Technical Questions on E-Callers

[JoshT]

I'm not sure if this is cool, but if you guys see others with technical questions on E-Callers, I will be glad to answer them, only if they are asked on FnF. I see someone from another forum with a caller Freezing up, I could provide some input.

JoshT

[Hawks Feather]

Thanks for the offer.  It is always nice to have our own private consultant. 

Jerry

[snowcamoman]

JoshT,
Thanks for taking the time to offer some help and answer question on RF stuff. I have a question regarding the use of an FRS radio for a remote for an e-caller. Do you think that I would be able to have something like this built nowadays if I wanted to go that route? Or better yet, what would it take for somebody to make up their own transmitter that plugged into a FRS radio and sent a signal to a FRS receiver rigged up for activating a caller? It seems like it'd be perfectly legit with FCC since no modifications to an FRS would be needed. If you or somebody could make something as simple as a remote that plugged into a FRS radio and controlled a MP3 player with amplifier plugged into another FRS radio, it'd be a simple, killer setup I'd think. It wouldn't require any FCC certification at all would it, due to the fact that the manufacturer wouldn't be selling an RF device? Not that it's ethically right to do or safe for people who legitimately need the FRS channels, but it's an idea.

[FinsnFur]

It's cool with us Josh. Nice gesture, I appreciate that.

[alscalls]

If I knew how to do all that stuff I would not be working so hard to save money to buy one.
I wish I could build my own e- caller with remote, I would be wearing it out in the field.

[JoshT]

Snowcammoman,

Good to talk to you again my friend! You have a steller idea there, unfortunately the FCC will shut down anybody trying to sell a device that transmits data over a non data qualified FRS radio. Now, the FCC does allow small data packets to be sent over FRS radios, however, the radio must be certified to send data. This was designed to allow positioning informatoin to be sent, probably lobbied for by Garmin. The kicker is that once a small packet is sent (must be less than one sec), you can not transmit data again for 30 seconds. Not a real practical solution for game calls.

JoshT

[snowcamoman]

JoshT,
Thanks for the reply, that's what I thought, and Garmin has been a manufacturer with an approved FCC license to transmit small data bursts on the FRS channels as you said. So basically at this point in time nobody will be selling any more FRS based remotes is what I'm gathering?

You were going to answer some questions regarding battery use in cold weather as well, and I'm interested in your ideas? I have plenty of experience  using all of the callers in -30ºF temps and there is definitely a battery that surpasses all others in the field. The Lithium Ion battery packs 14.8Volt types  have proven themselves exceptionally strong in the cold. Next are the SLA's followed by the NiMH's. Any suggestions on other methods or strategies other than sticking handwarmers around the batteries for pro-longing life in the cold?

If an individual were to make up their own FRS based remote keypad and receiver it would be totally legit wouldn't it? As long as it's not being sold, FCC shouldn't have any gripes. If so, maybe you can put your RF experience to work here and make a few dollars designing one for me. Let me know if you're interested and maybe you could design a circuit for the receiver/speaker to plug in an iPod Nano and power it all from a single 14.8v Li-Ion pack. 

[JoshT]

snowcamoman,

I am definately not an expert in batteries, so I will not pretend to know a lot about them. I did find a good web page with a comparison table at the bottom:
http://www.batteryuniversity.com/partone-3.htm

I think adding hand warmers is a pretty novel idea. I know that systems that are designed to operate in rugged environments have battery heaters and coolers. From the table on the above web page, it looks like at -30F you are beyond the limits of most batteries. You can also damage Li-Ion batteries if you take them down too cold (read the first page of this pdf doc):
http://www.lxe.com/pdf/wp_Li-IonBatteries.pdf

JoshT

[JoshT]

snowcamoman,

Forgot to answer some of your other questions: Yes, there are provisions to experiment, so long as you do not exceed the transmit limits, and you don't try to manufacture or sell without qualification. It is also okay to send out demo units, so FauxPro sending out the Furie as demos was not illegal as some people are saying, so long as it was marked properly and not sold.

Sorry my friend, no time to develop stuff on the side for me. I have a pretty full plate.

JoshT