Does no aluminium block heat sink = fried 4G modem?

Okay, have dramatically cut out most of what was becoming a very long first post:

1.) Think the Omnia is JUST what I need, as it can do 4G too.
2.) Would like to buy.
3.) Without the aluminium block/heat sink, the modem will fry.
4.) But, no way I could know what size aluminium block to get - as the original seems no longer available. If too big, I don’t have the tools to shave it down.
5.) I therefore cannot risk to buy.

If you want to buy the original all in one kit ⇨ look here.
If you want to go more powerful get ⇨ the alloy block, a good WWAN-card like Sierra Wireless MC7455 from a dealer near you, as well as pigtails and external antennas of your choice and make sure you follow instructions from ⇝ this thread.

Thanks a million for that. Much appreciated.

I’ve been reading everything I could, yet couldn’t find that concise detailed information.

You’ve really helped me out.

I’ll be purchasing before end of this week

I’ve no problem with heat. I put a tiny fan on top of my MC7455.

Ah, thanks for that too.

A question: Is the 4g robust enough (overheating) to be used as the ONLY main source? People talk about the 4G on this hardware as being a fallback for when the main WAN goes down. I’d be using 4G 100% of the time.

There are some outtakes that happen, but with the script in the linked thread above (credits to @Nowaker and @lampra) it was running like a charm for three weeks starting 09’2020 for me in my allotment stand-alone power/“automation” system before I winterized everything. I am using the alloy block for cooling.

Excellent!Gets better by the minute.


Btw - never give up easily when dealing with Linux stuff. There might be some occasions where you get really lost (e.g. bugs and when you try to solve a really special solution), but normally there are some helping hands out there. Just be patient for them if you digged deep into it and still can’t solve something.
@Nowaker’s thread popped up just when I was trying the very same thing and was about to give up on this topic :hugs:
And: really use search functionality. Sounds stupid but vary your queries and you may get better results. Just my 2 cents :wink:
Edit: several topics are also discussed in the “upstream” openwrt forum.

And last one: get yourself some decent antennas e.g. like the DeLock 88808 (or similar depending on your carrier). But be cautious - they don’t work with the Quectel WWAN-cards.

I’m currently running Arch Linux, so I know all about not giving up. So yes, never say die! Always get there in the end.

Okay, I’ll look at the upstream openwrt forum too

Will look into that too. Maybe just get the standard package first and see how I go from there.

The problem with the standard package is:

  • limited DL/UL-bandwidth with the card itself and
  • due to the fact it isn’t compatible with external (high-gain) directional antennas you might not get the desired radio reception

All good info. Hope this thread helps other newbies who are a also little confused with the whole Omnia 4G thing. Thanks.

Just to let you know that so far, most of the issues I faced with omnia 4g were caused by the modem (EC20 getting unresponsive even to AT commands) and the sim cardholder (switching off sim). I achieved minimal 4g stability using a script that checks the connection, the modem, the sim card state and performs some actions (reset the modem, power on sim) when needed. Though, compared to other 4g routers-modems that I have used and other cheap sbcs with minipcie (eg espressobin) I would not recommend it for 100% 4g usage except if you are ok with the issues mentioned above. If you need, always on, remote connection from the internet, better don’t rely on the 4g connection. Also bear in mind that to my knowledge there is no support from cz.nic on 4g issues. Finally, I could not bring up a connection using modemmanager and EC20 on omnia so far which would theoretically improve stability (waiting for Luci integration with the next 21.xx openwrt & TO release).
On the bright side, don’t know why but since turris os 5.1.8, the 4g connection seems to be more stable for me (75 hours without any issue!!).

Sorry guys, I haven’t read the thread all for now, but I’m using Quectel EP06 in my Turris Omnia since December, even though there were some issues at the beginning of January due to bad SIM, and once it was replaced, it works flawlessly!

I’m using it with T-mobile LTE as primary connection.

Appreciate the effort you’ve put into typing all that up. Puts another spin on it. We’re already approaching £400+ when you add on the 4G extras.


Ah! Guess the only way is to jump in and see.

Another quickie, still on the subject of heat:

While I’m waiting for my Omnia to arrive, been reading about the need for tiny thermal pads (sticky?).

I have zero knowledge about these, but a quick eBay search shows they’re very cheap and come in various thicknesses from 1mm to over 5mm. Can anyone tell me a suitable thickness to get?

Maybe they’re not even needed, but why waste time once the box arrives.

Can’t entertain the idea of a fan, as that would introduce noise into the equation.


I’ve used copper thermal pads with double-sided adhesive tape from AliExpress to build a heat bridge for the LTE modem (Quectel EC25-E) in my Turris Omnia.

Speaking of height, it took 10 pcs of 1.2mm copper pads, 8 pcs of 1.0 mm copper pads and 19 layers of 0.15mm tape.

This DIY heat bridge works quite good, temperature of LTE modem (as reported by AT command AT+QTEMP) is lower than temperature of Turris Omnia CPU (as reported by thermometer command) by 16 °C.

Thanks Waqur, most appreciated

However, as I’ll already have the aluminium block, I’m talking about putting thermal pads on top of that block to snug it up to the metal case above. Or at least that’s what I’m lead to believe other users are ordering/doing. Maybe I’ve read it wrong.

Or, maybe the block is very shallow and the case top high, and that’s what you’re talking about.