Reply With QuoteLiterally!Originally Posted by emmeesse68
Yepp... I did a simple test and noticed a remarkable improvement (see my post above, on Nov. 22th).
Then I removed the cable and started some investigation about a more subtle antenna, but that's still work in progress.
Stay tuned...
Literally!
Ive just come back to this thread after starting it some time ago. I had all but given up on a solution to this, but it appears that there maybe something in this USB cable trick. I have many of these lying around, so Ill give it a go.
The solution in the end for me, before reading this today, was a third controller. Once we got used to knowing which rooms were on which controller then its easy enough from the app to set what we want when we want.
Even people building new homes aren't going to go to the expense of having an RJ45 socket wired to every radiator. Even if it was in budget and the technology was there, trying to get a setup like that to look aesthetically pleasing enough to get passed by the wife would be impossible.
Perhaps rather than a range extender, Honeywell could do worse than look at a device which talks to all the HR92's etc within range and uses a wired backhaul connection to send this back to a wired controller unit/s.
I have to say that I'm excited to try the USB cable method though, it may take away a couple of my occasional connection issues with remote radiators which is at least one step forward. Why don't Honeywell at least offer something like this out of the box too? Are their product development and marketing teams asleep?
"Oh, you have a slight range issue with this radiator Sir, it may cause a couple of drop outs every now and then, but we could overcome it with this range extended radiator thermostat for an extra £19.99. Would you like it installing?"....
I know that is the settled view now, but I still find it odd that we are all happy to run a pair of 15mm copper pipes to each radiator but we worry that running a thin Cat 5 cable there would be too much hassle and unsightly.
Been lurking here for a while but have recently successfully added an external antenna to a couple of HR92UK radiator valves that are at the extreme end of my system and frequently threw comms errors on the Evohome controller.
I can, after inspecting the PCB, confirm that the actual radio is not connected to the micro USB connector. The control PCB of the HR92 is actually quite easy to get at once you have managed to see one disassembled, the key is to remove the bevel gear driven by the top knob first then the front of the unit just pops off (after a bit of levering). The internal antenna is just a piece of wire connected to the CC1101 output via some filtering via a press contact. I removed the contact on the main body of mine and tucked it down the side then drilled a hole and soldered in a SMA socket just below the ‘pop off’ window for the USB connectors. The SMA socket was then soldered via miniature PTFE coax to the ground and signal contacts on the PCB. I have some photos but can’t seem to post them.
I found that on one controller it was sufficient to just use an external SMA 868MHz antenna from Ebay but for the radiator that was a furthest away I fabricated a 868MHz 1/4 wave mag mount that just sits on the top of the radiator which acts as a nice ground plane. The benefit of adding an external socket is that the external antenna can be customised to suit.
A few words of warning... this is clearly something that is done at ones own risk and it needs a steady hand and some experience with a soldering iron. I’m a retired electronics engineer and radio ham with many years experience of SMD work. It has solved my problems but I take no responsibility for what others may decide to do!
I can only surmise that the commercial booster works by creating an improved ground plane for the internal antenna and would probably work best just laid under the controller, the only active part would be the shield of the cable that is connected to the shell of the micro USB connector so it could make some improvement in a marginal case and could be worth trying by using a normal micro USB cable unterminated at the far end.
Hope this helps a bit. I found this forum to be extremely useful when I installed my Evohome system and I glad to be able to give something back.
Clive
Thanks Clive for that useful and informative post.
P.
So how much will you charge to alter people's HR92s for them, Clive? I have three that would benefit from improved reception!
Also, I assume this works both ways - i.e. just improving reception could leave the HR92 able to hear the controller, but not able to talk back.
I think I might need a 24 element YAGI on one of mine - and maybe a rotator to get the right reflection !
Did you look at all into antenna improvement on the controller ?
73's Kevin
Not looked at the controller as although that would offer an all round improvement I don’t want the clutter where it is installed. The improvement ‘should’ according to accepted antenna theory be reciprocal i.e. for both transmit and receive. Actually in the case of mine the HR92s seemed to reliably hear the controller but the controller seemed to miss updates from the HR92 and flag up communication errors. I haven’t had an error now since I did the modification.
A few pictures...
28997B8A-158C-4699-A169-18896394246A.jpg CACF1789-3F2F-4B85-8709-726D2AA28B2A.jpg B48C93E2-3313-4BE8-B8EF-F5D49BDC59D4.jpg CC1214F6-1FEB-4ADB-933F-22816626B55B.jpg 22DB1972-2A38-4026-B6DE-176700A56712.jpg
And a few more...
CB028FD5-76F1-42E5-B678-8D9CDD0DDA10.jpg 25DF78C2-0B1D-4138-A794-A318D89EA057.jpg AD0912BF-2E98-4CDE-8684-5F2E67CAFB7D.jpg
The SMA sockets I used we’re actually ready made SMA to MCX cables that I had in my collection. I just cut off the MCX plug. With hindsight it might be easier to just remove the existing antenna from the contact on the main case and connect the external socket to that along with a ground connection.
Last edited by clivesanders; 8th June 2019 at 12:18 AM. Reason: Additional info
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