Cushcraft antennas and repeaters??? A good combo???

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n9upc
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Cushcraft antennas and repeaters??? A good combo???

Post by n9upc »

Our EMS repeater use to be (and still is in a way) on the outside dome of a building which was about 8 stories high or so sitting at the highest point in the county.
The spot for the repeater was great as it was 1.) FREE and 2.) had access pretty much anytime that we needed it.

Well the damn historical society popped up and stated that since the building is turning 100 years it is a historical building (which I agree it is) and it needs to be preserved. Therefore they pushed and pushed and have now got it so that the antennas on the outside of the building had to be removed.
This translated to a couple of cell companies moving locations, and a business machine getting taken off the air. (No big problems there as they all switch to NexHell and only had it on to hold the freq for some reasosn if they needed it.)

Anyways we were told we do not have to move out of there we just had to move the antenna to the inside of the dome. They understand how important it is for us to use this channel (even though it IS NOT our main dispatch channel just a talk around to help get off the county channel) and did not want to kick us off the air and that site as we can not really get on any other without paying $$$, really big $$$ per month.

So we had to move the antennas inside the dome and we noticed pretty pissy coverage. Our license is for 100 watts wideband on a pretty clean freq. Well when we noticed this coverage issue we called the cell company which said they would take down our antenna and remount them on the inside of the dome. They said that they remounted the antennas where we looked at before the move. It at first did not hit me but later what they said would.

So we thought we should walk on up and take a look at what was going on as when we moved it from the outside to the inside we maybe moved it down about a half a story. Now the dome is made of all wood. No metal or concrete or nothing just all wood.

Well when we got up there we found the repeater is now on two antennas one for TX and one for RX. The shocking thing was that niether of them was the antenna from the outside. In addition to that we found that both antennas were cushcrafts. One was an ARX-2B 7 dB (aka Ringo Ranger II) and the TX antenna was an AR2 3 dB (aka origianl Ringo Ranger).

The antenna configuration was set-up so that the ARX-2B was mounted correctly right up in the dome which was the RX antenna. Whereas the AR2 was mounted inverted on the cieling of the floor right below it for the TX antenna. In addition from the base of the one antenna to the other is only about 3 feet or so and our freqs for our repeater are about a half a meg apart.

Therfore we found the coverage sucks do to the TX interfering with the RX freq and thus why the repeater coverage is $hit.

Now before anyone says anything we also had a duplexer which is missing. So our original antenna and duplexer are now missing. We are giving the cell company one more week to return the equipment to us but they are running out of time, in addition to them claiming the antenna was old and damaged as well as the duplexer. This is total bull$hit well maybe the antenna could have used an updating but the dupplexer was good.

We tested the antennas and the SWR is within the acceptable range of 1 to maybe 2 watts reflected. We also found that they added some pass filtering on our freq. on the TX and RX side. They said this was to help in place of the duplexer which was bull$hit again. That duplexer was good and working well.

So as for my main question of the topic/post: Since the cushcaft antenna can handle up to 1000 watts and it tuneable from 136 Mhz - 166 Mhz and is tuned correctly has anyone else used this type of antenna for comercial/pulic safety use.

The nice part is that they did do this all for free so we got new antennas from what they llok like but never the less we lost coverage so we really did loose.

Now I did check our license as well as repeater power out (including ERP calculations) and we are within our license. We are also in the process of sending the update to the FCC about our antenna.

So all in all we are good except for the poor coverage. But back to the main question if we can find another duplexer that can handle a 1/2 meg or so split between TX and RX is this going to be an ok antenna to use. I see Tessco sells them as well as some other people suggesting them also. What say you board???
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tvsjr
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Post by tvsjr »

First, what's the construction of the dome? If it's metallic or has a metallic grid in it, you're inside of a Faraday cage... coverage isn't going to be anything like it was when the antenna was outside.

I wouldn't even consider running anything by Cushcraft in public safety service. I'm definitely picky, but the stuff I've seen used from Cushcraft is utterly terrible. My hammy repeater is even on a DB-264.

A duplexer for that narrow of separation will need to be something in the 4/6-can BpBr variety. This isn't going to be cheap - expect to spend upwards of $1500 for something new. You'll want something with pretty serious reject. I'm running a TxRx 6-can BpBr duplexer on my hammy repeater which has over 130dB of rejection (I wouldn't recommend buying a new one... insertion loss is about 2dB each direction).

Provided you can deal with 26' of antenna, I'd strongly suggest a DB-224. These will run $600-$700 new. If you need something shorter, look into a DB-222 (2-bay dipole, around 13').

I'd threaten the cell phone company with legal action. I'm surprised that they consented to move your gear for you in the first place... for them to keep your gear and try to stick you with inferior crap is ridiculous.

FYI - the term for a repeater transmitter taking its own receiver out is desense.
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kb0nly
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Post by kb0nly »

I say if they don't return your duplexer than you buy a new one and bill them for it!

But, all the legal and money battles aside. Just eliminate the lower TX antenna and put a duplexer back on keep the top antenna.

Sure, there is better antennas, but the Ringo's work rather well for the application at hand. I used to have a couple of them mounted upside down in my attic when i lived in a rental unit that had a no external antenna covenant on it. Wasn't my first choice for living accomodations having my habit of antenna installing, but at the time it suited my family needs.

The only reason i had them upside down, in case anyone asks, is because it was the easiest to mount them this way with a couple short pieces of conduit screwed to the peak of the rafters and the antenna mounted to that.
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Will
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Post by Will »

You for sure need a real antenna. Also what type of cable did they use?.

The Comtelco BS150XL3 series work verry well in duplex service. About $260, and I can have Lisa custom tune it for you.
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n9upc
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Post by n9upc »

As for the make-up of the structure of the dome it is ALL wood. This building was built 100 years ago and well the dome is wood and the lower part of fancy sort of gated type landscape is concrete but that is onyl about 2 to 3 ft tall and no where near the dome part of the building.

The cell company did it as a "favor" for us as we were at the meeting with them. There sales rep recently sold us all new high quality/durable handsets and a great service plan so I think he pushed them to do it as a "favor" for us.

I got a call first thing this morning and through some connections we have found a duplexer we can use that was originally tuned for a PS rptr pair which was a seperation of less then 1 Mhz. Something around 0.9 Mhz is the pair if I remember the freqs so I think that should work and be able to tune down another 0.4 Mhz for us. Well at least that is what we are banking on.

I think the cell company may bend here as I know our lawyer was going to be placing a little call to them with a little "here are the rules, heres what you did, shame shame shame." As I said before in my earlier post I do not mind the new antennas. Once we get a duplexer and take the other, less gain one, down then we will move that over to the station as we are getting a better base radio and need an antenna. However, this duplexer walking $hit is just that $hit!

There was no lighting hit or anything which has made that duplexer good bad. We in recent years has always had the system checked by me monthly for a quick power out and panel alarm check, and at least a once a year PM check. (We felt a yearly one is ok because we check the repeater every month real quickly for SWR and alarms).

Once again thanks for all your input. I think we also maybe able to use the small 3dB antenna as it is only about 3 ft tall and put it up in the pigeon coop and hide it behind one of the posts up there. In a way the antenna would be outside and the tip of the new location/antenna would be at the same height as the old location/antenna.

Oh the one last question I did not answer was what type of feedline were they using. It appears they used LMR-195 at a run length of about 22 ft. If we move up to the pigeon coop we will be adding on another 20 ft and with a total of let's call it 50 ft we will try to move to LMR-400 as 195 is getting to be a little stretch at about a line loss level of 3 1/2 dB at 50 ft. (if mind hazey mind is working correctly).

Will keep you updated.
" ah the fatman made a funny!" - Stewie from the family guy.

I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
tvsjr
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Post by tvsjr »

Don't assume that a duplexor good for 0.9MHz split will work at 0.5MHz. Look up the specs and ensure it'll work at your separation before you spend money for it.

Also, some people have complained about noise generation when using LMR cable for repeater service. You might want to consider sticking with 1/2" Heliax (or, if you really need the flexibility, Superflex).

I'd still demand all your old equipment back, whether or not you use it. If the old antenna was decent, toss it in a corner for a rainy day or something.
CTAMontrose
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Post by CTAMontrose »

someone replaces my nice commercial antenna for some cushcraft hammie garbage has got some serious 'splainin to do!!

thats pure BS
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mr.syntrx
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Post by mr.syntrx »

It's also a criminal offence. I would be pursuing it through the police.
Will
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Post by Will »

I would hope the flakes over at the cell co. do not need any EMS help. You'd have to change out good organs for poor quality replacements. Or their office does not catch fire.....



Really, make them cough up a REAL antenna, maybe a Sinclair or a Telewave blue broad band job. And some REAL Heilax cable too.

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n9upc
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Post by n9upc »

Well we went to the PD and advised what had happened and the main thing they said we would need to do is get our paperwork in order to try and help spped things along and show proof.

The other problem we run into is that the cell company is out of state and we are working with the local office and also the main office which is blowing us off to a degree as they want to know why the local office did what they did. Now not that they swapped antennas but that they did the work and for FREE in the first place.

As for know we are getting bad desense into the repeater. If we "kerchunk" it we can hear the quick sql tail for some distance. But the minute we try talking on it the range is $hit do to the desense. I have been able to get a duplexer through some favors and stuff that have been called in and was set-up for a system with a seperation of freq not to far from ours. So we will tune it up and hopefully have it in place by either this monday or tuesday.

So we are slowly moving forward which is good, but not as fast as we would like to move forward. The main concern is duplexer replacement cost as we do not have money in the budget for this. As for the antenna I spec'ed them both out and I think since we were going to have to buy one next year anyways we will just use it for the time being. Once we get the duplexer in we might take the other one and put it a top our building for a better base radio antenna.
" ah the fatman made a funny!" - Stewie from the family guy.

I went to the doctor and all he did was just suck blood. Never go to Dr Acula - M. Hedberg
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Big BOB
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Post by Big BOB »

Thats why they call them a "Ringo Resistor". You get what you pay for.
CTAMontrose
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Post by CTAMontrose »

yeah really... ringos are doo doo, i would almost take a 1/4wave groundplane over it.
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kb0nly
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Post by kb0nly »

Why are so many of you having problem with the Ringo? We had one on a local repeater for about a year while the club was saving up for better coax and antenna.

They almost left it up there because it never caused a problem. I'm not saying they are the best antenna made, far from it, but like anything else operator/installer error plays a huge role. And from what i have heard of this conversation so far those "cellular" guys probably didn't know diddly anyway.

If i had to choose an antenna, budget minded, i would say Ringo Ranger or Hustler G6 or G7. Though they also have the fully enclosed fiberglass model of the G7 as well.

If i have a little more to work with then its a Diamond brand antenna. I laugh when i hear how much the "commercial" guys spend on a antenna for repeater service. Recently one of the local UHF repeaters took a lightning hit, this was last summer, and the commercial grade antenna on it was just blown apart. Turns out the antenna is designed so its not grounded at the mounting plate to the support structure. That was its internal design! So if the antenna took a lightning hit it would just buzz down the coax instead of possibly losing a lot of its energy to the tower or other support structure.

We put up a "ham" antenna, and three lightning strikes later all is well. Its on top of a water tower and quite vulnerable. But adequately protected after the incident with the commercial grade antenna. I wish i could remember the brand name, will have to dig it out of the club presidents basement and see if there is still a label left on it anywhere.
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Jim202
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Cellular company moved antenna

Post by Jim202 »

You need to find out what tower crew did the work for the cellular company. Go after the tower crew. It takes forever to get some of the cellular site people to respond. Is the cellualr company in the same building? Maybe talking with the property owner and seeing what the lease for the cellular company says. The building owner may have the right to terminate their lease if any conditions were not met or were broken.

One thing a cellular company understand is the cell site not working. Find out who the cell site service tech is and get the contact info from him. He should know just which crew did the work.

I have know some rather shady tower crews over the years. If it isn't bolted down, they will lug it off and sell it when they get a chance. Sounds like a simple claim of stolen property to me for a start. Sick the cops on the tower crew. You will get faster results.

Jim
RKG
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Post by RKG »

Tell the cellular people to call their general counsel and use the word "conversion." That will get their attention.

Whatever tower crew was employed by the cellular company was functioning as the cellular company's agents; the duty to return your stuff lies with the cellular company. Dealing directly with the tower company could let the cellular company off the hook.
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Post by Jim202 »

[quote="RKG"]Tell the cellular people to call their general counsel and use the word "conversion." That will get their attention.

Whatever tower crew was employed by the cellular company was functioning as the cellular company's agents; the duty to return your stuff lies with the cellular company. Dealing directly with the tower company could let the cellular company off the hook.[/quote]

I have found in the past that as RKG said the tower crew were acting as an agent for the cellular company. This is true, but it is easier to get the attention of the tower crew and then let them in turn rattle the cage of the cellular company. I find it works much fast that way.

Reason being is the tower crew doesn't want to take the rap. They were just doing as they were told. On the other hand, if you can nail them and start the spaks flying, they will tell the cellular company they won't do any more work for them and spread the word so no other tower crew will either. In just a couple of days the cellular company is standing there with no tower crew willing to touch a piece of work for them. You will be amazed just how fast this works and then how fast the cellular company comes around.

Spent 14 years working for several different cellular companies. They have some strange people that work for them in the site construction and operations side of the companies.

Jim
roadhawg00
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Post by roadhawg00 »

USE THE PRESS, I KNOW IF THE GREAT CITIZENS IN MY COUNTY FOUND OUT THAT THEIR EMERGENCY SERVICE WAS DONE HARM BY COMPANY XYZ, THEN THAT MIGHT CAUSE XYZ TO LOOSE BITNESS. NO COMPANY WANTS THAT KIND OF PRESS. APPEAL TO THEIR GREEDINESS.
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jim
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Post by jim »

The Ringo is a POS ham antenna- period. It has no reason to be on a repeater- espeically one that's in public safety. Remember- this is a professional and commercial communications system where lives depend on this system. This is why a Ringo is $69.00 and a commercial-grade antenna for repeater use is $1400.00


Using a Ringo is like using two Alinco 610s and a Palomar linear to build the repeater and running Radio Shack RG8 coax.
techie
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Post by techie »

What I don't understand is why, if they were just moving the antenna, they would have needed to touch the repeater at all, except to disconnect or reconnect the feedline.

What ended up happening?
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davco3
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Less than 2 cents worth.

Post by davco3 »

We are talking an INSIDE location! No corrosion, no wind and no temperature extremes!!
From RF performance alone, there is not much difference between commercial and ringos of similiar hieght.

Free tower work is free tower work, I personally would leave the difference in cost between a used commercial antenna and two ringos as trading capital.

What hopefully hasn't been thrown away or destroyed is that duplexor. If the people who did the work can be contacted, and talked nice to without threating lawsuits and criminal action. A peaceable solution should be be worked out. Tower people don't know RF usually, especially not VHF RF compared to 800 Mhz work with many Mhz seperating RX and TX freqs.

I hope the old duplexor can be found!!!

I would even consider disconnecting the "T" and hooking TX side to the bottom antenna, and RX side to the top antenna. The antenna seperation should bye a db & a half better performance. If you have to retune the other duplexor, I would definately go to the seperate antenna's


I pesonnally think RCV desense is the biggest problem of the current set-up, and not antenna hieght.

Off the cuff, I would say seperate antenna's with true vertical separation may give better performance than a higher single antenna (speaking of only 20') depending on local terrain.

This advice is probably worth less than what you paid for it! ;)
Have a Good un!
ASTROMODAT
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Post by ASTROMODAT »

Considering the huge cost of any kind of tower work, I think you came out way ahead here. I'd suggest a nice polite low key approach, and try to work with the cellular company. I bet a nice carrot will get you a lot further with them than trying to wave around a little stick that will only make them tune you out.
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