Tag Archives: Repeater

DMR Repeater Progress

Not a lot of progress has been made on the new DMR repeater, but progress is progress, right?!

The cabinet is repurposed from an old GE MASTR II receiver rack. It will house the MMDVM board, Raspberry Pi, in addition to the 12 and 5 volt power supplies. It is being designed and built as a low power (~5 watts) repeater in a nice portable (and rack mountable) package.   Keep checking for updates!

224.580 Repaired-Online

Well, thanks to my new radio, I thought something serious had gone wrong with the repeater. After getting home from work today and fixing supper, I loaded the truck with some tools/supplies and the kids and headed to the site. On the way down, reception of the repeater on the mobile was VERY poor, and the audio very VERY distorted.  As I got closer, I noticed I was hearing it fine on the HT, but still poor on the mobile.  About 2/3 of the way there I noticed an extra icon on the display of my new Alinco DR-235 that wasn’t there before. I finally remembered what it was…I somehow put the mobile into AM receive.  After some random button pressed, I manged to get the radio back into FM mode, and the repeater sounded great like it normally does. Since I was within 5 minutes of the site by then, I went ahead and stopped in to see how it was doing.

The output of the Uniden amplifier had dropped a little more, it is now down to ~50 watts output instead of the original 110+.  I need to find a source for some Polyfet F1004 and see about fixing it back up. Installed the rest of the intermod panel, and did some tests. Forward power after all the filtering is 35 watts, reflected at the feedline is less than 0.5 watts. Intermod panel is now complete, and includes a dual port isolator, followed by a low pass filter, band pass filter, then the 4 cavity pass/reject duplexers. I did a quick test for desense by transmitting a very weak signal over the air and disabling the transmitter, no noticeable difference in received signal.

All is well again!