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Repeater Advice

This forum is for discussions regarding System Infrastructure and Related Equipment. This includes but is not limited to repeaters, base stations, consoles, voters, Voice over IP, system design and implementation, and other related topics.

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KG4LHQ
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Repeater Advice

Postby KG4LHQ » Fri Mar 01, 2013 7:08 pm

Hello guys,

Looking for some discussion in regards to my UHF ham repeater that I am in the process of installing.

The repeater is a Kenwood TKR-851 doing 10 watts going to a repeater amplifier doing 100 watts. The duplexer is a Celwave 526-4-2 tuned with 2db loss to my amateur repeater on 443.325. The site is at a water tower in an outside equipment cabinet with 7/8" hardline going to the top of the city water tower at 145 feet. The only thing I am not sure is the antenna on top of the site. I thought originally that it is a Comet GP-9 but I can not confirm and that information seems MIA. The antenna is not completely straight as it appears to have tilted some. I am in the process of going to switch the antenna to a DB-408 probably done this spring. Anyway, I checked the SWR and seems close to resonant on 443/448 under 1.3. To further test, I connected a service monitor to the repeater with the duplexer and found the repeater opens TX at -120dbm or about .16, I did not test it to see what quieting is. The transmit seems decent but probably with a better antenna would improve but the RX seems sub-average. I was doing some range testing and while I could hear the repeater decent, it could not hear me as I was just static. I FINALLY was able to get into my repeater as soon as I hit the county line of the county where the repeater is. The tower is 145 feet tall, the HAAT of the site is 90 and the ASL is about 850 feet not including the tower. I am stuck on what to do to improve receiving, the repeater has been tuned down to Ham.

I have checked for desense doing the simple test of disabling the TX and do not notice any difference upon enabling....

Help/Thoughts/Advice would be greatly appreciated. Here is a pic of the site.
Last edited by KG4LHQ on Fri Mar 01, 2013 7:20 pm, edited 2 times in total.

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Re: Repeater Advice

Postby KG4LHQ » Fri Mar 01, 2013 7:15 pm

Image

RFguy
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Re: Repeater Advice

Postby RFguy » Fri Mar 01, 2013 7:23 pm

Your repeater is transmitting at 100 watts. How much power is your field unit transmitting? Mobile or portable?

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Fri Mar 01, 2013 7:27 pm

Mobile is 50 watts to a 1/4 wave and a portable of course is 4-5 watts

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escomm
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Re: Repeater Advice

Postby escomm » Fri Mar 01, 2013 8:48 pm

Seems a coverage plot of talk in and talk out are in order to set expectations, from a theoretical perspective at least.

AEC
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Re: Repeater Advice

Postby AEC » Sat Mar 02, 2013 12:50 am

Perform a SINAD test as well as a desense test to be certain you are not your own problem.
2dB is a good loss level overall, but you may have TX noise getting into your receive side of the cans, limiting the actual range of the system.

Note that some of the amateur band 'base' antennas are not well suited for repeater duty, and create P.I.M and do not duplex well in this service.
Of the amateur antennas I have tried with great success, the Hustler G6-440 has always performed very well, and works great as a repeater antenna also.
I have had difficulties with a few Comet products for use as repeater antennas, and returned to the best antenna, the DB-420.
Check your receive sensitivity with the transmitter active and inactive, noting the point in dBm where the receiver opens on both, the differance will be the IMD level you need to eliminate to obatin peak range. This is where notch cavities shine. The best bang for the buck is the Telewave TPRD-4544 BpBr duplexer, this is a 4 cavity design with notch adjustments, simle tuning and easy notching of the transmitter and receiver, keeping one out of the other.
Low SWR does NOT always indicate a properly performing feed/antennas system, it only indicates a good match has been obtained, with nothing indicative of a good transfer of signals to the antenna. I have seen dozens of perfect SWR plots where the analyzer reported a perfect antenna/feed system, but the receiver was deaf to anything but a near field signal. The loss of the cable actually presented a perfect load to the analyzer, and it reported no problems, only issue was that the antenna was still part of the overall system!

Perform a fine tuning of the cans first, get the intercavity noise as low as possible, actually, you should be able to notch out ALL the offending transmitter nose as well as the receiver once you get the main cans aligned, then tweak the notches, and go back to touching up the individual cans.
Doing this a few times, you can normally remove any noise your receiver is detecting from the active transmitter, thereby improving talk-in range and QOS on reception.

Even a dB of transmitter noise passing through to the receive port on your cans will ruin your repeater's range, as well as the noise floor will increase as well.

Once you eliinate ALL the noise from the cans, then you can install a GOOD GaAs FET preamp at the receive port of your duplexer to bring the weak signals being detected, to a higher level froma greater range, as the noise floor will be lower, but the incoming signals will be heard at a far lower level as well, which is the main reason for the preamp to begin with.
Last edited by AEC on Sat Mar 02, 2013 12:34 pm, edited 1 time in total.

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Wowbagger
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Re: Repeater Advice

Postby Wowbagger » Sat Mar 02, 2013 6:55 am

OT: Is that water tower really that tilted? Is this the water tower in Groom? I didn't recall it being that freshly painted.
This is my opinion, not Aeroflex's.

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I AM NOT the Service department: You want official info, manuals, service info, parts, calibration, etc., contact Aeroflex directly, please.

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Bill_G
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Re: Repeater Advice

Postby Bill_G » Sat Mar 02, 2013 7:13 am

Send me the lat and long, and I'll create some plots for you.

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Sat Mar 02, 2013 9:04 am

The water tower isnt tilted but my phone was when I took my pic LOL!

Thanks Bill. I will get them for you.

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Re: Repeater Advice

Postby Bill_G » Sat Mar 02, 2013 10:37 am

You're welcome. Even a rough idea - town and cross streets - will let me Google Earth the lat long.

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Re: Repeater Advice

Postby KG4LHQ » Sat Mar 02, 2013 11:04 am

37-44-14.2 N, 086-25-02.9 W

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Bill_G
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Re: Repeater Advice

Postby Bill_G » Sat Mar 02, 2013 8:02 pm

You have some complex terrain out there. I plotted using the worst case for your portable inbound to the repeater. Between the lumps and the trees, you could probably swing a cat further. We have the same problem here. I put your portable in Fort Knox and looked at the profile. The water tower clears the surrounding terrain and tops of the trees pretty good until you get further out. You get good coverage on all the high spots and poor to bad in all the low spots. To be expected. The color plot has the map centered on the repeater using the values you gave. Red is -120db where you said the squelch closes. Yellow is -120 to -108db area where you can expect anything from usable to good quality signal. Green is greater that -108db.

If you send me a PM with your email addy, I can send you a kmz file of the plot that lets you zoom in on specific areas in Google Earth rather than trying to imagine them on this map overlay.

Image

Image

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Re: Repeater Advice

Postby motorola_otaku » Mon Mar 11, 2013 7:34 pm

AEC wrote:Note that some of the amateur band 'base' antennas are not well suited for repeater duty, and create P.I.M and do not duplex well in this service.

This x100.

...the best antenna, the DB-420.

Also this.

You could also look at it this way: if you're spending big $$$ on a real (i.e. not Hamtronics) repeater, a good duplexer, and big hardline, then why go cheap on the antenna? And don't worry about a 450-470 DB420 antenna having high SWR on 440-450; every one I've ever touched was >2.0 or better, and some had some excellent nulls in the 441-444 range. That goes for the DB413 as well as the 420.
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Re: Repeater Advice

Postby MSS-Dave » Tue Mar 12, 2013 8:53 am

motorola_otaku said......
Quote:
...the best antenna, the DB-420.

Also this.

You could also look at it this way: if you're spending big $$$ on a real (i.e. not Hamtronics) repeater, a good duplexer, and big hardline, then why go cheap on the antenna? And don't worry about a 450-470 DB420 antenna having high SWR on 440-450; every one I've ever touched was >2.0 or better, and some had some excellent nulls in the 441-444 range. That goes for the DB413 as well as the 420.


+100 on this suggestion. Been there, done that. In the end, I have had 20+ year old DB 413 and 420 given to me that are still up and have been hit repetitively by lightning. StationMasters and other fiberglass antennas usually don't do as well. Diamond and Comets even worse, aren't built as good and can create crap loads of intermod in a high RF environment.

I've attached plots of my DB 413 inverted at 1000 ft and the only sweep I have of my DB420 standing up in the front yard. As you can see, SWR is really no issue, would just be the pattern. I have had nothing but spectacular results with these 2 antennas. Try to run a 450-460 fiberglass co-linear antenna out of band this far and the pattern is so screwy you will swear it's broke.

Image
Image
Image

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Tue Mar 12, 2013 10:17 pm

Hello guys,

I have secured a DB-410D antenna (I only have the bottom piece that I'm installing) and show about a 1.3 SWR on where it needs to be but now looking at the top of the tower there doesn't appear to be ANYTHING that I can secure it to on the top other then the vent at the center top of the water tower. Do they make a bracket that will securely hold the antenna w/o worry using the vent? If not is there a mount that I could mount it to the rail of the ladder going to the top? I know its not the best method of mount because the ladder is for human safety not radio antennas but if the city allows it and as little as ANYONE is ever up on the thing then it is an option?

Thanks for all the great advice.

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Re: Repeater Advice

Postby KG4LHQ » Thu Mar 14, 2013 4:21 pm

Better pictures looking for ideas... I had considered getting a bracket and mounting it on the tower vent but I see there is a nice cap over that so not sure if that will hurt my idea or not.

Image
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]Image
Image

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Re: Repeater Advice

Postby Jim202 » Fri Mar 15, 2013 3:22 am

Some one is having a major coverage problem with that leaning antenna. The radiation pattern on the lower side is into the ground and the other side is in the clouds. You may have some luck off the other two sides to get some distance. Bottom line you would be better off with just a 1/4 wave whip up there with the way that antenna is leaning.

As for mounting an antenna to the ladder, I would have a chat with the owners of the tank. Some times they will allow an attachment at the top of the ladder as long as there is nothing sticking out into the climbing area. Another way is to take several tower sections and stand them up against the ladder. Put the tower base on the walkway where the ladder to the top of the tank starts. Clamp the tower to the ladder. This way you have the ability to get up over the top of the tank and don't have to worry about the antenna sticking out into the climb area. It's just a bunch of work to get the needed tower sections up to the top of the tank.

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Re: Repeater Advice

Postby Bill_G » Fri Mar 15, 2013 4:54 am

It's that, or build phasing harnesses, and place three to four antennas around the tank on the handrails with offsets.

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Re: Repeater Advice

Postby SlimBob » Fri Mar 15, 2013 5:16 am

The magic for a 120 degree sector is a 15 or 30 degree negative anhedral angle on the reflector, if you're looking down the top of the antenna. But to pull that off with gain, you'd need something like three DB-224s backed with those troughs, mounted around the tower, and fed with equal-length phase lines so the fields match.

Look and some broadcast antennas or patents and you'll see it.

This approach also appears to work for towers of sufficiently large faces, as well as buildings.

Slot antennas may be another idea, depending on what sort of free time you have.
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KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Fri Mar 15, 2013 6:14 am

Yeah, I would be willing to bet that is my antenna as the other antenna is the road department repeater that I installed as well and it works awesome compared to mine.

I am trying to see if they will let me climb it to see what kind of mount device they have holding these antennas and what I can do to change it to hold a db antenna successfully.

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Re: Repeater Advice

Postby Will » Fri Mar 15, 2013 2:38 pm

This may work for your application:

http://www.comtelcoantennas.com/html/Sh ... Inv_ID=576

I get them custom tuned to frequency, no extra charge.

EDIT: The OP mentioned a directional type antenna to favor one direction.
Last edited by Will on Mon Mar 18, 2013 12:52 pm, edited 1 time in total.

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Fri Mar 15, 2013 7:56 pm

What is that?

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Bill_G
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Re: Repeater Advice

Postby Bill_G » Fri Mar 15, 2013 8:23 pm

It's a sector antenna with a 120 deg beam. It takes three to go around a water tower, building, or large tower that shadows your antenna. Fed with a power splitter or phasing harness. The concept is most commonly applied in cellular (in a different band of course).

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Re: Repeater Advice

Postby Jim202 » Sat Mar 16, 2013 6:30 am

Bill_G wrote:It's a sector antenna with a 120 deg beam. It takes three to go around a water tower, building, or large tower that shadows your antenna. Fed with a power splitter or phasing harness. The concept is most commonly applied in cellular (in a different band of course).


Just remember if your going to use a power splitter, you will only get 1/3 of your TX power going to each antenna. It also works the same on receive, you will only end up with 1/3 of the receive antenna signal coming out of the slitter going to the radio.

Jim

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Re: Repeater Advice

Postby Bill_G » Sat Mar 16, 2013 7:24 am

Jim202 wrote:
Bill_G wrote:It's a sector antenna with a 120 deg beam. It takes three to go around a water tower, building, or large tower that shadows your antenna. Fed with a power splitter or phasing harness. The concept is most commonly applied in cellular (in a different band of course).


Just remember if your going to use a power splitter, you will only get 1/3 of your TX power going to each antenna. It also works the same on receive, you will only end up with 1/3 of the receive antenna signal coming out of the slitter going to the radio.

Jim


Easier to construct and balance though.

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Re: Repeater Advice

Postby KG4LHQ » Sat Mar 16, 2013 2:09 pm

I have been told that the dipole bay antenna that I have will be easy to get up there so all plans go for that DB-410 to go up there.

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Re: Repeater Advice

Postby KG4LHQ » Sat Mar 16, 2013 6:16 pm

What are the boards thoughts on using an epoxy to mount the antenna ontop of the tower?

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Re: Repeater Advice

Postby Bill_G » Sat Mar 16, 2013 6:43 pm

KG4LHQ wrote:What are the boards thoughts on using an epoxy to mount the antenna ontop of the tower?


No.

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Re: Repeater Advice

Postby KG4LHQ » Sat Mar 16, 2013 7:05 pm

The tower climber/company suggested this. I was leary myself.

gtriever
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Re: Repeater Advice

Postby gtriever » Sun Mar 17, 2013 3:10 am

KG4LHQ wrote:Hello guys,

I have secured a DB-410D antenna (I only have the bottom piece that I'm installing) and show about a 1.3 SWR on where it needs to be but now looking at the top of the tower there doesn't appear to be ANYTHING that I can secure it to on the top other then the vent at the center top of the water tower. Do they make a bracket that will securely hold the antenna w/o worry using the vent? If not is there a mount that I could mount it to the rail of the ladder going to the top? I know its not the best method of mount because the ladder is for human safety not radio antennas but if the city allows it and as little as ANYONE is ever up on the thing then it is an option?

Thanks for all the great advice.



Check out the mounting system at this link: Magnemount

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Re: Repeater Advice

Postby Bill_G » Sun Mar 17, 2013 5:20 am

gtriever wrote:
KG4LHQ wrote:Hello guys,

I have secured a DB-410D antenna (I only have the bottom piece that I'm installing) and show about a 1.3 SWR on where it needs to be but now looking at the top of the tower there doesn't appear to be ANYTHING that I can secure it to on the top other then the vent at the center top of the water tower. Do they make a bracket that will securely hold the antenna w/o worry using the vent? If not is there a mount that I could mount it to the rail of the ladder going to the top? I know its not the best method of mount because the ladder is for human safety not radio antennas but if the city allows it and as little as ANYONE is ever up on the thing then it is an option?

Thanks for all the great advice.



Check out the mounting system at this link: Magnemount


Those are cool!

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Re: Repeater Advice

Postby KG4LHQ » Sun Mar 17, 2013 6:44 am

Trust me, I like the magnet idea but 8,000 just for it is way way out of my budget.

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Re: Repeater Advice

Postby FMROB » Sun Mar 17, 2013 6:00 pm

I would have to say that the leaning antenna is prime culprit. Your signal will work great for aircraft or the mining company, lol. As a side note, I would never even think about using a ham grade antenna for any installation above residential chimney height. For reasons of reliability, survivability, and performance. Hell, I even have commercial grade antennas on my chimney.

I will also have to completely stand by my notion of not using those folded dipole bay antennas. I swear that every single time we use one of those, they never cover as well as a good fiberglass stick, if your looking for omni characteristics. I obviously am saying this with a grain of salt, as I have done no actual scientific measurments, other than just knowing the sites, antennas, and coverage from each, they just never really work well. To boot, around here with all the salt water air, the phasing harnesses turn to crap in a matter of 5 years. For the omni specifications I have gorwn to absolutely love the telewave ant450F6, F10 or whatever flavor you need. They are built very solid, haven't had one fail yet even after strikes. They have held up to our wind and salt air, and they cover really well. The price is not bad, compared to the dipoles, and no crappy harnesses to chase with crackles.

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Re: Repeater Advice

Postby Jim202 » Mon Mar 18, 2013 3:57 am

When I was working in the Cellular field engineering and building sites, we ran across a company that had developed a system to use a capacitor discharge system to spot weld on water tanks. The design of the system was to be able to weld brackets to the water tank without damaging the internal liner or paint. The instant heat of the spot weld system and the heavy steel of the tank material kept the heat down low enough.

Never used the system myself, but it looked good and a number of water tank builders have approved the process. Not sure of the cost involved as I never had my back to the wall to be forced into using the process.

Jim

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Re: Repeater Advice

Postby Bill_G » Mon Mar 18, 2013 5:15 am

Jim202 wrote:When I was working in the Cellular field engineering and building sites, we ran across a company that had developed a system to use a capacitor discharge system to spot weld on water tanks. The design of the system was to be able to weld brackets to the water tank without damaging the internal liner or paint. The instant heat of the spot weld system and the heavy steel of the tank material kept the heat down low enough.

Never used the system myself, but it looked good and a number of water tank builders have approved the process. Not sure of the cost involved as I never had my back to the wall to be forced into using the process.

Jim


That is the basic problem with attempting to mount on water reservoirs of any type whether they are elevated on a tower, or surface tanks. They either have an epoxy lining or a membrane lining that cannot withstand the heat of a welder or the penetration of a self tapping screw. Some water managers are quite adamant about not allowing anything to be mounted on their rez's. It's not just No - it's h*ll NO. Others are a bit more willing to accommodate especially if there is monthly revenue involved. But, the engineering costs to get through the planning phase can equal the construction cost. Handrail kits are by far the preferred method since they don't disturb the main tank. Some clever installers have used epoxy mounted cleats on a tank that allow you to install a kindorf / unistrut mounting system. But, there is no way to certify the wind loading or the weight bearing of that structure. If you are lucky enough to have an access tube at the top, you can built a monopole collar platform to attach your antennas to. For a cellular or public safety user, the cost is the cost, and hopefully the ROI is under a couple years. For an amateur, it would be an expensive endeavor.

For this particular project, getting up there to see what happened is the first priority. Look it over. Determine why the mount failed, and come back with a better solution.

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Re: Repeater Advice

Postby KG4LHQ » Mon Mar 18, 2013 7:35 am

Well i've finally been able to determine these are Stationmaster antennas. So my question is which will work better? I know this question is probably related to which is a better vehicle Ford or Chevy but if I can save some expense cost and get a decent coverage repeater w/ this stationmaster antenna then I will just have them do better to secure the antenna to be straight and leave it as such.

My understanding this antenna is a stationmaster antenna, will it be perfectly acceptable to use for my ham repeater and should see good improvement once its back straight instead of this crooked crap that I'm dealing with now?

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Re: Repeater Advice

Postby Will » Mon Mar 18, 2013 12:49 pm

KG4LHQ wrote: My understanding this antenna is a stationmaster antenna, will it be perfectly acceptable to use for my ham repeater and should see good improvement once its back straight instead of this crooked crap that I'm dealing with now?


Depends on the frequency that the Stationmaster (TM) antenna was made for. AS you go out of the freq range the pattern gets very distorted. One of the disadvantages of the series feed collinear antennas/design.

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Re: Repeater Advice

Postby KG4LHQ » Mon Mar 18, 2013 1:17 pm

The antenna was used on 451/456 so would have to assume this make/model is a 450-460mhz UHF stationmaster.

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Re: Repeater Advice

Postby KG4LHQ » Mon Mar 18, 2013 1:45 pm

The websitr says: Bandwidth Mhz for Less than 1.5:1 VSWR Iis 10 mhz so id it is indeed a 450-460 antenna then it should still work based on the bandwidth range.

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Re: Repeater Advice

Postby KG4LHQ » Fri Apr 26, 2013 6:46 pm

Just an update:

Finally have received permission to repair mounts on the tank. Will not be able to install a DB-408 or similar so I went with a commander technologies 1151-2N 8db Omni Directional.

Work will be completed on May 16.

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Re: Repeater Advice

Postby guy being a guy » Sun Apr 28, 2013 8:34 am

Only ideas to chew on ................
Are you guys on this water tower BOTH UHF ? At least in the 400mhz regardless of HAM band and 450 - 470 ? I also never read anywhere what the other guys band was - UHF or VHF, maybe 800 ? I state this as I would not compare a guys coverage at 150Mhz. is going to be mine at 440Mhz - Apples and oranges type of thing .
Maybe a combiner and share the antenna. Less antennas on a tower is always a good thing.
I am never disappointed when tower top RX amps are installed !!!!!
Is the other guy running 7/8 in coax too ? I ran loss on your setup and it came back at like 1.1 db of loss on that coax at 440Mhz. Its says it's good , but man thats a long run for 7/8 in !!!! Did I mention I am a huge fan of tower top amp's !

This is a backwoods way of testing something, but worth a try just for the knowledge.
Take your service monitor somewhere away from the building . Power it with an inverter and place it on the hood of your car if you have to. Just not in the shelter sitting next to it.
Generate the proper freq. and code thru a portable antenna on your monitors correct port . Determine 12 DB sinad to key your repeater and then repeat for the other repeater. Are they reletively close in RF levels to key them up (what ever the DB level is) ? If they are both UHF it's not a bad ,EASY, QUICK test ......VHF vs. UHF though....... take results with a grain of salt .

You already have climbed up and down that tower a few times .......Just asking ...........CAN YOU ......Have a helper in the equipment shelter at the ready ....You go and swap the coax cable ONLY while your helper moves it over as well - quick and painless ...........Smoke a cigarette and enjoy the view while some users do various radio checks and determine if that coax alone is the issue, or is it the antenna you have . Just requires a few friends to help 'ya out in the field - Thank them for their time and then switch the coax back . This test detirmines which way to invest time and money - coax , bad connectors or is it indeed my antenna.

You may even find out that this is just the coverage your going to get and NOTHING is broken - I don't know I'm 1,000 miles away just trying to help . All my advice ONLY involves labor and some testing so you spend money where it gets the biggest bang !!!
Please lets us know the outcome !!!!

SlimBob
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Re: Repeater Advice

Postby SlimBob » Mon Apr 29, 2013 7:10 am

Capacitive discharge systems can work with as few as 2F at 30V - 40V. The deeper you want to go, the more amps you need.
Slippery Sal's Saber Shanty! Sorted Simply, stuck in sacks! Standard, SECURENET, and Submersible! Sold in sets of six and seven!

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Mon Apr 29, 2013 3:09 pm

guy being a guy wrote:Only ideas to chew on ................
Are you guys on this water tower BOTH UHF ? At least in the 400mhz regardless of HAM band and 450 - 470 ? I also never read anywhere what the other guys band was - UHF or VHF, maybe 800 ? I state this as I would not compare a guys coverage at 150Mhz. is going to be mine at 440Mhz - Apples and oranges type of thing .
Maybe a combiner and share the antenna. Less antennas on a tower is always a good thing.
I am never disappointed when tower top RX amps are installed !!!!!
Is the other guy running 7/8 in coax too ? I ran loss on your setup and it came back at like 1.1 db of loss on that coax at 440Mhz. Its says it's good , but man thats a long run for 7/8 in !!!! Did I mention I am a huge fan of tower top amp's ! [/quote}

The other antenna is a VHF Stationmaster believed to be on top of the tower.
Will not be able to share antennas due to the difference in band.
The other guy which the repeater that I maintain as well is running 7/8" hardline as well.
I know there is a difference between the range on VHF and UHF but mine is NOTICEABLY DECREASED and I'm thinking the pattern is very skewed due to the leaning of the antenna.


This is a backwoods way of testing something, but worth a try just for the knowledge.
Take your service monitor somewhere away from the building . Power it with an inverter and place it on the hood of your car if you have to. Just not in the shelter sitting next to it.
Generate the proper freq. and code thru a portable antenna on your monitors correct port . Determine 12 DB sinad to key your repeater and then repeat for the other repeater. Are they reletively close in RF levels to key them up (what ever the DB level is) ? If they are both UHF it's not a bad ,EASY, QUICK test ......VHF vs. UHF though....... take results with a grain of salt .

Will give that a shot and see what happens sir. THanks for the idea.


You already have climbed up and down that tower a few times .......Just asking ...........CAN YOU ......Have a helper in the equipment shelter at the ready ....You go and swap the coax cable ONLY while your helper moves it over as well - quick and painless ...........Smoke a cigarette and enjoy the view while some users do various radio checks and determine if that coax alone is the issue, or is it the antenna you have . Just requires a few friends to help 'ya out in the field - Thank them for their time and then switch the coax back . This test detirmines which way to invest time and money - coax , bad connectors or is it indeed my antenna.

No I have not climbed the tower this was all installed by the previous owner of the site.

You may even find out that this is just the coverage your going to get and NOTHING is broken - I don't know I'm 1,000 miles away just trying to help . All my advice ONLY involves labor and some testing so you spend money where it gets the biggest bang !!!
Please lets us know the outcome !!!!


I get the biggest impression its the antenna, its working on a freq that its not tuned to be working at like it should be, the antenna has a severe tilt on it which is highly affecting the pattern, etc. I have NO reason to be believe coax is the issue and only thing to fallback on is the antenna.

guy being a guy
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Re: Repeater Advice

Postby guy being a guy » Mon Apr 29, 2013 3:32 pm

" its working on a freq that its not tuned to be working at like it should be " - Kinda a no brainer as to why you have poor coverage.


Would have been nice if maybe that info was given in your opening paragraph.

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Tue Apr 30, 2013 6:24 am

The antenna is shows a 1.3 SWR but again appears to be a 450-460 so that on top of the leaning issue with a skewed pattern is hurting it.

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Mon May 20, 2013 7:18 am

Just wanted to give an update.

Last Thursday; DB-410 antenna was installed at 160 feet and wow what a difference. Still working on range tests but seems to be considerable difference! Thought I would show all a pic of the install.

Image

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Bill_G
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Re: Repeater Advice

Postby Bill_G » Mon May 20, 2013 7:23 pm

Probably exceeding the plot I sent you.

KG4LHQ
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Re: Repeater Advice

Postby KG4LHQ » Mon May 20, 2013 8:03 pm

Yes sir it is. Base station can get back with some static from South end of Louisville at the same time a base station with 35 watts can get back from the West side of Owensboro.

I'm pleased.

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FMROB
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Re: Repeater Advice

Postby FMROB » Wed May 22, 2013 5:39 am

Looks good, ugh - a folded dipole.

RFguy
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Re: Repeater Advice

Postby RFguy » Wed May 22, 2013 7:11 am

FMROB wrote: ugh - a folded dipole.


Interesting how different areas have different preferences. We almost exclusively use folded diploe antennas (Sinclair). The have a wide bandwidth, more rugged (stand up to icing much better), tend to last longer, easier mounting to tower structures.

I notice other areas are almost the opposite. I see tower pictures from other geographical areas that are covered in monopoles.


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