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MaxTrac question
Posted: Thu Feb 22, 2007 7:25 pm
by KB!DAN
First of all, I did search for the information first but could find nothing on this specific radio, D43MJA73A5CK it is a two channel 45 watt 146-174 maxtrac (want to go to 145.

) , My question is, how would I go about adding in the manual power control to the radio, (I know this has been covered before but I must be thick) but the pictures on the repeater builders and another site have pictures of what look like a totaly different logic board. My bord number is HLN9123A. My request is if any one has "instuctions" or pictures of a radio modifyed, any help would be great. My goal is to stop this wonderful peice of equiptment from burning itself up due to transmitting close to 80 watts.
please e-mail me any information or links.
As I said I allready looked at the RBTIP and the radio board looked different.
Posted: Thu Feb 22, 2007 8:12 pm
by n7maq
I have done this with every VHF Maxtrac that I have had. I have a repeater on 145.490 and I could not have the PA running wide open with no control. It works very good for me. You will need a service monitor to retune it.
All you have to do is use LAB RSS. Blank the board, and then re-initialize it as a low split unit. (136 to 162MHz IIRC) You will need to do a complete realignment. Your radio is a high power, and on the LAB RSS that I have seen only has a 25 watt low split model. Don’t worry about that, just tune the TX output to 45 watts for all of the two meter band and above. I normaly left the lower values down to 30 watts due to the amp being out of band just a bit, plus I never use anything below 144MHz. You will get a warning from the RSS about going above the radios rated output. It assumes it is a 25 watt unit and when you get above a certain soft pot value it warns you.
Good luck, and let us know how it works for you if go this way.
Jim
MaxTrac
Posted: Thu Feb 22, 2007 8:35 pm
by KB!DAN
Thank you for the quick reply, I will look into that tomarrow and post back here with results (might take some time I have to borrow equiptment) n7maq you woulden`t happen to have some screen shots or somthing like that that will show me what to do, or a list of some sort telling me what values to wright down.
Thanks in advance,
Ps, im using this for an echoirlp simplex node.
[edit to fix spelling error that was bothering me]
Posted: Thu Feb 22, 2007 9:02 pm
by n7maq
I have a PDF file that Monty Sisco wrote. It is a very good guide, you can down
load it here.
http://members.trainorders.com/x4449/5pin.pdf
Once more the info was put together by Monty.
Jim
Posted: Thu Feb 22, 2007 11:38 pm
by Will
n7maq wrote:
. x4449
Would the "4449" be a reference to my favorite locomotive?
I have not seen her in several years....
Posted: Fri Feb 23, 2007 7:05 am
by n7maq
Will wrote:n7maq wrote:
. x4449
Would the "4449" be a reference to my favorite locomotive?
I have not seen her in several years....
Yes it is.
MaxTrac
Posted: Fri Feb 23, 2007 9:59 am
by KB!DAN
Sweet, Thanks a bunch jim thats what i needed. i will post back with results.

MaxTrac
Posted: Fri Feb 23, 2007 4:11 pm
by KB!DAN
Perfect, that is great info it works great, 45 watts on 145mhz with soft-pot adjustments
Thanks Jim you were a great help, it runs nice and cool.
Re: MaxTrac
Posted: Fri Feb 23, 2007 6:46 pm
by n7maq
KB!DAN wrote:Perfect, that is great info it works great, 45 watts on 145mhz with soft-pot adjustments
Thanks Jim you were a great help, it runs nice and cool.
Good deal!! Like a lot of others here, the Maxtrac was my first radio to "hack" and/or upgrade. They are darn good radios.
Jim