xtvr max output ? setting help please

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  • Updated 3 years ago
Hi, i got one og those russian 2m transverters and tying not to blow it up.( its 10 watt max input)

 it seems to go upto 15 dbm in the smartsdr setting in xtvr tab, ( i have it set at 2.0 at the moment) there is much confusion in my head as the log10  formula dosent seeem to work out to internet searches etc..
so.. What should i set it at for say, 7 Watts into the transverter ?
 thanks rob
p.s.
theres a video here detailing it by a guy, wich was very helpfull but hes using a linear with his so wants a much lower input as the output is quite dirty apparently
https://www.youtube.com/watch?v=w8JQ0SIUlI8
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Rob Blackie

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Posted 3 years ago

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Brian Morgan VK7RR/4

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Rob, If you have one of the transverters from the Ukraine, a comfortable level to set your Flex output to is 6dbm. I would not go above that. It is a conservative figure. I have experimented with these devices on 2 metres and 440. The 2 metre one is sort of okay, with the crystal not being as stable as I would like, but every 440 one I have looked at has been unstable and has a spur on about 480 mhz. I have stopped using mine.
Hope this helps,
Brian.
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Rob Blackie

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hi thanks Brian,  according to online calculators, 6dbm converts to 39mw .. is this correct ?
(Edited)
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pa0bie

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0 dBm = 1 mWatt

+6 dBM = 4 times more is 4 mWatt

+10 dBm = 10 times more is 10 mWatt

+20 dBm=  100 times more is 100 mWatt.

+30 dBm is 1000 times more is 1000 mWatt is 1 Watt.

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Rob Blackie

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yes, i was going to buy just the xvtr board from the ukraine but then saw a chap in uk selling one 2nd hand barely used, all made up as sold so i figured what the hell
 :) cheers rob  2M0LDT
(Edited)
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Ken - NM9P

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If you leave the attenuator inline, you will likely get very little power out of the transverter, consider that the attenuator was designed to take a maximum  ten Watts down to a safe 100 milliwatts.  That is a 20 dB drip in power.  30 dB if it was dropping it all the way down to 10 milliwatts.  That doesn't leave much drive power.

BTW:  Once you remove the attenuator and get things running, I would not recommend driving the transverter to a power much more than 2 or three Watts of measured output.  Doug Hall has published data that says the supposed "10 Watts" output of the transverter starts to get very dirty above about two watts.  It would be better to drip power to the transverter and use an external amplifier to get higher power output.
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Rob Blackie

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yes indeed Ken, i dont mind getting a little dirty  :0)
but yes, thanks for the advice
Ron  2M0LDT
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Rob Blackie

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too weird ? nothin worse than spelling your own name wrong .. lol
(Edited)
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Rob Blackie

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update
seems to work fine with attenuator board in, but will remove it is i see any issues
thanks again chaps :)
Rob 2M0LDT