Low Power Transceiver 144.mhz

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jeepsandradios

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Looking for recommendations on a low power (5 watts max) transceiver for a solar project. I've found some but are crazy expensive. Our SAR team does some stuff in national parks and want to build a small self contained APRS digi. I am using the argent board but a mobile is killing battery life and I really don't need 90% of the features. Also size is a concern. Really want all of this in a small box with a small battery. I would think someone would make a telemetry style transceiver. I'd love to find a maxon data radio but all I find are up in the 173 mhz area.

Thoughts ?
 

tweiss3

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Why not use an HT? Seems to check most if not all of your boxes. FT-60 is pretty inexpensive.
 

AK9R

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I Googled "vhf data transceiver". After the high-end vehicle locating system radios was a link to Alibaba. Several possibilities there, but still kinda spendy.

Argent Data used to sell an inexpensive, Asian VHF radio branded "Friendcom" with an Argent Tracker2 built in, but I think Scott ran into supply chain problems.

Byonics still sells their MTT4B: Byonics - MTT4B Kinda spendy, too, but they have APRS TNCs built in.
 

mmckenna

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Yeah, those little data radios are a good option. Most of them have the ability to do a mic input/audio output in addition to the data. You can often find them used on EBay.
 

jeepsandradios

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Handhelds are junk for this scenario. It needs to be flip a switch and walk away for SAR folks. Also dont want them to have to open a box push buttons or anything like that. Litterly flip a toggle switch and its on.

I found some maxon data radios but none went low enough (146/148 mhz). I'll check out the Ritron. This is a donation from myself as the team doesn't have the funds to do it so I didn't want to spend a $1000 on it.

Most of the ones I find that are a transmitter and APRS board are trackers only. None I have seen support true Digi traffic. Byonics is supposed to but I was never able to get my TT4 to work as a proper digi. That's why I went with the Argent Tiny board. It works amazingly and is truly tiny.
 

AK9R

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The SHARI Pi-Hat doesn't have much output power.
"250 to 500 milliwatts RF output power"
 

ko6jw_2

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Although they are not cheap the Yaesu FT5 has a built in GPS and using the DN mode will transmit voice and one sub band and position information on the other (in addition to call sign and name). This information can be displayed on each users radio. No APRS digi required. I believe the new Kenwood tribander has this capability too.
 

AK9R

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Although they are not cheap the Yaesu FT5 has a built in GPS and using the DN mode will transmit voice and one sub band and position information on the other (in addition to call sign and name). This information can be displayed on each users radio. No APRS digi required. I believe the new Kenwood tribander has this capability too.
I think the OP is dealing with a situation where APRS position reports are being transmitted by units in areas that don't have good digipeater coverage. So, the OP's current solution is to deploy an APRS digipeater in a high location to provide additional digipeater coverage. But, their current digipeater uses a mobile radio that draws too much current thus draining the digipeater's battery. He's looking for a digipeater solution that uses less electrical power.

Is there an app or software package that will display the System Fusion position reports on a map? I think that's the OP's goal with wanting to digipeat APRS position reports.

Your solution would require that the OP's SAR team all buy Yaesu System Fusion radios. Seems like an unnecessary expense if the team members already have voice radios and APRS trackers.

The Kenwood TH-D75 has D-STAR and DPRS capability, but not System Fusion capability. Like all Kenwood APRS radios, it will show a received APRS position report relative to the user, but would still require a software package or app to show those position reports on a map.
 

AK9R

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Our SAR team does some stuff in national parks and want to build a small self contained APRS digi. I am using the argent board but a mobile is killing battery life and I really don't need 90% of the features. Also size is a concern. Really want all of this in a small box with a small battery.
Several years ago, I built a portable digipeater for use at a 3-day orienteering event being held in a national forest in southern Indiana in January (approx. 30 deg F during the day, 10 deg F at night). The hardware consisted of an Alinco DR-135T mobile radio set to operate at low power (5 watts), an Argent Data Tracker2, and a gel cell battery of the size used in motorized wheel chairs. Everything was packaged in a small, hard-sided cooler. The package was carried to the top of a fire tower in the middle of the forest. The antenna was a quarter-wave whip on a mag-mount stuck to one of the ribs of the tower.

This digipeater functioned well and still had battery power remaining after three days. I'm not well-versed in solar power, but it seems that a sufficiently-sized solar panel and a solar battery tender would keep the battery charged.

You say that the mobile is killing battery life. Are you running the mobile at high power? Do you find that it's necessary to run high power for the digi to give the performance you want?

You say that the "argent board" has more features than you need. I assume you are talking about an Argent Data device. Which model? OpenTracker? Tracker2? Tracker3? One of the micro or mini models? Yes, the Argent Data have lots of features. It's been my experience with APRS devices that the "dumb trackers" can send APRS position reports, but they don't have the horsepower or features to act as digipeaters. So, you are forced to buy devices with lots of features in order to get the feature, digipeating, that you want.
 

tweiss3

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Similar to what @AK9R above mentioned, which mobile are you using, and which argent device? Quickly looking at the options around, a DR135T with the internal Argent Tracker3 model T3-135 appears to be by far the lowest power draw I have seen searching this morning. Argent is rated at 50 mA, and the DR135T is 0.6A max on receive, and approximately 4A on transmit. Anything RaspberryPi based will draw 3A minimum all the time. Also, many other transceivers have a much higher RX current draw.
 

ramal121

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If you read the specs on the Ritron DTX it has a standby of 25mA around 1A on transmit. That's what you should be shooting for instead of a mobile hog.
 

jeepsandradios

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Sorry crazy work week. I was using an ADI mobile on low power. 3 7ah GEL batteries were dead by 1400. Unit was turned on at 0430. First issue was the fan appears to run non stop on the mobile. Thats fixable by unplugging it but then the display is lit also. In the end its just an issue with battery I guess. I called Ritron and trying to get a price from them. They actually sell it in board level with no case.

Yes goal is to put a digi in an area that the trackers can be seen in command. We run a mix of Yaesu, Tiny Tracks and other trackers. The Argent board seems to work well for this scenario. If I can't find a small radio I'll just keep using the mobile. I'd like it all in a smaller box but keep digging into stuff. I did think about tearing a portable radio (Commercial LMR) apart and using just the board for this. Hopefully hear back from Ritron next week with a price.
 

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Most of the ones I find that are a transmitter and APRS board are trackers only. None I have seen support true Digi traffic. Byonics is supposed to but I was never able to get my TT4 to work as a proper digi. That's why I went with the Argent Tiny board. It works amazingly and is truly tiny.


I am currently running a mobile digi that I built, it uses a Yaesu FT-8800, a TinyTrak4 and some LiFePO4 batteries. Its all contained in a normal size tool box and will run for approximately 3-4 days before needing recharged. Thats at 50 watts and being a W2 digi.

The setting in the TT4 for digi'ing is ALIAS. Set that to WIDE1 or whatever your using in you paths.


Heres the link for the LiFePO4 batteries. I have 2 of the 20Ah in the digi box and get good results.
 
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