P. C. Electronics 2522 Paxson Lane Arcadia CA 91007-8537 USA (c) 2013

Tom (W6ORG) & Mary Ann (WB6YSS) Tel: (626) 447-4565 m-th 8am-5pm pst (UTC - 8)

Web site: www.hamtv.com Email: ATVinfo @ hamtv.com

THINKING ABOUT PUTTING UP AN ATV REPEATER?

HERE ARE SOME THINGSTO THINK ABOUT BEFORE

SPENDING ANY MONEYThere is no denying the ego boost

of being able to say that you puttogether a repeater, are the owner, orthat it carries your call. And sure youwill get a lot of verbal encouragementfrom the local ATVers for you to do it.

Most repeater owners or builders Ihave talked with over the years havetold me their club or group at first wasall for it with promises of money andhelp. But when it came down to it thathelp disappeared or each had differentideas about how it would be configuredor placed. It usually ends up with oneor two people doing all the work.

So the first thing I suggest is to planit all out and then have everyone thatis going to be involved have their part,whether it is building something, buyinga part or just giving funds, defined onpaper. Discuss it all and select asystems manager to see thateverything comes together in a timelymanner, and a technical manager whomakes sure the right components areselected and go together properly.Have each person initial or sign for hispart of the project so that there is nomiss-understanding months later as towho was supposed to do what andwhen.

Things will change over the courseof the project, and as they do thesystem manager can up date thetasksand keep everybody informed as to

By Tom O’Hara, W6ORG © 2005

progress and what is needed.When you nail people down like

this you quickly separate the talkersfrom the doers.

THE SITEThe most important decision after

you have all the players is to select therepeater site. Chances are that thehighest and best coverage spotalready has repeaters on it by otheramateurs, business, government, etc.A meeting with the site manager orowner should be set up with only thesystem manager and technicalmanager to find out the rental costs,are there U.S. Forestry or BLM permitsrequired, what are the frequencies andpower output of other systems thatmight be of interference potential, siteaccess restrictions, technicalrequirements, antenna type andplacement, coax or hardline length,rack space, etc.

Decide if you are going inband orcrossband repeat and horizontal orvertical antenna polarization. Have ameeting with your areas frequencycoordination council and discuss thealternatives with them. Coordinationis done by site and it’s area of coveragewhich has the most effect oninterference probabilities. Keep itfriendly and technical. It may takemore than one meeting and sometesting.

An inband will be the hardest tocoordinate due to taking up so muchspectrum. See page six for info about

the different considerations in the 420-450 MHz band plan. Take it with youto the meeting. Remember you willneed at least 12 MHz frequencyseparation in order for the VSB filtersto do their job. I suggest 421.25 outputand either 434.0 or 439.25 input.

Crossband has the benefits oftaking only one channel on 70cm foran input, and leaving the other forsimplex and DX. Low in and high outgives the most performance and leastcost to your users because it is veryeasy to put a preamp at the antennato save the higher feed line loss withfrequency than a transmitter and amp.Most existing ATVers will have a 70cmtransmitter for simplex and DX and willjust have to add a downconverter andantenna which is much less cost thana whole new transmitter and hard line.Transmitting equipment costs go upgreatly with frequency.

The other benefits are users beingable to see their own video comingback for more accurate video gain,lighting, and focus adjustments andother testing when no one else isaround. It is also easier to sell to thefrequency coordinators. The optimumfrequencies as far as harmonicrelationship and other economic andcoordination considerations is 426.25in and 923.25 or 1253.25 out.

As you can see there are a lot ofdetails to be worked and planned outbefore the first piece of equipment isbought. I generally tell people to planon about $3000 on the average beforethey have a good working machine,and not to just try to get by with whatis in the junk box or could be throwntogether especially if it is at a sharedelectronic site - see pages 9 and 10.

The biggest cost will be for thehard line, antennas, and vestigialsideband filters. These items will beof most interest to the site owner asfar as physical placement and anytechnical requirements. Thetransmitter, receiver, power supply,VOR and ID are actually the easiestto place and take up the least room.

W6ATN OAT Mountain CA 434.0 & 2442 in / 923.25 out ATV Repeater Site

1

CHECK IT OUT The next step is to make tests atthe planned site to see what thecoverage and interference patternsmight be. I suggest two trips.

The first time to do it is when theother site transmitters are on the air,and the second when convenient to getmost of the ATVers in the area on theair. I know of people who thought theyhad a nice quiet site when they wentup to the hill top on a nice Sundayafternoon with their ATV transceiverand had no problems, but were wipedout by intermods from pagers and RCCtransmitters during normal businesshours. Or the one ATVer who was yourbest supporter has a multipath ghostor building blocking the path.

So make your tests over a longenough period of time during the peakuse segments of the day that the othertransmitters are operating. Get theword out to the local gang about thetest hours, day, ATV frequency and 2meter coordination talk back channelin plenty of time.

Each case of interference is uniqueand the cure can be equally uniquesuch that it would be a large applicationnote on its own. But most often thecause is insufficient filtering andshielding both by the ATV system andother systems at the same site or withina few miles.

You may find some interferencefrom other mode users quite a distanceaway will appear with the antenna nowquite a bit higher in the air than youhave at home. While frequencycoordinators may give you a frequency,it is difficult to accurately predict if adistant link or repeater could be seenat your site. Assuming the site checks out goodand your potential users andsupporters are happy with the signalstrength from your test transmissionsat the site, you are ready to startbuilding the machine.

FILTERS AND CABLEThe longest lead item is usually the

VSB filters and should be ordered first.I suggest two good sources: TX RXSystems for inband duplexers, orindividual filters, and DCI for good low(1 dB) insertion loss and low cost VSBfilters. These filters are absolutelynecessary in the antenna lines of boththe transmitter and the receiver. A lowpass filter is necessary in the receiveline since VSB filters pass the 3rdharmonic - Mini-Circuits Lab NLP-550.

Next is feed line. All coax needsto have 100% shielding both down from

the antenna as well as allinterconnects. RG55 double shielded50 Ohm coax is good for interconnects- While mandatory between the filtersand the transmitter and receiverantenna ports, it includes short video,audio, control and DC power lines.

With the antenna line you haveperformance verses costconsiderations. The best line to theantenna would be 1" copper hard linedown to Belden 9913 depending on thelength you need to run. Up to 100 ft,9913 at 2.7 dB loss per hundred feet isnot too bad. Over 100 feet on 70 cmor on 33 and 23 cm, the largest copperhardline you can afford to keep the lossdown to 2-3 dB is the way to go.

Use one continuous run and typeN connectors to minimize moisturecontamination or connector losses. Ido not suggest aluminum hard line asthe shield often oxidizes and loosensat the connectors from moisture andwind vibration (job security for manycable company maintenancepersonnel).

Route the cable separated fromother cables as much as possible,especially the receive, to minimizecross talk. After you verify all is wellwith a power meter check at both thetransmitter and load ends of the cable,weather proof all outside connectorswith coax seal or 2 layers of vinylelectrical tape. Secure the cable upthe tower at different distances tominimize mechanical resonances thatcan occur in high wind conditions.

ANTENNASMost all repeater antennas are

intended to be omni directional. Theywill probably only be omni if yourantenna is the one in the clear on top.But at any shared electronic site yourswill be one out of many at the antennafarm. You may not have manymounting options that would not greatlyaffect the antenna omni pattern.

All you can do is to try to stick itout 2 or more wavelengths from anyother metal supports or antennas onan arm. This is another reason to knowwhat frequency your neighbors are onso you can have the most verticalseparation from those closest to yourfrequency.

Think of the worst storm in yourarea you can remember, add manypounds of ice, and then solidly mountyour antenna to the structure with thatin mind....plus keep your fingerscrossed! Support the antenna with across arm not only at the bottom, but

an insulated one at the top.When the repeater antenna and

coax is installed it is not a bad idea tocheck out the coverage again, just tosee if the mounting didn’t happen to puta null right toward the meanest mostvocal ATVer in the area. Moving themounting a few inches can oftenchange the pattern to a new set ofconditions.

With all omni antennas, vertical orhorizontally polarized, the higher thegain, the narrower the vertical beamwidth. This could be a problem for thoseclose to the repeater if the site is 500 ftor more above the average terrain. Thecure would be a down tilt antenna(usually the resonant length is justabove the transmitting frequency for thedown tilt) or a lower gain and thereforebroader beamwidth antenna. Antennaplacement again could be the cause byputting a null right at the wrong guy(another one of Murphies laws). Yougenerally want the highest gain at thehorizon in the vertical lobe for DX. Thesignal is usually still quite strong closein such that the vertical lobe gain rolloff at large angles below the horizonwill still give a snow free picture.

Commercial sites may require morerugged commercial antennas than theusual amateur types. TelewaveANT450D6-9, DB Products DB420 andothers make 70cm 6 to 10 dBdbroadband exposed dipole type verticalomnis for single antenna & duplexersystems. Diamond has a 9.3 dBdvertical stick (F-718) with 3 models tocover 10 MHz segments of the 70 cmband at a relatively low price. Theseare good for 2 antenna inband systems.Lindsay makes the TZU zig zaghorizontal omni for 70 or 23 cm with 4.5dBd gain and they also have a 8 bay70cm version with 9 dBd. Olde AntennaLab quad Big Wheels and HERD Rib-Cage slot horizontal ominis get 6 dBd.The Comet FP20 33cm has10 dBdvertical gain. The F1230 has 11 dBdon 23 cm.2

Exposed Dipole broadband vertical omni

TZU - Zig-Zag horizontalomni (side mounted)

Frequencies and modules will vary depending on inband or crossband repeat. Inband may also use a TX-RX Duplexer to onebroadband antenna instead of two. TheVideo Operated Relay is put in its own CAB247 box with an Intuitive Circuits OSD-ID(PC)video ID board, not in the receiver or transmitter box. The high current power amp must have its own separate power supply. Seemore repeater examples and priced out parts lists on pages 9 and 10.

OK, you have checked out the site,coordinated the frequencies, gotten theantenna(s), feedline and filters, now forthe fun part, the repeater itself.

Repeaters tend to evolve andchange over a few years so a modularapproach makes much more sensethan putting it all in one chassis orenclosure. It also allows changes andadditions to be made easily withouthaving to make many trips to the hilltop to bring the system down to thebench for major surgery. One trip tothe hill to sub or plug in a small modulealso saves the wrath of the flock thathave no patience for down time.

To start, there are 3 basic activemodules: The transmitter, the receiverand the control/ID units. See the blockdiagram. Each should be mounted init’s own completely shielded box withappropriate coaxial connectors forinter-connection. They can be boltedto 19" panels if they are to be put intoa rack at the repeater site.

RTX series TransmitterI like the LMB CU247 diecast

aluminum boxes, but there are othersthat have complete contact along allseams. The shielding is absolutelynecessary to keep your transmitter, andany others near by, from desensing thereceiver. You would be surprised howRF can get through cracks in chassisand less than 100% shields in coax.

It is possible to shield and filtereffectively. I had interference freeweak signal video at my 434 MHz inputrepeater sharing the same building andantenna structure with five 70 cm FMrepeaters and links. Some ATVrepeaters share a site with megawatt

UHF broadcast TV stations.DC lines can be fed thru the chassis

with 500 to 1000 pF feedthru caps.Audio and video lines should be coaxialconnectors with bypass caps mountedright at the connector with as short oflead length as possible. I use 100 pFfor audio lines and video lines. Do notuse beads on video lines.

I suggest double shielded oraluminum foil + braid coax for allinterconnections. Any lead that is not100% shielded and bypassed at theconnector is likely to become a poor butsignificant antenna to conduct unwantedRF into the box.

TRANSMITTER Careful attention must be made toall internal RF connections andconnector assemblies. Any VSWR inthe transmitter that makes the reflectedenergy travel on the outside of the thecoax and over every nook and crannyof the box can reach the receiver.

Many do not realize that a goodVSWR reading outside of the transmitterbox does not mean the interconnectingcoax from the transmitter board to thechassis connector is good. Coaxialintegrity in the receiver is also importantto keep unwanted ground currents fromsneaking inside.

So keep the RF inside the coax asmuch as possible with very short centerconductor and shield leads. It does notmake much sense to pay the bux for agood quality VSB filter to have itbypassed by poor shielding andconstruction practices.

Run RG-58, 55, 6 or 8 coax for theleads to the power supply to minimizepickup or radiationto or from the trans-mitter. You can use the same supply asthe receiver if the transmitter draws 1Amp or less, but all power leads mustconnect directly at the power supply ter-minals, not to a junctionstrip on leadsaway from the supply.

Make sure that all composite video

inputs are resistively terminated in 75Ohms, and that all output waveforms are1 Volt peak to peak with the properbandpass and setup levels at eachmodule. Do not attempt to compensatefor a shortcoming in one module byadjusting another, as it will all change asother video sources are added such asthe ID, TVRO Shuttle video, links, etc.

The RTX transmitters are availablealong with companion amplifiers for 70,33 and 23 cm depending on the bandyou want to output on. The blockdiagram example shows a crossbandrepeater starting with a 923.25 MHzRTX-33 transmitter driving a Downeastamplifier, but you could substitute a RTX-70 driving a 50 or 100 watt amp or a RTX-23 driving the Downeast amp forcrossband output or link.

AMPLIFIERSCloser attention must be paid to

driving amplifiers within their linear regionwith repeaters than the home station.Any non-linearities, intermods, incorrectsetups by the users stations will bemultiplied by those present through therepeater. Another factor is the possibilityof 100% duty cycle and continuousunattended operation.

For reliability reasons the amplifiersare purposely run at 90% of the peakpower capability for best linearity. Therepeater version of many amplifers areconstructed as a 19" rack panel that isall heat sink and or have a fan.

But more important, the sync tip isset to not exceed 90% so that the soundsubcarrier riding on the sync at -15 dBchas the head room to swing just up tobut not exceed the 100% power level. Ifthe sound gets squashed on the sync tipthere might be some audio buzz added.Likewise, the video gain must be set notto exceed 10% power swing on the whiteareas.

Intermod generation goes up athigher power swings which raises thesideband noise and video modulationproducts such that the VSB filters will not3

TVC-2GTVCS-2syn conv

IF/ATVreceiverRG55 coax

between units

434.0 MHz ATVR-4 Receiver

9913coax

omniantenna

audiovideo

Downeast

omniantenna

9913coax

+13.8vdc

Transmitter 923.25 MHz

@3.5 Amps

20 watt 70cm/33cm Crossband ATV REPEATER or LINK block diagram - Example

3310PAAmp

RTX-33

+tx

xmtr

Control

VRC45bDiecast Aluminum Box

+13.8 Vdc @ 1A

DCI 8 poleVSB Filter

DCI 8 poleVSB Filter

X510NJFP20

LowPass

Min i-CktNLP-550 KPA5

exciter

VOR

Video IDerOSD(PC)

VOR-3

CAB247 Diecast alum.Box

be able to reject them enough to keepthem out of the repeater receiver.

Also it is desirable to run the colorburst down at a level that does not gettoo far into the amplifiers compressionlevel. If each amplifier starting at theusers transmitter and amp up throughthe repeaters receiver and ampcompresses or rolls off the color bursta little it will add up to loss of color onall but the strongest stations.

So it is better to underdrive arepeater amp than over drive it formany reasons. If need be in the caseof overdrive, the insertion loss of anadditional bandpass filter, fixed coaxattenuator or long length of doubleshielded coax can be used at thelowest level to insure linearity. The RTX transmitters 1.5 Watts pepwill properly drive the recommendedamplifiers without attenuation and nearpeak power capability. But if the TXA5-70d/PA5 20 Watt module system isused to drive a Mirage D1010ATVN-R, follow the final amp p.e.p. output andpedestal setup proceedure to drop thepower down to the linear range. Theadjustments are on the TXA5-70dboard. An additional VSB filter isrequired between the duplexer andD1010NR for a single antenna inbandrepeater system for additional desenseprevention.

Air should be blown across anyrepeater amplifiers fins even if rated for100% duty cycle to insure that heatdoes not build-up especially in acabinet.

The Mirage repeater amplifiers donot have any filtering on the 13.8 Vdcpower leads. They can act as antennasto pick up stray radiation inside the ampshield and re-radiate it outside to causereseiver desense. You can wrap foilaround the leads to help minimizeradiation, or better yet is to mount aSO239 connector on the chassis afterpunching the the red lead hole out to5/8” dia. and drilling 4 holes for theflange mounting screws. Sand paperthe anodize around the holes for goodground contact. Run the red and blackwires internally to the SO-239connector and add some 100 pFbypass caps with short leads from thecenter red lead pin to the ground lugunder one of the connector mountingscrews that has the black wire solderedto it. Run RG-213 with a PL-259 plug

to the power supply. Any amp drawingmore than 5 Amps should have its ownpower supply and the leads as large andshort as possible.

RECEIVER All ATV repeater receivers should becrystal controlled. Even a temperaturestabilized free running oscillator willslowly change frequency with age, dustaccumulation, oxidation, etc. Once themachine is up and operating well, youprobably will not want to make severaltrips to the hill top to just tweek the LOback on center frequency.

ATVR-4 complete ready to go ATVrepeater receiver

Outputs from the receiver moduleshould be one or two composite videoand one line level audio. The receivercomposite video output standard is 1 Vpeak to peak into 75 Ohms just like it isfor cameras and other video devices. Itis handy to have one video output togo to the transmitter, and another oneto go to a local monitor to aid monitoringand adjustment while at the site. It couldalso go to a crossband repeat or linktransmitter.

The line audio is also about 1 voltpeak to peak but operates into a 10Khigh impedance or 600 Ohm load.Another nice feature is to have the audiosquelched to keep the audio noise downwith the weaker video signals that cankey up the horizontal sync operatedrelay but are not strong enough to quietthe sound. A local speaker amp is alsoof benefit for monitoring at the site. TheATVR series of receivers have all thesefeatures.

Especially for an inband repeater,a separate power supply from the oneused by the transmittermust be used ifthe transmitter draws more than 1 Amp.There could be some conductedinterference on the common powersupply lines, and the final amp varyingload with video modulation could set upa feedback path through the receiver.Run RG-58 coax for the power leaddirectly to the power supply terminals.

I recommend single frequencyconversion directly to the standard 45.75MHz TV IF as in the ATVR receiverrather than to a channel 3 TV receiver.A channel 3 receiver has a free runningLO that can drift, and also more possiblesystem mix and image products fromstrong near-by transmitters.

The 45.75 MHz TV IF SAW filtersare made to favor the lower vestigialsideband. To properly receive thestandard upper VSB, the local oscillatorin TV tuners is above the receiver inputfrequency to invert the VSB. So if youhave a downconverter for channel 3, itis not just a simple matter of moving thelocal oscillator up 15.5 MHz to outputon 45.75 MHz instead of 61.25 MHz. Itactually has to be moved up to 107MHz.

Many new repeater receiversystems start out having way too muchsystem gain which ends up beingswamped by the stronger ATV stationsand makes it more susceptible tointermodsand desense cycling.

Total receiver gain should be justenough to start the video AGC voltageto move on noise. Any more gain doesnot improve sensitivity, it just pumps upthe AGC with the amplified noise floor.Adding preamps ahead of a goodpreamp in the downconverter most oftendoes not improve sensitivity but rathergives more intermod interferenceproduced in the overloaded first mixeror following stages.

To check your system just measurethe video IF AGC dc Voltage, not theRF or delayed AGC, with thedownconverter turned off and then seeif it changes much when turned back on.Ideally the voltage change should beslight assuming no signal input andproperly terminated.

The noise floor in most TV receiversis no better than 10 microvolts due tothe noise power floor with the 3 MHz 3dB bandwidth of the video luminenceamplifiers to minimize intermod with the3.58 MHz color amplifiers. The preampstage should have the best noise figuredevice possible to get as close to the 1uV as you can. But you may have todump some gain with resistiveattenuation between the downconverterand the receiver to also have widedynamic range.

You want to get the weakest signalsbut at the same time be able to4

accommodate that guy 2 miles awaywho won ’t turn off his 100 Wattafterburner and wonders why therepeater picture is rolling and distortedfrom clipping. The RF or delayed AGCwhich controls the preamp gainis setto start between 150 and 200microvolts. This level is consideredsnow free, or P5, for ATV.

ID AND CONTROLFM voice repeaters key by means

of a carrier operated relay from limitercurrent or squelch, or by sub-audibletone (CTCSS) decoder. The same canbe done with ATV, but with the wideband nature of video and all the othermodes that can get into the passband,a video operated relay is morecommonly used.

A video operated relay (VOR)looks for valid horizontal sync out of async separator. The probability of falsekeying from radar, voice or digitalmodes is low since the signals mustfirst go through a sync separator andthen a tone decoder at 15734 Hz. Tofurther protect from unwanted signalcapture, a time delay of a second orso of valid horizontal sync can bedesigned in before keying the actualrelay that applies the voltage to thetransmitter exciter. DC power to thefinal amplifier is left on at all times.

The PC Electronics VOR-3 orATVC-4 board have an exciter B+relay, timers and another relay forswitching between the received videoand a video ID or to key a MCW ID(Comm. Spec. ID-8) to meet legalrequirements. You must identify withlegible letters in the video or by audiowithin every 10 minutes of continuousand at the end of a transmission(97.119). The OSD-ID board willgenerate an ID video and/or the ATVC-4 controller board has a MCW ID.

While the FCC rules used to saythat a repeater must turn off within 5seconds, it was a common practicebefore as is now to keep the video IDand repeater transmitter on for 5 to 30seconds after some one dropped theirtransmitter in order to have some videosignal to tune their receivers or aligntheir beams to.

Some illegally have video ID orother locally generated video turned onby anyones two meter tones. FCCrules forbid primary control below

220.5 MHz. One possible way aroundthat is to also repeat the 2 meter audioon the sound subcarrier in which caseit is a crossband repeater in the samemode and the video secondary.

Turning on the ATV repeatertransmitter with video ID by a timer withno one inputting to the machine(beacon mode) is also illegalbelow 902MHz. These are grey areas that areusually not challenged but, you as arepeater owner should be aware.

SOME WHISTLES AND BELLSOnce the basic machine is up and

running, the real fun begins by addingsome additional functions.

Mixing in the local 2 meter ATVcalling frequency at about half theincoming ATV sound level helpseverybody hear those that are onopposite sides of the hilltop or too faraway for normal 2 meter simplexcommunications or for repeaters thatare not co-located. The IntuitiveCircuits ATVC-4 can mix 4 audios plusthe remote control audio, scan or selectup to 4 video inputs - Space Shuttle,weather radar, links from other ATVrepeaters, video S-meter from theOSD-SSM board, remote camera, - dothe ID timing and switch in the on boardMCW ID or external video ID. Both theVOR-3 and the ATVC-4 have a beaconmode where you can transmit the videoID every 10 minutes for testing or DXpurposes.

The OSD series of video overlayboards canboth ID as well as give othertext info about the repeater.

The DTMF-8 Controller Board has8 relay outputs which should be morethan enough to switch relays for variousvideo and audio sources and evenspecial modes for camera pan and tilt.You can parallel as many DTMF-8’s asyou want with their own access codes.

I suggest the decoder beconnected to the incoming soundsubcarrier to make it easy for ATVtransmitting stations to use. A timer canbe added to limit the on time if the usersvideo goes away and they forget toreturn it to normal repeat mode.

TWO ANTENNAS VS DUPLEXERThis question is asked a lot by

those about to put up an inband 70 cmrepeater. A crossband repeater has

such freguency separation that simplersingle bandpass filters in each antennaline may be good enough, but an inbandATV repeater has much tougherrequirements.

The broadband noise out of an ampwith just carrier is probably no betterthan 70 dB. Add to that the video sourcenoise at 40 dB additionally rolled off bythe video modulator, amp intermod andsideband harmonics and you have a lotof energy next door waiting to go intoyour 1 to 2 microvolt receiver.

If you have a 100 Watt amp, thepeak power is 157 dB above amicrovolt. Depending on what theactual transmitter noise and videosideband harmonic level are from allcauses at the receiver passband, theVSB filter on the transmit antenna linehas to knockall that noise andsidebands down to below one microvolt.

Also the receiver VSB filter has toknock the transmitter carrier as well assideband power down to at least 1/10milliwatt (70 dB below 100 Watts) so asnot to overload or intermod with thedownconverter preamp or mixer. This is a tall order for a filter with lowinsertion loss and a flat 6 MHzbandpass. A good quality VSB filter has80 to 100 dB of rejection 12 MHz away.It also means no leakage from poorshielding or coax around the filters. TheTX-RX Systems 26-66-01A Duplexer orthe individual DCI 8 or 10 pole VSBfilters do a good job with less than 1.2dB insertion loss. But we still need atleast 50 dB more attenuation to preventoverload or desense.

With a two antenna system youneed vertical separation. Regardlessof polarization, an omni will have aminimum field above and below it. Thehigher the gain the greater the isolationat the same distance, since the verticallobe is narrowed. For the old PhelpsDodge 10 dB stick Station Masters, 20ft end to end gave about 50 dB at 450.

If your antenna is less than 10 dBd,but you don’t have much room on thetower to get added separation, tryfinding a magic null point. Fix thetransmitting antenna at its location onthe tower and transmit. Connect aspectrum analyzer or other calibratedsignal strength device to the receivercoax without the VSB filter. Havesomeone slowly move the receiveantenna up and down on the tower to5

find a minimum point and lock it inplace.

With the TX-RX 70 cm duplexerto a single broadband antenna,another VSB filter from DCI or SI canbe put in the line between the duplexerand amp to get the added rejection. Ifyou have excess drive you can tryputting the filter between thetransmitter and amplifier, but theamplifier IM products may exceed the50 dB requirement. In either case donot over drive or over modulate, or elsethe sideband harmonics may captureyour receiver and make it cyclebetween the video ID and noise.

70 CM ATV FREQUENCYSELECTION CONSIDERATIONS

Here are some pros and cons toconsider when determining the ATVbandplan for your area. Only 2frequencies can be used for ATVwithout a high probability of mutualinterference as well asto leave plentyof space for other modes. The choicemust also be made between an inbandrepeater with simplex shared on therepeater input or output, or a repeaterinput with crossband output and aseparate simplex channel.

421.25 MHzThis is most used output for

repeaters and requires a VSB filter inthe antenna line of every transmitterto keep sidebands and final generatedintermods from interfering outside theamateur band below 420 MHz. Thechannel occupies 420 to 426.0 MHzand corresponds to cable channel 57.It is listed in ARRL bandplan for ATVrepeater or simplex, but shared withcontrol links and experimental. Irecommend it for repeater outputs only,since the VSB filter requirement foreach user is impractical.

FM or packet links, control, etc. canthen use 426.0 to 431.0 with 3 MHzchannel splits. This gives 80 duplex25 kHz channels and 40 simplexchannels or less combinations withsome multiple adjacent channels usedfor higher baud rate or voice fidelity.Packet can use 431.0 to 431.6.

426.25This is the most popular simplex

or secondary channel. Half of all ourtransmitters sold to date have had thisfrequency requested. There has been

least interference noted on this channelin the lightly populated areas. Mostused by state and local governmentamateur radio emergency groups, R/Cmodelers, robots, and special purposevideo links.

426.25 MHz is uggested as a goodcrossband repeater input, howeverother mode users at the bottom of theband should be high in low out near thesame site to prevent overload.

Sometimes 426.25 is used as arepeater input for crossband or when439.25 is used as an output in active440 FM areas.

The channel bandwidth is 425.0 to431.0 MHz. Other modeswould occuply420 to 425 MHz. Channels at 421.75and 422.67 +/- 200 kHz (32 NBFMchannels out of the 120 possible)should be assigned last when all othershave been filled, and only at which timeVSB filtering would be required of thosehaving enough LSB color or soundsubcarrier power to actually causeinterference.

427.25 MHzUsed in a few areas instead of

426.25 because it corresponds to cablechannel 58. Listed in ARRL band plansolely for ATV simplex, not shared.However, 426.25 was preferred to mini-mize possibility of the 427.25 soundsubcarrier at 431.75 from overloadingany near by 432.0 weak signal or EMEreceivers. Today modern narrowbandweak signal receivers generally haveenough dynamic range and rejection.Occupied bandwidth is 426.0 to 432.0.

This channel would give 40 more25 kHz channels (total of 120 from 420-426 MHz) for FM Voice links with 422.75and 423.67 +/- 200 kHz to be skipped.

434.0 MHz It ’s the most popular input

frequency to switch to when local FMrepeaters fill in below 444.0 or use highin/low out in areas using 439.25 ATV.This frees up to 200 FM voice repeaterchannels from 440 to 450 MHz. 433.25MHz, cable channel 59, would havebeen the logical choice, but weak signalusers were concerned about sidebandenergy at 432.0. While this frequencyuses 432.75 to 438.75. Experimentsshowed most energy down ≥40 dB andrandom at any one spot frequency 1MHz from the video carrier. This is

below the FCC bandwidth definition ofbandwidth (-26 dB) so technically doesnot violate the repeater prohibition in the435-438 satellite segment. Verticalpolarization also minimizes energy to432 MHz DXers who are horizontal.

FMinks would be located between438.7 and 440.0 MHz instead of 433 to435 MHz. Simplex packet would be at431.0 to 431.6 MHz.

Experiments with satellite usersshowed no interference between 435 to438 MHz except for one person withina mile with beams pointed right at eachother. However satellite uplink stationsgreatly interfere with video down to -40dBc. Since satellites are not in view forvery long, the convention is when thevideo gets hit with uplink signals, waitfor 15 minutes, and come back laterwhen the pass is over.

Alternately if the video is important,like a public service event, etc., known2 meter calling frequencies are used towork out a temporary schedule on agentlemanly basis. In SouthernCalifornia the Satellite users are on144.144 USB, weak signal operators on144.170 USB, and ATVers 146.43 FM.

Likewise if there is a UHF contestwe give up ATV for that weekend, andin fact we get on and give the contesterssome points.....helps change theirattitude about sharing the band. Theystay off during the Rose Parade andsome of the other public service eventsthe local ATVers do.

439.25 MHzOccupied bandwidthis 438 to 444.0

MHz and corresponds to cable channel60. It’s the most popular frequency eastof the Rockies for repeater input or DXsimplex where UHF FM repeaters havenot filled up the 40 25 kHz channels from444.0 to 445.0 or are high in/low out.Some use 439.25 for repeater outputand 426.25 as an input if UHF FM re-peaters give too much interference and434.0 is not available. It is the only frequency available tothose in Canada or above the A line perthe ARRL band plan. Some have used434.6 DSB or 434.0 VSB or withoutsound subcarrier in Canada. Also somerepeater inputs have favored the lowerVSB instead of the upper, when unableto get FM repeaters to stay above 444.0.

439.25 is listed as an ATV repeaterinput in the ARRL Repeater Directory

6

70 cm band plan. However 442-445 isalso shown as FM repeater inputs oroutputs. This is incompatible as FMwill tear up a video signal if below 444and a video signal will interfere with FMif on 442.83 or 433.75 +/- 200 kHz,the color and sound subcarrierfrequencies. But this is what you getwhen ATVers do not take an active andtechnical part in the band planning andspectrum management.

Optimum FM repeater offset wouldbe low in and high out to keep anynearby or at the same site FMtransmitters from overloading the ATVrepeater receiver, even with a goodVSB filter. Since there is likely to beso few ATV repeaters in any given area,those FM repeaters closest or at thesite should be placed as high in theband as possible. Use of CTCSS byall FM repeaters is recommended.

CROSSBAND REPEATERThe 33 cm band (902-928 MHz)DX

is roughly half that of the the distanceslisted on the 70 cm table. While thismakes an inband 70 cm machine lookmore desirable, the 6 dB difference canbe compensated for with the smaller,higher gain antennas and antennamounted preamp by the users.

A crossband repeater with itsoutput on 33 or 23 cm, although havingmore path loss than 70 cm, may stillbe well within the antenna height RFhorizons for snow free pictures withinyour coverage area. The benefit offreeing up the other 70 cm ATV channelfor simplex and users being able to seetheir own video coming back is wellworth serious consideration.

23 cm(1240-1300 MHz) issuggested over 33 cm in the morepopulated areas since amateurs sharethis band with many other services thathave priority such as vehicle location.

Cross-banding makes it easier tolink into adjacent repeater areas. Ifyour area outputs on 33 cm and theadjacent one on 23 cm, than all that isnecessary to link is a receiver on theothers frequency. The video can beselected via tone control to repeat the70 cm receiver or the adjacent areasrepeater outputs receiver. Another selectable crossbandreceiver can also be used for specialpurpose links to bring in Space Shuttlevideo from someone’s TVRO, weather

radar video, or other public service eventthat needs to be keyed in for longperiods without chance of some oneaccidently coming up on the normalrepeater input.

ATV REPEATER DXWhile it is almost impossible to

predict actual ATV DX due to differentterrain and conditions, the line of sightsnow free picture distance can becalculated given all the controllablefactors. We must know the transmitterpeak envelope power (p.e.p. - sync tip),coax loss, and antenna gain over adipole. At the receive end, we must alsoknow the system noise figure andbandwidth. The chart assumes noantenna obstructions between them,TVC-4G GaAsfet downconverter, orTC70 Transceiver connected to a goodTV set with 3 MHz IF bandwidth, 3 dBloss in coax at both ends, and snow freedefined as a carrier to noise ratio of 40dB (about 200 microvolts). The distances in miles are shown inthe order of 1/20/50/100 Watts which isthe RTX70-1 by itself, RTC-70S (20W),RTX70-1 driving a Mirage D26N (50Watt) or Mirage D100ATVNR (100 Watt)linear amp. To find the possible DXunder line of sight conditions find yourantenna model or equivalent gainacross the top. Then go down to thereceive ends antenna or gain. Nowread the miles that corresponds toyour transmit power.

The purpose of the DX chart is toenable you to better figure what isneeded in your system to have the bestchance of getting good pictures whereyou want them. This is especiallyimportant to repeater owners or thosesetting up for a public service event tofigure the expected area of coverage.

The Diamond F-718 antenna usedon two antenna in-band machines is anexample of a popular high gainbroadband omni vertical that is used for

inband repeaters with a duplexer or atbase stations. The DB Products DB420exposed multiple dipole array is closeenough in gain also for comparison. Ifa repeater is running 50 Watts to aDB420 or F718 omni, it could besnowfree to a station 56* miles awayusing a 5L-70cm beam. Distance willdouble or half with each 6 dB change.

There is no accurate way to figurenon line of sight conditions due toobstructions or terrain. Differentstructures and foliage have differentattenuations at different frequencies. Ihave measured 20 dB of changedropping just 5 ft below the top of aWalnut tree 50 ft from the antenna. Icould still see the repeater through theleaves and branches.

Normal RF horizon if the land wereperfectly flat is only 10 miles from thetop of a 50 ft tower. If raised to 100 ft itgoes to 14.1 miles. If you are luckyenough to have a 5000 ft above averageterrain mountain top to put your machineon, the horizon is now 100 miles. Thedistance in miles equals the square rootof twice the height in feet. For more infosee the 1986-94ARRL Handbookchapter 22 or 94-02 books pg 21.20.

This means that the line of sightcalculations are valid, assuming noobstructions, if the sum of the repeatersRF horizon and the users RF horizonare equal to or less than the distancesshown on the table.

Temperature inversion ducting canmake UHF signals skip almost like HFones giving DX many hundreds of miles.However if the repeater antenna is ona hill top that is above the inversionlayer, it can act as a lossy barrier. Besttime for inversions is around sunset inearly summer, but conditions vary in allparts of the country.

The 70cm 420-450 MHz distance miles are in the order of 1.5/20/50/100Watts.

TRANSMIT 0 dBd 9 dBd 16 dBdDipole Diamond DSFO-25

F718L beamRECEIVEDIPOLE 0 dBd .9/3.4/5.5/7.7 2.4/8.5/14/20 6/21/34/48

5L-70cm 8dBd 2.3/8/13/19 6/22/36/50 14/53/84/120

DSFO-25 16dBd 6/21/34/48 15/56*/88/126 37/133/210/300

7

33cm 902-928 MHzband will be half the70cm distances, and23cm 1/3.

Distances are line fosight, P5 snow freepictures. For P4pictures multiply thedistances by 2, P3 by4, etc.

23CM BAND PLAN & USAGE

Experimental

Satellite

Digital

Weak Signal

Point to PointLinks

NBFM & Repeaters

ATV

DX, EME, SSB

1 2 6 0 - 7 0 1288- 94

1 2 6 0 - 7 0

1248- 52 1 2 9 7 - 0 0

1 2 4 6 - 4 8 1 2 5 8 - 6 0

1270- 76 1282- 88

1241 .25 1253 .25 1 2 6 5 . 0 1277 .25 1289 .25CH1 CH2 Simplex CH3 Simplex

1 2 4 0 1 2 5 0 1 2 6 0 1 2 7 0 1 2 8 0 1 2 9 0 1 3 0 0MHZ

inputs outputs

1 2 9 5 - 9 7

1 2 9 4 - 9 5

Simplex

Ch 1,2,3 RPT

12 mHz split25 kHz channels

Weak Signal: CW, SSB, SSTV, FAX, ACSB, & narrow band experimental. No FM. 1296.1 SSB Calling.FM Simplex Calling: 1294.500.Novice SSB Calling: 1294.900 (1294.8-1295.0).Packet Calling: 1294.100 (1294.0-1294.2).Remote base simplex calling: 1294.700.

1 2 9 4 . 1Packet calling1294.100

May vary in different areas, check with your local Frequency Coordination Council

23cm Snow free line of sight Miles per 1/18/35/100 Wattsomni beam

XMIT. 0 dBd 10 dBd 16.3 dBdDipole Diamond F1230 2424LYRM

REC.Dipole .4/1.6/2.5/4 1/4/6/10 2/8/11/20

Diamond F1230 1/4/6/10 2.3/10/14/24 5/20/28/50

2424LYRM 2/8/11/20 5/20/*28/50 10/42/59/100Similar to the 70 cm example, the

snow free line of sight DX of a 1253.25MHz crossband repeater outputrunning 35 Watts from a RTX-23 drivinga Downeast amp to a 10 dB omni willget *28 miles snow free P5 pictures tosomeone using the 24 element, 6 ftlong loop Yagi. The RF horizons wouldjust make it if the two towers were at100 ft each or more likely the repeaterat or above 200 ft and the user at 50 ft.

If you still had line of sight past 28miles to the repeater, you cound getP4 pictures up to twice that distance.8 of the Southern California repeatersare crossband to 23cm with goodpictures over 100 miles. The 6000'mountain range with all the repeatersites on the tops really help.

Some of the 23 cm SouthernCalifornia ATV repeaters are linked to

their adjacent 33 cm neighbors via 2.4GHz FM ATV. ATN links Las VegasNevada, Los Angeles, San Diego andSanta Barbara California ATVrepeaters together. Plans are to link withPhoenix AZ and Tucson next. The 23 cm band has 5 AM ATVchannels which can be used forcombinations of repeaters, links andsimplex. If FM ATV is desired, it will takeup two of the AM channels at the bottomof the band below 1260 MHz. You willhave to work out shifting of the othermode users with your local coordinator.We suggest 1252 MHz. With 4 MHzvideo deviation and 5.5 MHz sound, theoccupied bandwidth is 19 MHz. 2442MHz FM ATV is also used for repeat orlink using low cost converted part 15license free gear with line of sight DXup to 25 miles running 100 mW. page 8

EQUIPMENT SOURCES

ATV Research - remote camerasBox 620, Dakota City NE 68731(800) 39203922

CMC- Sinclair - 70 cm antennas7020 Hayvenhurst Ave #EVan Nuys CA 91406(818) 994-4455

DB Products - antennasPOB 569610, Dallas TX 75356(214) 631-0310

DCI - 70, 33, 23 and 13 cm VSB filtersPC Electronics (626) 447-4565 orBox 293, 29 Hummingbird BayWhite City, SK, Canada S0G 5B0(800) 563-5351 dci@dci.ca

HERD Elect. Rib-Cage Slot Horz. omni2596 Church Rd, York PA 17404(717) 764-4805

HI-Spec - 100W 33 & 23cm ampsPOB387, Jupiter FL 33468(407) 746-5031

Intuitive Circuits DTMF-8 Decoder,OSD-ID(PC) video IDer, OSD-SSMvideo S-meter and ATVC-4 ATVrepeater controllerP. C. Electronics (626) 447-4565

Lindsay antennas - TZU antenna50 Mary St.Lindsay Ontario Canada K9V 4S7(705) 324-2196

Mini-Circuits Lab - NLP-550 low pass(417) 335-5935

Mouser Electronics - die cast boxes,big catalogue of electronic parts.(800) 346-6873 www.mouser.com

Olde Antenna Lab - Horiz. Big Wheels41541 Dublin Dr, Parker CO 80138(303) 841-1735 W6OAL@aol.com

P.C. Electronics - xmtr, rcvr, ant, etc.2522 Paxson Ln, Arcadia CA 91007(626) 447-4565, fax (626) 447-0489tomsmb@aol.com www.hamtv.com

Telewave - 70 cm antennas1155 Terra BellaMountain View CA 94043(415) 968-4400

TX-RX Systems - VSB duplexers8625 Industrial ParkwayAngola NY 14006(716) 5494700

1/2006

ATV Repeater Cost Examples

PARTS LISTDescription Model # Manufacturer Source CostAntenna 430-440 MHz X510NJ Diamond P. C. Electronics $209Antenna 420-430 MHz F718L Diamond P. C. Electronics $238ATV Receiver 70cm ATVR-4 P. C. Electronics P. C. Electronics $299ATV Transmitter 70cm RTX70-1 P. C. Electronics P. C. Electronics $289Video Operated Control board VOR-3 P. C. Electronics P. C. Electronics $7950W (60 w pep) Linear Amp D26N MFJ/Mirage AES $259.9970cm VSB filter 421.25 MHz DCI-421.25-8C DCI P. C. Electronics $44970cm VSB filter 434.0 MHz DCI-434.0-6C DCI P. C. Electronics $399Die Cast Aluminum box 1590D Hammond Mouser Electronics $24Low Pass inline filter NLP-550 MiniCircuit Lab MiniCircuit Lab $40Power Supply 13.8 Vdc @ 2.5A RS 22-504 Radio Shack Radio Shack $39.99Power Supply 13.8 Vdc @ 20A RS-20M Astron AES $119.9550 Ohm Coax Cable, 250 ft roll 9913 Belden AES $129.95Video Identifier OSD-ID(PC) Intuitive Circuits P. C. Electronics $139 (optional)

Total $2714.88Add about $200 for misc. cables, connectors, hardware etc, and mabe a DTMF decoder/relay board to remotely control thesystem on or off. An Intuitive Circuits ATVC-4 Plus ($349) four input controller can be substituted for the VOR-3 and an oldcamera for the video IDer. You could substitute a Mirage D100ATVR in place of the D26N for 100 watts out . A fan must beadded to the D26N to blow air over the heatsink fins.

PARTS LISTDescription Model # Manufacturer Source CostAntenna 430-440 MHz X510NJ Diamond P. C. Electronics $209Antenna1240-1300 MHz GP21 Comet P. C. Electronics $169ATV Receiver 70cm ATVR-4 P. C. Electronics P. C. Electronics $299ATV Transmitter 23cm RTX23-3 P. C. Electronics P. C. Electronics $399Video Operated Control board VOR-3 P. C. Electronics P. C. Electronics $7940W 23cm Linear Amp 2340PAHS Downeast Micro. Downeast Microwave $40070cm VSB filter 434.0 MHz DCI-434.0-6C DCI P. C. Electronics $39933cm VSB filter 1253.25 MHz DCI-1253.25-6C DCI P. C. Electronics $399Die Cast Aluminum box 1590D Hammond Mouser Electronics $24Low Pass inline filter NLP-550 MiniCircuit Lab MiniCircuit Lab $40Power Supply 13.8 Vdc @ 2.5A RS 22-504 Radio Shack Radio Shack $39.99Power Supply 13.8 Vdc @ 10A RS-12A Astron AES $79.9950 Ohm Coax Cable, 250 ft roll 9913 Belden AES $129.95Video Identifier OSD-ID(PC) Intuitive Circuits P. C. Electronics $139 (optional)

Total $2,805.93AM or FM Transmitters, antennas and filters may be substituted for higher bands. 9 1/2006

P. C. Electronics 2522 Paxson Lane Arcadia CA 91007-8537 USA ©2013

Tel: (626) 447-4565 m-th 8am-5:30pm pst (UTC - 8) Tom (W6ORG) & Mary Ann (WB6YSS)

Web site: www.hamtv.com Email: ATVinfo @ hamtv.com

TVC-2GTVCS-2syn conv

IF/ATVreceiver

RG55 coaxbetween units

434.0 MHz ATVR-4 Receiver

9913coax

9 dBd omniantenna

audiovideo KPA5

exciter

VOR

Mirage/MFJD26N

9 dBd omniantenna

9913coax

+13.8vdc

Transmitter 421.25 MHz

.@20 Amps

1.5 or 50 watt 70cm Inband ATV REPEATER block diagram - Example

optional 50W Amp

ATVR-4

Control

VRC45bDiecast Aluminum Box

+13.8 Vdc @ 1A

DCI 10 poleVSB Filter

DCI 8 poleVSB Filter

X510NA

F718L

LowPass

Mini-CktNLP-550 Video ID

OSD(PC)

CAB247 Diecast alum.Box

PTL +

+13.8 Vdc @ 1A

RTX70-1va 1.5W

TVC-2GTVCS-2syn conv

IF/ATVreceiverRG55 coax

between units

434.0 MHz A TVR-4 Receiver

9913coax

omniantenna

audiovideo

Downeast

omniantenna

9913coax

+13.8vdc

Transmitter 1253.25 MHz

@10 Amps

40 watt 70cm/23cm Crossband ATV REPEATER or LINK block diagram - Example

2340PAHS40 Watt Amp

RTX23-3

+tx

xmtr

Control

VRC45bDiecast Aluminum Box

+13.8 Vdc @ 1A

DCI 8 poleVSB Filter

DCI 8 poleVSB Filter

X510NJU200

LowPass

Mini-CktNLP-550 KPA5

exciter

VOR

Video IDOSD(PC)

VOR-3

CAB247 Diecast alum.Box

P. C. Electronics 2522 Paxson Lane Arcadia CA 91007-8537 USA ©2013

Tel: (626) 447-4565 m-th 8am-5:30pm pst (UTC - 8) Tom (W6ORG) & Mary Ann (WB6YSS)

Web site: www.hamtv.com Email: ATVinfo @ hamtv.com

PARTS LISTDescription Model # Manufacturer Source CostAntenna 430-440 MHz X510NJ Diamond P. C. Electronics $209Antenna 420-430 MHz F718L Diamond P. C. Electronics $238ATV Receiver 70cm ATVR-4 P. C. Electronics P. C. Electronics $299ATV Transmitter 70cm RTC-70-20Sa P. C. Electronics P. C. Electronics $589Video Operated Control board ATVC-4 Plus Intuitive Circuits P. C. Electronics $34970cm VSB filter 421.25 MHz DCI-421.25-8C DCI P. C. Electronics $44970cm VSB filter 434.0 MHz DCI-434.0-6C DCI P. C. Electronics $399Die Cast Aluminum box 1590D Hammond Mouser Electronics $24Low Pass inline filter NLP-550 MiniCircuit Lab MiniCircuit Lab $40Power Supply 13.8 Vdc @ 1A 22-504 Radio Shack Radio Shack 39.99Power Supply 13.8 Vdc @ 5A RS-7A Astron AES $59.9950 Ohm Coax Cable, 250 ft roll 9913 Belden AES $129.95Video Identifier OSD-ID(PC) Intuitive Circuits P. C. Electronics $139 (optional)

Total $2964.93See Source list on page 8 for phone numbers.

Inband 420-450 MHz ATV Repeater Cost Examples cont.

10 1/2006

Remote Tower Mounted Pan and Tilt CameraA camera at the repeater site can show the sky line, local weather

conditions, approaching storms, site intruders, broken antennas andcables, etc. The camera pan and tilt can be controlled by an IntuitiveCircuits DTMF-8 decoder from a receiver audio line - be it the repeaterreceivers sound subcarrier or control receiver. Most pan and tilts runoff of 24VAC and can be controlled by the DTMF decoder throughrelays. If the decoder is mounted in the weather proof enclosure withthe camera all you need to run up the tower is an audio tone controlline, camera video coax and 24VAC. 12 VDC for the camera anddecoder can be recified and filtered from the 24 VAC. Some run thecamera video through a OSD-ID(SA) video IDer and use the towervideo as the repeater ID source. Otherwise another DTMF-8 decoderor ATVC-4 four input ATV repeater controller must be used to switchthe video sources to the transmitter.

ATV Research has the Pelco line of outdoor pan and tilt systemsand weather proof camera housings. For their catalogue of these itemsand cameras call 1-800-392-3922 or see their web sitewww.atvresearch.com

TVC-2GTVCS-2syn conv

IF/ATVreceiverRG55 coax

between units

434.0 MHz ATVR-4 Receiver

9913coax

omniantenna

audiovideo KPA5

exciter

VOR

omniantenna

9913coax

+13.8vdc

Transmitter 421.25 MHz

@5 Amps

20 watt 70cm Inband ATV REPEATER block diagram - Example

ATVC-4

RTC70-20S

PTL

20 WattTransmitter

Control

VRC45bDiecast Aluminum Box

+13.8 Vdc @ 1A

DCI 10 poleVSB Filter

DCI 8 poleVSB Filter

X510XJF718L

LowPass

Min i-CktNLP-550 Video IDer

OSD(PC)

CAB247 Diecast alum.Box

cont.