Spectra UHF HI power Duty Cycle

[cbus]

I'm interested in finding out the rated duty cycle (TX) for the UHF 450-482 Hi power (100/110w) Spectra's.

Anybody got some documentation showing the specs ??

Thanks in Advance

[wavetar]

I can't find anything in the basic & detailed service manuals regarding duty cycle. However, it's been said several times here on the board in the past the Spectra should not exceed 20% duty cycle at full power (1 minute on, 5 minutes off). The addition of larger heatsinks & fans can raise this significantly.

Todd

[RKG]

I believe the "normal" design spec for a mobile LMR is 90-5-5 with a 2x to 4x margin.

[cbus]

Thanks for the replys

[kc7gr]

I will add that, with a 110-watt radio, you can also throttle the power back to 75 watts for the high set-point, and 55 watts for the low side. You'll barely lose anything on the high side as far as signal at the receiving end goes, and you'll significantly ease the stress on the PA and your vehicle's electrical system.

Keep the peace(es).

[JAYMZ]

I concur.

My Astro Spectra, when originally installed was pushing a solid 110 watts and drawing 26 amps. I backed it off to 80 and my total draw on transmit is 19 amps. Makes a BIG difference when you are transmitting and running emergency lights at the same time. Not to mention the less you pull all at once, the less stress on your battery and alternator.

[AEC]

.....Not to mention the lessening of the possibility of PA lead delamination due to heat stress, and the resultant solder migration as well due to thermal stresses.

I had six from the Grand Chute, WI. PD come in with this very problem, and one cure was to use silver bearing solder here, and program the timeout timer to less than 3 minutes, they had a previous shop disable the T.O.T for some dumb reason.


Just my previous observations with both the 45 watt and 100+ watt Spectras.



Enterprize.....One to beam up!