[Repeater-Builder] Re: GE Mastrll
Nate is correct in that it depends on where it's going. In general, the transmitter will tune up anywhere in the 2M band. For me, if the 66 receiver is on 146 or 147, then it generally works with no mods. If the RX is in the 144 or 145 range, then I get high side injection crystals (when ordering) and it works with no mods and has good performance. The first one I tried with lo side injection down in the 145 range had poor sensitivity. Instead of doing the mods (I'm lazy), I re-ordered the crystal for high side injection and it tuned right up. Dwayne Kincaid WD8OYG [EMAIL PROTECTED] wrote: So if I found one with DC56YAS66A number, it could still be put into the 2 meter band, correct? Depends on where you're going in 2m, but generally -- yes. It's a bit of a stretch to pull them to the bottom of 2m, but they almost always go and work to factory spec. (See archives for discussion of high-side vs. low-side injection crystals, too.) Nate WY0X
Re: [Repeater-Builder] Re: GE Mastrll
It will be in the 147 portion. Rod Nate is correct in that it depends on where it's going. In general, the transmitter will tune up anywhere in the 2M band.
Re: [Repeater-Builder] Re: GE Mastrll
[EMAIL PROTECTED] wrote: It will be in the 147 portion. Piece of cake. Dot the i's and cross the t's on the coordination paperwork, tune 'er up according the factory docs, build a nice filtering/antenna system, and she'll fly. You'll probably want a pre-amp on the receive side -- factory-spec MASTR II receivers are not nearly as hot sensitivity-wise, as most (barn-door-wide) modern mobiles and HT's. In order to balance the performance of the repeater, it'll need more receiver sensitivity. It's already a very selective receiver with nice built-in filtering (helical cavities on the front-end), which is why they're popular... but adding the pre-amp then also usually means adding proper band-pass filtering if you're in a high-RF environment. That all depends on where it's being installed and your desired coverage. Most folks squeezing every last ounce of performance out of their MASTR II's have added high-quality LNA's somewhere in the receive path. It's easier to build an alligator with a MASTR II (big mouth, no ears) than an elephant (big ears, small mouth). You're shooting for something in the middle, so you probably need some help in the receiver side to make it balance out. (Remember the MASTR II Repeater/Station radios were built to be used in a system where the mobile rigs also regularly ran 100W! The design -- as originally conceived -- was balanced -- but the average ham today is using a 5W HT for almost everything. No one wants large trunk-mounted rigs with 6 gauge running from the trunk to the battery of the vehicle these days.) Nate WY0X
