Batboard

Just curious what everyone thinks about lowband? good or bad?I work for a rural eletric co-op that operates a repeater on 47Mhz.(110W @230ft) Most of the mobiles are 110W maratracs and some micors. Our coverage seems to lack and the repeater is noisiy in places where it shouldn't be.(10 air miles) Most of the old guys said back 15-20 years ago the coverage was aweome and and now it stinks. My dad is a retired state trooper and I can remember him talking to other troops 10-20 miles on 42Mhz simplex car-car. He thought the SP lowband system was fine. Now the newer troopers have problems talking to each other and to the posts.
Whats the deal? is this somekind of solar cycle? or has lowband always sucked

I'd suggest contacting a qualified 2-way repair tech to check the repeater for bad feedline and/or antennas and/or other problems.

Also, make sure the mobiles have a good ground plane. This is very important for low band in a mobile install.

Really, you should get a 2-way tech to sniff things down.

If everything is OK, it should outperform VHF or UHF over hill and dale....Lowband tends to have more noise that varies day to day though, and ignition noise can be a problem. HOWEVER the Maratrac has an excellent noise blanker- it powers up on, you can turn it on and off by holding the monitor button in till the 3 beeps (low pitch=off, high=on).
It is very hard to get a repeater set up without desense, I would suspect a problem there. How is their simplex coverage?

A lowband repeater? I didnt think the FCC allowed repeaters on lowband. I know Hams have them on 6 meters, but I didnt think they were allowed commercially. Could this be a remote base station? Mebee I missed something.

Fowler

Well the last time I checked, the only users not entitled to low band repeaters is commercial. Most of the West and Southwest State Police use low band repeaters, a power company would also be allowed to. With enough money and the right connections, you can get anything from the FCC, look at Nexthell.

Don't forget in 15-20 years all sorts of obstructions may have come into play..new trees, new buildings... we have the same problem with some folks on VHF.. in the old days (10 yrs ago)..they could talk 40 miles to the other side of the other town..now they get to just this side of the other town....10 years of development has put up a concrete barrier to RF signals...Z

Well, there's a repeater on low band at the site with our ham repeaters . . . so they ARE around.

As for the obstructions Znarx mentioned, I wouldn't expect them to be a dramatic problem on low band, unless we're talking about the mobiles driving in an area immediately surrounded by such obstructions (city buildings, etc.) Foilage in particular is a UHF/800 problem for the most part, not low band.

I'd go with the suggestions to contact a service tech for a checkup. This system should be checked every year anyway - isn't frequency and power output still checked annually anyway? I believe it's supposed to be. If not, it's still a good idea. If it's been a few years, it NEEDS to be done. Things deteriorate over time, and one day everyone remembers how well the system USED to work. Or one day it just doesn't work so well and it gets brushed off. Get it checked and fixed.

Good luck,

Give me a phone call and I may be able to help. 1-800-543-6324 ex 241


David Epley
Lead Communications Supervisor
Navopache Electric Co-op
Lakeside Az, 85929

I'll ad my opinion based upon many years of expierence. A well maintained low band system will out perform a VHF or UHF system, either simplex or repeater. This means good mobile antennas installed in the proper place on the vehicle, no "L" brackets, or antennas mounted to luggage racks, ladder racks, headache racks, or other non-counterpoise locations.

Back when the tech would always put the old Bird 43 inline and "peak" the final tune and load for max forward power, check the receiver and retune the extender "by the book". Finally, he would check the base location for noise by using an isolated Tee and his trusty model 80. Brings back the day of listening to the whine of the power supply in that T71LHT.

I have a Lowband Orion at 90 watts (so I save my PA) and I can talk in the So. Calif area easily 10-20 miles car to car and sometimes more, I do use a Bird 43 and make sure the stuff is set up correctly. Most of the Lowband problems I have seen, when I was in TN was antenna's not tuned. TN Highway Patrol had 1/4 wave ball & whips & most were not tuned well or they did not ground the antenna well when it was installed. Also I don't think many people really check radio's anymore, they take them out of the box and install. I have never found one that was right on. MAKES A DIFFERENCE

I'm sorry, I should have given alittle more info....Most trucks use 1/4 whip, ball-spring..some roofmount maxrad baseloads all tuned. Our repeater antenna, feedline (1/2") duplexer(no desense) all less than 2yrs old. Simplex coverage doesn't impress me either compared to 150Mhz especially with 110W mobiles. We are still on lowband because some of our service area is hilly and management thinks thats what we should use. I wonder if lowband is supposed to be so good than are there so few users anymore? We also have some portables that are pretty useless as well due to poor range.

We have been on Low Band since the early 70s in the 48.XX range and every mobile install is checked, our repeater is split site and it out performs the hell out of our 150 and 450 systems at similar distances.

On several of the simplex channels we use we have had excellent coverage as well.

One thing we discovered long ago is that the LB portable is for close range therefore we have equipped all of our vehicles with a VRS set up and we use UHF portables.

Car to Car we cover easily 15 to 20+ miles on the repeater we cover easily a 60 to 70+ mile radius from the tower.

Rule #1 which we follow religiously is to make sure our antennas are mounted correctly, and checked with the Bird.

If your system is having as many problems as you say its time to change service companies because apparently they either don't know what they are doing or they are trying to degrade the system in an effort to convince the management to upgrade.

One other thing that came to mind is that if you are using 1/4 waves with the spring and they have been in service a long time it is a good idea to flex the spring and check if the braid that runs inside the spring is intact, they do corrode and occasionally break wreaking all sorts of havoc on reception and transmission.

vcaruso wrote:One other thing that came to mind is that if you are using 1/4 waves with the spring and they have been in service a long time it is a good idea to flex the spring and check if the braid that runs inside the spring is intact, they do corrode and occasionally break wreaking all sorts of havoc on reception and transmission.

This is a very important issue that VCARUSO brought up. Only the old timers on here will tell you about the braid inside the spring. I have seen the braid go bad in as short a time a six months. It kind of depends on the enviroment.

In the past I have made regular contacts mobile to mobile with 100 wat radios over a 30 to 50 mile range. The area your in will effect this. Down here in the flatts of South Louisiana, you should be able to get 40 to 60 miles with good equipment and a good mobile antenna.

Don't cut any slack on testing the antenna on the mobile. Get the reflected down as low as posible. The more the whip is out in the open, the lower the reflected power will be. If you mount it on the side of a truck with a rack or some other metal near it, you may not be able to lower the reflected power.

I have also used the base loaded coils and whip for a roof mount. Kind of got stuck on Larson NMO mounts. Never had a problem with them except for the cement trucks that keep trying to move tree limbs with the coils.

A low band repeater should walk the pants off of any other radio band around. If not, you need to start looking for the cause of poor performance. I would look first at the base station antenna system.

Most low band antennas take a beating from lightning. Go climb the tower and look close at the whole antenna. Again from long time use, I am partial to folded dipoles for low band base use. Put a pair of them on a tower (in phase) and it should do great.

Look at the orientation of the dipoles if that is what you have. Many DUMB tower climbers, don't know there is an up and down for how to mount these antennas. If one of them in a phased system is inverted, it will play hell with system performance.

I have had to draw a picture of how to tell up from down to some climbers while installing dipole antennas. Look at the coax cable connection and make sure the center connection is up and not on the down side. Make sure the phasing harnes connections are tight.

It is not uncommon to find that someone has twisted the brade off on one of the special harnes cable connections DB uses a special gell filled coax that is not 50 ohms in their harneses. You just can't make up a replacement out of RG-8 or RG-55 of the same length. It won't work. These phasing cables are of a criticle length.

The length of the diploes are criticle. If the wrong antenna was installed, it should show up as a high reflected power.

By any chance, has water got into any of the 1/2 inch connectors. This causes corrosion that may not show up as reflected power. The center pin could be ate off from the corrosion. Many things could cause poor performance.

Need to start at the repeater and make all the test that go into repeater adjustments and system testing. You could even try a ground plane antenna low on the tower to see if coverage changes. If you still get the same coverage,then you know the high antenna has a problem.

Just a few thoughts on where to start looking.

Jim

RADIOMAN2002 wrote:Well the last time I checked, the only users not entitled to low band repeaters is commercial. Most of the West and Southwest State Police use low band repeaters, a power company would also be allowed to. With enough money and the right connections, you can get anything from the FCC, look at Nexthell.

abbylind wrote:A lowband repeater? I didnt think the FCC allowed repeaters on lowband. I know Hams have them on 6 meters, but I didnt think they were allowed commercially. Could this be a remote base station? Mebee I missed something.
Fowler

Whelp...(My 5cents) (or 52cents if your reading this Will!)
The shop I work for was just given 10 lowband freq's (5 input/ 5 output)
all in the 42 to 49MHz spread.
So the FCC has changed the structure of this area.
We aquired about 30 VX3000 mobiles and Some Maxtracs and are testing the coverage in the NH./MA./ME. areas.
Best (direct)distance has been 32mi. as best we could tell from GPS' data,
over land not hill-topping.

The only problem we're having is part15 cordless phones that are still in use on 2 of the channels.

Haven't decided on the repeater yet (build or buy) but got some paging cans @ the HossTraders flea and you should have seen them hanging out the back of my truck!

Since this topic brought out the lowband people...a quick on-topic question about the ball mount lowband antennas:

I need a lowband antenna on my new '02 Impala. It would be mounted on the left fender, behind the fuel filler, like Illinois State Police. Radio is an X9000. Assuming that I install the antenna per mfgr spec's, what do I need to do with the coax? Leave it at 17 feet or cut it to fit?

I've never had to install lowband before, and I know that coax length plays a part in tuning.

Thanks!

007--

If the coaxial cable really has a characteristic impedance of 50 ohms, if the antenna is really set up and tuned properly, and if there are no other problems, then cable length should be unimportant. In my experience, when antenna instructions say not to cut the cable it is either because

--the antenna naturally runs with a lot of reflected power (high SWR) and is using a lossy cable to protect the transmitter from that power or

--the cable used is some obscure or low quality material and the manufacturer knows that once you cut it, you'll never be able to get a connector back on it.

Also...I'm surprised that no one has brought up the old low-band "rule-of-thumb"...in fairly level terrain, 100 watts at 100 feet equals 100 miles.

My dad used the Bird 43 for 25 years but since I have used the site master cable and antenna tester.
Time and quailty are now go hand in hand partner.
It also gives us a print out of the full range of the antenna. It is fast and very good.I put low
mileage on the watt meter vswr back into the radio.I only
use forward and the site master.Tools of the newer tech's.

On 800 mhz I have not found one antenna that did not need to be matched.Thanks site master.A cutting chart starts the match
but the sitemaster goes the full mile.Yes the vhf low
100 watt is not set-up right.

Yes companies try to sell more
expense equipment to the customer.It is hard to get a newer
tech who really knows how the radio functions.

My dad showed me many tricks that most newer shops
had not been able to learn.
Sites like Batlabs
help us to keep the older gear going strong.

73's from Canada

Low Band Rules Thats all i can say.

I work Down in the New Haven Area For a Sup Contrator Who is the Automated Meter Reading Company For United Illuminating Company.

they have a Low Band rpt and the Thing Rock I have heard reports that the thiung can be heard in New hampshire and down to New jersey

Amen to Lo-Band rules. No wonder the dang used equipment is almost a expensive as new stuff these days. It the last resort, the last frontier.
Rptrs on lo-band? Cripes?! before MSP went 800 astro, they had rptrs all over the place . In metro Detroit there were at least 6 lo-band rptrs.
To overcome the desense, they used separate antennas for RX/TX. Rx antenna was on top a tall building, TX was on another location and interlinked by Telco lines. Until about 4 years ago, the entire Northern Mi. LEa's all had lo-band rptrs for each county, and also included the MSP lo-band system.
Since then , alot of the county LEA's have taken over what was originally some of the MSP Vhf freq's and have recieved better equipment, such as MCS2000's, HT1000's, and the like.
A couple years ago, I had crosbanded my BC760 by designing a COR relay and to key the PTT of my 800 Maxtrac mobile on my work simplex freq. It didn't go very far, about maybe 1 mile, but it was great to walk around our property and area in the north and still get all the action off an 800 mhz Visar. The local LEO's were just absolutley amazed that this could be done.!!!!!!!!!!! Well guess who were coming by all the time for coffee and my wifes pastries?
Jimmy

To everyone: Why do you think all of these agencies leaving lowband? Like I said in the origial post, the local troopers say their lowband doesn't work so ISP gave them cell phones! I can see larger metro areas going 800 but majority of posts in Indiana only have 5-6 cars on patrol per shift. Personally I think ISP's system has been purposely degraded as an effort to justify statewide 800.

Are you talking ISP as Indiana or Illinois? Right now (at work) I'm listening to Indiana SP on ILEEN (WISPERN here) out of Indy talking to a local SO...they are almost 200 miles southeast of here!!

I love lowband. I'm pissed that every state around WI that was lowband isn't anymore, or won't be shortly (IN, MI and IL)

Oh well. Just have to play on 6m more! I'm just torn what antenna to use on my Impala - NMO or ball mount.

I am running the GE Orion 110 w, 35-50 radio with a center trunk mounted Comtelco 42 Mhz antenna on 2 different vehicles, this radio talks wonderful, I even can sneek a conversation with my old dept. since the sky is calling radio waves right now in the morning. If anyone on this board knows where I used to be. LOL

I would get a GOOD low band Loaded 1/2 wave and tune it right and go smoking down the road.

Sorry that should have been 1/4 wave NMO

007,

We debated the same thing a few years ago and started using the NMO mounts on the supervisors vehicles.

If properly tuned you should have similar results as using the 1/4 wave.

We use Motorola and from time to time the Comtelco NMO Mounts ( we had bad experiances with other mfrs).

As for the vans and trucks we stick to the ball and whip for durability.

You will have to drill and you will need a good ground plane trunk lip mounts may work on higher freqs but it will not fly on low band.

I hate lip mounts, so everything I do is NMO.

I have 2 nmo mounts on the trunk right now, side by side about 22 apart. I could get an nmo 1/4 lowband antenna and mount it right now. If I put a 3rd nmo in the center, then I will have 3 antennas within ~23 inches of each other.

The ball mount would eliminate the problem of spacing, and since the decklid of the Impala is so small, I'm worried about high SWR and antenna interaction.

What type of gasket seal does the Comtelco base have? O-ring or something a little beefier?

About lowband:

It is an excellent choice for agencies in the plains, where terrain is no issue. I was suprised to find out the heavy useage of lowband out east! I think it is a great medium distance band, and I look forward to using it in my new car. Being that I can't come close to filling the 64 modes in my X9000, I'm hope to add some PS freq's and listen to those while I meander about the countryside this summer.

The Comtelco is an NMO style loaded 1/4 wave antenna, about 800 Khz bandwidth. It uses an O ring in the base for seal at the vehicle plus internal compnents that prevent leakage. They make them in Series Fed & Shunt Fed which is what I use. One of the vehicles that I have equipment in is a 1999 Lumina Police car and it is 20 " from my dual band VHF/UHF antenna, 9 " from my 800 antenna and 4 inchec down from the top of the decklid in the middle and it sweeps wonderfully on a HP 8953c network analyser but better yet it talks GREAT.

Thanks, Stan.

My last car was a '98 LTZ...nice car, except the tach hated RF!

My operations agenda has changed for this car, and I need to find a good duplexer that I can dump 110w into for VHF and UHF. Any suggestions?

I'm looking hard at these Comtelco gain dual bands because I can get a closed coil in black, unlike the larsen. My scope and focus has changed, and now it's going to be a stealth car (as much as possible).

I need to find a Comtelco dealer so I can order a lowband antenna from them and give it a shot.

If you're going from a car with metal trunk to new Vic's(1992 and up) with the aluminum trunk, beware of the funny SWR's you'll get on lo-band.,
I had a 45 MHz radio that had to go from an 88 CV to a 99 cv(YES!, the 88 was well kept.) When I connected the Ant. Meter and had to keep checking it again, I thought I was gonn lose my marbles. I had to cut nearly 2.5" off the whip to even get the REF to come down. And cutting it in 1/4 " lengths didn't help.....let's see 2.5/.250= 10 times to the grinder.
No wonder I lose weight.
Jimmy

And how many radio shops have JUST TRANSFERED that antenna??????????????????????????

Tell's me that there are a lot of POOR performing radio's out there simpley because the tech DID NOT know what they were doing.

A watt meter is a wonderful thing if it is used.

powerlineman wrote:To everyone: Why do you think all of these agencies leaving lowband? Like I said in the origial post, the local troopers say their lowband doesn't work so ISP gave them cell phones! I can see larger metro areas going 800 but majority of posts in Indiana only have 5-6 cars on patrol per shift. Personally I think ISP's system has been purposely degraded as an effort to justify statewide 800.

Indiana state police are still running 4 channel lowband MICOR's with MT500 hiband portables for the Pac-RT. The whole Lowband system is ancient. Also, they are phaseing out the 1/4 wave ball mounts and going to NMO antennas on the rear fender. Not the best place for a lowband antenna. I think if they would invest a bit of $$ into the system they got (new mobiles....update the sites....maybe try a lowband repeater system) they would have one killer system.



-RC-

Stash, I bult the car in 88, stripped it in 99, and did the re-install in the 99 vic. Yes, of course it went through at least 4 antennas in it's lifetime. Simply because you can't take a long whip through a carwash!!!!!!!!!!!!! The other time was when an unruly decided to bend the whip into a pretzel.
The interesting part is, the car still belongs to the city and is still in service with the Building Dept.
Engine and body work was performed by a local mech., I did all the radio//lightbar/siren service. The radio was a Syntor X with siren and switch panel option, who could ask for more?
Definitely was your one horse town.
Jimmy

I attended a M school on site equipment and the Tech rep showed a slide of the top of the Sears tower. One folded dipole on top of the roof, and Standard Oil could talk both ways to Tennessee.

Getting back to the original problem stated, checking the radio, coax, and antenna with a Bird is a no brainer. But has some one climbed the tower to test it AT THE ANTENNA! Recently I had a customer who runs a 350watt Micor for school buses, all of a sudden has all sorts of problems, the system used to work good was the complaint. Tested the station 10 times, checked the power out, etc. No problem found each time. Then we decided to climb the tower and check it at the antenna, well there was 250 watts going to the antenna, and 250 watts comming back. Don't know what kind of antenna you have on the tower, but the Phelps Dodge, now Cellwave antenna, just crapped out. The glass insulator cracked, we think from frezzing and thawing. The extra long run of coax, (excess of 500 ft was giving an erroneous reading on the reflected, water in the coax can give you even more headachs, you get 0 reflected, because the water, absorbs the reflected power.
My recomendation is to climb the tower and check the antenna at the source.
Jim D

A good number of base station range problems are due to bad coax. Seems like most radio techs don't or won't climb a tower. Break the connection open at the antenna and measure it. You will learn several things. If you measured the forward power at the TX, this will give you how much loss the coax has. It will also show how much reflected power there is.

Don't be surprised if water comes aout of the connection. Waterproofing the coax connectors takes some talent. Not many of the tower climbers I see today have much of that. They look at a poor connection as job security.

If your in the business that uses tower climbers every day, you get to know the good from the bad. Take my word for it, there are more out there that do poor, sloppy work than there are that do a good job. You weed them out fairly fast. Cost is no indication of the quality of the work they do.

I have seen some major service companies that do a bad job. Bad part of it is that not too many customers are willing to talk about poor contract work.

Any way, take the advice of several people on here and have the antenna system checked out. The low band does play for ever. If your not seeing that type of coverage, not too many places to look.

Jim

6m were open the other i Know i was On ssb i talked all the way to FLA from CT 100watts into the 1/4 ball

It might not be a bad idea to cut a slice of the 1/2 inch coax's outer insulation and see if water comes dripping out.

Just thought I would put in my 2 cents. We have a low band repeater system as a "secondary" radio net using 2 Maxtrac mobiles and a dipole antenna. 37 MHz out with 39 MHz mobiles. Power out of the duplexer is only about 40 watts. The cars have both Maxtracs and CDM1250s using base loads with the newer cars having ball mount quarter waves. Our older cars link the UHF mobile to the low band using a RICK and we are trying some Vertex VXR1000s as true vehicular extenders. The low band system talks in many more areas than our UHF system. Some areas are quite dead on UHF but the low band is clear as a bell with the repeaters at the same site !!! We have very hilly and mountainous terrain near the Cumberland Mts. in East Tennessee. Hope to upgrade to "real" repeaters in the near future and we plan on expanding our low band system. For us, low band is here to stay.

Mark102 in East Tennessee.

i thought i'd seen it all.

till one day, when working on a glanayre 800 mhz 500w paging xmtr - i saw the local consumers power lowband rptr.

what a site those can's were, 10 in dia by five feet high!

and i thought my vhf can's were big.


i'd agree with the others check out the rptr's antenna system.

i've found water in cables with "water tight connections" and leaky phasing harness's that turned 200 ft of 1/2 hardline in a good water pipe - not to mention the cracked (split) jackets and connectors when the water in the cable freezes.

Bill

My 2 cents is that in our semi-rural Pennsylvania area- lowband has THE BEST mobile to mobile and mobile to base coverage- period. Licensing is easiest on LB (here in the northeast, at least, where every freq is taken.)

Downside?- Pagers are marginal except Minitor III/IV which are USELESS
Portables are spotty as well.
Skip during sunspot. I remember about 10 yrs ago, was
receiving Pasco County Florida on a minitor I (or was it a
plectron??) hanging on my belt. They were setting off
peoples sirens up here!!

Repeaters?- I considered the project until I priced the duplexer at Tessco.
BIG chunk of change. That's why there is a ham that makes
them to your specs out of hardline. Nobody can afford the
new ones.

Mobile antenna and coax- unless you diplex 2 antennas for wideband Syntor X, X/9000 I never found coax length to be much of an issue.

As far as the tower, my local radio shop can't go any higher than a stepladder- liability/ worker's comp insurance.