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Member postings for Peter Christy

Here is a list of all the postings Peter Christy has made in our forums. Click on a thread name to jump to the thread.

Thread: Spektrum DX7
18/10/2019 09:07:24

I don't think there ever was a "common convention" for the polarity of the chargers. Even aftermarket power supplies for electronic devices had reversible plugs to accommodate the different polarities.

This is why most manufacturers fitted protection diodes, to prevent reverse polarity connections doing any harm. Oh, and most modern peak detect chargers work very well with the diode still in place! It was only very early ones that got caught out by the diode. No need to short them out these days, unless you have a very old charger!

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Pete

17/10/2019 14:27:09

And of course, the *best* option is spread spectrum plus frequency hopping with a high MUF (duty cycle, though its a bit more than that - for the pedants!). But for that, LBT is mandatory - in the EU, anyway!

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Pete

Thread: Latest CAA Update
17/10/2019 14:22:47

Thanks for clarifying!

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Pete

17/10/2019 13:51:34

I thought the GDPR only applied to data held on a computer. If you store it on an old-fashioned card index, it doesn't apply. Or have I misunderstood?

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Pete

Thread: Spektrum DX7
17/10/2019 13:41:42

Steve J: Also DSM-2 only "Listens Before Transmit" at switch on. Once its found two empty channels, it sticks with them regardless. That's why it failed the EU regulations, which require a "listen before every hop" - not really practical when you are only hopping between two channels. (There are other ways around this by reducing something known as the Media Utilisation Factor - MUF - but lets keep it simple!)

But just because it doesn't meet the latest EU regs, doesn't mean its no good! And if your gear predates January 2015, you can carry on using it quite legally.

Nigel: Its not quite as simple as you make out. Frequency hopping is NOT the same as spread spectrum. It is perfectly possible to make a frequency hopping system that is not spread spectrum. Indeed, you could consider the old fashioned method of crystal swapping as very slow frequency hopping!

Frequency hopping adds an extra layer of resilience on top of spread spectrum, but much of the immunity comes simply from the spreading process, regardless of frequency hopping.

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Pete

 

Edited By Peter Christy on 17/10/2019 13:46:38

17/10/2019 11:10:08

Nothing at all wrong with DSM-2. I've still got several models using it, including a large, scale, gasser helicopter. The only real issue with it is that you are limited to 40 DSM-2 transmitters in use at once (!), not really an issue here in the UK!

My personal experience has been that Spektrum quality control seems to have gone downhill in the last few years, and their support for older gear is not good, but there is nothing fundamentally wrong with the system.

I bought one of the original DX-7s when they came out, sold it on when I got a JR DSX-9 (also DSM-2) to replace it, and as far as I am aware, it is still in use today. Certainly my DSX-9 has proven to be just as reliable as any other radio I've owned, and most of my DSM-2 receivers are Spektrum.

All my new builds use FrSky, mainly due to the very good value-for-money receivers, plus excellent reliability, but I'm not planning on replacing any of my DSM-2 stuff anytime soon.

"If it ain't broke, don't fix it!"

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Pete

Thread: Software Updates
16/10/2019 08:48:32

The only system I know that provides updates via windoze, mac AND Linux is OpenTx. Everyone else seems to assume that the world runs according to Micro$oft....!

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Pete

Thread: Veneer lifting problems
15/10/2019 16:43:40

Like Martin, I used a covering iron (turned up high!) on an old wing. This worked on 90% of the wrinkles. Only the worst ones resisted and needed more extreme measures!

Back in the day when foam cores came as just that - cores with no covering - I always used Copydex as the adhesive, and those cores NEVER wrinkled! It is heavier than watered PVA, though.

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Pete

Thread: Plane that can have lots of modifications.
15/10/2019 10:07:55

You are probably looking at something with a wooden structure, rather than a foamie. The few foamies I have owned all seem to have very cramped interiors.

I bought a Wot-4 foamie as a test hack for radio gear, only to find the receiver compartment so tiny that only smaller receivers can be squeezed in!

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Pete

Thread: Model shops, SW England
13/10/2019 10:18:59

Don and I managed to get together for a couple of hours on Friday morning! Always good to put a face to a name and have a chat about all things flying!

Hope you got back to France OK!

Cheers,

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Pete

Thread: Switches...
13/10/2019 10:14:43

Are we talking about ignition switches or radio switches?

I would always recommend keeping anything connected to the receiver as far away as possible from ignition circuits. Of course, this isn't always possible and anyway, modern 2.4GHz gear is generally less susceptible to ignition noise than 35 MHz gear.

However, it never does any harm to keep the receiver and its associated wiring as far away from sources of interference as you can manage.

Don: Guess you made it back to France OK? Good to catch up with you on Friday!

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Pete

Thread: Model shops, SW England
10/10/2019 19:24:24

Don,

Sorry I missed your call today! You picked the one 30 minute period during the day when there was no-one in!

The weather isn't looking great this week-end, but if you still fancy a trip to the Charmouth heli event, directions are here: **LINK**

The red route is from Newlands Holiday camp, where most participants stay. From Brixham, you would be coming along the A35 from the top left of the picture, and doing an almost-Uturn at the first roundabout at Charmouth.

I'll be leaving early afternoon tomorrow, so still the possibility of a local meet-up if you fancy it.

Cheers,

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Pete

Thread: Suggestions for sport planes for an OS 25 FX engine
09/10/2019 18:07:55

Philibuster? (Search Outerzone)

One of my favourite small sports models from the 70's! laugh

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Pete

Thread: Jumper 4in1 module problem
09/10/2019 15:18:11

Just heard from Mike, and there's been a change in the default behaviour which I haven't seen flagged up anywhere.

Previously, the default config was to compile all 5 memory banks. This has changed to just compiling 1! You need to change a setting in the _Config.h file to get all 5 with newer releases.

Ooops!

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Pete

09/10/2019 09:16:17

Richard: Yes tried that and every variation, without success. Set the rotary switch to 15, hold bind button and switch on. Result: A short burst of flashes, then a steady single blink. No amount of pressing the bind button - short or long - would make it change banks. Try again, only pressing the bind button after power on. Exactly the same result.

Believe me, I've been through every possible permutation and combination including the original, incorrect, instructions (as referred to by Flight1 above). Those instructions are only correct with very early versions, it seems, and when the board is flashed, it follows the instructions on github.

I've got an IRangeX module myself, and that behaves exactly as outlined on github. This particular Jumper module doesn't, and I am forced to the conclusion that it is faulty.

No matter now, as I've worked around the problem.

I couldn't find any definitive, Jumper specific instructions, but was fairly convinced that the Jumper module was a minor variation on the "standard" version, and should work with the github instructions. My post here was to verify this, which you have all done.

Thanks to all for confirming my suspicions!

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Pete

Thread: Latest CAA Update
09/10/2019 08:35:59
Posted by Steve J on 08/10/2019 21:47:52:

Posted by Martin_K on 08/10/2019 21:33:13:

Dave Phipps does not make reference to the specific category, Matty does.

If you go back to Opinion 01-2018, the draft article that became article 16 explicitly referred to the specific category, for some reason it no longer does, but article 3 makes it clear.

"(b) UAS operations in the ‘specific’ category shall require an operational authorisation issued by the competent authority pursuant to Article 12 or an authorisation received in accordance with Article 16, or, under circumstances defined in Article 5(5), a declaration to be made by a UAS operator;"

Steve

Edited By Steve J on 08/10/2019 22:07:14

And presumably only when there's an "R" in the name of the month!

Who writes this guff? Where's the Campaign for Plain English when you need them?

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Pete

Thread: Jumper 4in1 module problem
08/10/2019 22:18:03

Hi Mike, and thanks for confirming. That's exactly what I expected to happen, but it didn't!

The history of this module is unknown, but I had to solder extra connectors inside to flash it, so I assume this had never been done before. It works fine with a serial data stream from OpenTx, but stays resolutely stuck on the first bank in PPM mode.

I've by-passed the problem by moving the DSM programming to the first (and only accessible) bank. The guy who will be using it is not a modeller, and not very familiar with RC stuff, so it needs to be kept as simple as possible for him. The Tx only has four operational switches, to start or stop remote cameras, and that's all it needs to do.

In fact this is a spare for him. His original developed a fault, now fixed, but he wisely asked for a spare, and DSM-2 modules are hard to come by these days. Even the Orange ones appear to be unobtainable at present, so a second-hand mulit-protocol module for very little money was an opportunity not to be missed.

Looks like it was a faulty module, then, but at least it will now do the job required of it!

Many thanks for confirming that what I was doing was correct!

Cheers,

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Pete

Thread: Latest CAA Update
08/10/2019 19:17:07
Posted by Steve J on 08/10/2019 12:19:16:

Posted by Peter Christy on 08/10/2019 12:10:17:

Have they changed it, then? The last time I looked it was still saying 18?

You need to learn the difference between the operator and the remote pilot. See CAP1789 pages 9 & 10.

Steve

PS The remote pilot age limit is from 1st July next year, there isn't one until then.

Edited By Steve J on 08/10/2019 12:23:32

Hm! But I thought that the unlamented Baroness Vere was saying that for model flying purposes, the two were the same. At least, that's the way I interpreted her statements about it being "inappropriate" for Associations to register as the operator. Are the DfT now reconsidering this? I sincerely hope so! Nothing brings the law into disrepute quicker than palpably nonsensical regulations!

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Pete

Thread: Jumper 4in1 module problem
08/10/2019 19:09:10

Piers: I know, this one has been driving me nuts! I've got an IRangeX module (very similar) and that behaves perfectly! This one's history is unknown. It came out of a Taranis, and works perfectly in a Taranis, but on an old PPM transmitter - which is where it is destined - it refuses to switch banks!

Flight1: Yes, tried that too! Although that should only be the correct method if it has the original Jumper firmware. Upgrading it to the latest multiprotocol firmware, should make it behave the same as an IRangeX, but it doesn't!

In desperation - and because it will only ever need to operate in DSM-2 - I've modified the firmware, switching two of the banks around, so that DSM-2 is available in the only accessible bank.

Its a spare for a film job, being used for switching cameras on and off in darkest Africa. Repair facilities out there are hard to come by!

I've now got a solution that works, but I'd still love to know why it wouldn't work as intended.......!

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Pete

08/10/2019 17:42:54

I'm hoping Mike B will be along to advise on this one, as I'm stumped!

A friend has come along with a Jumper 4in1 module for use on a PPM transmitter. It needs to be set to DSM-2 22mS. I found one setting on the rotary switch which gave DSM-2, but at 11mS.

I tried to switch memory banks, but was unable to get it to respond in a meaningful way. Having no idea of the firmware version, I decided to upgrade it to the latest version, so that I at least knew where it should be.

Flashing went OK, after a couple of false starts. According to the documentation, DSM-2 22mS 8 channels should be on the second bank at position 6. However, nothing I've tried will make it switch banks!

Setting the dial to 15 produces a steady green light, with the red one giving a short burst of flashes (too fast to count), followed by a steady single blink. A short press of the bind button brings the red led on for a second or so, followed by a steady single blink. Switching off and on again still produces a short burst of red flashes, followed by a steady single blink.

According to the instructions, a successful bank switch should produce blinks corresponding to the bank selected, but I cannot get this to work.

Some instructions say power it up with the dial set to 0 and the bind button pressed, but this doesn't work either!

The protocol is correctly installed, as if I put the module in my Taranis and set the dial to 0, I can select the required DSM-2 protocol from the Taranis set up screen.

I just can't get it to work in a PPM transmitter!

Any help appreciated!!

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Pete

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