Digi modes, HL2 power, temp C, fan, duration and I think I need a fan!

[KC3QVF]

I think I need a fan to cool the HL2 during digital mode TX.  I am inviting you to submit data for your HL2 running digital modes in CSV snippets.  I will start with mine:

Thor56, 4W, 42, no fan, 5min

The longer I run, the higher the temp.  I have examined the archives here and seen FT8 generatiing 32C but without a power value.  I am interested in some questions, like:

1. does the PA linearity degrade above 2W?  (N2ADR has a note about this in Quisk)

2. are some modes more demanding than others?

Let me know if you have measured these.

73 KC3QVF

[Chung Ung Kim]

I purchased HL2 on June 3, 2021.

By using HL2  I made 3145 QSO records and 2071 QSL records on LOTW.

99.9% is digital FT-8 mode QSO.   Hot Summer temperature in Korea is mostly over 30 degrees and I often operated HL2 in full power (around 6W) without fan uninterrupted 

more than one hour.   Temperature of HL2 hit more than 40 degrees.

However my HL2 had no problem. HL2 is tank like strong and never die.

I am very much happpppppppy with HL2.

De HL2IR

2023년 11월 26일 일요일 오전 8시 5분 17초 UTC+9에 KC3QVF님이 작성:

[KC3QVF]

HL2IR,

Thanks for your remarks! Congratulations on so many FT8 contacts.  If I made an entry for your FT8, would it look like:

FT8, 6W, 40, >60min

Do you agree?

73 KC3QVF

[Ron Lewkowicz]

FT8,6W,35,no fan,>60min

[Steve Haynal]

Hi HL2IR,

I am happy to hear your HL2 is working well for you. In general signal quality will degrade if an amplifier is set to higher amplification, but I have not seen problems with FT8 or WSPR at ~5W.

The HL2 has built in protection in case your PA does get to hot. It will stop transmitting until it cools. 

In the hottest environments, you can point an external fan at the HL2 to help. Small internal fans don't help much, but external air movement can help cool.

73,

Steve

kf7o

[Chung Ung Kim]

I never experienced stop transmitting during my long continuous FT-8 QSOs.

Temperature drops rapidly under 40C during 15 seconds stop period if it rises over 40C. 

I do have an external fan but I do not think I will use it for HL2 in the future.

I am enjoying daily scan 4 bands and catch new country.

The HL2 is the most readiness radio for quick QSO.

I thank you very much for giving me an awesome radio

73 HL2IR   

2023년 11월 27일 월요일 오전 11시 2분 21초 UTC+9에 softerh...@gmail.com님이 작성:

[Kristofer Danner]

I did some fan experimentation a few years ago and it did drop the temp a good bit. https://groups.google.com/g/hermes-lite/c/pEczEEx0378/m/_087l4dyCAAJ

["Christoph v. Wüllen"]

I wonder whether there really is a problem.

I have a HL2 without heat shim and without fan, which seems to the the typical
case for most of the "older" HL2s.

For TX at full power, the temperature rises rather quickly, but also goes quickly
down after TX, which indicates resonable thermal contact between the finals and
the case (this is where the screw in the bottom plate, seen from outside,
is good for).

Up to now I have never worried about the temperature going up to 40 - 50 C,
as long as it goes down to about 30 C during RX. With my external PA and
its huge heat sink, these temperatures are also seen (however changing
at a much slower rate).

So the question is: are temperatures in the range 40 - 50 C
that terrifying?

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[KC3QVF]

>> So the question is: are temperatures in the range 40 - 50 C that terrifying?

This is a good question.  The datasheet for the LDMOS output devices:

Datasheet for AFT05MS003NT1 NXP Semiconductors MOSFETs | Octopart

says good to case and device temperature of 150C, but MTTF will be affected at that temp.

73 Constrainted

[KC3QVF]

The gain measurements are taken at 25C.  I wonder about the linearity of the PA at higher temps.  The device manufacturer probably has that data in "application notes."

73 KC3QVF

[Ron]

I expect extra heat speeds the breakdown of components. In practical
terms does this really matter? If it means they fail in 20 years instead
of 30 do we care?

I try to keep my electronics running cool though. If there is an easy
way to let them run cooler then why not? I had one DVB-S2 tuner that
would become a little unstable at times. I just sandwiched the unit
between a couple old CPU heat sinks and haven't had an issue since.

On 2023-11-27 10:55 a.m., KC3QVF wrote:
> >> So the question is: are temperatures in the range 40 - 50 C that
> terrifying?
>
> This is a good question.  The datasheet for the LDMOS output devices:
>
> Datasheet for AFT05MS003NT1 NXP Semiconductors MOSFETs | Octopart

> <https://octopart.com/datasheet/aft05ms003nt1-nxp+semiconductors-70299197>

> https://groups.google.com/d/msgid/hermes-lite/2fa689b6-10e6-42b1-be3e-6b141e108347n%40googlegroups.com <https://groups.google.com/d/msgid/hermes-lite/2fa689b6-10e6-42b1-be3e-6b141e108347n%40googlegroups.com>.
>
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[Steve Haynal]

Hi Group,

There are equations that allow you to calculate the die temperature based on PCB temperature reading. (Heat transfer through PCB traces, and then package.) I went though these when designing the HL2. I decided 40C-50C was an acceptable range based on the PCB temperature measurement the HL2 makes. TX is disabled at 55C and is not enabled until the temperature falls below 50C. I agree with Ron that higher temperatures speed the breakdown of components, but also agree with him that we are probably talking 20 years versus 30 years, although I've never tried to calculate that. I regularly operate FT8 in the 40C to 50C range. For a commodity budget radio like this, I think that is perfectly acceptable.

73,

Steve

kf7o