On 24 Dec 2019, at 18:24, Mark Gottlieb <kk2l@...> wrote:

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

Hi Mark,

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

Yep there is a fan.  On my radio ( I am exclusively digital ) it runs a lot.  It is not the quietest fan around either.  It also will add some noise on the monitors baseline, but usually down 70 or 80 Db from carrier level.  When running digital and using a hardrock 50 amp, the duo power is under a watt.  So the heat must becoming from the idle current in the finals. 

You will like the Duo, but maybe not the fan noise.

 

Peter WA7MOX

 

Sent from Mail for Windows 10

 

From: Klaus Brosche, DK3QN
Sent: Tuesday, December 24, 2019 3:11 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] FM DUO Heat

 

Hi Mark,

 

I don't recall that there is a fan inside the DUO.

 

Klaus, DK3QN

 

Am 24.12.2019 um 19:24 schrieb Mark Gottlieb:

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

 

 

Yep there is a fan.  On my radio ( I am exclusively digital ) it runs a lot.  It is not the quietest fan around either.  It also will add some noise on the monitors baseline, but usually down 70 or 80 Db from carrier level.  When running digital and using a hardrock 50 amp, the duo power is under a watt.  So the heat must becoming from the idle current in the finals. 

You will like the Duo, but maybe not the fan noise.

 

Peter WA7MOX

 

Sent from Mail for Windows 10

 

From: Klaus Brosche, DK3QN
Sent: Tuesday, December 24, 2019 3:11 PM
To: EladSDR@groups.io
Subject: Re: [EladSDR] FM DUO Heat

 

Hi Mark,

 

I don't recall that there is a fan inside the DUO.

 

Klaus, DK3QN

 

Am 24.12.2019 um 19:24 schrieb Mark Gottlieb:

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L

 

 

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I'm also running 1W WSPR. The fan starts approx 15 seconds before end of cycle, i.e. about the same time as yours.

Thank you.  It is nice to know that I am not alone.

 

Peter WA7MOX

 

Sent from Mail for Windows 10

 

From: Kjell-Goran SM4GRP
Sent: Tuesday, December 31, 2019 8:23 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] FM DUO Heat

 

I'm also running 1W WSPR. The fan starts approx 15 seconds before end of cycle, i.e. about the same time as yours.

73 / Kjell-Goran SM4GRP

 

Hello all,

First, I wish you all a happy new year 2020 !

With the attached photo you can see how I solved the issue. It's a bit rough but very efficient. Since I've done this, the internal fan is almost never active any more. I found the pair of heatsink on ebay.

And I did not notice the internal fan giving an additional noise level. I don't think I will ever do, now.

Best 73's,
Alain F4HFS

Le 31/12/2019 à 20:11, Andreas Rehberg a écrit :

I attached a 40mm fan on the right side of the DUO
(12V running on 5V) which is barely noticeable..
so the internal one never turned over again..

[the internal is noisy in two aspects.. it sounds
like a jet.. and adds noise to the signal..]

73 & all the best for 2020, Andy, DF4WC
.

Am 31.12.19, 19:41 schrieb phoekzema Hoekzema <phoekzema@...>:

Thank you.  It is nice to know that I am not alone.

 

Peter WA7MOX

 

Sent from Mail for Windows 10

 

From: Kjell-Goran SM4GRP
Sent: Tuesday, December 31, 2019 8:23 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] FM DUO Heat

 

I'm also running 1W WSPR. The fan starts approx 15 seconds before end of cycle, i.e. about the same time as yours.

73 / Kjell-Goran SM4GRP

 

--
Alain Reiner

Hi Klaus, all,

Stop wondering, because I have not.

My reasoning is this one :

When I started using this nice transceiver, I noticed it was hot after 30 mn ~ 1 hour dialoguing. So I assumed the aluminium box was involved in the TRx cooling but was not up to the task. I just decided to help it.

I fixed the 2 heatsinks with double sided thermal tape. I did not even opened the box.

By the way, I'm not fair : I'm using a home made driver outing up to 20 W, attached to a BLA 350 PA from RM Italy. To get more than 300 W in RTTY out of the BLA350, the DUO just gives 150  to 200 mW. Perhaps my "solution" would be less "efficient" if I used the DUO at 5 or 8 W...

Honestly (now), I don't know if these additional heatsinks would be efficient for cooling the DUO at 5W or more, but I'm sure they would really help. It's easy and cheap. Why not testing it ? Anyway, they are easily taken off...

If you were interested, I could take my driver off and directly connect the DUO to the BLA350, and run it at 5 or 8 W. I would get 100W out. I could do it for 1 hour or more and see how the DUO would be heating that way... let me know.

ha, I'm not a QRP guy. IMO QRP is a lie. The guys pretending QRP have good antennas. The antenna power outweighs the Tx power. In my case, my antenna is a MagLoop in my attic. If I used 5 w feeding the magloop, you would not hear me :).

Best 73's,
Alain F4HFS

Le 01/01/2020 à 11:39, Klaus Brosche, DK3QN a écrit :

Hi Alain,

Happy New Year!

That dual-heatsink should be OK for another 100+ watts RF ;-)

I wonder how you've attached the final MosFet to these 'beasts'?

73, Klaus, DK3QN

Am 01.01.2020 um 09:28 schrieb Alain Reiner:

Hello all,

First, I wish you all a happy new year 2020 !

With the attached photo you can see how I solved the issue. It's a bit rough but very efficient. Since I've done this, the internal fan is almost never active any more. I found the pair of heatsink on ebay.

And I did not notice the internal fan giving an additional noise level. I don't think I will ever do, now.

Best 73's,
Alain F4HFS

Le 31/12/2019 à 20:11, Andreas Rehberg a écrit :

I attached a 40mm fan on the right side of the DUO
(12V running on 5V) which is barely noticeable..
so the internal one never turned over again..

[the internal is noisy in two aspects.. it sounds
like a jet.. and adds noise to the signal..]

73 & all the best for 2020, Andy, DF4WC
.

Am 31.12.19, 19:41 schrieb phoekzema Hoekzema <phoekzema@...>:

Thank you.  It is nice to know that I am not alone.

 

Peter WA7MOX

 

Sent from Mail for Windows 10

 

From: Kjell-Goran SM4GRP
Sent: Tuesday, December 31, 2019 8:23 AM
To: EladSDR@groups.io
Subject: Re: [EladSDR] FM DUO Heat

 

I'm also running 1W WSPR. The fan starts approx 15 seconds before end of cycle, i.e. about the same time as yours.

73 / Kjell-Goran SM4GRP

 

--
Alain Reiner

--
Alain Reiner

Hi Everybody,

I should have my red transceiver this Friday and am looking forward to it.  Having owned a KX3 and KX2, one of my concerns would be heat buildup while operating the digital modes or SSB at full power.  In my opinion, the Elecraft QRP rigs' achilles heel is that they quickly overheat while operating continuously either in digital or SSB modes.  At that point, both radios revert to 5 watts, or less, output which is not made clear, of course, in their promotional materials.  I do know there is a fan in the ELAD so that should mitigate the issue.  I only see a few posts in the group regarding this.  Would anyone care to comment?

73

Mark
KK2L