I've been a CW op since 1957, though I am a relative newbie on satellites (6 weeks now). Hasan has helped me realize how little uplink power is needed for successful contacts. (Translation = I was using too much power the first week or so.) Part of the problem was inexperience. Another factor, however, was my shiny new Icom 9700, which controls output with a knob and "percentage" indications. What does 10% output mean, actually? I hooked up my Bird wattmeter to find out. On 2M, percentages corresponded pretty much with output. 5% = 4W, 50% = 48W. But on 70 cm, percentages do not correspond, given less reduced output to begin with. Here, for instance, 5% = 2W. Also, realize that you're still putting out power at 0%! 900mW on 2M, it turns out to be, 100 mW or so on 70 cm. The latter explains why I've made contacts with power supposedly cranked all the way down to zero. I operate U/V, by the way. I calculate that I have 9 dB gain with my Cushcraft A449-6S, 33 feet of LMR 400, and three lossy UHF connectors. This means, on uplink on 70 cm, 0% = 800 mW ERP, 3% = 8W, 5% = 16W, 7% = 24W, 10% = 48W, and 20% = 80W. Bottom line is that I have no trouble making Mode B contacts with the knob on the 9700 set at somewhere between 0% and 7%, and usually at the lower end of that range. Hopefully this information is of help to other CW ops, especially new ones with 9700s. Keep a hand on or near that power output knob, reducing power when not needed and especially when your waterfall is looking as strong as the beacon waterfall. Other ops in the bandpass will appreciate this courtesy.
Wes NA1ME
participants (1)
-
Wes Baden