with no superpowers comes no responsibility. --rly
