Final temperature

Geert Balsma PA3CPS

I often run maximum power in Digital mode (FT8). Can this harm the final from my Flex 6500?
My DDutil temperature readings are 60 degrees celcius when i run maximum power.

WK2Y

Is the fan going into high speed?  

Geert Balsma PA3CPS

I don't no. My Flex is located in another room. But i can test that.  

Mark WS7M

don't take this as "the word" but I think the flex is pretty well protected if temp gets too high I believe things are shutdown.  Hopefully someone more knowledgeable will weigh in.

But to be sure I power limited my radio to 75 watts in the radio setup.

I also typically use my amp.  I set my flex to like 3 watts which drives my SPE 1K to about 175 watts.  

With my lousy antenna this probably works out to an ERP of like 50 watts (sigh)

Ken - NM9P

I run my 6500 at close to full power, (about 80 watts to make sure my signal is always clean) and with the 15 seconds on / 15 seconds off duty cycle, the rig hardly knows it is transmitting. I have not had the fan go to high speed, On JT-65/JT-9, it is another story. It often hear the fan switch up to high after several QSO's in a row in those modes. Though the temp never seems to get excessively high. Btw... your rack mount looks very clean, neat, and tidy. As long as you have adequate ventilation..... Ken - NM9P

Bob G W1GLV

Why so much power, I''ve made plenty of contacts around the world at 15 watts maximum.

Ken - NM9P

Ft8 only copies reliable down to about -20 dB. If you are only -23 and go from 15 to 60 Watts, that is a 6 dB increase, taking you to -17 dB. The difference between a good contact and not being heard at all.

Mark WS7M

I use as little as possible.  I have run my amp with 1 watt out from the Flex.  That gives me about 40 watts created at the amp.  I have a pretty lousy antenna and I would figure with coax loss and antenna inefficiency that I am radiating (with 35 w from the amp) about 20 watts.

I usually start there.  If I am not heard I bump up 1 watt on the flex. At 2 watts I get 80 from the amp.  Again I figure ERP is about 50 perhaps. I keep working it up as I need to.

I find when I have the amp running about 80 W that I can get to almost anything on FT-8.  There are a few nodes on my antenna that I just can't overcome.

But keep in mind that JT65 and the other modes in that software are "weak signal" modes.  Not "low power" modes.  While it is always a great idea to use as little as possible there is nothing wrong with adding power to get the contact done.

NX6D Dave

This question comes up regularly. The answer from Flex has always been 'no'. Processors in the radio watch voltages and temps and other parameters carefully and will shut down the radio if damage would be done by continuing.

NX6D Dave

The cooling fans going to high speed are an indication that the monitoring systems are working. 

Chris DL5NAM

..and lower signal from TRX into a amp will bring a cleaner signal out. ( here 3 Watt in gives me 2k out )

KC2QMA_John

To my knowledge the 63/65/6700 are 100% duty cycle or close to it. The P.A is designed to be able to cool under full load. That being said if you were to place the radio in a very hot room or in direct sunlight once the PA exceeds the maximum allowed temperature the radio will go into protect mode until it returns to safe temperature.

The new radios have an even better cooling system because of it’s lager heat sinks and lager fans.!

Tim - W4TME

60C is 10 degrees under the threshold where the fan starts rotating at high speed.  You're fine.

KC2QMA_John

K3SF

KC2QMA_John

Neal Pollack, N6YFM

KC2QMA_John

Chris DL5NAM

Make no sense if you ask here same question 10 times - it's a user board. Technical support make only FRS direct, so try to phone them or write a email

Chris

KI4P

Well, there you go, a reason not to mess with the computer part of the band! Ha!

John KB4DU

Ken;

I have tested my 6400 with a dummy load on FT8, calling CQ several times. The temp reported by FRstack reaches about 90C after several iterations, with the fan at high speed, but the temp seems to stabilize there with the 50% duty cycle at about 80 watts. Sometimes the power will reduce a little also.

KC2QMA_John

A better fan with more CFM's would sure help keep these temps down.
90C is very HOT 100C can boil water!!!

https://community.flexradio.com/flexradio/topics/6600m-fan-speed-questions

Joe N3HEE

Last weekend during the contests I found calling CQ (CQ TEST N3HEE N3HEE)every three seconds for five minutes or more on CW the PA would reach 60 C and stay there. The fan was ramped up on high. 

I also notice that even at idle the radio warms my air conditioned shack !  It is generating a lot of heat !

KC2QMA_John

Joe N3HEE

Yep, it would melt down !  I only noticed how warm it made my shack while it was in for service.  When I got the radio back and running 24/7 I noticed how warm the shack was getting.  It generates more heat than my computer.  The computer has two 400MM case fans one front and one rear, power supply has a large fan and the CPU has a fan.  The computer does not warm the room if the radio is turned off.

KC2QMA_John

Michael N3LI

Go all caps next. Bold type isn't yelling loudly enough. Hey John in all seriousness - we are the user community, not the designers and holders of the specifications you are demanding. You might try communicating with Flex directly, instead of becoming angry with us because we don't know. 

Joe N3HEE

John is not angry with us !  He just wants some simple answers.  AND SO DO I 

KC2QMA_John

Neal Pollack, N6YFM

So, again, call Flex and put on a support request.

Lionel

Excellent point about magnetics.  The Flex in many cases, maybe most, will be the strongest element in the entire antenna system/transmitter.

I've seen the SWR creep up using FT140-31 or 61 (don't recall) at full T4X power.  I stopped pre-smoke.  SWR creep as you note, hopefully not leap, is a warning.  I homebrew all of my baluns/ununs, some actually work as intended, but lessons learned.

Good info Neal.

I'm pretty sure my 6400 will protect itself from ME.