900MHz Desktrac Repeater

[4n6inv]

I'm new to the 900 ham band, so assume that I don't know anything about it. That would be a fair assumption. I've read a lot of the posts about converting different models to the 900 ham band, but I'm still very confused about what will and what won't do the ham splits on 900. I am wondering - point blank - if a 900 MHz Desktrac repeater can be (resonably) modified to work as a 900 repeater. And if so; what steps would be needed to accomplish this?

On another note; I just bought an MTX9250 HH to use on 900. I know that is essentially a software issue, but can someone walk me thorugh it, or point me to a comprehesnsive post that can?

I'm also interested in converting a 900 Spectra to do the same.

What I'm trying to do, is set up as many different band base and portable radios for the local CERT team and equip an emeregency operations center to cover all of the ham bands, as well as all state and national interoperabilty channels.

I'd appreciate any help that you can offer me.

Thanks,

Jim

[4n6inv]

Echo, echo, echo.... Anybody out there? Anybody with 900 experience?

[Max-trac]

The Desktrac is just a housing for Maxtracs or Spectras.
See repeater-builder.com about modifying those radios.
I suggest NOT using the desktrac unless you have one, they are really just a power supply and interconnecting wires.
NO duplexer, NO IDer, NO controller other than simple hang time.
You can get a Maxtrac repeater-delay interconnect cable for 2 maxtracs on ebay for about $15 that will do the same thing.

[MSS-Dave]

Jim... You need to determine what type of Desktrac you have. /\/\ offered the 900 Mhz Desktrac in the StartSite trunking package in the early '90's. I do not remember if they offered it in a conventional package. Desktrac IS made up of Maxtrac pieces and people have been making repeaters out of Maxtracs for ages. Now, they don't make the BEST repeaters but at least Desktrac box has a fan in it. If you don't have Desktrac RSS, you might be able to use Maxtrac conventional RSS but there is a common control panel that you plug programming cable into and rotate a selector switch when prompted to program the RX, TX and the controller. BTW, are you SURE it's a Desktrac? You could get control stations in the same cabinet using Maxtrac and Spectra mobiles. Look somewhat simular

First thing I'd do is determine what you have. Post up the model #. If it followed Desktrac repeater convention it should be something like L27 or L37SUM700_T. It may have something completely different. Gurus on the older /\/\ system stuff (Dan, xmo, Bernie ) might remember. Somewhere in my pile, I have a flyer on 900 MHz StartSite that used Destracs. Just an opinion, I have NO idea how these things even worked in a high RF environment.

Dave

[xmo]

O.T. material deleted. Please use P.M. for personal discussion / comments.

[n9wys]

I just picked up one of these DeskTrac units from a popular auction site. Price was good, so I grabbed for all the gusto I could handle. Now I have more "gusto" than I was expecting...

Ok, down to brass tacks... Model number on the unit is L37SUM5070B. However, this thing has two antenna connections - one for RX and one for TX. It is NOT configured as a repeater - it is a Privacy Plus station (one radio only). I can supply photos to anyone who asks. I would prefer any PM via my regular e-mail (n9wys <(at)> ameritech <(dot)> net) that way I can attach photos, etc. I'm not that familiar with the PM options here, and prefer to avoid the learning curve for now.

This thing has a couple of options that are not documented - I wonder if anyone here knows what they are, and if that makes a difference in why it has two antenna connections. The undocumented option codes are: B827 and L992.

Can anyone tell me if I can disconnect the second (RX) antenna cable and reconnect the "normal" one that appears to go to the PA section, assuming there is an antenna relay in the PA section?

So many questions...

Thanks in advance!

[AEC]

Two antenna ports indicate either A: diversity receiver option, or B: full duplex operation in conventional modes only.

That's my take on the information supplied.

[com501]

If it is at 900, and was originally a full duplex base or repeater (as indicated by the two antenna ports) the RX unit should work fairly well as a repeater RX on the low end of 902. I would reprogram it and try it.