N5MBM Chappell Hill 220 MHz Repeater - Operational
1.25 meters - 224.900 tx 223.300 rx with a tone of 103.5 -AllStar Node 42471 - Operational as of 07/04/2015
Currently acting as a "stand alone" repeater to facilitate local communications.
05/15/2015 - I found some interesting documents talking about modifying TYT TH9000 radios for a repeater - Build a repeater from TYT- TH9000 Mobile Transceivers - http://crompton.com/hamradio/BeagleBoneBlackAllstar/TYT_mod.pdf I was intrigued, I had a couple of these Chinese radios. I ordered the parts from Digi-Key and sat on my hands for a few days waiting for the USPS lady to arrive with my goodies. The "modification" consisted of soldering up a little jumper cable for a 6 pin plastic plug to connect to the printed circuit board, wired to a little 9 pin serial connector you screw into the back of the radio under the heat sink (There's a hole there already!) attached to the radio with a couple of screws stolen from the outside bottom case cover. It was a VERY simple mod! It brings everything you need to interface with a repeater controller/IRLP node/other radio out of that little 9 pin connector.
6/25/2015 - We recently acquired several sets of "used and stored away for years" Remec-Wacom WP-747L3/447L1 duplexer cavities from Clay W8JVV after a rather interesting trip to Arkansas to retrieve them. I did some research on these and the web holds very little information but I found KA1RCI had worked with these before! Luckily he posted lots of info on his web site. Here is what they looked like in their original configuration.
6/27/2015 - I changed it up from the factory configuration and arranged them like this photo below, after cleaning them up. Sort of like the original configuration but I changed it up a little to make everything flow right and all the cables actually reach! This is a 3x3 BpBr set, topped with a Bp cavity on the transmit and receive side to nullify noise. 8 cans in all. This should allow me to run 100 watts with little to no worry of desense or spurious emissions coming in OR out. (I am hoping!)
Remec-Wacom WP-747L3/447L1 220 MHz repeater duplexers - Cable lengths and tuning notes
Now I am trying to be patient until I get someone to tune them for me with the proper test equipment. I tried tuning them myself using some test equipment I had on hand - just to get them close and see if they would work at all. I found these instructions and ran with them. I got them VERY close! They work! I got them so close I could probably put them on the air - but I am going to wait until they have been tuned properly and I KNOW they are "right"!
06/30/2015 - After modifying a pair of my TYT TH9000 220 MHz radios, I hooked them up for testing and VOILA! They work! Now I am using the 220 receiver as a remote base and listening to the IRLP nodes in Houston, listening to people from all over the country chatting - over my repeater now! I tested the transmitter and I tested the receiver, and they both work GREAT!
It's NOW fully functional!
07/04/2015 - I got brave and bold, I hooked everything up except the transmitter today. Instead, I tried it with an HT in the transmitter port on 1 watt, then 5 watts - I saw nothing on the receiver. Next I plugged in the transmitter on low power (10 watts), STILL nothing in the receiver when I keyed up the transmitter. I bumped up the power to max (55 watts) - STILL nothing in the receiver. Now, reality check, I don't know about desense, but it didn't pound itself with RF to the point that I didn't hear the hiss change on the open squelch! So the cavities are awfully close if not dead on! YAY!!! (I still have some tuning to do, I am sure, if for anything it would be for less loss!) Next I hooked up the controller... I keyed the 220 side, the transmitter came up and I heard my 220 repeater, fully functional with TYT Chinese radios at approximately 5pm on 7/4/2015. I was ecstatic! I keyed up the 2m side and the I could hear it on the 220 side. I keyed up the 440 side, and heard it on the 220 side. The home-brew 220 repeater works like a charm! AND now, all three repeaters work in concert now! I am one happy camper right now...
Everything on this repeater is courtesy of ePray! And I do mean everything! From the antenna to the controller cable, everything attached to this came from sources on eBay.com
My paperwork is in! I now have an official coordinated repeater frequency on 220 MHz!
The power got bumped up to 25 watts and we now have 15-30 mile coverage!
11/19/2015 - Now using a Comet CX-333 Triband VHF/UHF antenna with 7.8 db on 1.25m. at 35ft. AGL.
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