[TangerineSDR] DCC discussion list

Sat Sep 14 12:42:24 EDT 2019

Option C makes sense to me, too.

73 de Nathaniel W2NAF

From: TangerineSDR <tangerinesdr-bounces at lists.tapr.org> On Behalf Of Tom McDermott via TangerineSDR
Sent: Friday, September 13, 2019 9:46 PM
To: TAPR TangerineSDR Modular Software Defined Radio <tangerinesdr at lists.tapr.org>
Cc: Tom McDermott <tom.n5eg at gmail.com>
Subject: Re: [TangerineSDR] DCC discussion list

Hi Scotty,  I was hoping everyone would generally prefer Option C.
Now the question is which distribution option we should look at, 1,2, or 3?
(i.e. have the DE or interconnect board regulate and distribute, have each board do it on it's own, or external).

-- Tom, N5EG

On Fri, Sep 13, 2019 at 2:09 PM Scotty Cowling via TangerineSDR <tangerinesdr at lists.tapr.org<mailto:tangerinesdr at lists.tapr.org>> wrote:
Hi Tom,

Option C is the easiest and in my opinion, only viable option. A wide range input that includes 11-15V allows multiple battery chemistries, while enabling common linear and switching bench supplies to be used. Ech locale knows best how to get this standard voltage from their local mains supply. And while we will do our best to filter the input power rail, if the user connects it to a noisy solar system, it beyond our scope to mitigate his interference issues.

The typical modern mixed-mode designs do what John A was describing: start with a wide-range noisy input, then regulate to a narrow-range less noisy but still not quiet enough intermediate voltage, then use LDOs and lots of filtering to get analog-quality 3.3V, 2.5V or 1.8V supplies. Keep the analog power separate from the digital power. Use series inductors and multiple-capacitor filters where necessary (they are small and inexpensive at low currents).  If you pick your intermediate voltage(s) properly, you can minimize the power dissipation of the linear regulators while still gaining the low-noise advantages of LDOs.

Every design should have clock tree and and power tree diagrams along with its block diagram.

73,
Scotty WA2DFI

On 9/13/2019 11:52 AM, Engelke, Bill via TangerineSDR wrote:
Something to consider on this, for convenience of the user:   the Odroid N2, which we are thinking is the likely SBC in the Tangerine, runs on 12v also  (not 5v).

  *   73- Bill, AB4EJ

From: TangerineSDR <tangerinesdr-bounces at lists.tapr.org><mailto:tangerinesdr-bounces at lists.tapr.org> On Behalf Of Tom McDermott via TangerineSDR
Sent: Friday, September 13, 2019 8:29 AM
To: Phil Erickson <phil.erickson at gmail.com><mailto:phil.erickson at gmail.com>
Cc: Tom McDermott <tom.n5eg at gmail.com><mailto:tom.n5eg at gmail.com>; TAPR TangerineSDR Modular Software Defined Radio <tangerinesdr at lists.tapr.org><mailto:tangerinesdr at lists.tapr.org>
Subject: Re: [TangerineSDR] DCC discussion list

HI Phil - We certainly will need requirements on power & distribution characteristics.

However I think we first may need a plan.

Question 1: do we operate off:
Option A: 120VAC input  (North America)
Option B: 120-240VAC input (Worldwide)
Option C:  + 12VDC input?    [ +12V means in my view  +10.5 to +13.8 VDC, allowing a battery to be the power input. ]

In my view Option C is the easiest for project engineering, but requires the user to generate +12V, battery charge, etc.
Given the possible worldwide AC variables, battery type and size variables, etc., it avoids many issues.

If we were to choose Option C then, at the system level then:
Question 2 how do we create needed voltages:
Option 1. Data Engine regulates & distributes all the system voltages from a single +12VDC  (11-13.8V) input.
Option 2: Separate DC supply derives all the needed voltages from +12VDC (11-13.8V) input.
Option 3: Each module derives it's own voltages from a +12VDC (11-13.8V) input.

-- Tom, N5EG

On Thu, Sep 12, 2019 at 7:00 PM Phil Erickson <phil.erickson at gmail.com<mailto:phil.erickson at gmail.com>> wrote:
Hi Tom,

  It is probably good for item 5 to think about whether cleanliness specs for the power supply are required.  As you know, hash on the DC lines could be a major RFI problem.  (Batteries would tend not to have that issue, hence their mention earlier.)

73
Phil

On Thu, Sep 12, 2019 at 9:58 PM Tom McDermott via TangerineSDR <tangerinesdr at lists.tapr.org<mailto:tangerinesdr at lists.tapr.org>> wrote:
I've combed the meeting notes and some other thoughts and put together a frist draft of possible DCC discussion topics for HAMSCI / TangerineSDR.
Please review and send me additions, deletions, changes, etc. by Monday the 16th and I'll iterate once before the conference.

-- Tom, N5EG

HAMSCI project discussion Topics for DCC 2019

1.    Need cost estimates for the Clock, DE, RF, and Magnetometer modules.
2.    What is the schedule for the modules, testing, prototypes?
   a.    Data Engine
   b.    2-chan RF receiver
   c.    GPS Clock
   d.    Magnetometer
   e.    Other ? SBC, Power supply, etc.
3.    Each module will have a unique manufacturer serial number based on some PROMs that have this capability. Any issues with the number or format?
4.    Do we need to create any videos describing what the project is, what the objectives are, status, or other?
5.    No discussion so far on power supplies, other than a request for +12V battery power capable. Do we need a plan?
6.    HAMSCI 2020
   a.    Any more information on the location?
   b.    Should we plan a demo of TangerineSDR or the completed parts?
7.    Receive Antennas. Mike Pappas has acquired a calibrated filed strength meter, we discussed seeing if DX Engineering would let us measure a production lot of antennas (10?) to determine the field strength sensitivity and variance.
8.    Do we need a test plan for the system?
9.    Upload data compression appears feasible (3:1 ?).  Do we need any study or proposals of how much data we are asking folks to upload? Or is this better to determine experimentally?

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----
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