N5MBM Chappell Hill 6 m FM voice repeater - Operational 8/15/2015!

6 meters  -  52.35 tx  51.35 rx with a tone of 103.5  - AllStar Node 42413

Currently testing being dedicated to the WIN system 24 hours a day

100 watts at 48 ft. AGL covering Washington and surrounding counties.

Click here to see a world wide map of repeaters connected to this system


And now, for the rest of the story...

Six meters had always fascinated me.  But for years I tried to make a contact on the "Magic Band" and for years I failed to get even a single contact.  Not one!  I even tried mobile, on field day and on special event days where six meters was used - still nothing.  I searched for years for working six meter repeaters.  I tried SSB - still nothing.  Most of what I found were repeaters that were nothing more than a file in a filing cabinet.  So what do you do when you can't find something out there on the air?  In my case, I built my own!

I had gathered up some parts off of ePray, I found some commercial grade components, I pestered old friends until they caved in and helped me and I slowly cobbled things together and eventually made this repeater a reality!  It has been a long interesting road.  I found out that things get kind of wierd around six meters and good engineering practices are sometimes a bit skewed from what most of us consider "normal".  Anyone who builds a six meter repeater quickly finds that having a 700+ ft. tower and a lot of space is almost necessary for a first class setup...

Can you say "compromise"?  My tower is 50-60 ft. tall...

I built a half decent machine that needs another couple of hundred feet of tower to be REALLY useful!  But it works and has worldwide connectivity now!  Now I can drive around my county and make mobile contacts on six meters all day long - or sit on the porch while grilling steaks with a Wouxun six meter HT in one hand and a glass of bourbon in the other...  And talk to someone in Australia...

I find that rather cool...


6m Cavities    WP-604 Duplexer

Thanks to K5WH, he gave me his pair of 6m cavities off of his machine in NW Houston that is currently down.  Shown here above next to latest incarnation of the newer repeater rack you can plainly see they are of substantial size!  Thanks to WB5ITT I got a complete set of low band cans and a DB201 Low Band VHF antenna.  The cans are a complete Wacom WP-604 duplexer!  It hits the stops at 51.500 and that's as far as it will tune up without some serious open heart surgery that I am not really willing to undertake.  The cluster of Wacom cans is about the size of a normal apartment refrigerator!

Luckily the TX VHF FM Society gave us a frequency down low enough so I could use these new cans!   These cans are HUGE and take up a lot of floorspace!

So now we have all four WP-604 cans in line with the receiver down on 51.35 Mhz FM  The receiver antenna lead comes into three cavities and I have a VHF Low Band receive preamp in line just before the last cavity to strip off any "junk" the preamp feeds the receiver.  The pair of cans I got from K5WH are in line with the transmitter on 52.35 MHz.  I installed a 100 watt power amplifier in the transmitter chain to top things off.  I spent a few hours tuning things up, programming a pair of Motorola Maxtrac Low Band radios and tweaking with the service monitor - it looks pretty clean!

8/15/2015 1:45pm the switch was flipped and we are NOW ONLINE!!!  It's UP!

Cross linked to 2m, 220, 440 and 900 MHz on an all new Asterisk controller!

Most everything on this repeater is courtesy of eBay!  (except the cavities and antenna)

Range tests were rather disappointing (15-20 miles from a mobile) but the DB201 6m antenna is only at 48 ft.at this time.  It will be much better once we get it further up off of the ground!  We have plans to get up to 100 ft., we just haven't gotten there yet!  (That's a longer climb to the sky than it looks for an old man...)


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