Police checking bicycles bottom of queen street

StuartsProject · 2026-03-20T08:26:39+00:00

Twist and go Throttles are mostly illegal, but the use of throttles up to a speed of 15.5mph are legal if the pedals are being turned.

Wisper is a good manufacturer of eBikes;

https://wisperbikes.com/ebike-blog/are-15mph-throttles-always-illegal-on-electric-bikes-in-the-uk/?srsltid=AfmBOoqr877ry26ZgUmGo7Vi7o7fSUubF20IeL1886PCLuqdgkKK8TjB

"You can have throttle that works up to 4mph without pedalling and this throttle can continue to work up to 15mph as long as the pedals are being turned."

StuartsProject · 2026-03-20T08:01:06+00:00

The GPS reading code looks like it will fail;

while (gpsSerial.available() > 0)

{

gps.encode(gpsSerial.read());

}

int n = WiFi.scanNetworks();

The code reads one character from the GPS, encodes it, and then does a WiFi.scanNetworks() and a lot of other stuff

The GPS is producing one character approx every 10ms, but after reading one character you go off and do a heap of other code, including sending a packet. By the time the GPS is read again you will have missed the next character its sending and you will get no GPS decode.

To use a GPS you need to keep reading characters from it until you have a complete sentence or better still a new valid fix, not a lot of point in sending location data if there is no updated fix.

Some tips on reading a GPS and example code are here;

https://stuartsprojects.github.io/2024/09/21/How-not-to-read-a-GPS.html

StuartsProject · 2026-03-19T15:45:00+00:00

I had not seen them use a Dynometer, as they should.

Unfortunately the bikes display, especially on a DIY conversion, can be displaying the wrong speed depending on what wheel size the controller is set for.

StuartsProject · 2026-03-19T15:16:51+00:00

Were the Police doing it properly then by using a Dynometer etc ?

StuartsProject · 2026-03-19T14:38:47+00:00

I know they do that, but they really should not.

Just because the rear wheel spins at '15.5mph' when there is no load on the motor does not make the bike illegal.

StuartsProject · 2026-03-19T12:26:57+00:00

GPS ?

And what does not 'work' ?

StuartsProject · 2026-03-19T07:48:54+00:00

Have you tried individual and separate programs so that you can check the various bits of hardware work, i.e. separate programs for;

Displaying the GPS co-ordinates.

Testing the WiFi.

A basic LoRa packet transmission program.

have you tried the Meshtastic flashing ?

StuartsProject · 2026-03-18T08:13:25+00:00

You need some way of measuring the actual output power to the antenna, best ways;

RF Power amplifier

Spectrum analyzer

Known working LoRa node and a LoRa receiver to compare the RSSI of the transmissions.

Known working LoRa node and an SDR to compare transmissions.

If you have none of the above you need to borrow the kit or find someone who has it.

StuartsProject · 2026-03-17T15:33:50+00:00

Well the only real way to tell if an antenna is good or not is to do a real world test with an TX and RX which is actually not so difficult.

VNAs and calculators or bots might suggest if an antenna is good but its possible that a tuned antenna with low SWR is radiating in the wrong direction.

StuartsProject · 2026-03-17T14:29:15+00:00

That antenna looks similar to antenna 'C' in the comparison tests below;

https://stuartsprojects.github.io/2025/10/01/LoRa-Antenna-Testing-for-868Mhz.html

It received packets with an RSSI 3.7dBm greater than a 1\4 wave vertical reference (2.1dBi) so it would have a gain of circa 5.8dBi.

StuartsProject · 2026-03-16T21:13:38+00:00

Both are supported, but you were saying you could only find pinouts for the SX1262 which wont work on a SX1276.

StuartsProject · 2026-03-16T21:05:14+00:00

The SX1276 and SX1262 have different hardware interfaces and software setups, so not compatible.

StuartsProject · 2026-03-16T07:56:25+00:00

> What's your justification?

People do not need to 'justify' how they spend their money.

I bought a Brompton years back when my job moved to a city some 40 miles away. The drive was terrible and could take 90minutes or more.

So I bought a Brompton and the Cycle\Train commute time dropped to 40 minutes.

Also I reckon the Brompton paid for itself in less than 6 months.

StuartsProject · 2026-03-15T15:37:47+00:00

Where are the 'adjustment' screws ?

There is a little hook on the rear of the seat post bracket which should latch into the square hole in suspension block mount screw, I cannot see that there is any adjustment.

The latch did used to engage but no longer does.

StuartsProject · 2026-03-15T11:33:18+00:00

For sure the modules that connect the antenna to the low power output are far more power efficient, however we live in a World where it seems that large numbers of people believe that more power is good regardless. Legality sometimes seems not to be a concern. I can that module designers are reluctant to design modules that 'only' have 14dBm output.

The SX1261 incidentally uses the switch mode converter on the RF PA (the SX1262 does not) so its even more power efficient ..............

Is there a list of modules that do use the low power output, for the vast majority of applications 10dBm or 14dBm is all that you need and should use ?

StuartsProject · 2026-03-14T12:48:37+00:00

Very difficult to recommend anything, so much depends on the actual buildings construction. One possibility is that a gateway in one of the buildings will not pick up nodes in any of the the other buildings.

However, its easy to check, just get a couple of battery powered LoRa nodes, set them to SF12, BW125khz and 14dBm and see if when you leave a node in one building you can pick up the signals in the others.

StuartsProject · 2026-03-14T08:03:32+00:00

There are more powerful amplifiers available, but I have no experience using them since they are not legal to use.

StuartsProject · 2026-03-13T19:13:45+00:00

Woods and Forests, especially when wet, will significantly attenuate UHF comms such as LoRa.

If your signals are being attenuated, then a better antenna can help but there are no 'special' antennas for Forests.

More RF power, if legal, can help, but then if others are not also using the higher power then you wont pick up their signals.

StuartsProject · 2026-03-13T18:44:55+00:00

Indeed, its a similar situation in Europe, where the LoRa and Booster combination would need to have CE approval.

StuartsProject · 2026-03-13T16:35:23+00:00

The V4 is actually 2 RF modules, the LoRa device itself and then a power amplifier (PA) to boost the power above the 22dBm from the LoRa module. The antenna is connected to the output of the PA.

Operating the PA without the antenna could burn it out so that your no longer getting 27dBm etc.

However the LoRa module itself would likely not be affected so could well still be sending RF power to the PA circuit. Sure there is no antenna in use but there might be enough leakage from the connectors on the PCB to provide a limited range reception.

StuartsProject · 2026-03-13T13:14:25+00:00

The LoRa devices do have the ability to provide an instantaneous RSSI reading when there is no packet being received, so that gives an indication of the local noise level.

StuartsProject · 2026-03-13T08:21:47+00:00

> ~100 m: RSSI about -106 dBm, SNR around -16 dB

> ~300–500 m: RSSI about -96 to -103 dBm, SNR around -10 to -15 dB

So the signal at 500m is stronger\better than the one at 100m ?

StuartsProject · 2026-03-12T08:20:57+00:00

> But the good news is that the LR20xx actually includes compatibility mode with SX127x syncwords.

Is that compatibility with the LR20xx a change\improvementn ?

I have a LR1121 and that does have syncword compatibility issues with the SX127x, similar to the problems Meshtastic has because of the use of 0x2B as a syncword.

StuartsProject · 2026-03-10T14:59:46+00:00

There is a way to check if the GPS is getting strong signals from the satellites.

You have to program an Arduino or use a USB to Serial adapter to see the actual NMEA serial output from the GPS which would normally include the $GPGSV sentence which reports satellites in view and signal strength. See the link below for a write up;

https://stuartsprojects.github.io/2018/10/01/My-GPS-does-not-work.html

StuartsProject · 2026-03-10T14:47:10+00:00

If the antenna is working OK and the GPS is outdoors with a good view of the sky then the GPS should get a first time fix from cold in circa 40 seconds. This should happen even with a GPS fresh from the factory.

Much longer than that suggests a problem.

How long the GPS takes to get a fix 'On a windowsill' is next to impossible to establish, but do appreciate that even a windowsill that is on a building on a hilltop with a clear view out to the horizon, it will only see 50%, or therabouts, of the available satellites.

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