Quantar or Tait TB9100 for P25C?

[mmckenna]

The TB7300 is 1RU

Harris just released the Two47 line. Single RU 100 watt P25 repeater.

Two47 Base Station

Minimal Footprint. Maximum Performance. Relentlessly Reliable. Point-to-Point Secure. Backed With All-In, 24/7 Support.

www.l3harris.com

 

[BMDaug]

Harris just released the Two47 line. Single RU 100 watt P25 repeater.

Two47 Base Station

Minimal Footprint. Maximum Performance. Relentlessly Reliable. Point-to-Point Secure. Backed With All-In, 24/7 Support.

www.l3harris.com

Damn… that’s awesome! What’s the cost? I’m thinking it’s a bit out of budget for this project LOL!

-B

 

[mmckenna]

Damn… that’s awesome! What’s the cost? I’m thinking it’s a bit out of budget for this project LOL!

-B

I don't know, just saw it last week. Pretty sure it is in the "if you have to ask…." category.

 

[prcguy]

For amateur use I would say Quantar any day, they are cheap and all the components are readily available on Ebay. In my opinion a Quantar is the finest repeater an amateur can buy and the only thing better might be a GTR8000 but at a huge cost.

For commercial or public service use I can't imagine cobbling together some old used equipment that requires some really smart old guys to implement what the OP needs. That would be much better off thrown in the lap of a current vendor and let them figure out your solution. Then your needs will be guaranteed and under warranty for some time.

 

[speedway_navigator]

I have two frequencies but one is 152.915 and the other is 159.960. Does anyone see an issue with using these as a repeater pair?
/QUOTE]

I worked with a fire dept with a 154.445 TX and 154.010 RX, one of the biggest duplexers I've seen.

 

[BMDaug]

Well… the Tait TB9100 just arrived! This thing is sweet! It’s a really powerful platform and it seems much more modern than a quantar. It’s also a smaller footprint. Great logic/timer/task management, CWID, dual mode, voip, analog wireline, remote diagnostics and control. I really want to get a phone interconnect set up.

I don’t know if I’ll need any filters with the two frequencies so far apart. It’ll partially depend on what else is at the site, but I’m planning on using a folded dipole array for TX and another for RX and mounting receive directly above the transmit…

-B

 

[speedway_navigator]

These charts should help you decide how far apart to space the antennas.

 

[mmckenna]

I don’t know if I’ll need any filters with the two frequencies so far apart. It’ll partially depend on what else is at the site, but I’m planning on using a folded dipole array for TX and another for RX and mounting receive directly above the transmit…

-B

If you are going to install this at an existing radio site where there are any other users:
Get a duplexer and run one antenna
Get an intermod panel.

The antenna spacing is key, as speedway_navigator pointed out. Getting enough separation between the two antennas means a lot of extra coaxial cable and two antennas, two slots on the tower interface, two lightning protectors, extra install time, etc.

For all that, you can probably find a good quality used VHF duplexer and save yourself some headaches.

 

[BMDaug]

If you are going to install this at an existing radio site where there are any other users:
Get a duplexer and run one antenna
Get an intermod panel.

The antenna spacing is key, as speedway_navigator pointed out. Getting enough separation between the two antennas means a lot of extra coaxial cable and two antennas, two slots on the tower interface, two lightning protectors, extra install time, etc.

For all that, you can probably find a good quality used VHF duplexer and save yourself some headaches.

Thanks for the advice! I was sort of following the model that the statewide network uses when they set up sites. They use arrays of vertically polarized folded dipoles. They are stacked one immediately above the other. The idea is that since they are vertically aligned and vertically polarized, they sit in each other’s null. They also put an RX preamp on the tower, and then attenuate back down in the rack before going into the receiver. The coverage is pretty good on the system, though definitely not perfect.

All of that said, you’re right! A single antenna would require less tower space, less coax, and will almost certainly cost less. I guess I’ll start pricing duplexers…

-B

 

[mmckenna]

Are you sure that's not just a stacked dipole array? Does it have two separate feedlines, or just one?

I have some stacked dipole arrays like that at work. Really good antennas, wind bandwidth, a lot of gain, very durable.

The 'tower top amps' (TTA's) are nice. I have an 800MHz site where I use one and it improved coverage quite a bit. It's about 150' of 1 5/8" Heliax, but the TTA really helps on some of the hand held radio coverage.

 

[mmckenna]

The intermod panel may be required by the site owner. Even if not, they are a good idea. Makes you a good neighbor and saves you from having to deal with intermod issues your system may add to an existing site. They can really pay for themselves.

 

[BMDaug]

Are you sure that's not just a stacked dipole array? Does it have two separate feedlines, or just one?

I have some stacked dipole arrays like that at work. Really good antennas, wind bandwidth, a lot of gain, very durable.

The 'tower top amps' (TTA's) are nice. I have an 800MHz site where I use one and it improved coverage quite a bit. It's about 150' of 1 5/8" Heliax, but the TTA really helps on some of the hand held radio coverage.

So they use an array of three for RX and three more for TX. There are probably two feet in between a dipole in an array and the two arrays are two to three feet apart. I think some sites use arrays of two instead of three.

Man, intermod panels aren’t cheap! I think the duplexer is gonna be around $500-$700… I really need more places to shop for used radio products!

-B

 

[KK6ZTE]

Well… the Tait TB9100 just arrived! This thing is sweet! It’s a really powerful platform and it seems much more modern than a quantar. It’s also a smaller footprint. Great logic/timer/task management, CWID, dual mode, voip, analog wireline, remote diagnostics and control. I really want to get a phone interconnect set up.

I don’t know if I’ll need any filters with the two frequencies so far apart. It’ll partially depend on what else is at the site, but I’m planning on using a folded dipole array for TX and another for RX and mounting receive directly above the transmit…

-B

Good choice! The Taits are quite flexible, and once you start playing with Task Manager, you'll find there's a lot you can do with them and customize functionality. It's hard going back to something else...

 

[mmckenna]

So they use an array of three for RX and three more for TX. There are probably two feet in between a dipole in an array and the two arrays are two to three feet apart. I think some sites use arrays of two instead of three.

That is an odd setup. Usually there needs to be more vertical separation than a couple of feet.

Man, intermod panels aren’t cheap! I think the duplexer is gonna be around $500-$700… I really need more places to shop for used radio products!

-B

You can find IM panels used. While they are expensive, they prevent a lot of issues that quickly become much more expensive. They reduce the chances of your system generating intermod and impacting other repeaters on site. It's a "good neighbor" thing. Some radio sites might require them. It's usually a good idea to install one at any shared site. If your gear starts generating intermod, it will impact other users at the site. It'll take time and money to track it down. When they find it is you, you'll be on the hook to fix it. You'll also get a bad reputation.

 

[BMDaug]

That is an odd setup. Usually there needs to be more vertical separation than a couple of feet.



You can find IM panels used. While they are expensive, they prevent a lot of issues that quickly become much more expensive. They reduce the chances of your system generating intermod and impacting other repeaters on site. It's a "good neighbor" thing. Some radio sites might require them. It's usually a good idea to install one at any shared site. If your gear starts generating intermod, it will impact other users at the site. It'll take time and money to track it down. When they find it is you, you'll be on the hook to fix it. You'll also get a bad reputation.

So maybe I’m not perceiving the distances correctly… I’m surveying from the ground and maybe I’m not seeing scale properly, but it sure looks close.

Lots of the site owners are hams so I’m sure they have seen it all as far as installs go. We were just talking about having to move a repeater to a different site because someone moved in and used rg58 for two 60’ runs in opposite directions to a couple of yagis that they just laid in some trees… Something about repeating a TV station? I definitely don’t want to be that guy… I have three sites to choose from.

-B

 

[mmckenna]

I definitely don’t want to be that guy…

One of the reasons why we are very careful who we let on our sites, and we have certain standards that must be met.

If you want to see some sketchy installs, a lot of the local Wireless ISP's are running on a shoestring budget and are done by guys who's primary experience is installing data cabling in offices. Most of them don't have any RF background at all. I've seen some scary/messy installs. I've done everything I can to keep WISP out of our sites.
Unfortunately, wireless internet equipment manufacturers love to do "free" training to get these guys out there installing their gear. It has resulted in a lot of people in the industry that don't have any solid background in radio systems. I had one of our guys at work finally meet up with the local WISP installer and show him our tower climbing gear and pointed him in the right direction for tower climber training. Guy was climbing without a harness in tennis shoes.

 

[speedway_navigator]

This is how our PD gets video from the park, the installer must have had a 100' piece of coax and didn't care or know about line loss. Not sure if it's a 2.4 or 5 GHz link but the path is only about 900' so loss isn't too bad. The pole is 40' with the antennas at the top.

 

[mmckenna]

This is how our PD gets video from the park, the installer must have had a 100' piece of coax and didn't care or know about line loss. Not sure if it's a 2.4 or 5 GHz link but the path is only about 900' so loss isn't too bad. The pole is 40' with the antennas at the top.

IP link? We used to have some point to point radios that used a pair of RG-6 like that. Would sometimes find the same thing. I offered to make custom cables for them, but they weren't interested. Their attitude was "if it works, it works".

 

[speedway_navigator]

Yes, not sure the brand of the link, doesn't look like Mikrotik or Ubiquity. They love this but when I told the police chief I wanted them to use that same type of system to link internet from their existing station to the new one he wasn't too happy about it.
The new building is across a parking lot 150' wide, but they ordered a separate system at $325 a month, the old building is $230. Our town manager said he could fly a cable over so I'm going to see what the cost differences are.

If a consultant or vendor tells them something they take it as gospel.

 

[Cameron314]

So maybe I’m not perceiving the distances correctly… I’m surveying from the ground and maybe I’m not seeing scale properly, but it sure looks close.

Lots of the site owners are hams so I’m sure they have seen it all as far as installs go. We were just talking about having to move a repeater to a different site because someone moved in and used rg58 for two 60’ runs in opposite directions to a couple of yagis that they just laid in some trees… Something about repeating a TV station? I definitely don’t want to be that guy… I have three sites to choose from.

-B

Are you seeing a trucked site with combiner and receiver multicoupler antennas by chance?