MOTOROLA REPEATER CONVERSION 220 MHz
WELCOME TO ANOTHER REPEATER PROJECT
Coordinated Frequencies in Tucson
224.74 / 223.14 pl 136.5
Allot of information here, be
patient while loading.
For the MSR2000 conversion web-site
the Micor conversion. Receiver, Exciter (TLD5803b),
"If you build it they will come."
This is a HOW
TO article and work in progress on the Motorola Micor repeater, 100 watt
continuous duty HH (high band) VHF to 220 MHz conversion. It is my
intention to document the conversion of this repeater to the 220 MHz band for
amateur radio use. I would also like to thank my good friends
Craig kd7txo and John
wd7f for offering their expertise to this project. For
more information on the B.A.R.T. Group
click here. de k7iou
The repeater arrived!
Craig (kd7txo) and I (k7iou) unloaded it and stowed it in the garage. The next step is to
inventory all the parts, options, and to check the operation of the repeater.
Once operational, specifications will be checked and recorded per Kevin K.
Custer and his article on the Micor 220 MHz conversion @
repeater-builder web site.
5/21/05 Plugged it in today and it went into
transmit. 65 watts. Did some basic checks, settings on the squelch gate card
etc. Still goes into transmit.
RX TLD5784A 162-174
RECEIVER AUDIO & SQUELCH BOARD
TONE PRIVATE LINE DECODER TRN8834A
F1-PL CONTROL TRN8834A
BACK PLANE TLN5979A SP75
5/22/05 Played with the transmit problem
today. I reverted the squelch gate card to the RT station (straight repeater).
Replaced the cut jumpers on JU5, JU6, JU11, and JU12. Replaced the card and
still transmitted upon applying 120V. I then removed the F1 card and saw JU3 had
also been cut. The schematic said "line PTT". Since there was no explanation
why this was cut I replaced it. Reinstalled the card and repeater still went
into transmit upon applying 120V. I pulled the squelch gate card. Applied 120V
with no TX and started playing with the squelch with the PL disabled. I could
now hear the receiver. Then I applied the PTT switch on the Station Control card
and the repeater transmits. While transmitting into the dummy load I then tried
the power level adjustment on the PA and could adjust the TX from 0 watts
through 65 watts. So I think the Squelch Gate card is bad. One of the reasons I
suspect this is because after I tried it I pulled the card and found the white
wire from JU15 plugged into the (0) delay jumper. So possibly a diode or
transistor is shorted causing the PTT problem.
5/25/05 Removed the squelch gate card and
did some basic checks on the transistors. Lifted base on Q6 and checked, ok.
Pulled Q13, Q14 and checked, ok. I had pulled these thinking they may have been
bad due to a wrong jumper setting before installing. Went back to my
"gut" feeling that Q17 was the culprit. Pulled Q17 and checked,
shorted across all 3 legs. Replaced, and transmit problem was solved. The only
other problem I noticed was with JU15 in PL and I turn the repeater squelch
counter clockwise until it keys the PTT the repeater won't un-key when I turn
repeater squelch clockwise. I have to manually slide the PTT switch to key,
un-key, and the repeater drops. May be due to the repeater looking for the tone
on PTT? Will check later.
6/1/05 Bill Jorden (k7ki) AZ. 220 MHz Coordinator
faxed a copy of the approved coordination for the frequencies above. Thanks
6/2/05 Tested the time-out timer today,
works fine. Also worked on the test meter and the rotary control was stiff and
the plastic knob was cracked and slipping. Took the meter apart, lubed the index
and cleaned the contacts. Glued the cracked knob back together and reassembled.
We are scheduled for Friday night to test the repeater with the Marconi. We will
check for proper operation, then set up the receiver, transmitter, PA, tones
etc. Once this is complete and all functions are verified it will be conversion
Craig (kd7txo) and I (k7iou) put the Marconi on the Micor and this is what we
found. By-passed the duplexers and the TX was 90 watts. Through the duplexers 62
watts. Checked the CTCSS tone of 136.5, inoperative. Aligned the receiver, L101
didn't seem to have much affect. The peak wasn't as sharp as the other tuning capacitors.
Did the typical receiver readings. Test position 3 was 25 uA instead of 15 uA.
Test position 4 was 0, spec was 0. Test position 5 was high also spec was 1 or
less. The receiver has a hiss. We could not locate the source of the hiss but
this is what we found. On a car 10' away and the repeater into a dummy load, we
transmitted voice audio and a tone. On the car transceiver the hiss could
be heard. We then pulled the Squelch gate card. 90% of the hiss disappeared.
This unit was pulled from service because of problems. Looks like we are finding
them. We will located another squelch gate card and try it.
k7iou & kd7txo with the Micor project.
Last night we stowed 2 more of these repeaters in the garage. I took the squelch
gate card from one and checked the jumper settings. Installed it in the original
repeater and the receiver noise disappeared. So we are good to go for the 220
MHz conversion on this unit. The second repeater I went to test it and the power
supply is bad. Will check it later. I found out that this unit was in service
and they had a power failure. Since it had a battery back-up I think it took a
Also there are 2 schools of though on
converting this to amateur radio. One school is to leave the cards in place,
modify the squelch gate card for the controller. The 2nd school of thought is
you remove all the cards except the station control module and hook your
repeater controller directly to the pins on the backplane. After consideration
and recommendations I am leaning towards the 2nd school of thought.
Worked on the 2nd repeater today. Found a
white powder in the 15 amp fuse holder for the power supply. When we got this
the volume control was full clockwise, squelch un-squelched full counter
clockwise and the meter on "exciter". I think when the unit took a power outage
the fuse blew? Hence the white powder. Possibly it was checked, a fuse replaced
but due to the residue the circuit wasn't completed. Her is a pic of this
6/8/05 Special thanks to Tom ab7ic for offering to purchase a new G7-220 antenna
for the project. Way to go Tom!
6 /11/05 Research,
research, research! Took apart a duplexer today. This is
far as I got it without surgery.
more duplexer pictures after surgery, 2,
I read a very fine article on Repeater Builders web-site on Duplexer theory by
Jacques ve2azx. Theory
and Testing of Duplexers. Jacques is working with us on converting the
existing high band VHF duplexers to 224 MHz. This is the graph
Jacques sent me. I would like to thank him for his knowledge,
expertise and time. de k7iou
Been looking at power modules and the idea of running 2 of
them. 30 watts each. This is one that I'm considering using. Model # RA30H2127M, Frequency range 210-270, 12.5 V , 30 Watts, 40%
Efficiency, 50 mW drive, H2 design. Check it out at RF
Parts. I also saw talk of a Wilkinson divider on Repeater Builders. I
would like to thank Gary nz5v for sending it and explaining its construction.
"A Wilkinson power divider is just a standard 75 ohm 1/4w phasing harness
with a special modification... a NON-INDUCTIVE 100 ohm power resistor across the
center conductor of the two output ports. Be sure the 75 ohm cable is a
1/4 wave at the transmitter frequency... remember the MFJ is 50 ohms and
you have to correct for it, or since I have an HP S-parameter 75 ohm test set, I
can use the vector display on the network analyzer to "measure" 90
degrees at the desired frequency."
6/12/05 John (wd7f) and I worked on the tone problem today. We
checked all the jumper settings on the F1/PL card, and the Squelch gate card.
Set them for PL. Transmitter wouldn't key with the tone from the Marconi. John
took the schematic and used his "intellectualism" and discovered that
there was no PL
indicator coming from pin 14, or PL indication coming from pin 4 on the card. He followed the circuit on the backplane and
discovered there was nothing connected to the circuit. We discussed the possibility of another card
controlling it also. I dug threw a box and found a Code detector card. I
inserted it, tested the receiver with the Marconi and Walla! We now have a
working tone on the input. I also aligned the receiver, and the
exciter today. Everything looks good. Will be starting on to the 220 MHz
modifications this week!
6/13/05 Pulled the RF/IF board today. Then removed
the RF preselector.
6/14/05 Removed L 102 and L 103 and modified them
for 220 MHz.
Ordered the Crystals today from Bomar
as they were recommended by Scott Zimmerman (n3xcc) of Repeater Builders. He said,
"we have been using Bomar for the past few years because of some quality
issues with JAN. The other reason is that Bomar will temperature compensate the
crystals for a reasonable fee. Jan will not temperature compensate at all."
The crystal cost is $25 each plus $10 shipping UPS. Total cost of $60. Receive
223.14 KC1005/12 Transmit 224.74 KXN1019/18. I will keep you informed on the
quality and service from Bomar.
and the area of modification
enlarge and look close for parts I.D.
6/15/05 Purchased most of the components (caps)
from Elliot Electronic Supply in Tucson today. Was short (4) from the parts
list. Will have to locate from another source. Converted the duplexer to chassis
"N" connectors for testing. Notice the small hole between each
chassis "N" connectors. This is the access for the capacitor
adjustment on the "notch" stub. Craig kd7txo picked this beauty up
this am for testing. He will check the notch and the resonance frequency.
Pulled the exciter today and we have a different model. TLD5803B
(kd7txo) played with a duplexer today.
This is what he got with the initial test. Passes at: 201.75 MHz the top left
hump, reject at: 204.67 MHz
Span of : 2.83 MHz, with -43 db rejection, from peak to valley. Insertion
loss of: -3.3 db. More work needed.
6/17/05 Craig (kd7txo) played with the duplexer
again. "Today after some playing with the cap and adjusting I got an
insertion loss of: -0.5db ( 1/2 db loss ! ) Which is real good! The Max to
Min displayed is 1.635 MHz with 43 db isolation measured with the Spec AN.
This makes me a lot more hopeful that there may be a solution. We're
definitely not out of the woods but it looks much better." de kd7txo
6/18/05 A BIG special Thank You to Larry wa4fob
of Magnolia KY for emailing the schematic on the TLD8262B exciter.
6/19/05 John (wd7f) came by today and worked with the
schematics from the TLD8262B and compared it to our TLD5803B. He worked up a
conversion for the 220 MHz conversion so to speak. For the conversion of the
TLD5803B. We will give it a go when we
get the crystals from Bomar and try the alignment of the exciter. He also looked
at the PA and the power module specifications. He thinks possibly we can make
the SWR / power fold-back protection work also. He borrowed the manual and thought maybe
he would have a "epiphany or something" if he studied it hard
6/22/05 John (wd7f) and I (k7iou) tore into the PA
today. First we removed the assembly from the rack. Then we removed the
input bracket and cable assembly, power set board, harmonic low-pass
and the 100 watt PA board, (don't forget to un-solder the power connections for
the feed through capacitors before removal on the red and black wires where they
feed through the board). I then ground down, filed, sanded off the raised bosses
for the power transistors on the heat sink. I would like to direct mount the
power modules to the heat sink.
Also removed the helical band-pass filter
from the exciter location.
Then I modified the harmonic low-pass filter. I cut 1 turn out of each coil
(note; this mod in this picture is incorrect). I tested the filter and it didn't
pass the proper frequency. I went back to repeater-builders web site and
re-checked the modification instructions. At the bottom of the page there was a
obscure link and then I found this.
So be careful on this modification as the instructions call for 1 turn out of
every coil to be removed. But according to the .gif above L1 @ L6 is only 1/2
turn and L2 through L5 remove 1 turn. So I repaired the 2 coils to 1/2 turn only
and then checked the filter. Its still rejecting the frequencies up at 220 MHz.
Craig kd7txo will take it and play with it with his equipment to see if he can
solve the 90% loss problem.
6/24/05 Worked on the TFD6102A harmonic low pass
filter today. I made up a test cable with a RCA and a PL259 on each end.
Assembled the filter in the case and re-tested. On low power into a antenna and
through my Bird watt meter it passed 4 watts, on high power it did 20 watts. I
then removed the filter and connected the radio (IC-37A) direct to the Bird. It
did 5 watts on low and 19 watts on high. So I think we are in the ball park. I
believe the problems occurred during the original testing after the correct mod
was done due to not having the cover installed. The cover has cavities-shields
built into it for RF reasons. The second problem was the cable I was using had
alligator clips instead of the RCA connector.
Craig (kd7txo), John (wd7f) and I worked
late into the evening on the duplexer. We unsoldered the internal had and cut
1/2" off it and retested with the Spec An and Marconi. The specs went crazy.
I then had a epiphany and discovered that its relationship to the dual loops are
important. So we enlarged the hole in the top of the hat so it would slide
down the internal tube 1/2 "from the end of the tube and retested it. The
frequency moved up to about 218 MHz. We started about 8 pm and called it a night
at 11:30 pm.
6/25/05 I (k7iou) worked on the duplexer today. Cut
the internal hat another 1/8" and retested. the frequency moved to 224 MHz.
I cut another 1/8" and retested. It went to 228 MHz. I then soldered it
back on the tub at 3/4" up into the cavity from the end of the tube.
Retested again. Was on 229 MHz. I then took a piece of 3/8" copper tubing
inserted into the top of the duplexer (where the adjustment rod was) and found
with a 1 1/2" protruding out the end of the tube into the cavity the
frequency dropped to 224 MHz. I then removed the copper tubing and reinstalled
the fine adjustment shaft and retested. The frequency lowered approximately 1
MHz. I then cut some copper tubing 1 1/2" long and inserted on the
end of the shaft and retested. The frequency moved to far. I tried 1" and
it went to far the other way. I found 1 1/4" was perfect and adjusted the
fine tuning on the shaft for 224.74 MHz. I then called it a afternoon. I thought
about this adjustment later that evening and think I'll try using home made
washers and clip them on the end of the shaft with the original clip. Testing of
this will follow.
Special thanks to Keith (kr7rk) for donating
to the project a Communications Specialists TP-3200 controller! Found their web site Com-Spec
and downloaded the software and manual.
6/26/05 John (wd7f) and I (k7iou) played with the
duplexer today. I cut several copper washers to achieve the desired pass
frequency. Our preliminary test show this is going to work with about 38 dB.
Which will be fine with a 1.6 MHz separation. I will give it to Craig (kd7txo) for
the final tweaking on his spare time at work. I will ask if he can test it with
power / load.
6/27/05 Got this from a admirer and couldn't resist
posting it. "wow what a whippin, I did a Micor to 220 about 10 yrs ago....
still have sleepless nights over that one" de kb5wb
6/28/05 Ran a power test on the duplexer today. My
IC-37A through the Bird meter into a dummy load, 23 Watts. Next ran the IC-37A
into the modified duplexer, into the Bird meter and the dummy load, 20.5 - 21
Watts. Wow, less than .49 dB loss. I then Put the IC-37A in (- duplex) and keyed
the PTT to check the reject frequency (223.14 MHz) 0 Watts out! Ye Ha!
Almost home on these. In about 3 weeks we will modify the rest of them. de k7iou
6/29/05 Got the power modules yesterday. John
(wd7f) came down and we combined our brains and came out with this layout.
into some boxes of old gear and pulled out several junction strips. I did some
drilling and taping on the heat sink and behold our initial layout. I also modified the exciter band pass filter
TFD6112A per the Micor mobile instructions
on the repeater-builder web site. I tested it and had a 4.77 dB loss. No-go on
the filter. Need to adjust the slugs but Motorola used some type of epoxy
and glued them in place. Tried chipping, dissolving the stuff with no luck.
Another day on the filter. de k7iou
6/30/05 WD7F's proposed PA Schematic
Note: we didn't use this design, check the PA link at the top
of the page. UPS
delivered the Hustler G7 220 MHz antenna today. Thanks Tom!
7/01/05 I modified the exciter helical band
pass filter TFD6112A. John wd7f came down and we tuned it. Ended up with 1.02 dB
loss on 224.74 MHz! If you have one out of a repeater station the slugs are
glued in place with epoxy. I couldn't loosen up the epoxy enough and the slug
tool slots were stripping out. John (wd7f) came up with some coil forms. For instructions on
Also adjusted the PA pass band filter TFD5102A
today .23 dB loss! Pretty darn good if I have to say myself.
7/02/05 The crystals showed up last night.
Installed them in the elements. Very simple process. Use a small screwdriver and
push out the 2 indents on the sides of the metal cover. Pull cover off, remove
rubber cushion on end, remove plastic envelope. Unsolder crystal. Solder in new
crystal. Install plastic envelope, and rubber cushion. Straighten out indent in
metal cover and reinstall. Indent cover to secure and mark cover with new
frequency. I used white out and cover old frequency and a pen to write in the
new frequency. I also cut out the specs on the envelope Bomar sent and taped it
to the cover.
A very special thank you to Larry
of Magnolia KY for mailing the capacitors we needed and couldn't locate. This is what ham radio is all about.
7/02/05 We had a antenna assembling party today.
Tom ab7ic got a pass from the war department. John wd7f and I tried to help
also. Way to go Tom!
7/05/05 Finished installing the capacitors in the
receiver and exciter today. Then reinstalled them in the machine. Just need the
Marconi to align and set them up.
7/014/05 Started the alignment of the receiver but
need the Marconi. The exciter is a different story as it wouldn't align
properly. Off to the bench with the Spec-An. We will review the 220 MHz
modification and updates will follow.
7/015/05 Special thank you to Tom (ab7ic) for
purchasing the "N" chassis connectors for or duplexer project. We
found some locally at Elliot's Electronic supply. Amphenol 203/743-9272 $3.30
Craig, John and I had a repeater session. We
hooked up the exciter on the bench with a 12V & 9.6V power supply. And did
some basic checks. Didn't resolve anything but we learned allot.
7/16/05 Went to Elliot Electronic Supply after
the BART breakfast and loaded up on some capacitors.
7/17/05 John and I aligned the receiver
today. Worked fine. We were thrown for a loop though for a few minutes as we
were on a second peak on some of the adjustments. Tested the receive with the
220 rig in the mobile. Sounded good. Craig also came by and we played with the
exciter some more. John and Craig worked out the math
and got the tripler working and we are getting close.
Maybe another night and we should have it working. We temporally solder some capacitors
to the back side of the board for testing.
7/29/05 Been working on the exciter. We got about
180 Mw out of it with the wd7f conversion. We do have a problem as it starts
dropping off on the Mw as it warms up, and stabilizes about 114 Mw. The TX
crystal also is low on frequency. Its was running at about 224.55 and with a
capacitor change (in the element) directly behind the 3.5 pf adjustable capacitor is only came up
to 224.58. It had a 27 pf npo and tried a 22 pf npo with not much change. Then
tried a 18 pf npo and it increased to 224.58 So we are going to send this
back to Bomar with the element since the frequency is low.
n7kp writes "Just want to thank you
folks for your "how to" articles on your 220 MHz Micor conversion."
Thanks, de k7iou!
7/30/05 wd7f and I worked on the exciter today.
Took a can of cold spray and isolated Q406. When we hit it with the cold spray
and it jumped up to around 250 Mw. Replaced Q406 (M9390) with a mil spec
(2N2222z) metal transistor. Then tested the exciter. It went close to the 300 Mw range.
So we took all the caps and resistors and returned them to the component side of
the board. We tested each one separately after we moved them. By the time we
were done we had 368 Mw out of the exciter. This showed us the Mw loss with components
mounted on the solder side of the board. So the wd7f conversion is good to go.
kd7txo came by and checked the 450 MHz harmonics with the Marconi.
For our exciter conversion TLD5803b
8/13/05 Last night and today wd7f and I (k7iou)
spent about 4 hours combined working on the PA with the dual modules. I had
and installed the perf board on 4 studs with risers and star washers. I bent
the wire connections on the modules 90* to extend
through the board. I extended the power and grounds to extend through the perf
board also. We installed the capacitors and wired the assembly. Used a piece of
3M body side molding tape to install the TU-50 power divider. The input (TU-50)
will extend through the shield for the SMA connector from the exciter.
We need to make the Wilkinson power combiner and test the gate voltage. Bomar
shipped the TX crystal back to us and we should have it soon. They confirmed it
was off frequency.
8/15/05 A special BIG Thank You to Steve
for donating a TLD8262B exciter and TFD611A filter. I wanted to experiment with
the exciter and needed another filter for the 2nd conversion. Thanks Steve!
8/16/05 Got the crystal back from Bomar today. Its
on frequency, 224.74 MHz. Don't understand why they send them UPS orange when US
Priority mail is faster and cheaper?????? It took 2 days for priority mail on
the shipping of the crystal to Bomar and 7 days return including the weekend for
8/21/05 Last Friday night kd6txo, wd7f and I
(k7iou) worked on the pa.
We tested the modules separately and had 31 -34 watts out of each. We also
restricted the output of the exciter with a 180 ohm resistor at R436 for 110 mW
output. We then worked on the pa power combiner for both modules. Our design
doesn't seem to be doing the trick, so back to the drawing board.
8/24/05 Craig (kd7txo) called last night. He talked
to Stanly (wa7wnm) about our Wilkinson combiner. Seems Stanly thinks ours isn't
working because we aren't using phase stable cable like RG-400 or heliax. Stanly
also suggested a better design for the 2 modules using phase stable cable, 50
ohm, and a 5 watt dummy load. You build a bridge with the output at 12 o'clock,
the modules at 3 o'clock and 9 o'clock. At 6 o'clock is the dummy load. The
cables are cut as follows: from the dummy load clockwise to module 1 (9 o'clock)
cut it @ 90°, from module 1 to the output,90°, from the output to module 2
from module 2 to the dummy load 270°
(yes 270°). This design gives you
protection in case one of the modules goes caput. He also recommended BNC
connectors with T's at all the junctions. This way all the cables could be cut accurately.
We will try this one in a week or two. de k7iou
10/8/05 Well its been to long since an update.
Success today with the PA! The new job, vacations, school, business and the
family kept us until today from working on the project. Craig (kd7txo) and
John (wd7f) built some cables today. Craig had previously built the bridge. I
worked on brackets and cleaning up the PA today. Then the 3 of us went to work.
As you can see by the pictures we did it!
We had many attempts and failures trying to
combine the 2 modules. The 73 watts is out of the PA harmonic filter. We got rid
of the perf. board and directly mounted everything to the heat sink. Bonding was
a issue so we bonded each base of the modules. I will post the PA design and
instructions at a later date. Special thanks to Craig, John, and our wives and
families for putting up with our mess and hobby time! de k7iou
10/25/05 Well we had a productive couple of days
last weekend. Saturday wd7f and I worked on the PA and got the power set and SWR
protection wired up. John came up with 2 - 4.7k ohm resistors to lower the gate
voltage and we tapped them in the middle for the correct voltage. We adjusted
the watts with the power set for 55 watts and I tested the SWR protection. I
disconnected the dummy load and momentarily keyed the PTT. The power out dropped
to 18 watts. We will play with this later to see if we can get it to go to 0
watts. We used the repeater for about an hour Saturday and it quit transmitting.
I checked the gate voltage and it was 0. I suspected the exciter and pulled it
for a check. I found a cap bent over and touching pin 15. It ran us around for
about 5-6 hours and finally I was pushing on the exciter and it took off. So
Sunday I tried an original exciter at 172 MHz and it worked fine. I took the 220
MHz exciter and went to the bench with a magnifying glass. I touched up some
traces and joints and its been working since. I also checked the controller with
the software. I have to admit the software isn't user friendly as its in DOS.
But we were able to program it. For instructions and pictures of the PA we built
10/28/05 John (wd7f) and I (k7iou) worked on the
controller today. John wired up the squelch gate card
as you can see in the picture. We tried to cut the controller into the back
plane but our version of repeater had no discriminator audio on the back. So for
ease we decided to do the squelch gate card method. Here is a picture of the
repeater with the controller attached and running.
more to follow, de k7iou
11/05/05 John (wd7f) and I have been trying to
program the controller for several weeks as the carrier delay wouldn't go below
3 seconds. I emailed Com-Spec
and they replied I had to have it in the tone squelch mode. When I did this the
PTT would drop intermittently and some tones would work and others wouldn't. I
took it out of the tone squelch mode and we lost the CW id. It went to Morse
code heaven and was never seen again. So the process began looking for another
controller. I wanted a RC-110 kit but they are out of stock until the first of
the year. So we were looking at the RC-210. Its a Cadillac of controllers but
was out of our price range in the factory built model. So we were considering
the kit form at $250. Then John found Echo Station http://www.synergenics.com/sc/
Its a windows based computer program that lets you use a computer as a
controller. It has a voice synthesizer so you can add recorded wave files. So we
are currently using this on Windows 2000 Pro. The audio is similar to Echolink as
its not the best, but it is ok. We will be using this until we get the
controller kit assembled and hooked up. We will post the interface we made
on the quick links above. de k7iou
12/9/05 Sorry for the delay in updates. Had a
problem with Comcast and had to rework this site as it was full to the maximum
Ordered the new controller kit. Yes I
decided to save the $100 and build it myself. WHY? Because it is fun and
challenging! I don't like being an appliance operator. You know, plug and play
devices. I ordered the kit from Arcom.
Ken is very helpful in assisting you with any of their products. I
highly recommend Arcom. This was the first evening of building
the second evening
the third day, (Saturday) about 4 hours
I found this fun to build. The assembly manual is very good. In all it took me
about 8 hours. I did double check all resistors for proper resistance and used a
magnifying glass to id all components. Ken even has a email reflector which you
can join for questions and comments.
I also finished converting the duplexers.
See the quick links above for the conversion. On Saturday 12/3/05 kd7txo, wd7f
and I (k7iou) went down to Craig's (kd7txo) work and cut in the cables for the
duplexers. We used
for more info on cutting the cables. He sent me this in a .pdf file which I
converted to jpg.
We used the formula's for cutting the cables. This took about 4 hours and we did a quick adjustment of the pairs.
We got 58 db isolation out of the receive side and 52 db isolation out of the
transmit side. We used a Vector volt meter a Marconi and a HP Spec-an. We will
try to peak these after the antenna is up during the final tune up of the
I also noticed a problem with the repeater
in the early AM with my drive to work. The receive was horrible, Couldn't key it
from 1 mile away, but in the afternoon it was good 25 miles away. I played with
the squelch and the receiver alignment and all is well again.
Here are some pictures John wd7f took of the
duplexers after we got done with them.
John and I checked the loss on transmit. We had 50 watts into the duplexers and
42 watts out @ 0.75 loss. Pretty darn good if I have to say so.
12/11/05 ANTENNA PARTY!
I decided to
put the 220 MHz Hustler antenna on the tower behind the garage and to move the
repeater to the back of the garage. I prepared the tower for lowering and John
wd7f came by to help and to take all the pictures. Later Craig kd7txo and son Clint came by to lend a helping
hand. Thanks guys! Here is a picture of the winch I used to lower the tower
and the lowered tower, notice the vertical pipe with a pulley in the top.
Dave removing the 5 antennas.
view of the tower from the end.
Moving the repeater.
The hustler goes on.
Add on the surge control box with the Polyphaser.
Craig and Dave adding the coax.
Craig finishing the connection.
Supervisor "Clint" of antenna installations.
Ah up in the air!
The back view.
Whew! 45' to the base of the antenna.
12/17/05 John (wd7f) and I (k7iou) tuned up the
repeater today. We got a little more out of the receiver as a injected 1 KHz
tone would disappear @ -106 dB. "To
align the deviation, we first injected a 1000 Hz tone at 3 KHz deviation into
the receiver. With the Repeater
Level adjustment on the squelch gate card set to near maximum CW, we set the
voltage at TP1 in the controller to 0.75 V Pk-Pk (0.265 RMX) using DISC1 in the
controller. Then we checked the
exciter output and adjusted the deviation to 3 KHz with controller TX1. We
found that the PL deviation was too high, approximately 1700 Hz, so we increased
TX1 until we had 3.5 KHz deviation and then decreased it to 3.0 at the exciter
IDC. We repeated until we had about 1 KHz of PL deviation and the
exciter deviation was linearly tracking the receiver input deviation from 1 KHz
to 4 KHZ and at 5 KHz it rolled off to 4.5 KHz.
We noticed that the deviation was becoming non-linear at that point and
didn’t attempt to reduce the IDC and PL deviation
any more." de wd7f
A big Thank You
to Bob (n7zqk) for donating a Motorola Service Monitor to the BART group! We
used it for the tune up of the repeater today.
12/20/05 Noticed during the tune up the other day
L-104 on the pre-selector had a funny spot in it on adjustment. I believe this
was the problem with the COR light on the controller also. We would loose the
squelch and receiver when we hit this spot and the COR light would illuminate.
Then the next morning the COR light was on again, so I tweaked it and the light
went out. Returned home after a days work and it was on again. So I pulled the
receiver and the pre-selector and L-104. I checked it and didn't see any
problem. I went ahead and re-soldered the modification
and reinstalled. I then retuned the receiver. The bad spot disappeared. The next
day on the way to work the receiver didn't receive as good as before so today I
retuned it again. This time after the alignment procedure I injected a 1000k
tone at 3000k deviation into the receive duplexers and tweaked the pre-selectors
until the tone audio passed through the speaker the best as possible without
paying attention to the Motorola test meter. I also did this with L-108, 109,
110, 111. I kept lowering the injected signal (dB's/micro volts) as I tweaked
the adjustments listening to the tone in the speaker. When I was done I had -115
dB's or .397 micro volts. This was as far down as the Marconi would inject the
signal and still passing the tone! The true test will be in the AM on the drive
to work. Will update the test results. de k7iou
12/28/05 Ordered a preamp the other day. Its a P220VDG.
Will let you know how it works. http://www.advancedreceiver.com/page5.html
1/15/06 Got the preamp installed and it works
great. Made a big improvement. got over -132 dBm sensitivity out of the
receiver. Mounted it close to the receiver using 2 existing holes below the
receiver. I also used a short bnc cable from the preamp to the receiver.
1/22/06 Installed a fan on the PA. Its a nice squirrel
cage type with a rotate able motor. I made a mounting plate out of scrap metal,
used 2 existing screws and some 3M body side molding tape to secure it. A relay
was used to control the 120v and 12v to supply the relay. The RC-210 uses the
ground for control. Timing for the fan is set in the RC-210 program.
7/20/06 Well we had problems with the duplexers
again. Seems they just won't hold steady on the receive side with temperature variations.
So Craig purchased a set off eBay. So Craig (kd7txo), John (wd7f) and I installed them last Saturday. We had to change some cables and ends but
it seemed to go well. That was until Monday morning. There was a big problem
with the receive. So Monday evening we got back together and re-tuned, tweaked
and adjusted the deviation of all the systems including the links. Craig and
John came up with a better way for tuning and it seems to have done the job. Here are some
pictures. Special thanks to Tom (ab7ic), John (wd7f), Craig (kd7txo) for your
and here are the specifications, wow!
10/07/07 I have been lacking in my updates so here
goes. The RC-210 controller has had some problems. I have a love / hate
relationship with it. I love the features especially the L.E.D.'s as they let
you see with a glance the operations in process. PTT, COS, DTMF. The hate
part are the problems with the firmware. Especially the Time Out Timers with the
ports running only links. They affected also the repeater port so if one link
stayed PTT the repeater wouldn't time out causing a duty cycle test of our PA @
100%. The good news is the PA has held in there like a champ. So I guess our
design is a good one.
Next problem was the Bomar crystals. I had a
problem with the TX side right out of the box and Bomar corrected it. Then after
about 1 year of service the RX side started going low in frequency on us. I
changed the element and it corrected it for awhile but 4 weeks ago I noticed
DTMF was no longer being accepted. I tested the RX xtal and it was 10 kc low. I
tried contacting Bomar about the crystal problem with no response. So I am no
longer recommending them. I made a query on Motorola-Micor@yahoogroups.com
and an overwhelming number of responses were to use ICM
(International Crystal Manufacturing Co.) I mailed them 2 elements (1 as a back
up) and 3 weeks later I received the crystal installed with a full compensation.
Before you have your crystals made for any project please read this great
I received the new crystal from ICM
and installed it in the receiver. All is working fine now. Audio is again crisp
and clear and the DTMF is being accepted. Special thanks to Tom
03/20/08 Its been awhile since I have done the
updates so here goes. WD7F (John) and I (K7IOU) successfully adapted a CAT RLS-1000B to
the Arcom RC-210 controller. We first actually designed and built an extra port
but then I blew it by buying a IRLP embedded node. So we looked at the CAT and
we both came to the conclusion that we couldn't build a 3 port switch for the
price they sell the RLS1000B for.
So here it is.
Its working great and thanks to Craig KD7TXO for the loan of the Marconi and a
3rd set of hands for adjusting the audio on all the ports. The finished product.
Here are some pictures of the V.O.I.P.'s
Special thanks to WD7F for donating the monitor switch and AB7IC (Tom) for the
cash donation. I still have some house
cleaning to do but its all working A-OK. 73 de K7IOU
09/13/08 Last Thursday night we had a monsoon blow
through town and on Friday the system started acting up. After playing with the
controller for several hours re-flashing and loading the firmware I realized the
problem was RF related when the link on the 146.940 was receiving. The
controller started acting funny then the 224.740 transmitted when it shouldn't
have causing the link to drop the receive and go into TX. I also noticed
while using the local microphone on the repeater the DTMF led and the COR lights
would light up with an intermittent PTT on port 1. With the transmit switch off
on the repeater the problem ceased. So I left it over night with the 224.740
repeater disabled but the links up and running with the voip's. This morning I
decided to try my spare squelch gate card in the repeater and the problem disappeared.
Knock on wood! I also redesigned the cart that holds the computers and moved the
links to a shelf below the computers. Here is a recent picture of the system.
I would also like to thank Keith kr7rk
for the donation KVM switch to the B.A.R.T. system. I am using it for the IRLP
and Echolink computers which allows the use of one keyboard, monitor and mouse
with both systems. Thanks Keith!
Contributors to the
Tom ab7ic, Bob n7zqk, Craig kd7txo, John wd7f, Dave k7iou
|Bart Repeater Fund
|Summery of activity
|Total funds donated
|N chassis connectors/donated
|tld8262b donated n7kp
|tfd611a donated n7kp
|Duplexers from eBay
|ICM rx crystal
More to follow, so check back often.
Thanks to all.
de Dave k7iou
The following manual is a must; 68P81036E40-C
Email the Webmaster:
Crystal Co. 1800-526-3935 No Longer Recommend
them due to no response from the company
Computer Automation Technology
Controllers-Cat-250 & RLS-1000
B.A.R.T. Border Amateur Radio Team.
International Crystal Mfg Co. 1-800-725-1426
Amateur Radio Conversion website by Dave k7iou
NKX, Inc. 1814 Hancock St. Gretna, La. 70053 Talk to Pam at
Kenwood Sales and Service. Skipp May
Repeater Builders; Scott
Zimmerman and Kevin Custer
Gate Module to External Repeater Controller Conversion
Special thanks to
Skipp for your help and expertise!