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Gary_Gough

Radios, scanners, transmitters, SDR

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These things are everywhere, great receivers solid 4 watt transmitters. Measured frequency was better then the built in osc. in the Fluke frequency meter. ( using an external 10 MHz TCXO the error was below 10 Hz limit of resolution ) Li-Ion battery holds it's charge for ages, so good to go grabbed out of the pack. If your local fire dept. is still pre APCO25 they also can add to their comms. ( esp. handy if you are a volunteer dept. )

100_1708sm.JPG

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Here's why those hand helds all seem so similar. One chip handles all the receive and transmit functions, CTCSS, DTMF with a digital signal processor. RDA1846 , I've attached the datasheet. A micro processor sends settings ( Uses I2C control ) add a power amp and it's pretty much a full feature radio. The chip itself is also able to do the 220 MHz band but as that's only in the Americas, it doesn't seem to be supported by the MPU ( OTP processor , probably a EM78P568P or similar ) at least in the ones I've seen. There is a code hack to add more features from a computer programming the channels and if someone wants to play or gets one with a broken display, I2C is supported by most micros so you could do your own controller and push the radio chip out to it's limits.

rda1846_datasheet_v1.2e.pdf

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I have an awesome handheld scanner that I love, but when is there going to be a handheld that has a built in clock, GPS and  can be registered like a personal beacon that outputs on 406 and 121.5 ELT?

Looked at the webpages, and 406 Mhz seems the way it is going.

http://www.sarsat.noaa.gov/406vs121.pdf

http://polarpilots.ca/index.php/whats-new/59-newadds/79-406-elt

My beef Gary is that a person is shelling out 500$ for APRS capable handheld,

or about the same for a personal EPIRB, why not have the data go out to GLONASS -SARSAT if we are willing to register it ?  There are subscription systems for an individual  SAT based  systems for hunters, yet a person can register a 406MHz  ELT to a kayak !!

I am waiting for a handheld that will allow the 406 MHz to be used as a beacon, though despite what the web page says, lot's of pilots still monitor 121.5 Mhz as 'guard' as well as 243 military guard.

APRS is too much to ask to find a repeater on once in the sticks out of cell tower range.

For 100$ a person can get used ex military 7 inch Armor X7 tablet with GPS on Galileo on ebay and leave the maps at home, with a SIM slot!

http://www.ebay.ca/itm/DRS-Armor-X7-7-Tablet-Win7-Pro-2GB-RAM-40GB-SSD-HDD-Dual-Battery-RUGGED-GRADE-/111654609959?hash=item19ff222427:g:uZ0AAOSwymxVOsER

Half the battle right there. What about an ELT when itis time to throw in the towel ?   Am I asking too much??

maybe someone has figured this out..

 

 

Edited by Dan Seven

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Most of the price is because they can.. a GPS subsystem and a little code and those Baofengs have all the needed RF. Actually just a bit of code and they'd do the PLB ( no GPS ) as they sit. This is a bit like APCO25 which adds $1400 to the price of the hand held because the standard is Uniden, Motorola and one other sharing patents and "competing" with each other. The only difference is APCO25 has a 2 bit digital stream ( fsk 4 frequencies that decode as 00,01,10,11 ) and a compression algo to change that into audio ( poorly ). They also have a control frequency to assign channels for each transmission. ( where I am it's one channel so easy to guess :P  ) the DSP in the baofeng could easily take it to digital, and while I haven't checked how fast the I2C will clock, it wouldn't surprise me at all if you could dump that straight to the micro and decode it . 

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Thanks Gary...

I guess i will wait until this sorts itself out..considering the cost of a SAR operation to extract somebody, there may be a monetary barrier necessary for entry, at least for non maritime uses.

I like your description of where the tech is at. I like the Baofeng, and for the price is a great alternative to the "Family Radio" scene for the money with of course a lot of perks for the Ham.

Seems as though taking a portable 20m rig out is still a good albeit heavy alternative.

http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID= 102&encProdID=06014CD0AFA0702B25B12AB4DC9C0D27&DivisionID=65&isArchived=0

 

 

Edited by Dan Seven

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I guess i will wait until this sorts itself out..considering the cost of a SAR operation to extract somebody, there may be a monetary barrier necessary for entry, at least for non maritime uses.

 

 

http://radioworld.ca/857d-p-46.html This would work ( have one ) but the batteries would be a killer if sticking to lead acid. Of course 4 Li-ion in series = 14.8 volts, well in it's working range. so a pack of 16 , 18650 cells should be good for an hour of transmitting at full power. Not going to break anyone's back carrying either.

Tuning up an antenna is always a fun project too, not likely to be running it in the canoe xD

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Very nice Gary !  

I know that Elecraft has a little ATU that comes in kit form that makes thing a lot easier..

I guess old school might have to do till everyone is rich enough to keep a sat phone or new school figures out it's priorities and get's it's face out of the trough long enough to see to give us an option in survival comms that will not forsake a human life for the sake of profit of hardware or slavery of subscription. Some time ago Air Band with 121.5 Mhz guard with 2m band  handhelds were popular. Yaesu at one point stopped making a model claiming pilots were using 2m unlicensed and now the frequency is falling off the bandplan sooner than later by all appearances..

Seems my concerns are only for those well off the beaten path..and this post is funny...

http://www.ablogtowatch.com/breitling-emergency-ii-watch-featured-top-gear-last-aired-challenge/

I happened to watch this episode, and in the end it was the Top Gear Crew that showed up after flying all the way from London..then driving 3 or 4 days later, and no search and rescue team there first as was the expectation.

Sure that was a set up..

In the Movie   The Grey with Liam Neeson, same watch, same deal..no one came, but then that would have ruined the plot too..

 

Edited by Dan Seven

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Awesome DThomas..

Thanks for the picture of the Horse Comm Shack..Gary !

I have a small panel for 12v with an adapter for USB..works ok.

Somehow i am reminded of the Costner Movie  The Postman    where the post- apocalyptic USA is stitched together for the value of letters delivered to far flung survivor outposts on horseback.

Not getting the mail evoked enough rancor through basic communication disruption of personal and family relationships to raise an army !

I always wonder if the 5th C of the 5 C's should go from cordage to communications.

Which lifeline would we all prefer, or maybe not be able to do without ?

Not having a cellphone or internet is about the worst punishment for  teen nowadays.

What do You all think?

 

 

 

 

Edited by Dan Seven
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