Batboard

I want to build a homemade repeater, which could be portable. I have two Motorola gm300's and a power supply already. So i was going to put two uhf magnetic mount antennas for my antennas. if i don't use a duplexer, will having two antennas work just the same???????

my question is how do i build one? i was looking at buying this cable unit, to conncet the two radios.

http://www.ebay.com/itm/Duplex-repeater ... 484561282e


is it all this simple or is it more.

thanks, please let me know.

spend the money on ebay & get a duplexer.. you will wind up with alot of headaches with the setup w/o a duplexer..

Ok i sure will invest in a duplexer,

so that cable will work to the conncet the two mobiles together, to work as a repeater?

hfd921 wrote:Ok i sure will invest in a duplexer,

so that cable will work to the conncet the two mobiles together, to work as a repeater?

I have used that same style of cable and yes that should work, you will need to program them correctly and get the the duplexer as well so you can use just one antenna

I vote get a duplexer too.

The cable described is for a crossband repeater. You want the simplex cable shown at the bottom of the page.

It really depends on what you need the repeater for. I built a mobile repeater years ago from a GE Master2. I was able to hear my friend's repeater just fine, but I wasn't able to get into it very well from work, so I modified the GE. I was never more than 100' from the car, & the GE was set to xmit on the input of my friend's repeater. I didn't need a duplexer, as a small HT antenna was all that was needed for the GE to receive the signal from my HT. The GE would tx on the car's mobile antenna & was set to 20 watts, as the repeater was only used when the car was parked. This set up worked just fine, as the HT was always close to the car, & tx was 1/2 watt. So if you just need a 1 way repeater & will always be close to the car, a duplexer isn't necessary. Best of all, it was transparent, & nobody could tell I was using it. My tx audio didn't change at all. GARY N4KVE

http://www.hamgadgets.com/index.php?mai ... cts_id=108

I used this cheap IDer/Controller and it is GREAT for portable repeater use

KF4NVX

You could always do the kit route and build the receiver and transmitter from hamtronics, get a CWID board(diode matrix), but kit costs are way up from years ago, so there might not be any advantage aside from the learn by building phase. Hamtronics kits also require a stable crystal, so the oven kit is pretty much a needed item here.

Forget the Maxtrac junk and get a pair of M1225s for the range you need, they are simple to interface to each other, easily programmed and adjusting the TX power is simple as well.
Maxtracs are too flaky and most are unusable for narrowband, plus they have a tiny heatsink and can overheat and run away on you in a short amount of transmit time.
The M1225 have the same accy. connection as the 'Tracs, CDMs and CM400 radios, Etc..

I have a maxtrac running as the TX section of a small Uhf repeater. I just flipped it upside down on the belt sander until the top of the heat sink was silver and bolted on a large heatsink from an old amplifier with some thermal grease in between plus a small PC fan on the top. It has been running great for over a year. But the fact is yes they will self destruct without some sort of compensation for heat.

KF4NVX wrote:http://www.hamgadgets.com/index.php?mai ... cts_id=108

I used this cheap IDer/Controller and it is GREAT for portable repeater use
KF4NVX

I would not call the ID-O-Matic cheap, anything but.

And here is the wiring and installation for Motorola radios, AKA R.I.C.K. replacement.

http://www.repeater-builder.com/maxtrac ... k-rev2.pdf