Good afternoon,
I was wondering if there is a way to be able to configure the initial
settings without the use of the TeleDongle/TeleBT by plugging the EasyMega
or Telemetrum into the computer via USB when I have everything connected
(battery and switch).
Thinking about it from an RF perspective and using some rules of thumb
from that domain I would think a twist of around 1/10th wavelength would
be the minimum to have reasonable effect. Given that you are likely
working in the near-field for this a tighter twist would be more
advisable too. One twist every 34mm is 1/20th wavelength and likely a
good starting point, or go shorter.
Stewart
VK3TRK
On 08-Dec.-20 6:00, altusmetrum-request(a)lists.gag.com wrote:
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> Today's Topics:
>
> 1. Re: How much twist to put in wires to avoid interference?
> (Clay and Carly Dunsworth)
> 2. Re: How much twist to put in wires to avoid interference?
> (Bob Finch)
> 3. Re: How much twist to put in wires to avoid interference?
> (Bob Finch)
> 4. Re: How much twist to put in wires to avoid interference?
> (Bdale Garbee)
> 5. Re: How much twist to put in wires to avoid interference?
> (David W. Schultz)
> 6. Re: How much twist to put in wires to avoid interference?
> (Will Marchant)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sun, 6 Dec 2020 14:05:02 -0600
> From: Clay and Carly Dunsworth <ccdunsworth(a)gmail.com>
> To: Altus Metrum <altusmetrum(a)lists.gag.com>
> Subject: Re: [altusmetrum] How much twist to put in wires to avoid
> interference?
> Message-ID: <F1AA29DE-5809-4F67-9039-CE7F94A61D32(a)gmail.com>
> Content-Type: text/plain; charset=utf-8
>
> When ?twisting? wires if found more twists are required to keep them together, but if you look in twisted pair like M27500 much less are used. Ethernet and canbus wires use more twisting. Shielded wire is pretty cheap to really expensive, but that?s what I?m going to start using in the future. Just drain the shields at a common ground. The cheaper M27500 is super available, and fairly cheap.
>
>> On Dec 6, 2020, at 12:36, Will Marchant <will(a)spaceflightsoftware.com> wrote:
>>
>> ?Hi Folks:
>> Any "rules of thumb" about how much twisting to do of the various avionics wires?
>>
>> One turn per inch? More? Less?
>>
>> Thanks in advance for any advice!
>> Happy holidays,
>> Will
>>
>> --
>> Will Marchant, KW4WZ
>> will(a)spaceflightsoftware.com
>> http://www.spaceflightsoftware.com/will/
>> _______________________________________________
>> altusmetrum mailing list
>> altusmetrum(a)lists.gag.com
>> http://lists.gag.com/mailman/listinfo/altusmetrum
>
> ------------------------------
>
> Message: 2
> Date: Sun, 6 Dec 2020 14:10:26 -0700
> From: Bob Finch <w9ya(a)amsat.org>
> To: Altus Metrum <altusmetrum(a)lists.gag.com>
> Subject: Re: [altusmetrum] How much twist to put in wires to avoid
> interference?
> Message-ID:
> <CAASHNdW4Fs7dDHKAt-Wp1Ga2ppZAq3J2L+z=Q8Z6BFaL+FReAQ(a)mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> Hey Will;
>
> If you place groups of wires together...twist them as "pairs"
> separately, i.e. B+ and B- (ground) together, and each pair of signal
> + and signal - (charge firing) together, and so forth. IDEALLY if you
> then are forced to place these pairs adjacent to one another AND they
> have a slightly different twist "rate" (amount of twist per
> "unit-of=-measure") things will be as good as you can get.
> ("Crosstalk" between pairs will be minimal as you can make it.)
>
> In the confines of a "electronics bay" this may seem a lot more
> theoretical than useful, but it forms good engineering practice, and
> ignoring the above rules completely can contribute to an "ebay cato".
> How so:
>
> When so twisted the wires can "take shape" so that the
> printed-circuit-board can be held in place by the wiring alone. So
> when the brunt of excessive g forces breaks the plastic screws you
> used for mounting (I know, everyone is a perfect flyer, so taking
> "hard landings" into account may seem "excessive".....grin.), you now
> have a chance of recovering a working unit....... !! (Ask me how I
> know.....er, um, another time please !)
>
> Anyways, my input......hope it helps you fiqure this out.
>
> Fly high, fly fast, fly safe....not nec. in that order.
>
> VERY best regards;
>
> Baab F.
>
> P.S... Shielding is not as useful as twisting on "balanced" circuits
> when considering coupling between each (non-coaxial) wire (or circuit)
> -pair, This is due to the lack of a third (tertiary) path on these
> two-wire circuits.
>
> On Sun, Dec 6, 2020 at 11:36 AM Will Marchant
> <will(a)spaceflightsoftware.com> wrote:
>> Hi Folks:
>> Any "rules of thumb" about how much twisting to do of the various
>> avionics wires?
>>
>> One turn per inch? More? Less?
>>
>> Thanks in advance for any advice!
>> Happy holidays,
>> Will
>>
>> --
>> Will Marchant, KW4WZ
>> will(a)spaceflightsoftware.com
>> http://www.spaceflightsoftware.com/will/
>> _______________________________________________
>> altusmetrum mailing list
>> altusmetrum(a)lists.gag.com
>> http://lists.gag.com/mailman/listinfo/altusmetrum
>
> ------------------------------
>
> Message: 3
> Date: Sun, 6 Dec 2020 14:14:18 -0700
> From: Bob Finch <w9ya(a)amsat.org>
> To: Altus Metrum <altusmetrum(a)lists.gag.com>
> Subject: Re: [altusmetrum] How much twist to put in wires to avoid
> interference?
> Message-ID:
> <CAASHNdU7sVFTTMiOEWp7watUn+94S9pZwgH49AMPCLXY8-UAHw(a)mail.gmail.com>
> Content-Type: text/plain; charset="UTF-8"
>
> O.K....P.P.S. (And more to the point);
>
> I twist the wires together as tightly as I can, and then a bit less on
> the next pair, and so forth. I try to make sure that each pair is
> twisted tightly enough to allow the board/unit in question to stand up
> using just these wire pairs and then mount the board with plastic
> "hardware".
>
> On Sun, Dec 6, 2020 at 2:10 PM Bob Finch <w9ya(a)amsat.org> wrote:
>> Hey Will;
>>
>> If you place groups of wires together...twist them as "pairs"
>> separately, i.e. B+ and B- (ground) together, and each pair of signal
>> + and signal - (charge firing) together, and so forth. IDEALLY if you
>> then are forced to place these pairs adjacent to one another AND they
>> have a slightly different twist "rate" (amount of twist per
>> "unit-of=-measure") things will be as good as you can get.
>> ("Crosstalk" between pairs will be minimal as you can make it.)
>>
>> In the confines of a "electronics bay" this may seem a lot more
>> theoretical than useful, but it forms good engineering practice, and
>> ignoring the above rules completely can contribute to an "ebay cato".
>> How so:
>>
>> When so twisted the wires can "take shape" so that the
>> printed-circuit-board can be held in place by the wiring alone. So
>> when the brunt of excessive g forces breaks the plastic screws you
>> used for mounting (I know, everyone is a perfect flyer, so taking
>> "hard landings" into account may seem "excessive".....grin.), you now
>> have a chance of recovering a working unit....... !! (Ask me how I
>> know.....er, um, another time please !)
>>
>> Anyways, my input......hope it helps you fiqure this out.
>>
>> Fly high, fly fast, fly safe....not nec. in that order.
>>
>> VERY best regards;
>>
>> Baab F.
>>
>> P.S... Shielding is not as useful as twisting on "balanced" circuits
>> when considering coupling between each (non-coaxial) wire (or circuit)
>> -pair, This is due to the lack of a third (tertiary) path on these
>> two-wire circuits.
>>
>> On Sun, Dec 6, 2020 at 11:36 AM Will Marchant
>> <will(a)spaceflightsoftware.com> wrote:
>>> Hi Folks:
>>> Any "rules of thumb" about how much twisting to do of the various
>>> avionics wires?
>>>
>>> One turn per inch? More? Less?
>>>
>>> Thanks in advance for any advice!
>>> Happy holidays,
>>> Will
>>>
>>> --
>>> Will Marchant, KW4WZ
>>> will(a)spaceflightsoftware.com
>>> http://www.spaceflightsoftware.com/will/
>>> _______________________________________________
>>> altusmetrum mailing list
>>> altusmetrum(a)lists.gag.com
>>> http://lists.gag.com/mailman/listinfo/altusmetrum
>
> ------------------------------
>
> Message: 4
> Date: Sun, 06 Dec 2020 18:59:30 -0700
> From: Bdale Garbee <bdale(a)gag.com>
> To: Will Marchant <will(a)spaceflightsoftware.com>,
> altusmetrum(a)lists.gag.com
> Subject: Re: [altusmetrum] How much twist to put in wires to avoid
> interference?
> Message-ID: <87r1o24br1.fsf(a)gag.com>
> Content-Type: text/plain; charset="us-ascii"
>
> Will Marchant <will(a)spaceflightsoftware.com> writes:
>
>> Any "rules of thumb" about how much twisting to do of the various
>> avionics wires?
> In practice, it turns out the actual twist rate isn't critical.
>
> When I'm twisting by hand in random hotel rooms, I shoot for at least a
> couple turns per inch. But, a "pro tip", clamping one end of the two
> conductors, then putting the other end in a cordless variable speed
> drill's chuck is a slick way to get nice even twisting and more twists
> per inch. I'll do a few feet this way, then cut suitable lengths for
> each of the things I need as I build an av-bay.
>
> Oh, and since people ask, I like 22 AWG stranded with PVC insulation
> when wiring up my ebays. Your mileage may vary...
>
> Bdale
>
Hi Folks:
Any "rules of thumb" about how much twisting to do of the various
avionics wires?
One turn per inch? More? Less?
Thanks in advance for any advice!
Happy holidays,
Will
--
Will Marchant, KW4WZ
will(a)spaceflightsoftware.com
http://www.spaceflightsoftware.com/will/
