# Radio interference - Xmas? **URL:** \ **Category:** emonTx\ **Tags:** radio\ **Created:** [14 December 2019 16:39 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736 "2019-12-14T16:39:51Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [14 December 2019 16:39 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/1 "2019-12-14T16:39:51Z")
I’ve just noticed that I’ve been getting blocks of missing data from one of my emonTx. Some may remember that I’ve got two - one in the house next to my emonBase and one some tens of metres away in the garage where my mains inlet is. It’s the remote one that is giving blocks of nulls, sometime for hours at a time. ![Screenshot_2019-12-14%20Emoncms%20-%20RSS%20graph](https://community.openenergymonitor.org/uploads/default/original/2X/2/2be71a9f208cd7f08f5b95817ec44b4850664c1e.png) The graph shows the radio signal strength from both emonTx. You may be able to see that prior to this month there have only been brief signal drop-outs, although there are three odd spike reductions in November (there are none prior). But since Dec 5 there are some noticeable gaps in the data. My immediate thought is that the gaps are due to radio interference of some kind and the only thing I can think of are Xmas decorations, particularly outside Xmas lights. We have several neighbours who are quite keen on them! Is there any way I can detect radio interference without special equipment? (What equipment would I need?) I’d like to get some confirmation before I go annoying neighbours with my concens. Thanks for any help, Dave ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [14 December 2019 16:56 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/2 "2019-12-14T16:56:13Z")
My first thought would be to boost your transmitted signal strength by [fitting a ground plane](https://community.openenergymonitor.org/t/improving-rf-signal-strength-emonth-emontx/5318/16). What you _ **don’t** _ want to do is improve reception of the interference by having a ground plane at the receiver - the emonBase. ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [14 December 2019 16:57 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/3 "2019-12-14T16:57:08Z")
That emonTx uses an external dipole antenna. Edit: and is wall-mounted. ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [14 December 2019 17:12 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/4 "2019-12-14T17:12:39Z")
I assume the neighbours lights are the flashing variety, and we’re assuming they went up on December 5th? Have you any idea which neighbour is the offender? In what directions from the base are the likely sources of interference compared to your garage? @Bill.Thomson is the expert on all things RF. ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [14 December 2019 17:17 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/5 "2019-12-14T17:17:05Z")
Yes, they’re all flashing, including my own, which went up sometime later. I don’t remember exactly when they went up, but Dec 5 would be the inference of my hypothesis, yes. There may be multiple sources of interference of course. I don’t know which neighbour. We have fields to the east and south of us. My lights and emonBase are to the south of the garage. All neighbours are either east or north of us. ---
**Author:** ![Robert.Wall](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/robert.wall/32/38246_2.png) [@Robert.Wall](https://community.openenergymonitor.org/u/Robert.Wall)\ **Post date:** [14 December 2019 17:21 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/6 "2019-12-14T17:21:11Z")
I don’t know how effective this might be: maybe a sheet of earthed reflective material (foil-backed insulation, chicken wire, or similar) behind your emonBase as seen from the garage direction? Let’s wait for Bill. ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [14 December 2019 22:41 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/7 "2019-12-14T22:41:03Z")
The first thing that got my attention was the ~10-15dB drop in RSS just after 1 December. So while it may indeed be the Christmas decorations doing the dirty deed, that might be just part of the story. There’ _shouldn’t_ be a problem with an RSSI of ~-70dBm, but _that_ combined with the Christmas lights _may_ be a problem. > [@djh](#): > > Is there any way I can detect radio interference without special equipment? There _is_ a low-cost way to do that. > [@djh](#): > > What equipment would I need? e.g. one of these (or similar): [https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Defined/dp/B011HVUEME/ref=sr\_1\_3?crid=98815UXAU0DK&keywords=rtl-sdr+v3&qid=1576361553&sprefix=rtl-sdr%2Caps%2C201&sr=8-3](https://www.amazon.com/RTL-SDR-Blog-RTL2832U-Software-Defined/dp/B011HVUEME/ref=sr_1_3?crid=98815UXAU0DK&keywords=rtl-sdr+v3&qid=1576361553&sprefix=rtl-sdr%2Caps%2C201&sr=8-3) Software defined radio. Price is 30 USD. Available on Amazon. Software cost is zero. [https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/](https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/) e.g. [http://www.hdsdr.de/](http://www.hdsdr.de/) That would enable you to check the RF spectrum from 24MHz to 1.7GHz. > [@djh](#): > > That emonTx uses an external dipole antenna. Edit: and is wall-mounted. Could you post a picture of that antenna? ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [15 December 2019 02:51 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/8 "2019-12-15T02:51:01Z")
> [@djh](#): > > We have several neighbours who are quite keen on them! Know what you mean there. These are in my front yard: [https://community.openenergymonitor.org/uploads/default/original/2X/4/4843e0337019c4e23ee09d46ed115ad2cf50714c.mp4](https://community.openenergymonitor.org/uploads/default/original/2X/4/4843e0337019c4e23ee09d46ed115ad2cf50714c.mp4) [https://community.openenergymonitor.org/uploads/default/original/2X/d/d77c7145f97af1fc63c92553761b39cf9dad1076.mp4](https://community.openenergymonitor.org/uploads/default/original/2X/d/d77c7145f97af1fc63c92553761b39cf9dad1076.mp4) ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [15 December 2019 13:06 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/9 "2019-12-15T13:06:40Z")
> [@Bill.Thomson](#): > > The first thing that got my attention was the ~10-15dB drop in RSS just after 1 December. And that’s the benefit of having an expert look at things 😁 I hadn’t even noticed that. So maybe my hypothesis is wrong or more complicated. Still, it makes me even more keen to investigate the source. The antenna is one of these [https://www.amazon.co.uk/gp/product/B07DNLBHH6/](https://www.amazon.co.uk/gp/product/B07DNLBHH6/) I looked at it this morning and it still seems to be positioned in the same place. > [@Bill.Thomson](#): > > Software defined radio. Price is 30 USD. Available on Amazon. It’s available on Amazon in the US but not here in the UK. The US site will ship to me but I think it will be easier and cheaper to order from Aliexpress. Thanks for the link, though, I’ll order one. Again it’s obvious what the solution is when you already know 😁 ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [15 December 2019 15:29 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/10 "2019-12-15T15:29:36Z")
> [@Bill.Thomson](#): > > Software cost is zero. [https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/](https://www.rtl-sdr.com/big-list-rtl-sdr-supported-software/) > e.g. [http://www.hdsdr.de/](http://www.hdsdr.de/) Ah, HDSDR is Windows. I run Linux so I’ll need to look at something else. The first few are: - Linrad - GQRX - CubicSDR - ShinySDR Do you or anybody else have any experience with them to know what they’re good for? Are there specific features in a package that would be good to have? There’s GNUradio and rtl-sdr packages in the openSUSE repositories as well as various other hits for SDR, so again it’s a question of [not] knowing what I’m looking for. I see there are various web pages about using SDR for interference analysis on linux systems but any known-good resources would be very helpful. ---
**Author:** ![dbrooke](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/dbrooke/32/12103_2.png) [@dbrooke](https://community.openenergymonitor.org/u/dbrooke)\ **Post date:** [16 December 2019 11:11 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/11 "2019-12-16T11:11:16Z")
Of those, I’m only familiar with gqrx but it can do what you need. Also look out for rtl\_433 which is capable of decoding many devices on 433 (and 868) MHz. I use it together with a bit of python to feed my emonPi with data from some CurrentCost power monitors and a weather station. ---
**Author:** ![borpin](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/borpin/32/193_2.png) [@borpin](https://community.openenergymonitor.org/u/borpin)\ **Post date:** [16 December 2019 12:57 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/12 "2019-12-16T12:57:34Z")
4 posts were split to a new topic: [Using rtl\_433 to get weatherstation data](https://community.openenergymonitor.org/t/using-rtl-433-to-get-weatherstation-data/12754) ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 13:13 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/13 "2019-12-16T13:13:22Z")
> [@djh](#): > > It’s available on Amazon in the US but not here in the UK. This should do the job: (Not bad for 10 quid) [https://www.amazon.co.uk/Andoer®-Portable-Digital-RTL2832U-Receiver-Blue/dp/B013Q94CT6/ref=sr\_1\_9?keywords=rtl-sdr&qid=1576501810&sr=8-9](https://www.amazon.co.uk/Andoer%C2%AE-Portable-Digital-RTL2832U-Receiver-Blue/dp/B013Q94CT6/ref=sr_1_9?keywords=rtl-sdr&qid=1576501810&sr=8-9) ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 13:31 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/14 "2019-12-16T13:31:56Z")
> [@djh](#): > > Do you or anybody else have any experience with them I’ve not run any of the Linux variants. > [@djh](#): > > Are there specific features in a package that would be good to have? Any of the avaiable apps will be able show you the RF spectrum at/near 433 MHz, so the choice ends up being a personal one. The display will be similar to this: What you’re looking for is signals at/near 433 MHz. e.g.: (this example shows the HF spectrum at 7.162 MHz) ## ![image](https://community.openenergymonitor.org/uploads/default/original/2X/2/270da715d35af8ffc9eddc6b9304a3d1434c33d5.jpeg) In particular, this part: ![image](https://community.openenergymonitor.org/uploads/default/original/2X/6/657d939bb6d661f9a2c25973aab93d9dbd5caa8f.png) will show you what signals it’s receiving, their frequencies, bandwidths and relative strengths. ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 13:37 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/15 "2019-12-16T13:37:09Z")
> [@djh](#): > > The antenna is one of these What I was hoping for was a picture of it as installed. It’s actually fairly easy to “detune” one (read that as decreased performance) if it’s not located and mounted correctly. ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 13:45 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/16 "2019-12-16T13:45:08Z")
> [@dbrooke](#): > > Also look out for rtl\_433 rtl\_433 is aimed at _decoding data_ from various personal weather stations and the like. While it’s something he might want to look into later, ATM his need is for a simple spectral display to detect any signals that may be interfering with his OEM system. ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [16 December 2019 17:25 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/17 "2019-12-16T17:25:37Z")
> [@Bill.Thomson](#): > > This should do the job I’ve already ordered the RTL-SDR kit. ☹ How would you use the Andoer unit, since it seems to have an omnidirectional antenna? My main question would be about software support for it though since it only mentions Windows. It looks vaguely interesting as a toy since I run TVH with a TBS 6805 quad tuner. ---
**Author:** ![djh](https://community.openenergymonitor.org/letter_avatar_proxy/v4/letter/d/e36b37/32.png) [@djh](https://community.openenergymonitor.org/u/djh)\ **Post date:** [16 December 2019 17:28 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/18 "2019-12-16T17:28:47Z")
> [@Bill.Thomson](#): > > What I was hoping for was a picture of it as installed. Here you go ![P1030338](https://community.openenergymonitor.org/uploads/default/original/2X/2/298640832081e08545a1ba32266dd1762fab5a0f.jpeg) The view is looking west. North is to the right and south, where the base station is, is to the left. ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 18:29 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/19 "2019-12-16T18:29:15Z")
> [@djh](#): > > How would you use the Andoer unit, Like any of the other SDRs. > [@djh](#): > > since it seems to have an omnidirectional antenna? The antenna isn’t hardwired. Viz.: ![image](https://community.openenergymonitor.org/uploads/default/original/2X/a/a0aef361ffb654ba7c8b8bab27c9a0695dde3369.png) > [@djh](#): > > software support _Many_ of the of the low end SDRs are based on the RTL2832U chipset and R820T / R820T2 tuner which is the chipset/tuner combo supported by _much_ of the available software. > [@djh](#): > > It looks vaguely interesting as a toy The same can be said WRT _almost_ all of the USB dongle type SDRs. There are some exceptions, but they don’t carry a 20 dollar price tag. Airspy (169 USD) and SDRPlay (99 USD) are two examples that come to mind. The _[RTL-SDR.com](http://RTL-SDR.com)_ V3 receiver is one of the better low-end units. ---
**Author:** ![Bill.Thomson](https://community.openenergymonitor.org/user_avatar/community.openenergymonitor.org/bill.thomson/32/1834_2.png) [@Bill.Thomson](https://community.openenergymonitor.org/u/Bill.Thomson)\ **Post date:** [16 December 2019 18:41 UTC](https://community.openenergymonitor.org/t/radio-interference-xmas/12736/20 "2019-12-16T18:41:47Z")
> [@djh](#): > > Here you go OK, that helps. Quite a bit. Three things. - mount it further away from the wall _if you can._ I realize that may not be practical/possible. - move it away from the wire bundle it’s adjacent to. _That’s_ a definite detuner / radiation pattern modifier. - bring the feedline straight out from the elements, i.e. perpendicular to them, for a distance equal to, or greater than, the length of one element. [Next page](https://community.openenergymonitor.org/t/radio-interference-xmas/12736.md?page=2)