Cross Band Repeat

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srpawski

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I understand the concept, however, is more than one radio required? I mean I am thinking about getting a portable go kit with a mobile unit and if using that radio by itself will this feature work or is another radio needed? Second, can I use my 2 meter only handheld to transmit within range of, have a dual band cross band repeat mobile unit pick up the handheld transmit and re broadcast it at higher power on either 2 meter or 70 cm?
 

nd5y

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I assume you are talking about dual band or quad band mobile radios with crossband repeat capability.

If you have to ask if another radio is required then no you don't understand the concept.
A crossband repeater by itself if useless.

You need a more than one radio to talk to other people through the repeater, otherwise you would just talk on the crossband repeat capable radio itself and there would be no point in using it in repeater mode.

You can't talk to the crossband repeater on 2 meters and have it repeat on 2 meters. The repeater function only works on different bands.

Normally you set up the repeater to transmit and receive both ways on a 2 m simplex channel and a 70 cm simplex channel. There are different ways to configure what channels the other user radios transmit and receive on depending on what you want to accomplish.
 

Mark

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Crossband comes in real handy if you are working a event or drill I can go indoors
at any location with handheld like my FT-60 with stubby antenna and have vehicle with FTM-400 outside nearby and crossband UHF simplex low power into car radio working 2 meter repeater easily.on
the A band.
Just remember to turn down power on your mobile repeater as had one member leave both
bands on 50 watts input/output and car battery died a while later.. :(
Low power in and medium power out solves that problem and of course maybe starting your car every so often if your battery is in not
good shape :)
Also add a PL tone to your simplex HT output and matching repeater input so you don't accidently get another Ham taking control of
your repeater radio.. ex:446.025 PL 107.2 input.
 
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ko6jw_2

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Cross band repeat can be a useful tool. You could, for example, configure your mobile to link your HT to a local repeater when you are away from the car. On the other hand, it can wreak havoc. As the trustee of two repeaters I recently started hearing the local sheriff's radio through one of our 2m repeaters. Some nitwit had set up a cross band repeater to receive the sheriff and retransmit on the input to the repeater. Annoying, stupid and illegal. I got on the air and asked that whoever was doing it to stop immediately. Wonder of wonders, they did. The person did not identify. This brings up another point, some radios that do cross band repeat have a feature that allows for a Morse identifier. This is a good idea especially if others will be using the same cross band repeater.

Bottom line: Just because you can doesn't mean you should.
 

srpawski

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The last two posters responding to my question basically hit on exactly what I was attempting to ask.

My hand held is only 2 meter. Most of the repeaters in my area are 2 meter including my county and surrounding county ARES/RACES repeaters. If I wanted the capability to have 1) 440 and/or 2) a higher transmit power to 2 meter than the 5 watts inherent maximum on my handheld, could I transmit on my handheld, and configure the mobile to pick up what is being transmitted on the handheld, rebroadcast it on the higher output that the mobile is capable of transmitting on or have it rebroadcast on 440?

The other question I have is this - if this is possible, would I choose a simplex frequency to broadcast from on the handheld that the mobile would pick up, and then choose the repeater input frequency to have the mobile rebroadcast what it receives in simplex from the handheld so that my broadcast would get into the repeater? What I am basically looking to do is have the ability to transmit on a higher power not investing in a stationary desktop transceiver in the event it might be necessary to have a higher power output to get into the repeater, or if I wanted to get into a neighboring county repeater also requiring a higher transmit power than 5 watts.

What I am unsure of, from a technical side of things as I have not yet researched enough, if this is possible to have the cross band pick up on a different frequency than it transmits on. It would seem you would not want both the handheld transmitting on the repeater input frequency and have it picked up by the mobile and then the mobile rebroadcasting simultaneously on the same frequency.

I have a Kenwood TH-K20A handheld and was looking at the Kenwood TM-V71A as the mobile unit.
 

ko6jw_2

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Yes, you would transmit on a simplex frequency from your HT and then the mobile would transmit on the repeater input and your traffic would go out through the repeater. Your mobile would have to have cross band repeat capability. On the receive side the mobile would repeat traffic from the repeater back on your simplex frequency. If you wanted to use this set up with a 440 repeater you would need to have you handheld transmit on 2m. You can't use the same band. That's why it's called cross band repeat. The HT doesn't have to be dual band.
 

srpawski

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Cool, thanks. I just found a Youtube demo of the TM-V71A doing this and this is exactly what I was asking and you had responded.

And yes, not cross band repeat if I wanted to transmit from my 2 meter hand held to the mobile in 2 meter an have it repeat in 2 meter, that is lock band repeat which this unit also supports. I checked the Kenwood manual and it supports this. So I should be able to basically do the same thing 2 meter to 2 meter. I didn't have the terminology correct for this use if I wasn't going to cross band. It would only make sense that if a unit could cross band it ought to lock band unless the lock band is something unique to Kenwood.

If I am wrong on my interpretation of this, please let me know. I have done a search on this and have come up with two different interpretations on two different sites as to how lock band repeat works. That said, if I am wrong, is there a mobile that repeats both directions on the same band?
 
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W9BU

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And yes, not cross band repeat if I wanted to transmit from my 2 meter hand held to the mobile in 2 meter an have it repeat in 2 meter, that is lock band repeat which this unit also supports. I checked the Kenwood manual and it supports this.
The point you are missing, I think, is that your mobile radio that you have set up to cross-band repeat cannot operate on the same band on both "sides" of the radio. It has to be cross-band. You can set the mobile radio up to receive on 2m and transmit on 440 or you can set it up to receive on 440 and transmit on 2m. But, you cannot have the mobile radio receive on 2m and transmit on 2m. Doing so would require a device, typically a duplexer, to isolate the two 2m frequencies.

I am very familiar with the cross-band capabilities of the late-model Kenwood mobiles. When they are set up for cross-band repeat, the radio listens on both 2m and 440. If it hears something on 2m, it repeats it back out on 440. If it hears something on 440, it repeats it back out on 2m. Think of this mode as a 2-way cross-band repeat. The locked-band repeat mode in the Kenwoods is one way. It can listen on 2m and repeat on 440, but it ignores what it hears on 440. Or, you can set it up to listen on 440 and repeat on 2m, but it ignores what it hears on 2m.

When would locked band repeat be useful? Let's say you need to operate form a location using your handheld radio and you are going to be operating through a repeater on a tall tower or mountain top. You can hear the main repeater just fine with your handheld, but the repeater doesn't hear your handheld very well. If you had your vehicle positioned somewhere close to you and your vehicle's radio and antenna were strong enough to work the main repeater, you could set up your vehicle's radio to operate as a locked-band repeater that would listen on 440 and transmit on 2m. Then, with your dual-band handheld, you would listen on 2m so you could hear the main repeater, but you would transmit on the 440 frequency that your mobile radio was listening to. When your mobile radio hears your 440 transmission, it will transmit back out on 2m with a strong enough signal for the main repeater to hear you.
 

srpawski

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The point you are missing, I think, is that your mobile radio that you have set up to cross-band repeat cannot operate on the same band on both "sides" of the radio. It has to be cross-band. You can set the mobile radio up to receive on 2m and transmit on 440 or you can set it up to receive on 440 and transmit on 2m. But, you cannot have the mobile radio receive on 2m and transmit on 2m. Doing so would require a device, typically a duplexer, to isolate the two 2m frequencies.

I am very familiar with the cross-band capabilities of the late-model Kenwood mobiles. When they are set up for cross-band repeat, the radio listens on both 2m and 440. If it hears something on 2m, it repeats it back out on 440. If it hears something on 440, it repeats it back out on 2m. Think of this mode as a 2-way cross-band repeat. The locked-band repeat mode in the Kenwoods is one way. It can listen on 2m and repeat on 440, but it ignores what it hears on 440. Or, you can set it up to listen on 440 and repeat on 2m, but it ignores what it hears on 2m.

When would locked band repeat be useful? Let's say you need to operate form a location using your handheld radio and you are going to be operating through a repeater on a tall tower or mountain top. You can hear the main repeater just fine with your handheld, but the repeater doesn't hear your handheld very well. If you had your vehicle positioned somewhere close to you and your vehicle's radio and antenna were strong enough to work the main repeater, you could set up your vehicle's radio to operate as a locked-band repeater that would listen on 440 and transmit on 2m. Then, with your dual-band handheld, you would listen on 2m so you could hear the main repeater, but you would transmit on the 440 frequency that your mobile radio was listening to. When your mobile radio hears your 440 transmission, it will transmit back out on 2m with a strong enough signal for the main repeater to hear you.

Gotcha. That explanation of the difference of locked and cross band makes perfect sense.

Thank you all very much for your replies to my questions. I now I have a clear understanding of how this feature works.
 

mikey60

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One thing to watch out for when operating in cross-band mode into a repeater. If the repeater has a long hang time, you won't be able to transmit until the repeater times out and drops the carrier. During that time, your mobile radio is still transmitting on the frequency your HT is using, so it won't be listening for anything on that frequency.

Cross-Band really works best when you're trying to extend range on simplex or a repeater with a short hang time.

Mike
 

SCPD

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Reading your question, Srpawski-- as I see it, it sounds like you'd like the capability of transmitting and receiving on 2 metre's exclusively..ie: talking and receiving into a remote 2 metre radio from a 2 metre handheld and having it listen and rebroadcast out on another 2 metre frequency. It can be done; what you are describing is a 2 metre repeater-that is, if the remote has separate input and output frequencies. But listening and transmitting on the same frequency?.. it can be done, but Oh !, the headaches and $$'s. It seems to me that some airports do this for low power ground control- same channel repeat-- but I am probably wrong.
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You can do a same in/out channel repeater quite easily; its called a Simplex repeater. A handheld can be set up as for simplex, and then the repeater plugs into the mic and speaker jacks. It will now receive, store and rebroadcast the message back on the same frequency.... they are called "Parrot Repeaters".. and they can be, like the bird itself, quite annoying. On the other hand they are cheap, and fun to play with- you can amuse yourself for days listening to your own voice... :)
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They do work quite well for extending the range of low power'd devices.
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..............CF
 

N4GIX

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One further example of how useful cross-band repeat can be. Where I live, I cannot get into either of our two club repeaters from an HT, so when we have our weekly net, I either have to sit at my desk in the shack for the entire net, or...

...set up my shack's dual-band radio to cross-band mode and use any of my HT's to work the net without tying me down to my desk. :lol:

147.000 +0.6 131.8 <----> 440.700 131.8 simplex

NB: Do not ever try to link two repeaters via cross-band though! :roll:
 

srpawski

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That, too, is a good point.

So do I assume correctly that, when the radio is in cross band repeat mode, that the broadcast channel to the repeater frequency input and output offset is programmed into the radio with corresponding PL tone as would be in a normal broadcast setting as this channel would have been programmed into the radio normally and selected as the output channel when putting the radio into cross band mode?
 

kc4jgc

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That, too, is a good point.

So do I assume correctly that, when the radio is in cross band repeat mode, that the broadcast channel to the repeater frequency input and output offset is programmed into the radio with corresponding PL tone as would be in a normal broadcast setting as this channel would have been programmed into the radio normally and selected as the output channel when putting the radio into cross band mode?
If I'm reading this correctly, yes. For instance, your simplex link to your dual band mobile radio is freq "A". When you transmit (not broadcast, there IS a difference) to your mobile, the mobile simultaneously retransmits (in your example to a repeater input) on freq "B". When you release the PTT on your handheld, your mobile then receives the repeater output (freq "C"), simultaneously retransmits that signal back to you on freq "A".

Cross-Band really works best when you're trying to extend range on simplex or a repeater with a short hang time.

Mike
Right. Something that can also work is if a repeater can be configured to transmit a PL tone only when a signal is present on its input. That way, the PL on the repeater drops as soon as an input signal stops but can still keep the hang time as long as the owner(s) want(s).This allows someone crossbanding to reply without having to wait for the repeater to drop. There is a 220 repeater in my area that does just that. Works seamlessly. Otherwise the quick/dirty way is having the repeater you're accessing to have a very short or no hang time.
 

nd5y

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Right. Something that can also work is if a repeater can be configured to transmit a PL tone only when a signal is present on its input. That way, the PL on the repeater drops as soon as an input signal stops but can still keep the hang time as long as the owner(s) want(s).This allows someone crossbanding to reply without having to wait for the repeater to drop. There is a 220 repeater in my area that does just that. Works seamlessly. Otherwise the quick/dirty way is having the repeater you're accessing to have a very short or no hang time.
Don't count on that. Unless you own the repeater you most likely have absolutely no control over how it is configured.

Depending on how the repeater is built and what kind of controller is used the owner might not even be able to configure it like that.

I have heard of some repeater groups doing the opposite to make it difficult to use for people on simple mobile crossband repeaters that don't have a full duplex control link.
 

SCPD

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Srpawski, I think you have the idea behind the cossband principle. I don't want to conflict with what the others have said, nor get too involved in technicalities. So I offer--
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"Coyote's Crossband Repeater-Redux'd" --
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A cross band repeater, by its very name, implies it repeats one band of frequencies to another- several examples:
#1. Handheld A transmits on 440.0 Mhz to a cross band repeater receiving on 440.0 Mhz. The repeater rebroadcasts out this signal on 146.0 Mhz. The Remote receives on 146.0 and re-transmits back to Handheld A on 440.0. Only two frequencies, in two seperate bands, are used.
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#2. Handheld B transmits to the crossband repeater on 440.0 Mhz. The remote repeater rebroadcasts this time on 146.16 Mhz, but listens on 146.76 Mhz and transmits back to Handheld B on 440.0. This would be the case in using the remote to access a distant 2 metre repeater. If this 2 metre repeater being access'd required a PL tone, the crossband remote would have to transmit it...ie: 146.16 Mhz, PL 67 Hz.
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#3. Handheld C transmits to the crossband repeater on 440.0. The remote rebroadcasts out on 146.16. The crossband repeater listens on 146.76 but transmits back to Handheld C on 445.0 Mhz. Handheld C is set to receive on 445.0. PL tones can be added.
As you can see, there are a lot of variations as to how this crossband system can be configured. PL tones are not necessarily required. You can design the system as simple as #1 above or go for it, making it a lot more complex.
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_____________________________________________________________
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A side note..... I have ponder'd at the legality of a ham crossband repeater. It should have it's own form of ID, though I guess the user announcing something like
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"this is KZ6XX transmitting thru the KX7XX remote..."
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....... should do it...but how often is that done** ??
The other thing that is murky-- to me anyway-- is using a 2 metre signal as the control frequency. Controls are supposed to be 220 and above.... seems to me years ago this was a controversy when a manufacturer came out with the first 2/440 crossband repeat-enabled radio. As I recall, it was determined to be legal.... doesn't matter, I operate one, scoff law or no.... ;)
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......................................CF
______________________________________________________________________
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**Virtually never in my case. I have a crossband remote myself- back home in the mountains-- it sits on a mountainside, listening/transmits(15 Watts) on 146.52 Mhz and transmits back on simplex on 423.xxx. Mhz. I turn it on in the summer to talk to friends summiting the peaks for SOTA, and the rare motorist hams that finds their way into our remote valley... it extends a UHF handheld out +100 miles to certain mountain peaks.... :)
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(I have even had an FCC engineer visit my home- quite a few times over the years (he is a friend.... for family hikes and dinners)... never a word's been said about it... I let "sleeping dogs lie......" ;) )
 
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srpawski

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That's a very good explanation. And yes after reading through those scenarios I do understand how I would set this up to work and as long as I get a dual or triband handheld to mate with the mobile I'll be good to go.

So I take it that 440 will broadcast further than 2 meter given the same transmit power? Is this due to the UHF vs VHF frequency? How much further would you estimate it to travel?
 

SCPD

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High Band VHF v.s. UHF-- oh Wow...that is one emotion filled topic, Srpawski! You will get a lot! of advice there.... highly charged, usually anecdotal...weigh it carefully- including the following :)
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Let me open the can of worms (laffing.)
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I can cite for you the physicist's litany of the science behind one band of frequencies; one as opposed to another... but in end it will come down to an anecdotes anyway. I will avoid the science and give my experiences instead.
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For starters- anything that is line of sight, no obstructions like trees, hills and such- any frequency will work equal to another (smiling- look at the Voyager 1, talking back to earth on 8 Ghz - truly 'line-of-sight'--its signal comes over a 30 hour path ! ----Sorry, I get carried away :) )
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Its when you start to introduce barriers in the radio path that the frequency band starts to come into play. Generally, UHF does a lot better in buildings and situations where the shorter wave lengths can penetrate apertures like doors and windows, hallways- the like. In hilly terrain, mountains and such, these barriers often shadow another station sufficiently as to make them worthless. In my home county, I have had discussions with the Sheriff about the new Colorado DMR 800 Mhz linked system. His review of it has been less than flattering... saying it's a great system for cities and out on the plains, but not suited for the mountains. I'll leave the subject there, except to say they are continuing to work out the dead spots that used to be cover'd with their old high band VHF system.
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High Band VHF does a much better job in the hills and valleys. Unlike UHF, which tends to be either 'there'' or 'not there', High Band VHF has its fading in and out slower. Better still, as in mountains and valleys, is Low Band VHF. So much better in practical usage, that it is what we use in our field work. In places where UHF signal simply won't penetrate, where High band is spotty- the low band signals are the most reliable (next to HF sideband or Satellite.) Low band isn't without its detractors though-- antenna lengths, skip interefence are but two. I find old fashion FM far easier to use than digital modes, btw.
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I hope this gives you some ideas. I am sure you will receive a lot of others. If I could leave you with one thought about all this repeater/remote business it is; Keep it Simple. If you don't need certain features, leave them out. Fancy modes and controllers are nice, but they come at a cost that isn't measured by the Headache Index.
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Good Luck Cowboy! This is a fun aspect of ham radio..... :)
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..............................................CF
 
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kc4jgc

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Don't count on that. Unless you own the repeater you most likely have absolutely no control over how it is configured.

Depending on how the repeater is built and what kind of controller is used the owner might not even be able to configure it like that.

I have heard of some repeater groups doing the opposite to make it difficult to use for people on simple mobile crossband repeaters that don't have a full duplex control link.
Right. The 220 repeater I was referring to wasn't originally configured that way. We got the idea from another ham from NC that had a repeater configured to have the CTCSS drop when the input signal stopped. The visiting ham sent to the owner instructions to route the input signal through the tone board in the controller (an old ACC 96).

With a repeater controller that can be reconfigured on the fly, a hang time can be changed easily. Our main 2m repeater in Virginia Beach had a norrmal 3-5 second hang time, but when it was being used to support a public service event, many of us use our mobiles to crossband. The majority from 440; I use 220. One of the control ops can change the hang time on the repeater to almost zero.

One event in particular, there was so much intermod around the start/finish lines, mainly from pagers, on both 2m & 440 but none at all on 220. For several years the ops at/near the start & finish lines were on 220, crossbanding through my 2m/220 mobile dualbander, which was at my station a block away. With the repeater on a super short hang time, it worked great.
 
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