Power Supply - Voltage drop under load

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lbcomms
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Re: Power Supply - Voltage drop under load

Post by lbcomms » Sunday 17th Feb 2013, 17:05

Current thoughts are towards building an 8 section coax co-linear with a supposed 9DBi gain, taken from a tried and tested 70cm ham antenna design. (obviously re-calculated to 446mhz)
That's only 1.4% above 70cm, a 9dB antenna will have probably 2.5% bandwidth under 1.5:1, so you should be able to use it as-is.
446mhz handset (doing 500mW!)
If I ever come over to the UK, I'll bring my Motorola Spectra with me and the locals will hear me for sure - 120 watts, 250 channels, programmable from 450 to 490 Mhz :D
It would only take a few minutes to re-tune it up a few megs from it's current home on the 70cm Oz ham band (420-450Mhz).
Cheers from a cold, wintry Cornwall!
2 weeks ago, Sydney broke its all time temperature record - 46.6 degrees (Celsius). The airconditioner outdoor unit burned out, then the utility electricity went down, so we called it a day, went home by lunchtime, and cooled off down at the beach :)

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Warf135
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Re: Power Supply - Voltage drop under load

Post by Warf135 » Monday 18th Feb 2013, 3:02

If I ever come over to the UK, I'll bring my Motorola Spectra with me and the locals will hear me for sure - 120 watts, 250 channels, programmable from 450 to 490 Mhz
Nice! The kenwood TK361 I used for the gateway will tune up to about 4-5 watts, but I reasoned there is no point setting the gateway a to a huge TX power when most legal PMR446 sets are limited to 500mw... everyone would all hear the gateway but not be able to get into it... People are raving about using a particular Uniden 446 base radio as a gateway, because it can be made to do 5 watts by cutting three links in the back, but no point i say. I've set my gateway to the legal limit (500mw) of course :angel: My gateway is on Channel 6 (446.06875 Mhz) - CTCSS 20 (131.8Hz) and with 250 watts you could probably get in from Down Under!!! :lol:
That's only 1.4% above 70cm, a 9dB antenna will have probably 2.5% bandwidth under 1.5:1, so you should be able to use it as-is.
Very True, but its a homebrew antenna project that I'll be building from scratch, so might as well calculate it to the 446 frequency i'm gonna use it on.

Cheers,
Norm

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