On Jun 13, 2008, at 10:47 AM, Charles Scott wrote: > Steve: > > Everything you say is correct, but you're not considering the poor HT > user. If you assume 0db of gain for the receive antenna you're > probably > anywhere from 6 to 20 dB above the signal actually received by an HT > on > someone's belt. For them the additional TX power is critical, > especially > for D-Star since with analog FM they might actually hear at least one > squelch crash. > > Chuck - N8DNX >
Don't forget that most reports are showing the HT's are quite a bit more sensitive (but not very selective) compared to the mobiles. One report I read (I haven't done it myself) was that an IC-91AD's 12dB SINAD point on Analog is down around .15uV. I'm having no problems at all hearing our repeater in buildings from more than 25 miles out... I haven't had a chance to try further, but it's full-scale at that distance. Today I talked into the W0CDS UHF Port B repeater (which is at at roughly 9000' MSL) from a location just under 6000' MSL 90 miles out with the ID-800H on low power. Diamond SG-7800 antenna (very good, granted) on this end. I'm limited more by curvature of the Earth than path loss out here, but we're still talking a rather large loss at 441.9625 on the input frequency. Additionally on our comm trailer at the same site, N0WBW's ID-800H is also accessing the repeater on a standard Larsen NMO mobile antenna on the roof. The repeater has no pre-amp, no amplifier, and good quality pre- selector single can on the receive, in addition to the good quality DB 4-can duplexer. 4-bay Sinclair 1/2 wave spaced folded dipole array, fed with 7/8" hardline. I agree with Steve. Start without the pre-amps and amps and build right, and then see if you need to add anything... these things work great. For 15 miles of my travels coming out of Denver to our contesting site near Limon, CO -- I held a QSO with someone while the signal strength indication on the mobile rig was nothing... zilch... no bars at all. Impressive. Who needs more than that? Who cares what the signal strength says, I'm 90 miles out and using the machine. At least in our territory where the machines can go on mountains (or mole-hills, in the case of our test site, can't wait to see what it'll do at 11,000 MSL or so) -- there's just no need for the PA's or the pre-amps. It's well-balanced as-is. My $0.02 and another $7 will get you some over-burnt Starbucks coffee. :-) :-) :-) -- Nate Duehr, WY0X [EMAIL PROTECTED]
