xtvr max output ? setting help please

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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 2 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 pa0bie, that was my understanding too.. so surly its very low power out the XTVR too low for 2m ?

i dont mind embarrasing myself to save my transverter :)

Edit
ok i get it now sorry wm in w out .. never used a transverter before guys

http://transverters-store.com/144mhz.htm
(Edited)
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Rob Blackie

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i assume that it dosent matter where the power slider is set on the main smartSDR GUI as it does not effect the XTVR power out ?
  thanks
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Ken - NM9P, Elmer

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When using the XVTR output, the power slider controls to power output delivered to the XVTR port. You can find exact numbers and calculations in this post:

https://community.flexradio.com/flexr...

I don't recommend using the ANT1 or ANT2 output for a transverter. Use the XVTR port instead in order to prevent accidentally sending high power to the transverter.
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David

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I have two of these you can safely set the XVTR Max Power (dBm) to 15.0 when using the XVTR connection (not ANT) which is the max that is possible with the Flex 6000. These are great low cost transverters for the money. They are not Down East Microwave quality but they are the price either.
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Rob Blackie

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thanks guys, much appreciated,
david, i have the attenuator board also ( made up in the box) i know i wont need it for the 6300 ( i bought it 2nd hand) but can i just leave it in place or should i take it out ?
cheers rob
ps yes i will be using XVTR out not ant :)

just realised itve been typing xtvr  all the time lol ..
(Edited)
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David

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I would leave it out since it isn't needed the XVTR connection and that removes a possible trouble shooting point if something isn't working. Also keep in mind since there is only one receiver in the 6300/6500 you can do XVTR or HF but not both. So you can't monitor your local repeater and jump on when it becomes active while using the HF.
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Rob Blackie

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thanks david, i dont have it yet, its due today so, as the att board it already installed, would it do any harm to try it as is ?
cheers rob
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Mark Gottlieb

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I have the same one, assembled, and, using the XVTR port, have the settings at maximum 15dbm and the drive, on SmartSDR, at maximum.   The Ukrainian XVTR can handle up to 10 watts, I believe, so there is no harm you can do to it at these settings.   Still, with these set-up, I am only putting out 32mw to the antenna which can get me across the street, if I am yelling.  I use the Mirage B310-G amplifier, between the rig and the antenna, to push out, maybe, 20 watts.  20 watts is enough to contact most of the 2 meter repeaters in my area.
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David

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No harm but probably wont work well since you will be reduce the already low power from the XVTR.
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Rob Blackie

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ok pal thanks :)
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David

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I image there should be a way to bypass the attenuator board. I got the XVTR 144 and 220 boards only and have used them with good success. The plan is put them in a single box with a switch to easily change which one is active and then feed them into a amp to improve coverage on 144.
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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, Elmer

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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