Internal issue every ten minutes.

[#1]

This one has got me stumped......
Asus rt-n66u, latest stock firmware, but may not be related.
Every 10 minutes at 09, 19, 29, etc my security camera starts to flash 'no connection' then almost immediately reconnects in a few seconds. This seems to indicate that every 10 minutes, on the dot at xx:x9, something is amiss that is causing a very brief issue.
Knowing the exact time it's going to happen I have triggered a Speedtest and that is completing through the disconnection time/period without issue. The router logs are showing no issues.
I've contacted the camera support dept and they have no issues their end.
So, what are the recommended steps to find out what's causing it?
Thanks

[#2]

Is this a wireless camera? Have a look in your router system / event log to see if there are any events at the same time as the disconnections. Might be the wireless dropping out, DHCP lease expiring, or NAT / UPnP mapping expiring. Are there any logs on the camera at all?

[#3]

Thanks
It's now 04:29 (don't ask) and so far this morning, 04:09, 04:19 and 04:29, no issues.  This has been going on for a few weeks now so I know it will start again later. The first I spotted yesterday was 16:19 but I'm going to try and spot the start time later.
The logging on the Asus is fairly basic but I'll have a look later. The camera has no logging (Y-Cam HD HomeMonitor)
All that has changed this year since it started is my phone is now recently Android Marshmallow, that connects on 5g, the camera is 2.4g. Plus I've installed a Panasonic HDD/DVD which is Cat6e to the router. Once it starts later I'll unplug everything  (Panasonic and Netgear Powerlines). PC and smart TV was off during the issue so those Cat6 connections should be OK.
I did upgrade the router firmware fairly recently but I can't remember when.

[#4]

FWIW, I have the same router (also on the latest firmware) but am not experiencing any wi-fi issues.  I have devices connected to both frequencies too.
The N66U is a decent quality router so I'd be surprised if that was the issue, TBH.  Did this issue start as soon as you started using the camera, or when you replaced your previous router for the Asus?

[#5]

I had a similar problem with a wireless printer and it turned out the printer didn't like having the same SSID on 5GHz and 2.4GHz. I renamed them to mynetworkname_5G and mynetworkname and everything was happy from then on. Might be worth a try, apparently quite a lot of devices don't like having one SSID for both channels (including Xbox One).

[#6]

That's a good point actually. I did change the 5GHz SSID on my Asus to something different when I set it up.

[#7]

Thanks for the info.
I checked with PN this morning and they confirm my router logs that I've had a smooth uninterrupted service for 79 days.
I'm beginning to think the DHCP licence bit could be a runner because my Sony Smart TV DHCP licence is due to run out in under 2 hours. The TV is on but no sign of it trying to update the licence. Currently showing:
tv20e3c0fcb113                  192.168.1.173          d8:d4:3c:a1:a1:e7        1:53:40
One hour 53 mins = about the same time it started playing up yesterday.
It did update this morning at 04:08 for 12 hours.

[#8]

The default DHCP lease period is 24 hours on these routers, which is quite short. You can check what your lease period is set to in LAN > DHCP server.
One way to confirm if it's DHCP related would be to temporarily give your camera a static IP outside the DHCP range, and see if the issue persists.

[#9]

How do I do that ?
It started again at 1759 and stopped at 1819, first to last disconnection. 18:29 all OK again and has been since.
DHCP is still odd. The TV picked up a new licence just after I posted. The dodgy one is the daughters smartphone. That only had a short while to go, expiring around 17:00 but the new licence didn't start till around 18:00 (24hrs) so there was an hours gap. Nothing in the logs. She comes in and immediately turns her phone off so that can't help. Trying to update but can't contact the phone?
Very strange, every 10 minutes at exactly xx:x9:04. Must be just a very brief disconnect because the camera comes back up in seconds.