Repeater Maintenance Log

Repeater Maintenance Log w0dp Thu, 07/10/2008 - 13:10

April 5, 2005 Tuesday (Repeater back at NADC)
KIØQ Dave Fitz
The repeater was re-installed at the NADC site on April 5, 2005 using the main Mitrek repeater along with the new feedline.

Power out of the duplexer was 16 watts. Reflected power was 0.1 watts. Calculated ERP is 41 watts, assuming 0.9 dB feedline loss and 5.0 dbd gain antenna.

UHF link ID was changed from NA0S to W0YL. The UHF control receiver is using the main 2m repeater antenna, fed by a Comet crossband coupler. UHF link transmitter is feeding a cabinet mounted antenna.

April 4, 2005 Monday (Repeater at KIØQ) Testing the Andrew LDF5-50A 7/8” feed line on water tower
KIØQ Dave Fitz
I went to the NADC site to test the antenna and feed line with my Bird 43 wattmeter. There was 0.35 watts reflected and over 25 watts forward at 147.24 mHz. I could not accurately measure the forward power with the slugs I had with me. If the forward power was 25 watts, the VSWR would be 1.27:1. Since it was over 25 watts, the VSWR is less than that. According to the June 2004 measurements, the VSWR was 1.21 with the antenna horizontal in my driveway. So, it looks like it is right where it should be.

April 2, 2005 Saturday (Repeater at KIØQ) Installation of Andrew LDF5-50A 7/8” feed line on water tower
KIØQ Dave Fitz

I wasn't sure that I could get on the site on Saturday. On Saturday, I ran 11 miles and then headed out for the water tower. There were people at the McCarthy office and they said “work all day” if you want. I rigged to put the hard-line up. I rolled out the Andrew LDF5-50A 7/8” hard line and decided which end to put at the top. There was a grounding tail that made a big spot on the hard line that would not fit through the hole in the cat walk that I was planning to use for the hard-line. I removed the grounding tail and sealed up the plastic jacket with tape and skotch coat. I figured that we don't need a grounding tail at the top since the antenna is grounded to the water tower.

I got the hard line up to the cat walk using pulleys to get a 2 to 1 advantage. But I couldn't use that rigging to get the coax through the hole in the catwalk so I had to go the rest of the way lifting the whole weight of the coax plus friction. I was wishing for a second person or maybe 1/2" hard-line. I got the coax up and tied on so it wouldn't fall and went for lunch. I came back and tied the coax to the electric conduit every 2 to 3 feet with aluminum wire ties. I installed the Andrew Super Flex jumper at the top. At the bottom there was about 50 feet too much hard line. I cut it off and removed the connector.

There was water inside the connector and there was some corrosion.

Where I cut the hard-line it seemed ok. I cleaned up the connector and installed it. I connected the Super Flex jumper from the hard-line to the lightning arrestor. I didn't have anything with me to do any tests. It was 5:00 pm so I took a few pictures and came home.

I don't know about the water. The hard-line has been inside all the time that we have had it. I think that the end of the coax that I used for the top was used at the top by the previous owner. The connector at the top had been sealed and the one at the bottom had not been sealed. So the water would be at the bottom. I hope the connector at the top is ok. I will put rf on it and we will see.

Now all that is left to do is check out the antenna system and install the repeater and get the power on.

April 1, 2005 Friday (Repeater at KIØQ) Antenna re-installation on water tower
KIØQ Dave Fitz

I got a call from the NADC/USDA regional manager in Peoria, IL a few weeks ago. This was out of the blue for me. The regional manager apologized for taking so long but our papers had been buried when she was out for knee surgery. They needed a certificate of insurance. I sent one to them and they sent me 2 copies of the new revocable permit that would be good for 5 years. 5 years is the max that they can make it for. The director lamented that they cannot make it permanent. I signed them both and sent them back and then they signed at least one and sent me a copy. I then called my contact at the Ames NADC and he no longer works for the NADC. But his voice mail was still there and it gave the number of his replacement. I called the replacement and they said that they would unlock the gate to the ladder anytime. I think they really mean that they would unlock it anytime during their normal hours.

So on Friday, April 1, 2005, I got tools and materials loaded into the blue van before work. I got my job for the day done at noon and called out to the NADC and they said come on out the gate will be open. I went out got through the McCarthy security and the gate was open. The 17 mph wind was up to 21 mph. I rigged to put up the antenna and got it up on top. The clamp bolts were painted so well that I could not get them to work. I sawed them off with a hack saw and installed other bolts that I had brought. I got the antenna up and it was 4:00 and the wind was gusting to 30 mph.

I didn't want to start on the feed line in the wind and the late hour. I tied down the rope and looked at the cabinet and there is no power. The circuit that we are on has an outlet on it that was being used to power an electric heater that was heating a temporary building that was protecting some water valves. There is new circuit that has been run to our cabinet and it is marked radio transmitter. It appears to be energized. I disconnected the old circuit and connected the new one except the hot wire. I didn't have my boots to insulate me. They were in the other truck. I left the ladder gate unlocked but closed and figured I would come back Saturday and put the feed line up.

November 14, 2004 (Repeater at KIØQ)
WØDP John Maurer

Having trouble getting formalized agreement to move back to NADC water tower.

June 20, 2004 (Repeater at KIØQ)
NA0S (now WØDP) John Maurer

Intermod problem reoccurred at 6:47 PM just prior to the Sunday evening. Lasted until 7:30 PM at least. Attempted to switch to PL mode but was unsuccessful.

June 19, 2004 (Repeater at KIØQ)
KI0Q Dave Fitz and NA0S (now WØDP) John Maurer

Examined the new (to us) 7/8" Andrew Heliax LDF5-50A that we bought on eBay. All looked good. Unrolled entire 225’ length and tested for loss. We did not have the proper slug with us but it looked as though it gave us about 3 watts out with 4 watts in, but the measurements are ball-park only – not accurate at all. We paid $325 including 2 female N connectors, 3 grounding kits, 40 stainless steel snap-in clips and shipping for the Heliax, which came from Alabama and was supposedly a 2-year old piece when we got it. Current retail price of LDF5-50A is $6.53 per foot, so the retail price would be $1471 plus connectors and grounding kits. We will not be able to use the mounting clips.

June 16, 2004 (Repeater at KIØQ)
KI0Q Dave Fitz

Repeater at KI0Q. Tuned up Mitrek receiver. Went from 0.5 micro volt to 0.25 micro volt. I remember that the discriminator meter circuit didn’t work. I can’t remember how we set the frequency. I think it was with a freq counter counting the frequency from the channel element. Also checked the duplexer. It was OK. There is more rejection on 147.24 than on 147.84. I would like to make new ¼ wave sections for interconnecting the cavities. The jumpers are ¼ wave at 147.24 about 13 inches. The current jumpers are made from double shield RG/58. The new ones would be double shield RG/8. RG/9 I think. Also took some pictures.

June 13, 2004 (Repeater at KIØQ)
KI0Q Dave Fitz

Repeater at KI0Q. Checked out the Celwave/Phelps Dodge Super Stationmaster antenna. The test setup used an ICOM IC24AT with 14.5 volt power supply and a Bird wattmeter with a 25 watt slug. The antenna was tested horizontal on sawhorses 24" above driveway with no radials attached.

WØYL 147.24 mHz Celwave Antenna June 2004
Frequency Forward Reflected VSWR
144.000 4.0 0.4 1.92
145.000 4.5 0.2 1.53
146.000 5.1 0.1 1.33
147.000 5.5 0.0 1.00
147.240 5.5 0.05 1.21
147.840 5.3 0.1 1.32
147.995 5.1 0.2 1.49

May 29, 2004 (Repeater at KIØQ)
The intermod lock problem is gone. It has been raining. The rain seems to remove the intermod problem.

May 28, 2004 (Repeater at KIØQ)
The back up repeater went in to the same intermod lockup that occurred last week. I searched for possible causes but found nothing conclusive. I put the repeater in PL required mode and eliminated the lockup.

May 27, 2004 (Repeater at KIØQ)
Received a call from Blaine Warner with McCarthy Building Company. He said that there was another insurance form that need to be filled out and that he would have McCarthy’s insurance company contact my insurance company (Triplett Real Estate and Insurance ). I talked to Keith Peterson at Triplett later that day and confirmed to that he had been contacted by McCarthy. The paper work had been started but was not complete yet.

May 23, 2004 (Repeater at KIØQ)
Changed back to the backup repeater. It worked OK.

May 22, 2004 (Repeater at KIØQ)
The repeater still not working because the intermod lockup problem. Then later in the day the problem was gone and the repeater worked. No changes had been made since this morning when intermod lockup was occurring.

May 21, 2004 (Repeater at KIØQ)
The repeater still not working because the intermod lockup problem.

May 20, 2004 (Repeater at KIØQ)
The repeater was locked up again with the same problem as the day before. I changed out the entire repeater to the equipment from the NADC. The lockup was still there.

May 19, 2004 (Repeater at KIØQ)
KI0Q, Dave Fitz

NA0S (now WØDP), John Maurer reported that the repeater was locked on with noise. The repeater is the backup repeater (Micor equipment) at the KI0Q QTH. There seemed to be inter-modulation. The problem was only there when the repeater transmitter was active. I searched for possible causes, such as a strong signal at 600 KHZ that would mix with the transmitter output and create a signal on the repeater input. I also checked for strong signals in the 144 MHZ band. I changed out the duplexer since I had all the equipment from the NADC here at the KI0Q QTH. This solved the problem and the repeater worked.

May 14, 2004 (Repeater at KIØQ)
Returned to McCarthy Building Company site at NADC. The Certificate of insurance was still not acceptable to Blain Warner, the McCarthy representative. Blaine Warner called Keith Peterson on the phone and discussed how McCarthy wanted the certificate worded. I was then allowed to enter the site. I retrieved everything but the cabinet including:
Beldon 9913 feed line
Beldon 9258 feed line
Cellwave super station master antenna 1 radial missing
Tower mounted preamp in water tight box
Fan control
UHF duplex radio
Mitrek receiver
Mitrek transmitter
Power supply
Repeater controller
Interconnecting coax and control cables

I did not see the clamps for the Super StationMaster antenna. I am hoping that they are still attached to the mounting bracket on top the water tower. I took a few pictures of the water tower to help with planning the new coax installation.

May 13, 2004 (Repeater at KIØQ)
KI0Q, Dave Fitz

Returned to McCarthy Building Company site at NADC. The Certificate of insurance was still not acceptable to Blain Warner, the McCarthy representative. I was not allowed access and returned to Triplett Real Estate to see Keith Peterson to get the correct certificate of insurance.I had made arrangements with Ron Crawford to get to the site also. Since I wasn’t allowed in by McCarthy, I didn’t meet Ron Crawford. I did call him when I got to a phone but only left a message on his answering machine. He later called and said that he had left the key for the water tower ladder on the cabinet and that I could come out anytime and go ahead.

May 12, 2004 (Repeater at KIØQ)
KI0Q, Dave Fitz Attended "Safety orientation" by McCarthy Building Company. This orientation is required for anyone who enters the construction site where the water tower is located. Also supplied McCarthy Building Co with a certificate of insurance, but it was not acceptable. Went to Keith Peterson, insurance agent for Dave Fitz Electric Co. to get the proper certificate.

May 7, 2004 (Repeater at KIØQ)
Called Ron Crawford again. They were supposed have an answer from the risk manager. He said that we could continue to use the site but said that insurance would be needed. I told him that I had contractors insurance. Ron mentioned that he may have a way to get me on the site. I said that I would be willing to meet all McCarthy’s requirements (unless it gets too expensive).

May 6, 2004 (Repeater at KIØQ)
Called Ron Crawford to touch base with him. He was supposed to be back from vacation. He was optimistic about the project.

May 5, 2004 (Repeater at KIØQ)
Called out to the NADC to see how the water tower painting project was coming along. I could not get Ron Crawford since he was on vacation. I talked with Mark Bulacheck and he informed that there may be complications with getting access to the water tower site. The site was now controlled by McCarthy Building Company who is working on a construction project for the NADC. It is estimated the site will be controlled by McCarthy for 3 years. To get access to the site a person would have to attend the McCarthy orientation, and then would be required to use the following safety equipment:
Hard hat
Safety glass with side shields
Reflective vest
Leather boots
Mark Bulachek also said that there may be some chance that the NADC would not allow the Story County ARC to have it repeater at water tower. He said that there was "90% chance" that we would still be allow to use the site. He would have to talk to the NADC Risk manager to get his approval. He would do this in the next few days.
Ron Crawford returns from vacation.
Mark Bulachek or Ron Crawford checks with the NADC risk manager to see if we get use of the site.

I also talked with Mike Yateman of McCarthy Building Company 232-8895 ext. 33. He confirmed what Mark Bulachek had said and also mentioned that full body harness with double lanyard would be required to climb the water tower. He also mentioned the insurance might be required. I would have to get safety glasses with side shields, a reflective vest and the full body harness with double lanyard.

October ??, 2003 (Repeater at KIØQ)
Went out to NADC to turn off repeater. Met Ron Crawford and went out to the water tower. The painters were under way on the painting of the water tower. They had removed the antennas and they were stored in the painting contractors trailer. I took the UHF Hustler G6 antenna with me. The painting contractor said that they would reinstall the VHF Super StationMaster antenna after the painting was complete. The painting was to be complete in 8 weeks. The contact at the painting contractor is Fred Arnold 612 -616 - 4403. Power to the circuit feeding the repeater was turned off. I turned off the power switch on the power supply. I offered to remove the feed line for the duration of the paint job. The painting contractor didn’t want me on the tower. They said that they would protect the feed line during the sandblasting and painting process.

October 21, 2003 (Repeater at KIØQ)
KI0Q, Dave Fitz

Received call from Mark Bulechek, 663 - 7769. Bulecheck said to talk with Ron Crawford who is charge of the water tower now. Phone for Ron Crawford is 663 - 7297. Called Ron Crawford. He said that he would call back about details for removal of antennas and brackets for reinstall.

October 21, 2003 (Repeater at KIØQ)
KI0Q, Dave Fitz

Called Denis Jones and left message about the repeater. Also sent Email to Jones.

Aquired new numbers:
Receptionist number 663 - 7217
Denis Jones 663 - 7218
Denis Jones Cell 231 – 83xx
Email: djones at(nospam) nadc.ars.usda

October 19, 2003 (Repeater at KIØQ)
KI0Q Dave Fitz

Changed antenna used by the backup repeater at the KI0Q QTH to VHF Super StationMaster . The repeater had been connected to a UHF Super StationMaster and the coverage was poor. Go figure.

October 17, 2003 (Repeater at KIØQ)
KI0Q, Dave Fitz

Report by K0CQ, Jerry Johnson that the repeater was off. Activated the back up repeater at KI0Q QTH.

March ?, 1992
You might notice a bit of a gap here. This 11 year omission will be filled in as time permits.

December 7, 1991
KI0Q, Dave Fitz
NA0S (now WØDP), John Maurer
WA7SSO (now W7SSO), Mike Chaplin

Went out to the NADC to solve the low audio problem in the 147.24 transmitter. The cables changes indicate that the trouble is in the VHF transmitter rather than the audio board. Put the interconnect cables back to the normal configuration. Found the low audio problem was in the connections on the channel element. The automatic gate was broken so we had to enter the NADC the north way. (Get a key for the north gate and unlock and lock the gate and then drive around to the north and then east and then back west to the water tower).

November 9, 1991
KI0Q, Dave Fitz
NA0S (now WØDP), John Maurer

Exchanged interconnect cable on the UHF and VHF receivers. This is an attempt to isolate an audio problem. If the audio problem is in the VHF transmitter there will be no change. (There will be low audio in the VHF transmitter ) If the problem is in the audio board then the problem will show as low audio from the VHF receiver to UHF transmitter. Also closed the vents and started the heater for the winter. Had trouble getting out through the automatic gate. It wouldn’t open. Used an auto patch to call the security guard to let us out.

May 12, 1991
KI0Q, Dave Fitz (At KI0Q QTH)

Repaired power supply, replaced the full wave bridge rectifier. (one rectifier shorted) Added 0.1 ohm resister in series with the Crowbar circuit. I think the crowbar circuit had triggered and burned out the rectifier. Added pull down resistor on the voltage regulator driver transistor. This now prevents the voltage from floating up when there is no load on the power supply.

At the NADC:

Installed the repeater power supply and retrieved my 4 amp power supply. Replace the UHF receive antenna with a Hustler G6 collinear at the top of the water tower. Installed the former mobile antenna that had been at the top of the water tower on the repeater cabinet to be used with the UHF transmitter. The previous UHF transmitter antenna was a Larson quarter wave mag-mount that will be returned to KI0Q. Changed a resistor in the in the VHF receiver preamp. R152 now has a 20K resistor paralleled instead of a 33K resistor. I counted the steps on the ladder up the water tower. There are 108 and ½ steps. (I don’t recall if this includes the curved ladder over the top.)

May 11, 1991

KI0Q, Dave Fitz
N0AN, Bob Schiers

Problem with desense. TX is OK. Duplexer has 99 DB of separation. Rx Amp in Mitrek receiver flying (oscillating). Minor tuning fixed the oscillation. I am guess that the oscillation will be back. 2 radial broken off the 2 meter Super StationMaster. Burned out the rectifier in the power supply. This happened while we were out at the site. Kept the repeater going by using KI0Q’s 4 amp power supply. The repeater power out is turned down to 5 watts.

Jan 1, 1991
KI0Q, Dave Fitz
K0CQ, Gerald Johnston

Reinstalled the repeater at the NADC. Added a heater to keep the cabinet warm. Power out on 2 meters = 15 watts reflected power equals .5 watt. Now using the Motorlola Mitrek transmitter.

Dec 27, 1990 (Repeater at KIØQ)
KI0Q, Dave Fitz


Changed the feed back capacitors in the audio op amp circuit from ceramic to mylar. This should help the problem with the temperature changing the audio characteristics.

December 25, 1990 (Repeater at KIØQ)
KI0Q, Dave Fitz


Found op amps in audio circuit flying (oscillating) Modified the op amp circuit by adding resistors in series with the output. Now the Mitrek transmitter works. Now the deviation can be set to the proper levels. Changed a capacitor in the VHF receiver squelch circuit. This should make it more temperature stable.

December 22, 1990
KI0Q Dave Fitz
WB0MJC, Rich Mercer

Squelch was open because of extreme cold. Remove to repeater to be worked on QTH of KI0Q. Found the duplexer slightly out of tune.

August ?, 1990
KI0Q, Dave Fitz

Replaced Micor channel element. No Help

June 30, 1990
KI0Q, Dave Fitz

Replaced the UHF tower mounted preamp. Tried the Mitrek transmitter. Some thing was flying in the audio. Put the Micor back. 20 watts out 2 reflected. More reflected power than there should be. Something may be going bad. Next time bring 12-24 tap to tap holes in rack rails.

May 12, 1990
KI0Q, Dave Fitz
N0AN, Bob Schiers
W0RSO Tom West

Replaced the Mitrek transmitter with a Micor transmitter. 25 watts out. Could only get 2.5 KHZ of deviation with Micor transmitter. Removed the tower mounted UHF preamp. Opened the bottom vent. The alarm switch got stuck on someway. Replaced the fan control.

March 17, 1990
KI0Q Dave Fitz

Adjusted audio levels. Removed light bulb heater. Replaced UHF preamp. Checked channel element in VHF transmitter. The channel element has a ICM label and crystal. UHF preamp not working well. Opened top vent on cabinet but forgot the bottom vent.

December 16, 1989
KI0Q, Dave Fitz

Insulated the repeater cabinet with ¾" Styrofoam.
Added 100 watt light bulb to heat the cabinet.
Set audio levels. Removed fan control.

December 9, 1989
KI0Q, Dave Fitz
WB0MJC, Rich Mercer

Replaced LM324 op amp in the audio board with LM2741N op amps. This may help with audio gain changes because of temperature change. Adjusted the audio levels. When tested at home afterward I found the audio level was low. I also removed the UHF preamp from the top of the water tower to get it working again.

September 24, 1989
KI0Q, Dave Fitz

Replaced the UHF tower mounted preamp. Bypassed the second MRF901 preamp. Removed the 147.84 receiver. K0CQ found the mixer transistor oscillating. Installed R113 shown in the manual but not installed on the circuit board. Also found the RF amp in the VHF receiver oscillating. Added a resistor in parallel with R152 to load the amp and stop the oscillation. Replaced the VHF receiver. Now the receiver has less desense.

September 18, 1989
KI0Q, Dave Fitz

Checked on desense with dummy load. There is still desense with the dummy load. K0CQ suggested that the UHF preamp may be oscillating and interfering with the VHF receiver. Removed the preamp.

August 26, 1989
KI0Q, Dave Fitz

Permission from Scott Rusk. Replaced UHF channel elements with different temperature compensated elements from International Crystal Manufacturing.
Adjusted the fan control. Check Desense on VHF. Remove Duplexer for tuning by K0CQ but found that duplexer was not out of tune. Replace the duplexer. Still plenty of desense. Lowered the ID’er audio level.
Power out on 147.24 mhz = 25 watts after duplexer

May 22, 1989
KI0Q, Dave Fitz

Permission from Don Braymen
Key Number 9 doesn’t work for ladder access.
448.250 Receiver not sensitive.
Determined that the problem was in the tower mounted preamp. There was a problem with the biasing in the second amp. And replaced MRF901 transistor in the first amp.

December 3, 1988 - Initial installation at water tower site.
KI0Q, Dave Fitz
WB0MJC, Rich Mercer

Contact Person at NADC Scott Rusk
Use Key Number x10 to access the ladder to climb water tower.
Repeater Callsign WØYL
Input Frequency 147.840 mHz
Output Frequency 147.240 mHz
Power out of Duplexer 20 watts
Antenna gain 5 dB
Feed line loss 3 dB (190’ of Beldon 9913)
Effective radiated power 31 watts
Antenna height above sea level to antenna base 1160 feet (water tower height 150’)

Install repeater at the NADC water tower for first time. The cabinet, the antenna, the feed line, the power had been installed previously.

The antenna is a Celwave "Super Station Master" . It is a 5 DB gain collinear antenna. The antenna is mounted to a bracket that is bolted to the top of the water tower. Holes were drilled and tapped in the top of the water tower to secure the bracket. The antenna is attached to the bracket using the brackets that came with the antenna. This arrangement allows the antenna to be mounted plumb even though the bracket is not plumb. The antenna is 21 feet long and has 3 quarter wave radials that are attached with a stainless hose clamp. The feed line is 190 feet of Beldon 9913 coax. There is a second run of RG/8x coax for a UHF antenna on top the water tower with tower mounted preamp. The coax feeds through 2 Polyphaser injector/ extractor lightning arrestors that allow a DC feed for the tower mounted receiving preamp. The UHF antenna is a Hustler 5 DB gain collinear.

The cabinet is an old cabinet that had been used by the rail road for some sort of equipment. It was donated by someone in Des Moines. I think that Charles Corcoran WB0URB ( now KD9UD) had something to do with the donation. When we went to pick it up the cabinet was lying out in a field and had been for some time. The cabinet is galvanized steel. It had been insulated with corn board. The corn board was decomposing. There were corn worms living on the corn board.

When I opened the cabinet after I brought it home a mouse ran out. My wife was not amused. The cabinet is 6 feet tall and 20 inches wide and 14 inches deep. There were rack rail located 6 inches back from the door. The top 3 feet of rail was cut off and moved out to the front of the cabinet. There is a vent on the top of the cabinet with 2 fans mounted in it. There was a damper that was control by a temperature sensitive actuator the would open the damper when the temperature rose. The actuator no longer worked. (I think the freon had leaked out.)

The fans still worked and control was made that used a thermister to sense the temperature and start the fans at a temperature set by a pot. I cleaned out the cabinet and painted it with rust inhibiting paint. I then insulated it with Styrofoam. I made gasket out of ¼ inch plastic tubing for the door that opened one whole side of the cabinet. The cabinet had steel rails that it sat on. I drilled holes to mount the cabinet to a concrete base. The concrete base was made at the NA0S (now WØDP) QTH and had 4 stainless steel bolts. The base was poured using concrete made from mortar left over from NA0S (now WØDP)’s concrete block equipment building. There was a meteor shower the night the base was poured. It was then moved out to the NADC. There is a JIC box mounted on the side of the cabinet where the power enters and all coaxes exit. There is a lightning arrestor on the power and inline Polyphaser lightning arrestors for the coaxes. The power is run in ½ inch aluminum conduit from an outlet on the water tower leg.

Log kept by KI0Q, David Fitz, Trustee

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