I went ahead and used the Brownells Hi Force 44 solder I had. It seems to hold really well so I think it will be good enough. A friend sent me a chunk of RG-214/U. I'm going to make up the rest of the tuning stubs and then work on shortening the interconnect cables. Hopefully my tuning is correct and I can get this thing all packaged up soon.

Got some interconnect cable made and hooked up the reject low side to test return loss.

51.150 reject shows -1.26 return loss.
52.850 pass shows - 47.04 return loss.
52.850 pass shows -.61 insertion loss. (with display normalized at top line 0.00db).

Seem reasonable?

Attached File

Attached File

Attached File

The two Syntor X9000s arrived yesterday and I got the Sirio Dominator antenna to put up on the tower yet.

I hope the duplexer works well enough.

Pretty sure I know that site.  Drive by it a lot.  Live about 15 miles from it.  Will be nice to have a 6M machine there.  The other setups reach a very long ways.

Hah nice. I'll try to give a shout out on the .36 machine with an arfcom reference from now on and see if I find you. What times do you go by there or are on the air?

Just got a new car so my gear is uninstalled. Still need to get my x50 up on the house.  Gonna have to rent a lift so im holding off.

Several weeks ago I was chasing a wx balloon and when the prediction shifted I holed up in the driveway of the repeater site for a while to see what was gonna happen.  It's a nice high point for things like that.   Only had about 20 degrees elevation on the signal so I was needing a nice clear spot.  

And regarding the 7.36, last year I was chasing another balloon and ended up near Melvern still able to hit the repeater.  But i'd say that was the fringes.  It's solid at Beto.

Interesting. How do you track them?

NWS launches them twice a day from Topeka.  LMS-6.  They TX on 400.25 most of the time.  There's a github project called Radiosonde Auto Rx that decodes the lat/long/alt.  It uses a usb SDR for the rx hardware.  The software can upload to HabHub, and the website does the prediction.  All runs easily off a RPi3.   For chasing, i use an old HP stream.    

Heres a link to the tracker site. Tracker I've gotta a few other people chasing and collecting them.    Free transmitters and GPS hardware inside the package.  We're working on reverse engineering them to repurpose.  

Interesting, I should put the airspy and log periodic on that freq and watch.

I use a 1//4 wave gmrs antenna.  As long as nothing blocks the signal, it travels a long ways. They're fun to spend some time to go get.   I've learned never to leave before it bursts because the pre-burst prediction can be wrong, more so with active weather.  


Back on topic, any room in that repeater shack for 10m setup?

I originally wanted to do 10m. The issue is the duplexer. If we had a second fairly close site we could do a split site. The closest is the town over to the West where I have access to the main site shack but no tower access. An antenna would have to go on a pole on the connex box type shack there which is originally where the .390 had been for years after it was kicked off the tower.

What's your ideas?

Not that anyone cares but I'm sort of using this as a blog to keep track of things now.

Anyway, I got the two X9000s and have them programmed. I wanted to run them without control heads and cables for a simple setup but they won't boot without the heads with a simple jumper on two pins like Spectras will. I dug into it more and found that the radio is seeing the FAIL 90 control head failure and is going dormant. I sniffed out the comms and found the "all is well at the control head" POST string. It is 00 00 05 3B 0D. Sending that over the SB9600 bus via a RIB box and terminal program wakes it back up. I can hear traffic and transmit by grounding the TX pin with no control head and cable at all. I'll just code up an Arduino Nano or one of the even smaller boards and put it inside the radio and tap the TTL data bus prior to all the RS422 stuff. When the radio powers up it will wait a bit then spit out the code and wake it up.

I also did the harmonic filter mod on one radio so far to push the roll off from 50 to about 56 MHz. That increased sensitivity and it's putting out 123 watts. I cleaned all the 30 year old thermal compound off and put on new Arctic MX-4 compound. Since the filter is in both TX and RX paths it affects receive sensitvity too. I am now getting down to about -126 db receive before the 1k tone was getting lost in the noise, haven't done a true SINAD. Might try to tweak the extender too while in there just in case it's needed.

Why do you want to run the headless?

To eliminate the need for the clutter mainly. There's no need for a cable and head if all I need is power, ground, TX, COR, RXaudio, TXaudio. I can just store the radio bodies away with fans and what not and route them to the controller. They will only ever be on one channel/frequency and nothing will change.

But now that I have command of it I can control it all remotely with SB9600 commands anyway, enable PL or carrier squelch, etc... These things were advanced for their age and set the standard and protocols still used up to now with the APX. I like this stuff for some reason.

I'm keeping track since this is in my AO.     Also replied to your PM.

@phlat

It's up an running now. I borrowed a CDM750 repeater setup from a friend temporarily. It's just two of the CDM750 mobiles and an ID-O-MATIC controller. I forgot to try to reduce the power on the TX radio so it's set at 60 watts still (I think he said it was set at full 60) but there will likely be litte traffic so should be fine with the forced air that's on it. It's 52.850 / 51.150 with a 151.4 PL. I still need to double check the duplexer tuning at the site since I had just tuned it at home and put it back togethere there.

I can key it up over into Ottawa while mobile but haven't had anyone to talk with on it to test if I'm actually getting into it decently. I lost it around the South end of Lawrence as well. I will be driving South tomorrow so will try that direction.

I will put the word out and see if people can get it. I dont have a 6M antenna at the moment.

You've got me looking into the 6m repeaters in my area now. Wonder if I can make any of them from my location.

So after all this a friend called and said he had a line on a mini 6 meter duplexer and GE Mastr II repeater. I picked it up last night.

WTactualF.... I have never seen anything like this. It's a DB4032 lowband six can duplexer. I asked him if it would fit in the back of the Jeep and he laughed and said yea... I was still skeptical. When I arrived this is what I was handed. Each leg is the size of a 12 pack of Coke. I put them together tonight and put them on the spectrum analzyer. Seeing about -90 dB notches for each rejection freq. Crazy stuff....

Attached File


Attached File


Attached File


I guess it's basically this scaled up from UHF to Lowband.

Notch only?

I wonder what kind of separation they require. That was one of the reasons we went with 1 MHz offset in Texas, all of the Texas Department of's at the time were using low band with a 1 MHz offset and migrating high band and it was discovered many of those cans just couldn't handle a 500 kHz offset.

Similarly, I have an old Motorola T1400 series notchplexer that needs at least 3 MHz of separation to work (but it's the same form factor as the T1500 series duplexers) that was installed in a Micor that I salvaged. Similarly, I salvaged RFS/Cellwave duplexers that shipped with two VHF Quantars and being the smaller, rack mounted 6 pack (roughly the same depth as a Quantar and 2U high when racked) and they require at least 1 MHz of separation to function properly.

They are notch only. The guy I got them from said they used to have a more elaborate stub and other type of harness on them but the original owner modded them to be simpler. He said they are fine at the 1.7 MHz offset we use here in Kansas for 6 Meters. I'm hoping to install them soon and will find out for sure.

What are you planning to do for the crystals for the Mastr II? Already have a suitable set or are you going to try to source and compensate them?

Seems that good, stable crystals are near non existent any more, that's the one thing holding up our Mastr II 6m system.

I don't know. I received a bag with some channel elements but of course the wrong freqs. I thought I read over at the repeaterbuilder groups.io that there were a couple places still around that will rebuild them. I need to look into that.

I picked up a couple of ICOMS on 52.525. I can get them recut but I'm unsure how the non balanced temp compensation will work.

Why not use something like an ad9850?

I've been thinking about that but haven't looked into it extensively. How would I modulate it?