SMART - F2
SMART's 52.68 Repeater aka F2:
THISTORY OF "F2" by Bill Hess, K8SGX
Most of the dates used in this document come from either
schematics I wrote or old orders from International Crystal that
pertained to getting or keeping the system into operation. If
anyone can refute or contribute to anything contained within,
please get the information to me for future addition or
correction.
In the time period that included 1969-1970, meetings of the East
Shore VHF Club were held in an old Nike site building in Manry
Park, Willoughby. (not a very fancy place) They had a relatively
low profile repeater on 53.70/53.46 with the callsign of K8NPY.
The transmitter was located at Manry park and the receiver at
the residence of George (WA8EYG) near White Rd. and I-271. The
input and output sites were connected with UHF links.
A new community center building was built in Willowick in 1968
and the club was given permission to have its monthly meetings
in the basement meeting room instead of at Manry Park. They were
also permitted to use a room adjacent to it which was designed
for operating emergency communications equipment. At about this
same time the East Ohio Gas Company donated one of their old
lowband base stations which was a ¼-KW unit manufactured by
F.M.Link. It used a single 250TH in the final and was of the
two-case vintage (ca 1948). The new community center would have
been a nice place to get the repeater started. Next to the
building were two 100ft. Union metal mast monopole antenna
towers.
Dave (WB8APD) and I wanted to try to get the donated equipment
on the air as the new transmitter for the repeater.
Unfortunately, the only radio club person who had keys to the
building was Dick Snow (K8CQY SK). When I approached him to also
have access to the building so we could get the old Link going,
he advised that no one else was going to get a key. It didn't
take a rocket science degree to realize it wouldn't work getting
him to let us in every time we wanted to work on the repeater.
My reply to this was fine, if that's the way you want to be,
I'll find other equipment and build my own repeater. From the
start of the project to the time I had the repeater first on the
air, it took about six weeks. I assembled it in the workshop in
my apartment on E200 St. As far as I can tell, this was sometime
in 1969 or 1970. The frequency pair F2 still uses, was
consistent with the OARC recommended band plan of 1970. I think
Alex (K8EUR) wanted to use the 92-68 pair in particular because
W8RRJ in Columbus had a repeater on 84-60 and the frequencies
were close enough to easily crystal switch in an older radio. At
the time, we were all using radios with at least a tube driver
and final and they would not tune the wider spacing from simplex
to the repeater that works with the solid-state transmitters of
today. Frequently, it was necessary to two-freq the radio to
even have a place to put a second channel (for the repeater). To
use the repeater, we all needed to install a new set of crystals
in the second channel in our radios. So......when you were
talking on 52.525 in the simplex mode and you were to the point
where you couldn't hear the station you were talking to any
more, you would call F2, F2. This meant go to F2 or the
repeater. The tradition has kept up through the thirty plus
years F2 has been on the air although admittedly it becomes easy
to use the repeater when you might be able to communicate
without it. Some people as a result have let the quality of
radio or antenna in their vehicle be a compromise. A 100 watt
radio coupled to a real mounted-through-the-fender full length
quarter-wave antenna performs the best. Lower transmitter power
or a shortened or multi-band antenna definitely makes for
compromised performance. Extender or other noise blanker in the
mobile receiver, good IM rejection and sensitivity and a low
amount of ignition noise are all requirements to make six-meter
mobile operation a success.
That is essentially how F2 began. I mounted the first
transmitter in a power supply I built. It used a GE
Progress-line transmitter strip which put out about 60 watts
into an Antenna Specialists ASP271. The antenna was mounted on
top of Art Sutt's (W8YOS, SK) tower at SR615 and 2 in Mentor.
The six-meter receiver was a Motorola Unichannel PL only (had no
carrier squelch) tube-type receiver and was located at Bill
Benjamin's (N8BC SK) house in Painesville. UHF links were made
with Motorola tube-type T44 equipment. Suffice it to say it was
always in need of repair or tuning. You were lucky to get a
couple good 2C39 tubes for the transmitter and then of course
they didn't last forever. Art came up with the clever acronym
for the system and its users: SMART which stands for Six Meter
Amateur Repeater Team. How Dave became the repeater license
trustee and yet I've done most of the work on it - well it just
started that way and continued through time.
I'm not sure when we put the input at Winton Place but for a
while that may have either been the only input or it was the
second input.
A short time after the 60 watt Prog-line transmitter was
operational, of course I wanted a transmitter with more power so
in July of 1972, I took an old strip from an 80D (Motorola
30-watt mobile transmitter strip), replaced the 7C5 pre driver
with a 2E26, the 2E26 driver with a 6146, and the pair of 2E26's
final with a 4CX250. Art donated the plate transformer which put
out 1110 volts at 1300 ma AC. It made a plate supply of about
1400 or so. The amp put out about 235 watts. The resulting
transmitter was somewhat in need of frequent tuning but Art
probably retuned it more than necessary. This was the birth of
The Art Sutt Award: for diddling a working piece of equipment
and the word diddleitis! The transmitter was given to Kim W8HD
after I built the 4CS250 amp with the idea that he use it to get
a repeater on the air in the Detroit area. He ultimately
acquired a Motorola Micor base station and had it on the air for
a short time.
In the constant search to place a repeater transmitter in a
higher profile location, we moved the transmitter to the top of
the API water tower on Wilson Mills Rd (near County Line Rd).
Although I worked at API at the time, the installation had been
arranged through Pat Chick (WB8MJB/N8DAQ SK). He and Roy Polizzi
were previously using the water tower site for a low profile
repeater which they stopped maintaining and leaving the site and
transmit antenna available to us for the F2 transmitter. The
receive site was relocated to Dave Foran's tower in Willoughby.
Some of the problems with the transmitter were alleviated by the
move because there was no one at the site to diddle it. At one
point, we had to salvage it and do some repairs. The boiler in
the same room caused the damage when the makeup water system for
it failed and a partial meltdown occurred. It burned hot enough
with no water in it for the firebrick on the sides of the boiler
to melt.
If you can find really old records of F2, one of the interesting
things you could find out were there were at least five meetings
between various hams interested in the repeater. Many of the
input sites discussed never materialized. The first one was held
on 18 JUN 80 and attended by K8EUR, K8SGX, WB8APD, W8FVL, K8GZQ,
W8AZO, and WB8MTE. At that meeting I noted the locations of
inputs and link frequencies of .875 at K8EIW (Cuyahoga Falls),
.825 at WA8TTS (Montville), .925 at WA8BRD (Winton Place, west
side) and .85 at Wooster. Then apparently we decided to move
WA8TTS to Painesville, K8EIW to the hill and the hill to
Wooster. I assume this referred to frequencies or equipment
moves. We also decided to raise the transmitter power to 500
watts. There were notes about moving various pieces of equipment
to different places. They indicated either present or proposed
input sites at the API 306 plant (we did have equipment there in
a cabinet on the roof). As we all know, the concept of radios in
outdoor cabinets always equals trouble. For a short time, we had
an input on the Union Metal mast at the OBT building at E260 and
the south marginal. As I remember, there was a lot of trouble
with interference we decided must be coming from all the
vehicles on the shoreway and we soon moved it elsewhere.
The next meeting was on 5 OCT 80, and was attended by K8SGX,
K8EUR, K8AET, W8CJB, WA8RQY, WB8APD, W8CZW, WB8RGC, K8WLF, and
W8AZO. At that time apparently the input at Winton Place was
dead and we decided to put an input at an unknown site in North
Ridgeville. (never happened) We were going to try to get the
users of 52.84-60 to move to F2. I promised to get the new amp
in service by the spring of 1981.
There was a meeting of K8SGX, K8EUR, WB8APD, W8AZO, and WB8MTE
on 5 JUN 83. We decided to change the CWID to DE WB8APD. (I have
no idea what the callsign was before the change.) Adding PL
receive to the hill input was decided upon. We would turn the PL
on and off by supplying a 1950 Hz tone on the monitor pair that
ran to the WTPD office (for Marv). (never happened) Apparently
we were having an interference problem with the 146.76
transmitter. There is mention of a 2A+B problem. I was supposed
to add a relay to the amplifier to lower the power to 100 watts.
I now realize that is not as easy as it sounds. There was
discussion about "use touch-tone memory stuff from Pugsley"
which I assume to be a reference to the controller we are still
using.
Next meeting. Small meeting. K8SGX, WB8APD, WB8MTE and W8AZO
decided, on the 18 NOV 83 to move the Amherst input to the new
tower at the 125 mile marker and the OTP. (also never happened)
There was some discussion about trying to get our input links on
the statewide microwave system. I'm glad that did not pan out. I
still feel we're better having control of all our own equipment.
At that time, apparently the inputs at least proposed were hill,
Thompson, Downtown, Winton Place, 125 mile tower (not), and Col
which must have meant Columbus and of course that never happened
either.
The last meeting I have records of having was on 30 NOV 85. It
was attended by WB8APD, K8EUR, K8SGX, and W8HD. Kim was supposed
to purchase a GE Mastr Pro UHF base from WB8APD to use for the
link to Michigan. (which he did) I was supposed to order
crystals to move the hill input to Newbury and add a receiver
for a control channel.
A couple of years after my friend George (Wooster) erected a 100
ft. tower, for his commercial two-way radio system, I finally
convinced him to let us put an input on it. In late winter,
1980, I had it working. There's an ASP600 (lowband) on top of
the tower and an ASP760 (UHF) mounted on the north side of the
tower.
In 1982, we were granted the opportunity to install an input on
the Thompson WVIZ TV ch67 translator tower. This site is used to
retransmit the signal from WVIZ and now also WKSU-FM for areas
mainly to the east of the location....Ashtabula County and
eastern Lake County.
In the continuing hunt to want to get an even better transmitter
location, we decided to move the transmitter to the Warrensville
Township hill at Sunny Acres hospital where the LEARA sites
still are. You (I) couldn't just move an old transmitter there
so during the winter of 1982-3, I built still another final
which used a pair of 4CS250 pulls from OBT IMTS transmitters
attached to a big heatsink. This one had an input with the
maximum legal power at the time of 900 watts (for an unattended
station) and produced about 600 watts RF. Dave came up with two
plate transformers from GE finals. I tied them in parallel. I
tried all sorts of arrangements including equalizing resistors
and capacitors to get diodes to work as rectifiers but could
never keep them from shorting. In a fit of desperation, I put in
two 3B28's. End of problems. In order to keep the output of the
transmitter clean, I actually ran the output of the amp through
two full sized cavity resonators. Marv purchased them and two
others that are now in the input circuit of the transmitter at
the radio station in an auction of surplus equipment from the
Shaker Heights Police Department. They were brand new. At the
time I didn't have the resources to make a PA output filter
similar to those usually put on the output of an amplifier and
we wanted to be extra sure there weren't any out-of-band
emissions to bother the hospital MATV. The antenna was a special
ASP600 with a phasing coil and another half wave radiator on top
so it gave 3db more gain than a standard '600. In order to keep
the amplifier from burning out the finals if there was a
problem, I used API meter-relays to monitor the plate current,
screen current, and reflected power meter circuits. These meters
however did not have remote reset like the present amp has so
every time the thing tripped out, you had to actually go to the
transmitter site to perform the reset.....which was a real pain.
It turns out the specially modified ASP600 had intermittent
problems where the top radiator connected to the phasing coil
and the amp would trip out from high reflected power every time
it was really windy. Everyone kept telling me there is a problem
with the meters and I kept saying it was the antenna. I finally
turned out to be right. We didn't take the antenna down often to
check it because it was mounted on top of a 21 ft. piece of 2½"
pipe. (heavy)
When we moved the transmitter site to the hill, a GE MastrPro
UHF receiver was installed for receiving the links. With the
lack of a voter, it was necessary to build a search for the
receiver so I built one using an idea taken from the early GE
two-freq searches only this one had outputs for four
frequencies. The oscillator ran at 40 hz which meant the sample
time was only 25 milliseconds per channel. The rest of the
circuit consisted of a 4013 connected in a divide by two
configuration. It drove a 4011 with buffers on the outputs. This
only worked because the links were not guarded at that time. It
gave quick attack time but as with all searches, if the signal
on the channel being received does not drop momentarily to
restart the search, a noisy signal can persist and continue to
be repeated even though a better signal is available. Unguarded
links worked in that era only because there was not enough
interference on UHF to mandate guarding. Carrier squelch attacks
infinitely faster than does tone squelch. I can't be sure but
the four inputs at the time were Wooster, Thompson, Amherst, and
Mansfield. Soon after came Downtown.
In 1985, we obtained permission through Cliff Bade to install an
input on the Surgis Rd. site of Rhonda Clock Answering Service
in Mansfield where there was a Rohn 25 tower owned by Cleveland
Mobile Radio. It had a couple antennas on it connected to GE KW
base stations. The equipment room was on the side of the garage
in the back. The plaster was falling off the walls and ceiling
and the whole thing was a real unkept mess. We were given a
piece of cable to replace the inadequate electrical service and
we completely rewired the room. Still didn't fix the problem
with the grape vines growing all over the building and up the
tower but at least we had electricity. The piece of equipment I
built for an input used an old GE EF6 final Dave Foran gave me.
When Dave gave it to me, it had a bad tube socket and I decided
that since the 4CX300's the amp used were so expensive, I
converted the amp to use a 4CX250. The EP6 I put with it was an
old boned out unit I acquired from Alex. The screen pot was gone
and the burned out blower motor was missing. There was no plate
transformer either. I replaced the screen pot with a rotary
switch and fixed resistors. The blower from an old Motorola
C53GKB vintage continuous duty base was the source for another
motor and I salvaged the lamp ballast from an old Ozalid machine
scrapped from the LFE warehouse for a plate transformer . We
acquired a GE Mastr Imperial transmitter and control board from
Cliff Bade for the exciter. The input receiver was of course a
GE Mastr Pro. Like with many power amps, the thing worked great
while you were there then the tuning would drift a couple weeks
after your last trip to Mansfield and it was again off the air.
Not the fault of the receiver, but we constantly had some kind
of receive interference at that site. It sounded like some sort
of brazz coming from the power line but we could never locate
it. A full 5 ft long pass cavity on 52.92 wouldn't get it out so
it must have been on-frequency.
In 1988 we had to retrieve the input after water came in through
the leaky roof in the radio room and ran inside the cabinet.
This equipment filled an old Motorola cabinet and probably
weighed about 200 pounds. Not the type thing you just throw in
the trunk of your econobox car. Next time I made a drip shield
for the top of the cabinet. While I was storing it at the
Warrensville Township PD garage, (courtesy Marv, W8AZO), I
installed a 443.975 receiver in the package with the idea of
relaying an input to be located in Mt. Vernon through Mansfield.
We never ended up putting the Mt. Vernon thing on the air.
In early 1989, the tower was replaced and a cellular repeater
was installed on it. This was the preface to the ultimate
installation of the full cell site.
The problem with the amp, receiver desense, along with the lossy
path back to the radio station on UHF were the best reasons we
were far better off when the site was moved to the OET tower at
rte 39 and I 71. The final reason we moved however was because
the site was turned into a full cell site and the new owners
placed all kinds of restrictions on us including requiring $5 a
piece stainless steel transmission line fasteners which we
couldn't afford. So when my search for a new input site began to
pan out, I jumped at the chance to relocate. The increased
profile of the new input site allowed us to decrease the link
transmit power from 250 watts to 100 watts and actually have a
better signal back at the radio station.....so a completely
solid state input was now a reality. The new equipment which is
still in place was operational in the fall of 1995. It consists
of a Mitrek lowband receiver and UHF transmitter coupled to a
Micor 100 watt PA mounted on a huge heatsink. There is still one
of the old lowband GE receivers there. It is tuned to the
repeater output so while you are working on the equipment you
can hear what is being repeated on the system and actually
listen to how quiet your link signal is. Another bonus of
running all solid-state equipment is it allows us to use the
station batteries that run other ham equipment there.
The UHF antenna is fed with more CATV cable but this is .860"
dia. It has attenuation characteristics similar to other
semi-rigid coaxial cables but I had to manufacture a pair of
connectors for it since I didn't know where to get the right
thing.
Another of the first locations farther away from the transmitter
site where we installed an input was on the 175 ft. tower in
Amherst owned at the time by Howard Baker, K8NHR. It provided a
really good location for our first western input and had a
line-of-sight path for the UHF link. We used GE Mastr Pro
equipment mounted in an old shipboard radio equipment cabinet.
The equipment was located in the chicken coop next to the base
of his tower. Several times, we had problems with mice getting
inside the cabinet. The hole we ultimately had to plug was in
the middle of the back of the cabinet and probably about only ¾
inch in diameter. Sure made a stinky mess inside a piece of
equipment in a short time. In Feb 1989, I built a GE PR portable
transmitter input for this site also. The power here was also
about 25 watts and the link stayed on 448.925. The site was
ultimately taken over by a local two-way company and we
left....although the main reason for leaving was that we had
obtained permission to get on the Berlin Hts water tower and
there were rumors that the location was going to be sold and
turned into a turnpike interchange......which never happened.
A crystal order dated 2-86 indicates that was the time when we
began working on the link from the hill to Michigan. Although we
had four 11-element beams aimed northwest, the path to Michigan
was never reliably full quieting. We had the GE ¼K UHF base we
had been using for the repeater on 444.95 until Dave acquired
the MSF5000 that's been in operation since perhaps 1988. The ERP
of the old link calculated to be around 20KW. Before moving the
repeater to the east side we had it operating from the Federal
Building. What a fiasco getting it out when we wanted to move
it.
When WDMT was going to erect another tower in Newbury, through
the Geauga County EMA, I contacted Ron Eging KA8YNO who was the
assistant EMA director and asked if we helped put the 147.015
repeater on the air on this new tower, could we also get another
piece of coax up the tower and put up a 2-element antenna on six
meters? The answer turned out to be yes and that was in 1986
where the transmitter still is located. We actually had power on
the new F2 antennas before the broadcast station moved to the
new tower.
Of course the same deal applied here too. I needed a new
amplifier for the new location. The FCC changed the power
limitation for amateur service in 1986 to allow 1500 watts
output, so I automatically needed something to accommodate this
new power level. The existing amp on the hill really needed to
stay there in order for us to have an alternate location for
transmitting in case there was a problem at the radio
station.......and it turned out there were many problems with
the new transmit antennas. They are fed with a continuous run of
special nuclear blast collapse proof solid copper clad aluminum
center conductor " Heliax. The about 1350 watts the amp usually
puts out is attenuated to about 900 watts by 800 ft of
transmission line. The jacket is molded to the outer conductor
of the transmission line so firmly that in order to get it off
you have to remove it with a power wire brush. To use a standard
connector with it, the A/S guys made a special drill bushing
fixture that centered the correct size drill so you could drill
out the aluminum center conductor.
So the presently in-service amp was the summer project for 1986.
Work at LFE (my employer at the time) was slow for a period then
and I remember asking my boss if I could work on a project of my
own when I had no company business that needed attention and he
said it was OK so most of that amp was built at work actually on
company time. It took about six weeks to complete the basic amp
and control circuit. I remember working on the control schematic
and other concepts of the amp while I was waiting at the airport
to fly to see mom and dad that summer.
It uses six grounded cathode cross neutralized 4CX250's
connected in push-pull parallel to a tuned-line tank circuit.
The about 50 watts of drive from the exciter passes through two
full size cavity resonators. Both the plate and grid are link
coupled. The filament and screen supplies are SCR regulated in
the power transformer primaries. The screen supply is changed
from 150 to 250 volts when the transmitter power is changed from
low to high and in the tune mode. The tube heater voltage is
raised from a standby of about 4.2 to about 5.0 during the time
the blower runs which is from the time the grid relay pulls from
applied RF until it times out which is about two minutes after
non-use. In order to have the amp start immediately after
standby but not have to wait for the blower to come up to speed
and operate the prove relay, the relay is bypassed for five
seconds during each blower startup. This allows immediate
transmit capability but permits the amp to be in standby with
the blower off. The plate transformer is a ninety pound 3.5KVA
ballast I scrounged from another cast-off Ozalid machine from
LFE. I had to completely disassemble it. It was necessary to cut
off the magnetic shunts (2) on each lamination and 2 more on
each center piece. (The end result configuration looks like an
EI core, and the pieces are like a square with a straight bar
through both windings). There was a half inch diameter hole
punched in each center bar to further accomplish the feat of
making the lump constant current instead of constant voltage.
Out of the cut off shunts, I made a punch and punched out enough
slugs to in turn press one into each half inch hole. When I put
the transformer back together, it worked perfectly except now
instead of the primary voltage being 240 volts, the original
primary winding would only take 208 volts before core saturation
began. This was actually a blessing since the radio station
voltage is 208 wye not 240. In order to run the amp at home, I
wound enough additional turns on it to get a winding that would
run with 240 volts applied. So now I have an amp that has a
power transformer that will run on either 208 or 240 volts and I
wasn't looking to do this in the beginning. The primary of the
transformer is driven with an old LFE SCR driver board and SCRs
and provides abut 800 volts for low power operation and about
1700 volts in the high power mode. (plate current is about 1350
ma in high power) While I dislike the size of the driver board
because it's rather large, I have used them in several
applications because the drive to the SCR gates is DC which
makes the devices turn-off proof in the middle of the power line
cycle. If that happens in an inductive load primary circuit, you
wind up essentially with DC on the load (transformer primary)
and saturation followed by a blown fuse results very quickly.
Fair Radio (Lima Ohio) had exactly the choke I needed to get the
filtering done. It is 1.5 henrys at 1.5 amps and has the name
Collins on it. Perfect....as things seldom are. It and the
ballast fit side by side on a 1/4 inch thick panel which when
completely assembled weighs in at a mere 150 pounds. The
filtering is completed with two 40uf 4000v oils. The tuning
adjustments (grid, plate, load, and reactance) are operated by
small military surplus planetary gear-head 24 volt DC motors.
You push one button to make the tuning go one way and the other
button to go the other way. (3 motors and 6 buttons) I put an
ACE round key lock on the supply to eliminate any possible
tendency toward diddling the PA and another ACE round key on the
cabinet front door.
Protection for the tubes is similar to that I used on the amp on
the hill-API meter relays. Only this time I used 3-inch meters
instead of 5-inch meters so they wouldn't take up so much space.
They again monitor plate current, screen current, and reflected
power. The interesting thing I have discovered is that in the
event of high VSWR, the best indicator of it instead of high
reflected power is higher than normal screen current.
This time, I had the help of Norm Hanks (K8TVD) using the A/S
$30,000 network analyzer to tune up the special amplifier
harmonic filter I built. Although I attempted to duplicate the
filter Motorola used on its high power tube-type finals, the
tuning wasn't close at the beginning. It required a couple of
trips to the lab to get it right. To give an idea of the
capability of the amplifier, on one occasion, one of the N
fittings on the filter arced over and shorted in such a way that
the reflected power circuit couldn't see it and the amp just
kept transmitting into the dead short without ruining anything.
There are residents quite close to the tower and we've never had
a complaint of TVI.
The UHF link, control, and repeater input receivers are coupled
to the antenna through an amplifier, a bandpass filter and then
a four-way power divider that feeds four more 4-way power
dividers. One of the final dividers has an extra amp on it that
feeds the Mansfield and West Lodi inputs, the control receiver
and the UHF (U2) repeater receiver.
The project didn't go without a hitch or two however. Troubles
with RG393 interconnect cables were one problem. Marv and the AS
guys made the first cables that ran from the end of the Heliax®
to the antennas out of RG393. It seemed like a good idea to use
the stuff because of its low loss but we soon found that the
outer insulation is not UV or weather stable and twice we
developed a high SWR because water seeped under the outer jacket
and corroded the shield braid.
The first antennas on the WENZ tower were DB212's. While they
were and are nice antennas, we didn't have the right hardware to
mount them (if such a thing exists) on 7 inch diameter tower
legs and once when the wind was strong, they turned so they
weren't vertical any more. They worked OK but we were afraid
they might come down. The lab guys at Antenna Specialists built
antennas which are single gamma fed dipoles mounted 1/4
wavelength away from the tower and located on the south side of
the south leg. The signal from the whole arrangement is better
than 20db quieting in a mobile at the bottom of the hill at
route 30 and I 71 in Mansfield some 90 miles away. The only fear
I have with them is someday they will fail and when they do,
there are no spares available. There has constantly been a
problem with them with SWR sometimes when it rains and that is
the time we need proper operation for Skywarn. In the fall of
2004, they were replaced. Later in this article I will explain
the problems encountered in this caper.
One of the things that made the project attainable without the
need for deep pockets was all the help we received from Jerry
Smith, K8AJG. His involvement with Warmus communications, who
was the contractor hired to erect the new tower, put him in
position to help us and he did. In fact, he personally put up
our antennas and when we were having all the problems with coax,
he personally went up the tower and on three different
occasions, changed the phasing cables.
After the move of the transmitter, the location on the hill
where the transmitter was could now be used for an input site
and we installed one there. The transmitter used there is still
in place in case there is a long term problem with the Newbury
transmit site. Hopefully there won't be any but I guess you
never know for sure. The interesting thing about the hill site
for transmitting is while it may have a lesser signal in
Mansfield, it is louder in Toledo than the transmitter at the
radio station gets with a higher profile and more power.
In 1988, I obtained permission to install an input on the Geauga
County Sheriff's new tower. It was also the main site of the new
Geauga County '800' system. We didn't have any trouble with the
'800' system but found the transmitter noise on 52.92 at that
location was so great that the input was almost useless. This
forced us to discontinue its use.
At the beginning of our construction of the Clarksfield input, I
tried to figure what I was going to use for transmission line
for the new six-meter receive antennas. Through the efforts of
my friend Jim Black (deceased) I obtained several end-of-spool
pieces of .540" dia 75 CATV transmission line. The inside of the
outer conductor turns out to be the correct size to allow you to
heat it a little with a torch. This allows the back of a PL259
to slide right under it. To make the connection tight between
the two, you use a small screw hose clamp around the aluminum
and it clamps perfectly. The center conductor fits nicely inside
the center pin of the connector and is copper-clad so it solders
with no problem. As far as impedance match and loss
characteristics are concerned---the line was free and the
receiver hears. To date it's the feedline for the receiver at
Clarksfield, Mantua, Mansfield, and West Lodi.
One of the inputs that has basically performed with few troubles
has been the one on the Clarksfield site where the antennas are
located practically at the top of the tower. There are two
DB212's close to the top of the 350 ft. tower and it hears well
enough with its low 4db of desense to sometimes be the voted
input for mobiles in Cuyahoga County on I71. The original
package consisted of a Micor 30 watt UHF transmitter and a GE
Mastr receiver with a Motrac PL decoder. The input performed
quite well until it was replaced with two Mitrek radios in 2000.
Shortly after installation, the new input quite coincidentally
began to be bothered by a strange signal which, when I finally
went to the site to find it, turned out to be the local
oscillator in an aftermarket subaudible tone decoder installed
in the RCA receiver for the 2-meter repeater that's on the
tower. Disarming the decoder quickly solved the problem. In the
last year however, one of the transistors in the transmitter
power control circuit has failed 3-times. That is getting to be
somewhat disconcerting. Once the failure was caused by a direct
lightning hit...the other two, I have no idea why.
Cliff (W8CJB) knew I was interested in finding other input sites
for F2 and he knew the owner of a good candidate to the west of
Cleveland so, in 1988 one nice day, I rode with Cliff to the
West Lodi site and met Jerry Katzenmeyer (N8BHU) who was the
owner of this ex-Western Union microwave relay station at the
time. From him, I obtained permission to install an input on the
West Lodi site tower. I built an input with a 30 watt UHF
transmitter and when we took it to the site, I was surprised
after having a full quieting signal from the Clarksfield site,
30 watts didn't make the path at all. Jim Pracker gave me a
Motorola ¼K uhf amp (uses two 4CX250's) and power supply which
after a lot of work, I made work but I had more trouble keeping
it on the air than I had with the old Mansfield transmitter. In
the end, this input was changed out to Mitrek with some extra
mods.
The GE voter never really worked all that well in the system and
would vote a poor signal in when there was a better one
available. (sounds familiar) It always seemed to require audio
level readjustment. At one point, we actually replaced all the
tantalum and electrolytic capacitors in it with the hope of
solving the problem. It helped some but not a lot. With all
Mitrek receivers and link transmitters in place, I now know that
although we had a lot of trouble with the GE voter, at least
some of the problems encountered with it were not its fault at
all but rather the fact that there were no two inputs built with
exactly the same equipment. Although the repeated audio from
each of them sounded close, there was enough difference in the
amount of high frequency audio received from one input to
another that misvoting was at least in part caused by the
different radios. The GE ExecII exciter board the (downtown)
input used as a transmitter always had bassier audio than any of
the others. Where did the GE voter come from? I'm not sure but
we installed the GE voter and the first six Motrac receivers in
1983, or shortly before we moved the transmitter to the radio
station. More than one link receiver was now necessary. Alex
came up with six Motrac receivers from a source on the east
coast. The first mounting arrangement for them consisted of all
six receivers mounted between two panels. While there was space
to mount the squelch and volume controls etc. on the panel on
one side, the concept of having the receivers side by side took
up almost half the rack with receivers......in comparison to the
current pigeon-hole or mailbox concept that allowed 15 receivers
in about 18 inches of rack space. In the winter of 2003-4, part
of the modification to the system included adding another row of
link receivers so the current capacity is two control receivers
and 19 inputs (totaling 21). The original mounting method didn't
permit easy removal of a receiver to exchange it if it developed
a problem.
The whole voting system was replaced with the Motorola Spectra
TAC voter I purchased at Dayton in 1989 and installed on 28 JUL
91. I later purchased a couple SQM's from a vendor at Dayton and
then found out I could from time to time get more and finally in
about 1998, purchased a lifetime supply of them remembering that
they don't just show up a every hamfest. Each receiver is
connected to an SQM which votes it onto the system if it has the
best received signal. The voted audio is routed through a octave
equalizer which fixes the audio so the repeated audio sounds
almost like a simplex signal. The EQ is powered from 12v by a
simple MOPA self-excited invertor followed by a little L/C
filtering to clean off the worst square wave corners.
Vice Bak gave me several GE PR portables and several Micor DPL
boards. This was the beginning of guarding the links and my
first experience with digital squelch. After a considerable
amount of experimenting, I was able to get the GE transmitter
and Motrac® link receivers to work with the Micor DPL boards.
This is probably one of the capers I've pulled with the system
that could have caused a lot of trouble but really hasn't. The
only thing that happened was-in the process of making it work, I
inadvertently have (and it still is that way), the code of the
receivers inverted so when you are transmitting code 162 for
instance, the receive code is 503. This is a real nuisance when
you're setting up a new code or input but that's about all.
The Lorain input was one of the first inputs I built after the
beginning of the implementation of the Mitrek UHF radios for
link transmitters. It is one of the few inputs that once I built
it, I haven't seen it since. It doesn't have a very high antenna
( 50 ft.) but it does seem to do a good fill-in job in the
Lorain area. Finally in 2004, I received permission from J.P.
Jones (WA8CAE) to move the input to one of his higher tower
sites in Lorain.
An input was installed at Dick Bomboy's (WA3USH) house, is
connected to an antenna at 160 ft. on his tower. With the
relatively good site he has, it gives us good coverage from
Thompson to almost the New York state line. It is connected to
his battery system.
In 1990, after the weather bureau replaced the WSR57 radar with
the WSR88 doppler and the subsequent closing of many weather
bureau stations around the country including Toledo Ohio, the
need now existed to be able to talk to a ham station in any of
the Cleveland CWA (30 counties). This meant transmitting to and
receiving from anyone south of Mansfield, west to Toledo and
east to Erie, Pennsylvania. Along with Dave Foran, I decided to
make F2 available to Skywarn to do the job of backbone
communications. They accepted the offer. There are problems in
Toledo receiving the signal but I think most of that relates to
the fact that the Toledo Skywarn building is only 2 or 3 floors
high. Later they installed a 6 meter to 440 package at the
Davis-Besse Power Plant.
I guess I'm not really sure exactly when we installed the Mantua
input but I'm guessing it was sometime in 1991. Anyway, I'm also
not sure who introduced me to Dave Dorson, the owner of the
site. When I explained what I wanted and that an input there
would help make the system work better for Skywarn, he decided
to grant us permission to install equipment on his tower mostly
because we are using the system for Skywarn. I think the
approximately 33db of receiver desense I measured last summer
must be worse than when we installed the input although it never
has heard the way I thought it should. The two DB212's I
installed there for receive antennas were about the first of
them I used. Without knowing I was creating a problem, I had the
sections of the shortened antenna tack welded. Some short time
later, Dave called to inform me that the loop ends of the
antennas were on the ground. The only thing I can figure is
either the welding fatigued the aluminum or it was suggested
that maybe someone shot at the antennas (which I think is the
least likely story).
In the summer of 1991, my friend George and I were taking scrap
metal to Metallics Recycling in Wooster. Part of taking scrap to
the yard for recycling is to look around to see if there is
anything you can buy and take home to use. I found a complete 48
volt string of Exide 1020 amp-hour low gravity switchboard
batteries that had just been removed from service at a small
central office in Wooster. I brought them home (all 402 × 12
pounds of them) and installed a set of 17.6 volts at the radio
station for backup power. There have been numerous times after
their installation that they have provided power for
communications when the power was out.
When we first moved the transmitter to the radio station, we
were going to put the 444.95 repeater there also. We had it
there for a short time but then installed it on an OET tower on
Harvard Rd. hill. That site has turned out to give Dave's UHF
repeater good coverage.
When the main transmitter site was moved to Newbury, I built an
input for the antenna on the hill. It too employed GE MastrPro
receiver and transmitter equipment. With the acquisition of the
GE PR portable transmitters for links, I was able to replace the
ET59 transmitter with the portable's transmitter. It consumed so
little power in comparison that I was able to run the entire
transmitter from the EP38 filament supply. As the years have
gone by however, that location has become more and more noisy
and we eventually moved the input to the site where the 444.95
repeater is. It's not that far away from the hill location but
it seems to make a difference. All was well there however until
WKYC-TV decided to put their DTV transmitter on channel 2 in
Y2K. That immediately raised the noise floor more to more than
30 DB so for all intents and purposes, that site is now a local
coverage receiver.
Not to outdone by another project but the addition of the 'U2"
repeater and the hassle of getting it on the air was rather long
and dragged out. I had used the frequency pair of 449.95 and
439.95 to experiment with trying to radio remote control the six
meter station I had at Jim Pracker's (K8QOT) house in Orange
village back in the mid seventies. When the guys wanted to put
the '95 repeater on the air, they asked me to move and I moved
to 449.975 but kept 439.95 as the other half of the link.
Although I used 444.975 some, it was never the primary but due
to use of 449.975, 444.975 was sort of kept open.
One day when I was at the radio station doing I don't remember
what, Barry Thomas the chief engineer at the time happened to be
at there also. He and I were looking at the tower and talking
about things in general when he told me about the removal of the
Federal Express '800' equipment from the tower and the fact that
when they tried to remove the transmission line the system had
bee connected to, they were unable to unscramble it from the
rest of the lines and if I wanted to use it, I should come up
with an antenna. He volunteered to have the steeplejacks put it
up while they were working on the strobe lights. (within a
month) Of course I immediately talked to N8NAP Ray and between
the two of us, we came up with the idea of putting a UHF
repeater on it. He had an antenna that had been damaged and was
able to repair it and modify it to work in the amateur band. We
only transmit from that antenna but the connection of U2 to F2
is quite convenient for some of us.
We put an input site on the Berlin Hts water tower in 1994 and
although it is a good site and really has a wonderful profile
looking to the west because of the geographic profile. The only
problem is that the water tower distorts the receive antenna
pattern so much that it doesn't hear very well to the east (the
antenna is on the west side of the tower).
In 1994, I decided that since we were using the repeater to
perform Skywarn backbone communications, it would be a real good
idea to have a battery backed transmitter so I built one out of
Mocom 70 parts. The exciter is a Mocom 70 and the final is six
Mocom 70 PA's connected in parallel. It puts out about 600 watts
and of course draws about 125 amps while transmitting. Although
the final has never been operational due to lightning damage,
the relays and other circuitry in place to also connect it the
U2 uhf repeater as a remote base and operate in that mode on
52.525. It has been used very successfully on the exciter alone
as a backup transmitter for Skywarn nets when the power was
interrupted.
In 1994 Dave Firis AL7OP gave me a transmitter from a Micor
lowband high split mobile. I mounted it on a panel and added
enough three fans and an extra heatsink on the back of the PA
casting. It is now the exciter. Although I connected a high
stability synthesizer to it so the frequency stability of the
carrier would be good enough to allow it to operate in a
simulcast system, the concept of adding a simulcast transmitter
to the system is really a large project that I finally decided I
was not willing to undertake. The other problem which proved to
be a little bit of an embarrassment was the fact that the Motrac
exciter I originally installed as the exciter put out spurious
signals if one of the multipliers wasn't tuned just right.
Fortunately the spur was inside the amateur band.
In April of 1995, I assembled equipment for the site in
Columbiana County. Ron Eging from the Geauga County EMA knew Jay
Carter who is the EMA director for that county. Jay permitted us
to install an input at their building. While it is not very high
profile, it does fill in towards the east. At one time, we were
trying to get communications on F2 to NWS Pittsburgh because
their bad weather frequently comes from us. Apparently they
don't have any hams to operate the station we gave them. The
other nice thing about the Columbiana County site is having a
ham as an EMA director. This equipment, while it is an input for
the system, also has a receiver in it on 52.68 so Jay (K8GLX)
can get on the 'backbone' himself to inquire about the weather.
There is a DB601 on top of a self supporting tower which was
donated by Bob Winston (W2THU) with two fairly long UHF yagi's
mounted right below aimed of course to the north.
In 1996 I installed a link at the West Lodi site which receives
the system and translates it to UHF. Its 100 watt transmitter is
connected to a (10db) corner reflector mounted at about 200 ft
AGL and is fed with " CATV cable. It doesn't put as good a
signal into Toledo as I had expected but it does help a few when
conditions are not good.
For a few years, I was in the position of wanting to start
making all of the input site equipment the same make and model.
This would permit better operation of the voter. At Dayton in
1995, I purchased the first six UHF and six lowband Mitrek
radios. The purchase of these radios gave me the start I needed
and a direction I would continue with a particular make and
model of radio for all input sites. I ultimately bought 10 more
UHF radios in 1996 and 10 more in 1997. (they don't all always
work-but caveat emptor)
Through experimentation, I found that I could jumper out either
the transmitter PA for about 20 watts out or the PA and IPA for
about 5 watts out. To date all of the old inputs have been
replaced.
In Feb. 1997, (then) CEI gave us 25 loband high split low power
Mitrek radios each in a small suitcase. Some went to people
using the 'backbone'. Others have been placed back in their
suitcases to make portable stations and several were used as
input receivers in the system.
The input at WFMJ (TV21 Youngstown), is quite a story itself. My
first attempt at getting on the tower was in the summer of 1998.
During the search to find a spot to put an input to cover areas
in that general area, in 1999 Ernie, KB8QDX was asked by Lisa
Montgomery at WFMJ to do an interview on TV about Skywarn. At
that meeting, he inquired as to the possibility of our getting a
spot on the tower. Of course a lot of posturing followed with an
ultimate no. Then, after more questions and getting the name of
the then chief engineer and ham Bob Pritchard, K3LRE, told us he
could get the job done. We went to the transmitter site at the
time he suggested which was at the time the tower was to be
repainted. While the painters initially said they would put the
antenna up, when it came to doing the job, they refused. Back to
square one. Perhaps a year or two later, the TV station wanted
to start up their own version of skywarn where the general
public was to call in severe weather. Ernie and I were invited
to the initial meeting. After the meeting and tour were
completed, I asked the general manager if it would be possible
for us to continue the project of putting the antenna on their
tower and much to my surprise, he agreed. The TV station also
gave us the use of a run of " Heliax that ends at about 550 ft.
It was previously used and later abandoned by Pepsi-Cola. The TV
station hired a climber to install the antenna for us. This all
happened within about a month after my finally getting approval.
The Willoughby input was just installed in the summer of 2000.
It fills in the places on the east side where the old downtown
input used to cover.
In 2002 the Shenago(Greenville Pa) receiver was installed on
AL7OP Dave Firis's Tower. It is an ex-western Union tower as
well, its receive antenna is shared with KE3JP 6 meter dipole at
the 275Ft spot and hears quite well.
Finally, as part of the changes employed in 2003-4, I redesigned
the DPL connection to the link receivers and eliminated the
code/inverted code problem. I also made carrier boards for each
of two DPL decode boards and mounted all of them in an old
Motrac base station control shelf. They were previously mounted
on 5-each small mother boards in the rear of the cabinet. Part
of the addition was to also include an LED to indicate correct
decoding of each respective DPL.
In the Fall 2004 after having lots of trouble with reflected
power on the main transmitter antennas when it rained, I decided
to replace them with Decibel Products DB212's. Since the feed
point insulators are at the 50-ohm instead of a high-impedance
point, they seemed to be the best choice. It is an antenna that
has been around for probably more than 50 years and the design
seems solid. So up went the new antennas. Unfortunately, when
they were being installed, I was short an ‘N' barrel. On the
following day, the steeplejacks were informed they had to
quickly finish what they were doing here and derig the tower so
they connected my antennas and left the site. When I arrived in
the afternoon after work to try the new antennas, I found they,
at the transmitter had about 80 watts reflected with 1350
forward which is absolutely unacceptable. This probably equates
to 800 forward and maybe 125 reflected at the top. It turned out
to be a defective wattmeter slug and the antenna was fine.
The other project of the fall/winter of 2004,5 has been to try
to finally get to the bottom of the problem with the Spectra Tac
voter. I've had some help from N8XUA since he has had some of
the same problems I have with the 146.76 repeater of WA3USH.
Both of us have taken lots and lots of data but haven't come up
with the secret as to why there are some receivers that vote
when they shouldn't. After lots of experimenting between N8XUA
and myself; we found a number of things that corrected the mis-voting
problem. The one fix that stands out the most is to lower the
repeat audio level on the links to keep the audio from being
compressed.
After two failures of the demodulator IC in the Micor receiver
in the 444.975 repeater, I decided to make a Mitrek into a
repeater. Mounted in a Motorola 40-inch cabinet are all the
parts of the repeater including a continuous duty power supply,
the telemetry transmitter, all of the repeater control
circuitry, and two cavities and two Micor circulators to combine
the RF onto one antenna. The PA circuitry in this radio is also
mounted in a very large external heat sink and has
thermostatically controlled fans and a heat limit snap action
switch.
In the summer of 2006 the Lisbon Input had to be moved due to
the Columbiana County EMA building being moved. It is now on a
Tower with much better coverage.
Also in the summer of 2006 an input was added in the Canton Ohio
Area.
November 2006: after a long period of time having no input in
downtown Cleveland, Bob Winston finally received permission for
us to install an input on top of the Standard building (where he
works). AL7OP, N8XUA and myself installed it on a very sunny
November day. It isn't the highest building but at 20 floors is
no slouch either and it gives us a site.
June 2007: A decision to add an input in Meadville has surfaced
on the WMVL 101.7 Transmitter tower.
Fall 2007: The batteries at the radio station were finally
degrading past the point of usability. N8XUA was able to acquire
8 2V 600AH Communication Site batteries that were only about 8
years old and in good shape. I made a new shelf system to put
the cells in and they were installed inside the blockhouse and
the old batteries were decommissioned.
At the present, the system has 18 receivers and the main
Transmitter has been in the same location for over 20 years. The
system covers (with a 100W mobile) from 30 miles east of Toledo,
Ohio all the way across Ohio through Pennsylvania to the NY Line
and as far as 30 miles south of Mansfield Ohio. In a nutshell it
covers the entire NWS Cleveland area and then some. It is a
closed system and only open to authorized operators.
The following are trademarks of Motorola, Inc: Unichannel,
Spectra TAC, Motrac, Mocom 70, Micor, MSF5000, PL, DPL, Mitrek,
Extender
The following are trademarks Of General Electric: Mastr
Imperial, Mastr Pro, PR
The following is a trademark of Chicago Lock: ACE
The following is a trademark of Andrew Corp.: Heliax
The following is a trademark of Bell Telephone Labs: Touch-Tone.
