BCD436HP/BCD536HP: What pins on the bcd436hp can I tap to get 3.3V

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bazil747

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Greetings. I wanted to add a gps to my bcd436hp. Well internally and this gps module required 3.3V to operate. It's a tiny gps from adafruit. All I wanted to know is where and what pins can I tapped into to get 3.3v . Thanks.










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Ive been putting this idea together as well..those GPS
modules are quite small & inexpensive..

I have put aside the idea of tapping the 436 for the power
too many chances foul the radio..
However,,,,
Small Lithium batts?,,,would supply the forward voltage for testing...
without any mods to the working side of the 436...
Also..
Testing to see if an internal GPS would add any RFI/EMI..
Anything added would have to keep EMC..or you could
wipe out sensitivity .. on certain bands.
(better to do with a temp power solution vs soldering
Then finding out its not viable)

Ill be watching this page with interest, Im going to order a GPS
Module when I finish posting here..

Keep us up to date..Im sure many are interested in this mod!...
I know I am...
 

EricCottrell

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Hello,

The best solution is to find a DC to DC Converter Board with a 3.3 Volt DC output and a 4.5 to 16 volt or so input. Then you could tap off the battery in the scanner or use an external battery.

73 Eric
 

bazil747

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bazil747

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Thanks

All i need too do now is check the current draw.

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Greetings. I wanted to add a gps to my bcd436hp. Well internally and this gps module required 3.3V to operate. It's a tiny gps from adafruit. All I wanted to know is where and what pins can I tapped into to get 3.3v . Thanks.










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Which gps are you using?..have a link..
 
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Also..See this post for that 3.7v tap...
http://forums.radioreference.com/uniden-tavern/330695-bcd436hp-discriminator-mod.html#post2550115

To add...
the operating voltage for these small modules is variable..
3v to 4.3..no resistors would be needed..and for operation
3.7 seems like it would be optimal..

My only 2 concerns,

Module size, though small...is it small enough.
(dont have the part in hand yet)
and
Power interrupt - an on/off switch,,so the gps is
not just pulling milli-amps continuously..

this is the smallest spdt i could find...(quick search)
10 PC Lot Micro Mini Toggle Switch SPDT on
Ill thumb thru the Newmark catalog when I get home
to see if i can find smaller..

BAZIL...can you post a link to that datasheet?
 
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bazil747

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Not have have all my parts here. Quick question. Would removing the metal shield to accommodate this gps module have a significant effect on signal receptions.
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bazil747

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One more thing the little 3.3v voltage regulator i might use to tape intp the battery with a on and off mini switch. Still thinking

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Where did you source the voltage reg?...

I do not have an answer to your interference
question...

Waiting on the GPS module today...Looking at
using 1 of 2 diff modules..Have to write the parameters
for the baud & set the protocals to NMEA n such...
 

EricCottrell

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Hello,

I would not recommend removing a metal shield as it could increase interference. There was a reason for using the metal shield, usually to reduce RF emissions from the digital electronics.

73 Eric
 
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