Need help to lower the RF power on a MT1000 & HT600

udt · Post by **udt** » Wed Mar 16, 2005 4:51 pm

Hello to all i have a MT1000 & HT 600 uhf i need to know where the pot on the board is to lower the RF power any help would be great i like to lower it about a 1 watt or so i have a service monitor but no info on these radios
thanks Jim.

spectragod · Post by **spectragod** » Wed Mar 16, 2005 6:45 pm

No pot, it is programmable via RSS in the service menu.

SG

kc7gr · Post by **kc7gr** » Wed Mar 16, 2005 8:46 pm

spectragod wrote:No pot, it is programmable via RSS in the service menu.

SG

Actually, not with the HT600 or MT1000. There's no setting in the RSS, that I know of, for either one for transmit power.

I've had a great deal of success in lowering the output power of HT600's simply by detuning the final PA trimmer cap slightly. The trick is to cut the power back, but not increase the current drain.

If you decide to try this, make sure you have the radio hooked up to a bench power supply which allows you to continuously read the current draw. I would imagine the MT1000 can be treated in the same way.

Happy tweaking.

kcbooboo · Post by **kcbooboo** » Thu Mar 17, 2005 4:36 am

Why do you need lower power? To conserve battery life, or is the HT feeding another piece of equipment? If it's feeding something else that needs less power, it might be easier to add a 3dB or 6dB attenuator to the output of the radio to reduce the output power. Of course, the current draw will be the same.

As stated above, there is no power adjustment on HT600s other than the PA tuning which should be adjusted for maximum power and minimum current within the rated values.

Bob M.

udt · Post by **udt** » Thu Mar 17, 2005 10:12 am

Hello again i like to conserve batt life this is what i like to do i already enabled the battery saver mode from the RSS software but still the batt will last about 1/2 hr on transmitt but will last around 6-8 hrs on standby (rec) this is a prostare psm-5447jh 10volt 1700mah-ni-mhand its new just bought it right now i can get into the locally repeater with only around a 1 watt and like to lower the rf down from 4 watts to 1 watt . thanks again Jim

kc7gr · Post by **kc7gr** » Thu Mar 17, 2005 2:38 pm

udt wrote:Hello again i like to conserve batt life this is what i like to do i already enabled the battery saver mode from the RSS software but still the batt will last about 1/2 hr on transmitt but will last around 6-8 hrs on standby (rec) this is a prostare psm-5447jh 10volt 1700mah-ni-mhand its new just bought it right now i can get into the locally repeater with only around a 1 watt and like to lower the rf down from 4 watts to 1 watt . thanks again Jim

You really don't want to go that low. Trust me.

Dropping any RF PA below about 50% of its rated output is a Really Bad Idea. Doing so can result in spurious emissions, unstable operation, and possibly self-destruction of the amp in question.

With that in mind: Don't take your output below 2 watts.

In response to an earlier query of "why low power?"... One example where this would be needed is on the MURS frequencies. They have an FCC-mandated limit of 2 watts TX output.

Happy tweaking.