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  1. Xiegu-X6100
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R1CBU FT8 Power restriction

 

Just started using RiCBU firmware and it's great.? I was just curious as to why he limits FT8 to 5 watts, as the X6100 only does 10 watts at best.
I would like a few more watts to compensate for my poor location which makes it difficult to be heard.
?
?
 

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even at 5 watts the back of the radio can get hot, I had a cooling fan until I removed the back and battery and replaced with a printed assy with a fan to keep cool.


On 1/23/2025 2:04 PM, Bill via groups.io wrote:
Just started using RiCBU firmware and it's great.? I was just curious as to why he limits FT8 to 5 watts, as the X6100 only does 10 watts at best.
I would like a few more watts to compensate for my poor location which makes it difficult to be heard.
?
?
--
Gregg W9DHI, ORC Repeater VP, Webmaster and CTO
 

Looking around at previous threads, it seems FT8 at even 5 watts produces quite a bit of heat ( /g/xiegu-x6100/topic/20_minutes_of_ft8_at_5w/92587544 ).? In my own use, the radio has gotten slightly warm just answering CQs.
 

@W9DHI - Would you happen to have a picture or better description of the mod you did with removing the battery and adding fans?
 

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printed this:?


On 1/23/2025 3:32 PM, John via groups.io wrote:
@W9DHI - Would you happen to have a picture or better description of the mod you did with removing the battery and adding fans?
--
Gregg W9DHI, ORC Repeater VP, Webmaster and CTO

20250118_101258.jpg
20250118_101316.jpg
20250118_101320.jpg

 

I did the heat sink mod to the back of the unit.? It made a big difference, and when I run FT8 at 10 watts (original software with computer), it seems to run warm, but not too hot.? I try not to overtax it, though.
Do wish I could get a bit more power, as R1CBU firmware has so many advantages.
?
 

I find 4W adequate most of the time but if I need more, I run the 50W amplifier between 20W-50W.??
?
 

The reason is because FT8 as a general rule should only be safely run at 35-50% of a solid state transistor’s rated output.
 


The reason is because FT8 as a general rule should only be safely run at 35-50% of a solid state transistor’s rated output.

The problem is not in the transistors, but in the X6100 output transformer.
There have been many cases when the output transformer burned out when working in FT8

73!
 

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Mmmh, I run the x6100 with 8Watts for now more than 18 months, sometimes also several Hours Long, only warm and no problems?
Von meinem iPhone gesendet

Am 24.01.2025 um 15:10 schrieb Oleg - R1CBU via groups.io <belousov.oleg@...>:

?

The reason is because FT8 as a general rule should only be safely run at 35-50% of a solid state transistor’s rated output.

The problem is not in the transistors, but in the X6100 output transformer.
There have been many cases when the output transformer burned out when working in FT8

73!
 

Oleg-
?
Thanks for the explanation.? Once again, great work.
?
Bill
?
 

On Fri, Jan 24, 2025 at 05:13 PM, dc2jr wrote:
I run the x6100 with 8Watts for now more than 18 months, sometimes also several Hours Long, only warm and no problems
You don't have to take my word for it. Anyone can open up their transceiver and look at the diameter of the wire in the output transformer (;
73!
 

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The x6100 RF final is the exact same MOSFET as fitted to the icom 705… this is a well trodden and usually false assumption trodden path. I was one of the first people to significantly document the RF final issues in the x6100 and can tell you it is rated to far in excess of 10w. The issue is the case. The issue is the soldering of the MOSFET to the die. The issue is most people think the heat is dissipated via the back and it is not it is transferred via the middle H alloy heat sink to the top and bottom of the radio. The issue is the design is bad for air flow and 10w ft8 often boils the solder on the ?rear of the MOSFET and it starts to loose power so people drive it harder and harder till it goes. In this forum I documented multiple steps to remount and BOLT down the mosfet using graphene film. This will.. I repeat WILL prevent 99% of radios ever going wrong through heat transfer (or lack of it) . A fan on the case back will help yes of course but it is pathetically effective compared to taking heat from the correct place (the bottom). Xiegu dropped a ball on the mounting of the mosfet and that is the end of the story. Fix it or drive it at 5w and lower duty cycle to avoid issues.?

Greg did the ?? right thing limiting it to prevent an influx of complaints of broken radios?

Sorry but this topic of 5w/heat/fans and al manner of stupid claims and theories needs putting to bed guys.?

Cheers
M0RWV?


.

On 24 Jan 2025, at 13:56, Randy K7RAN via groups.io <padawer@...> wrote:

?
The reason is because FT8 as a general rule should only be safely run at 35-50% of a solid state transistor’s rated output.
 

Spot on Scot. Did they resolve this on the 6200,can't see a lot of difference in case design apart from removable battery.
Also 5w ft8 is same power as 10w ssb due to duty cycle. ?
 

I trashed an X6100 using 10w on ft8. It was under warranty, and they replaced it with a suggestion to not run ft8 on 10w for very long. I would rather have an operating radio and potentially less contacts than the extra 5w that may or may not make a difference.
 

I would say that you will lose very few QSO wiht 5 W compared to 10 W on TFx.
?
73 de SA5QED David
 
Edited

Try with 10ish V DC external power supply and note the difference in heat on the radio.
?
73 de SA5QED David
 

I believe that the temperature of the output transformer depends on the output power, not on the external power supply voltage. Reducing the external power supply voltage helps reduce the heat dissipation of the transistor. But as far as I know, the transformer is weaker than the transistor.
So - 10V PSU will make your transceiver cooler, but it might not prevent from burn in case of long work with 10W on ft8.
--
Georgy // R2RFE

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