开云体育

ctrl + shift + ? for shortcuts
© 2025 开云体育
  1. Repeater-Builder
  2. Topics

My ammo can repeater build

 

I thought I'd share my recent ammo can repeater build.?
?
The goals were:
As small as possible
Portable
AC and battery power
DMR and FM
Good performance
?
Parts list:
2 Motorola CDM1250 radios with control heads removed.
Repeater Builder STM32 MMDVM paired with a Raspberry Pi 4.?
100W Mean-Well switching power supply.
Mobile duplexer
3D printed assembly that holds all of the parts together
Fat 50 PA-108 Ammo Can
80mm Noctua fan
?
Build notes:
In order to fit size constraints all wiring and cables are purpose-built. I couldn't even use the standard SAE power connectors for the radios. I used tefzel mil-spec wire for all wiring.?
?
To optimize cooling for the TX radio there are 3 front exhaust holes for that radio compared to one exhaust hole for the RX radio and duplexer sections.
?
There is a foam sheet top and bottom of the assembly between the assembly and the can to hold it all together tightly and provide some shock protection.?
?
The TX radio is set to 20W. At 20W the radio only draws around 5A, so the small power supply is more than sufficient. The cooling fan is quiet and runs continuously. Temperature rise is minimal even with a long stretch of continuous use. The whole thing uses about 800ma at 12V at idle.?
?
I started with pi-star on the raspberry pi but could not get it to work without an internet connection. Since I wanted to use this in the field with no internet, that was a deal breaker. Fortunately WPSD will boot up find and work without internet. So I'm using WPSD.?
?
I'm thinking I can build a custom Lithium battery pack with 21700 cells that will fit in the space on top to allow for 100% self contained field use. That will be next.
?
Performance has been very good, better than expected in fact.
?
Larry, N6TXX
?
 

Bring it down here to Texas and we'll see it melt in field testing ?..

Cool job!! Well maybe not cool.
.. but nice!?

Sorry the Hank Kimball mode just took over ??

Chris WB5ITT?

On Thu, Aug 22, 2024, 2:39 PM Larry N6TXX via <misc3=[email protected]> wrote:
I thought I'd share my recent ammo can repeater build.?
?
The goals were:
As small as possible
Portable
AC and battery power
DMR and FM
Good performance
?
Parts list:
2 Motorola CDM1250 radios with control heads removed.
Repeater Builder STM32 MMDVM paired with a Raspberry Pi 4.?
100W Mean-Well switching power supply.
Mobile duplexer
3D printed assembly that holds all of the parts together
Fat 50 PA-108 Ammo Can
80mm Noctua fan
?
Build notes:
In order to fit size constraints all wiring and cables are purpose-built. I couldn't even use the standard SAE power connectors for the radios. I used tefzel mil-spec wire for all wiring.?
?
To optimize cooling for the TX radio there are 3 front exhaust holes for that radio compared to one exhaust hole for the RX radio and duplexer sections.
?
There is a foam sheet top and bottom of the assembly between the assembly and the can to hold it all together tightly and provide some shock protection.?
?
The TX radio is set to 20W. At 20W the radio only draws around 5A, so the small power supply is more than sufficient. The cooling fan is quiet and runs continuously. Temperature rise is minimal even with a long stretch of continuous use. The whole thing uses about 800ma at 12V at idle.?
?
I started with pi-star on the raspberry pi but could not get it to work without an internet connection. Since I wanted to use this in the field with no internet, that was a deal breaker. Fortunately WPSD will boot up find and work without internet. So I'm using WPSD.?
?
I'm thinking I can build a custom Lithium battery pack with 21700 cells that will fit in the space on top to allow for 100% self contained field use. That will be next.
?
Performance has been very good, better than expected in fact.
?
Larry, N6TXX
?
 

Larry,
?
Don't mind Chris, he's probably just OTR... (Love you, Chris ;))
?
Very nice build! I'd imagine the fan does a good enough job of keeping things cool. What would be even better would be to design a second ammo can battery pack that plugs into your repeater with a small cable. Fill it with cells and let the thing run for days! Just plug them together with a link cable.
?
Excellent job.
?
Chris/KF6AJM
?
?
On Thu, Aug 22, 2024 at 12:38 PM, Larry N6TXX wrote:
I thought I'd share my recent ammo can repeater build.?
?
--
Chris Baldwin, CETSr. (KF6AJM)
Trustee - MetroNET Cal. Intertie (KB3PX)
 

Do you still have the .stl files for the CDM housing that you made and would you be willing to provide it to me? I have a project that would greatly benefit from it!
?
Thanks
Joseph KI5TLZ.tx@...
 

Here you go.?

Body.stl
Body.stl

 

That is a great setup. Do you have any cooling challenges??
I'm getting ready to build the same setup but have many questions. How did you program the radios. Exactly what were the settings in the CPS??
  1. When programming the radios what are the parameters? Does the Rx radio have both Tx & Rx programmed on the Rx frequency of 462.7250, and the Tx radio have both Tx & Rx programmed on the Tx frequency of 467.7250?
  2. Are there additional radio parameters needing set in the CPS to enable the radios to work in tandem as a repeater? I’ll be using the GMRS travel pl of 141.3 in & out.
  3. How about the pin setup in the radios for the interface cards? Are any modifications needed for compatibility here or just plug & play? I understand there is a right and wrong as far as plugging them in right side up or down. Is there a good way to determine what is ‘right side up’?
  4. Are there settings mods for audio when using these in tandem as a repeater.
Any help or guidance you have is appreciated.
Thanks,
Gregg
 

Good Job Larry.
Just add a few whips and you can plant it on some Mountain Top.
It would look like a GeoCash box and no one would disturb it.
? ? My repeater was in a water proof Motorola 15 Inch case.
5 Watts, 2 transistors, one diode and no software.
Still working after 65 years.
See
“奥6础蚕驰, Early VHF FM Mountain Top Repeater in Southern Calif”,
?
Paul? w0rw
 

Very nice work! I recently built a portable repeater using a pair of Motorola XTL1500 radios, no controller, just jumpered the rear panel connectors for COR to PTT and RX audio to TX audio. Radios are set for 20w and programmed for MPL or front panel PL selection on the fly. The RF deck pulls out easily for tuning the duplexer, internal 12V supply with Corcom AC line filter and external Anderson Power Pole DC input. Works very well. I purchased two of these Zero Halliburton enclosures about 30yrs ago at a swap meet and have been wanting to use them for a project. Finally found one.
?
 

Mike:
?
? ? ?That looks good. The big challenge in these projects is finding a case that fits what you need without too much wasted space.
?
Gregg:
?
? ? ?Cooling seems adequate. After I made the original post I added two DS1820 sensors and wrote some C code on the pi to read and log them. One sensor measure ambient and the other is attached to the TX heat sink. It takes about 30 minutes of continuous transmission to get the max temp rise on the TX heat sink of about 30 degrees C. That is with the transmitter set to 20 watts.?
?
? ? ?Regarding the CPS questions, it depends. I have built two versions, 1 with the MMDVM for a DMR repeater and also a simple ID-O-Matic controller for an FM repeater. For the DMR repeater the radios are set to Flat Audio. For FM normal pre-emphasis and de-emphasis are used. I programmed a single simplex channel for RX and TX radios to guarantee that the radio powers up on the proper channel. If there is just one channel programmed that is where it powers up. If there are more than one channels programmed, the last one selected when the radio was properly shut down is used, but you need a control head connected to make that channel selection.
?
? ? ?From your questions it seems like you are proposing a GMRS FM repeater. You'll need a controller for ID. I suggesting the ID-O-Matic. They offer pre-built cables that work with the CDM series. Their documentation and cables should answer all of your questions. https://hamgadgets.com/ID-O-Matic-IV-KIT_p_44.html
?
? ? ?Also since that original post I have given up on WPSD. The nightly updates drove me nuts and I could not figure out how to keep them from happening. I compiled MMDVMhost and DMRgateway from the GitHub repositories and run those standalone with no dashboard. That has been rock solid.?
?
Larry
 

开云体育

Larry:

I am prosing a GMRS FM repeater using two CDM1250 radios. I have the HID-O-Matic controller with voice ID’er and the interface cables. Is the interface cable ‘plug-n-play’?

What are the individual radio settings? Do you have a ‘playbook’ for your builds?

Gregg ?????????gregg@...

?

Gregg Wardlow

From: [email protected] <[email protected]> On Behalf Of Larry N6TXX
Sent: Saturday, March 1, 2025 1:54 PM
To: [email protected]
Subject: Re: [repeater-builder] My ammo can repeater build

?

Mike:

?

? ? ?That looks good. The big challenge in these projects is finding a case that fits what you need without too much wasted space.

?

Gregg:

?

? ? ?Cooling seems adequate. After I made the original post I added two DS1820 sensors and wrote some C code on the pi to read and log them. One sensor measure ambient and the other is attached to the TX heat sink. It takes about 30 minutes of continuous transmission to get the max temp rise on the TX heat sink of about 30 degrees C. That is with the transmitter set to 20 watts.?

?

? ? ?Regarding the CPS questions, it depends. I have built two versions, 1 with the MMDVM for a DMR repeater and also a simple ID-O-Matic controller for an FM repeater. For the DMR repeater the radios are set to Flat Audio. For FM normal pre-emphasis and de-emphasis are used. I programmed a single simplex channel for RX and TX radios to guarantee that the radio powers up on the proper channel. If there is just one channel programmed that is where it powers up. If there are more than one channels programmed, the last one selected when the radio was properly shut down is used, but you need a control head connected to make that channel selection.

?

? ? ?From your questions it seems like you are proposing a GMRS FM repeater. You'll need a controller for ID. I suggesting the ID-O-Matic. They offer pre-built cables that work with the CDM series. Their documentation and cables should answer all of your questions.

?

? ? ?Also since that original post I have given up on WPSD. The nightly updates drove me nuts and I could not figure out how to keep them from happening. I compiled MMDVMhost and DMRgateway from the GitHub repositories and run those standalone with no dashboard. That has been rock solid.?

?

Larry
 

Greg:
?
? ? ?OK, here it is. The PDF schematic is attached and is very specific to my build and includes lead lengths in inches. The TX LED is not fully implemented because the polarity and levels do not match. I use the ignition sense to power up the radios, otherwise the radios will not power up after a power cycle.
?
? ? ?If you use the purchased cables you do have to figure out the pin mapping. I made my own cables because I wanted special wire and custom lengths.
?
Larry
?
####################################################
Motorola CPS for FM repeater
####################################################
?
common
? ? Radio configuration
? ? ? ? Lights/LED's
? ? ? ? ? ? Mobile Backlight Intensity High
? ? ? ? ? ??
? ? ? ? Tx Power
? ? ? ? ? ? Tx Low Power? ? 20
? ? ? ? ? ? Tx High Power? ?30
?
? ? ? ? Accessory Configuration?
? ? ? ? ? ? Rx Audio Type:? ? ? ? ? Filtered Audio
? ? ? ? ? ? Data PTT Audio Source:? Ext Mic Audio
? ? ? ? ? ? Ext. PTT Audio Source:? Ext Mic Audio
? ? ? ? ? ? Ignition Sense Type:? ? On/Off & Ignition
? ? ? ? ? ??
? ? ? ? Option Board
? ? ? ? ? ? Enable Flat Tx Audio un-checked (If checked no PL is sent)??
? ? ? ? ? ??
? ? ? ? Accessory Pins??
? ? ? ? ? ? 3 External Mic PTT
8 PL and CSQ Detect (Output)
?
??
? ? Conventional Personality
? ? ? ? Basic
? ? ? ? ? ? Squelch? ? ?TPL
Bandwidth? ?25
? ? ? ? ? ??
? ? ? ? Options
? ? ? ? ? ? Tx Power? ? ? ? ? ? ? ? 20 Low or High, depends on radio
? ? ? ? ? ? TOT? ? ? ? ? ? ? ? ? ? ?180
? ? ? ? ? ? Busy Channel Lockout? ? Disabled
? ? ? ? ? ??
? ? ? ? Advanced
? ? ? ? ? ? Compression? ? ?Disabled
? ? ? ? ? ? Expansion? ? ? ?Disabled
? ? ? ? ? ? Emphasis? ? ? ? De-Emphasis and Pre-Emphasis
?

Repeater_ID-O-Matic.pdf
Repeater_ID-O-Matic.pdf

 

And before somebody asks, here is all the info on the MMDVM version. This uses Scott Zimmerman's MMDVM board.
?
?
#################################################### ? ? ? ?
Motorola CPS for MMDVM repeater
####################################################
common
? ? Radio configuration
? ? ? ? Lights/LED's
? ? ? ? ? ? Mobile Backlight Intensity High
? ? ? ? ? ??
? ? ? ? Tx Power
? ? ? ? ? ? Tx Low Power ? ?20
? ? ? ? ? ? Tx High Power ? 30
? ? ? ? Accessory Configuration?
? ? ? ? ? ? Rx Audio Type: ? ? ? ? ?Flat Audio
? ? ? ? ? ? Data PTT Audio Source: ?Flat Tx Audio
? ? ? ? ? ? Ext. PTT Audio Source: ?Flat Tx Audio
? ? ? ? ? ? Ignition Sense Type: ? ?On/Off & Ignition
? ? ? ? ? ??
? ? ? ? Option Board
? ? ? ? ? ? Enable Flat Tx Audio un-checked (If checked no PL is sent) ?
? ? ? ? ? ??
? ? Conventional Personality
? ? ? ? Basic
? ? ? ? ? ? Squelch ? ? CSQ
? ? ? ? ? ??
? ? ? ? Options
? ? ? ? ? ? Tx Power ? ? ? ? ? ? ? ?20 Low or High, depends on radio
? ? ? ? ? ? TOT ? ? ? ? ? ? ? ? ? ? 180
? ? ? ? ? ? Busy Channel Lockout ? ?Disabled
? ? ? ? ? ??
? ? ? ? Advanced
? ? ? ? ? ? Compression ? ? Disabled
? ? ? ? ? ? Expansion ? ? ? Disabled
? ? ? ? ? ? Emphasis ? ? ? ?none
? ? ? ? ? ??
? ? ? ??
TX
? ? Radio configuration
? ? ? ? Accessory Pins ?
? ? ? ? ? ? 3 Data PTT
? ? ? ? ? ??
? ? Conventional Personality
? ? ? ? Basic
? ? ? ? ? ? Bandwidth ? 25

RX
? ? Radio configuration
? ? ? ? Accessory Pins ?
? ? ? ? ? ? 8 CSQ Detect (Output)
? ? Conventional Personality
? ? ? ? Basic
? ? ? ? ? ? Bandwidth ? 12.5

Repeater_MMDVM.pdf
Repeater_MMDVM.pdf

1 - 12 of 12