Will a cross band repeat rig solve my problems?

[kb1oev]

I have recently found out about the cross band repeat function offered by some radios. I think I am in a situation where it would be very beneficial to have, but I would like some input before I buy anything.

Here is my situation:

I typically carry a Yaesu VX-7R around with me at college. My roomate also carries one and we use them to communicate with each other as well as the local repeaters. In some locations, especially within buildings, the HT's are not powerful enough to communicate with. To hit the closest repeater, I need to be outside, and the signal is still scratchy.

I am thinking that if I put a cross band repeat radio in my room with a good size vertical antenna on the roof, that it will allow much easier communication between the HT's and the repeater. Does this sound correct?

The other case where I would like to use this is at Boy Scout events. These usually take place in large wooded summer camps which make the HT's questionable for direct communication, and make repeater communciation out of the question. If I placed a cross band repeater in my truck and parked it in the camp, I would think that it would improve communications immensely. Again, does this sound reasonable?

Any suggestions on alternate methods of improving communication are also welcome, as well as discussion of the pros and cons of different rigs for cross band repeat or other functions.

Thanks in advance
-Blake

[ab0wr]

Quote[/b] (kb1oev @ July 30 2007,06:49)]I have recently found out about the cross band repeat function offered by some radios. I think I am in a situation where it would be very beneficial to have, but I would like some input before I buy anything.

Here is my situation:

I typically carry a Yaesu VX-7R around with me at college. My roomate also carries one and we use them to communicate with each other as well as the local repeaters. In some locations, especially within buildings, the HT's are not powerful enough to communicate with. To hit the closest repeater, I need to be outside, and the signal is still scratchy.

I am thinking that if I put a cross band repeat radio in my room with a good size vertical antenna on the roof, that it will allow much easier communication between the HT's and the repeater. Does this sound correct?

The other case where I would like to use this is at Boy Scout events. These usually take place in large wooded summer camps which make the HT's questionable for direct communication, and make repeater communciation out of the question. If I placed a cross band repeater in my truck and parked it in the camp, I would think that it would improve communications immensely. Again, does this sound reasonable?

Any suggestions on alternate methods of improving communication are also welcome, as well as discussion of the pros and cons of different rigs for cross band repeat or other functions.

Thanks in advance
-Blake
I don't know about the college campus situation but at the Boy Scout camp, if you can't hit the repeater when you are in the woods you will probably find it difficult to hit your truck as well. At 2m or 70cm propagation is mostly line-of-sight. If you can't hit a high antenna on a repeater it will probably be difficult hitting the lower antenna on your truck.

tim ab0wr

[n5rfx]

I agree with Tim. On the college campus you said you will be able to get an antenna on the roof. That will certainly help.

In the woods you might want to bring a 20 or 30 foot push up pole and possibly guy material and set up a temporary dual band antenna. Metal pushup poles are heavy, but I have used 30 foot fiberglass poles that are used for windsocks and have removed the small diameter tubing a the top until I get a good diameter tube to attach the antenna to. Usually I have 20 feet.

I have had great luck with the military aluminum poles that were used for holding up camouflage. The quality of the aluminum is great, and there are guys who sell guy rings too. You can go up to 40 ft. with those, but they are unwieldy if you set it up yourself, I usually limit myself to 30 feet. Here is an example (http://www.tmastco.com/).

You should scout around for a high place to do the installation and that will help with the line of site. RF in heavy canopy is a challenge, but if you are not trying to cover an enormous area, you should be successful. Good luck and
73,
Mark N5RFX

P.S.
fiberglass telescopic poles (http://www.geodatasys.com/pole3.htm)
base spike for aluminum masts (http://www.american-milspec.com/p1375.html) - diameter must be increased, you can do this with friction tape.

[kb1oev]

Mark,

It sounds like you are talking about using the temporary 20-30 tower with the cross band repeat rig. Is this correct?

On a more general note, in both locations (camp and college) I can get into the repeaters just fine with my 50W mobile and 4' whip. The 5W HT with a 3" rubber duck has trouble getting decent audio to the repeater at college.

At the camp, the parking areas is on the highest point, and most of the rest of the camp is down lower. When you are on top of the hill, you can get a straight shot to the repeaters in the area, but if you go down into the rest of the camp, you lose the line of sight, and since the repeaters are not really close anyway, there is no hope of hitting them w/ the HT's. But, leave a vehicle with a cross band repeat rig up top, and as long as you can get a signal to the vehicle then I think hitting the repeater should be no problem. I like the idea of the portable VHF/UHF tower, but I would also like this to be able to work with just the whip antenna on the truck's roof if I can't put up a pole or don't have time.

[k0cmh]

I believe what you are suggesting will most likely work for you, particularly the part about Boy Scout camp.

However, I would recommend that you pick the two frequencies after checking what inputs and outputs of repeaters that are possibly within the range of your signals.

It is good operating practices to not interfer with coordinated repeaters, and can cause the FCC to issue a nastygram for that.

You can get the repeater information from either your state's repeater coordinating council, or from web sites that list repeaters information.

Here is one of the web sites that you will find doing a google searchf or Ham Repeaters: http://www.artscipub.com/repeaters/

The ARRL web site can also get you to state repeater coordinating groups.

[n5rfx]

It depends on your situation. If you just want local communication then you don't need to cross band repeat into the distant 2 meter repeater, if you want to access that repeater to talk with others not at the camp, then yes you would need to cross band repeat to the remote repeater.

I think the issue will be getting the signal from your cross band repeater to the HT's. Your parking lot sounds like a good location and you might be able to use the mobile dual band antenna.

The portable tower thing is not that hard to come up with. I use mine during field day mostly, and it usually holds up the center of a doublet for HF. I have used it for VHF/UHF dual band antennas to do almost what you are wanting to do. I am looking at possibly using this setup for portable WiFi with a 24dBi grid parabolic antenna. Its just fun to be able to be portable with a mast.

Good luck.

73,
Mark N5RFX

[ab0wr]

Quote[/b] (kb1oev @ July 30 2007,07:41)]Mark,

It sounds like you are talking about using the temporary 20-30 tower with the cross band repeat rig. Is this correct?

On a more general note, in both locations (camp and college) I can get into the repeaters just fine with my 50W mobile and 4' whip. The 5W HT with a 3" rubber duck has trouble getting decent audio to the repeater at college.

At the camp, the parking areas is on the highest point, and most of the rest of the camp is down lower. When you are on top of the hill, you can get a straight shot to the repeaters in the area, but if you go down into the rest of the camp, you lose the line of sight, and since the repeaters are not really close anyway, there is no hope of hitting them w/ the HT's. But, leave a vehicle with a cross band repeat rig up top, and as long as you can get a signal to the vehicle then I think hitting the repeater should be no problem. I like the idea of the portable VHF/UHF tower, but I would also like this to be able to work with just the whip antenna on the truck's roof if I can't put up a pole or don't have time.
I know that using two HT's at our BSA camp is problematic at best when you are are separated by very much distance. The foliage just chews up the RF very badly. I suspect it would do it even worse at 70cm than at 2m. The mobile rig may have a better receiver that would work better.

It's not hard to try it. That's the acid test. Nothing we can spectulate on will be as good as an actual experiment.

tim ab0wr

[kb1oev]

Ok, sounds like I should give it a try. I've got a 2m mobile now and wanted to get a 2m/440 for a while, so paying a little more for the cross band repeat won't be too bad.

I've been eyeing the FT-8800 for this purpose, does anyone have other ideas for a 2m/440 mobile with 108-500MHz RX and cross band repeat?

Also, now that I have seen the website for the aluminum masts I've started drooling. I can see one of those in my future real soon.

Thanks to all for the help so far.

[n5rfx]

Quote[/b] (ab0wr @ July 29 2007,09:06)]The foliage just chews up the RF very badly. I suspect it would do it even worse at 70cm than at 2m. The mobile rig may have a better receiver that would work better.
I agree. It will be the clutter that will be your biggest problem. In this case the clutter I suspect is foliage, mainly trees. The idea is to get your cross band repeater antenna above the clutter as much as possible to reduce your path loss from the HTs to the cross band repeater. More than likely you won't be able to eliminate the clutter, but reduce the amount of clutter that your signal has to pass through, thus improving reception. Height above average terrain in the area you are trying to cover is key. Now a chain saw on the other hand.... http://www.qrz.com/iB_html/non-cgi/emoticons/smile.gif

I agree with Tim, give it a shot.

73,
Mark N5RFX

[K4GUN]

I'm a big fan of cross band repeat capabilities. I use it daily. While at work, my HT can barely hit my favorite repeater. It will drop in and out and just isn't reliable. I park my truck about 200 yards from where I work and I set up the CBR. The truck's antenna is much better than my HT (Diamond SG7900 which is 5 DBi gain on 2 meters) and has no problems hitting it. Reception is also much clearer.

I've even played around with ranges on this set up. I have used another vehicle to drive away form my truck. My truck is not parked on high ground and I'm in a suburban environment with lots of buildings, walls and other obstructions. I can get well over a mile away and still hit the truck and therefore, the repeater.

The HT is a Yaesu VX6R and the mobile is a Kenwood TM V708A.

One other hint is that you probably want to set up a tone control on the UHF side of the system. In my area, there seems to be a lot of stray signals that opens up the squelch on the HT unless I use tones.

[N5USR]

I like using crossband repeat as well. Additional comments I would make are:

- Will the CBR radio transmit with enough power to do the job while crossbanding? Odds are it'll be fine, but my older FT-5100 is limited to just 5W on both bands when CBR is turned on. You may have to make up the difference with antenna gain.

- Will the CBR radio survive? Your scenarios don't sound like high-usage situations, but remember that if anything is being received on either frequency, the radio will be transmitting on the other. So if you use it to link to a busy repeater, it'll be transmitting the whole time. Most mobiles aren't designed for 100% duty cycle (which is why many, like mine, limit the power level for CBR).

- One catch with crossbanding to a repeater is that you will have to wait for the repeater to drop before you can talk back. This can get very annoying, especially if the repeater has a long tail.

[KC5SAS]

Quote[/b] (N5USR @ July 30 2007,13:54)]- One catch with crossbanding to a repeater is that you will have to wait for the repeater to drop before you can talk back. #This can get very annoying, especially if the repeater has a long tail.
Man I hate long tails on repeaters. Some here are 5 seconds and if you are trying to crossband into them it's nearly impossible to have a conversation.
Another thing that wasn't mentioned and I've learned the hard way, the CBR radio is hooked to your car battery. Use it too much and you may get back to your car and find you don't have enough juice to crank the engine. Then it's jumper cable time. Oooppps.

[W1SK]

Will the 8800 ID itself?


Joe

[K4GUN]

Quote[/b] (N5USR @ July 30 2007,13:54)]- Will the CBR radio survive? #Your scenarios don't sound like high-usage situations, but remember that if anything is being received on either frequency, the radio will be transmitting on the other. #So if you use it to link to a busy repeater, it'll be transmitting the whole time. #Most mobiles aren't designed for 100% duty cycle (which is why many, like mine, limit the power level for CBR).
Which is why I use the tone squelch feature on the UHF side. That doesn't do anything about a busy repeater but does knock down constant use when odd signals hit my UHF frequency (which seems nearly constant).

By the way, I have left the CBR on for 24 hours and was still able to start the truck. Your results may vary, but in my situation, it was fine.

[wb6mmj]

Quote[/b] (kb1oev @ July 30 2007,06:49)]I have recently found out about the cross band repeat function offered by some radios. #I think I am in a situation where it would be very beneficial to have, but I would like some input before I buy anything.

Here is my situation:

I typically carry a Yaesu VX-7R around with me at college. #My roomate also carries one and we use them to communicate with each other as well as the local repeaters. #In some locations, especially within buildings, the HT's are not powerful enough to communicate with. #To hit the closest repeater, I need to be outside, and the signal is still scratchy.

I am thinking that if I put a cross band repeat radio in my room with a good size vertical antenna on the roof, that it will allow much easier communication between the HT's and the repeater. #Does this sound correct?

The other case where I would like to use this is at Boy Scout events. #These usually take place in large wooded summer camps which make the HT's questionable for direct communication, and make repeater communciation out of the question. #If I placed a cross band repeater in my truck and parked it in the camp, I would think that it would improve communications immensely. #Again, does this sound reasonable?

Any suggestions on alternate methods of improving communication are also welcome, as well as discussion of the pros and cons of different rigs for cross band repeat or other functions.

Thanks in advance
-Blake
As a ex- repeater owner, I don`t recommend doing anything like that without first contacting your local frequency coordination organization.
A cross-band repeater is still a repeater anyway you look at it. It needs to be coordinated.
#When I had my three UHF repeaters I was getting constant interference from people using these radio`s in the cross-band repeat mode. They were the number 1 cause of interference to my systems.
#People that used them would call them "remotes". Not True!. They are a repeater, with a input and a output, simple as that.
Hope that helps you.

[kr9d]

Quote[/b] (wb6mmj @ July 30 2007,16:20)]When I had my three UHF repeaters I was getting constant interference from people using these radio`s in the cross-band repeat mode. They were the number 1 cause of interference to my systems.
You can prevent this problem by not using full-duplex cross-band repeat, right? With a dual-band HT, you can receive on the 2m repeater frequency, and transmit on the UHF frequency, and the CBR radio will only be transmitting when you are talking into the repeater. I think my TM-733A will do that, but I haven't tried it yet.

For a full-time CBR radio, I agree that it's really a full-time repeater and should be coordinated. But it's relatively easy for temporary use to avoid UHF frequencies in local use.

Rick "who can receive the local 2m repeater on an HT, but who can't get it into it without more power" Denney

[K0RGR]

There is a small catch with using the common ham gear to do cross-band repeat. If you transmit on UHF, and have it retransmit you onto the input of a VHF repeater, you can ID both your handheld and the UHF transmitter when you ID. But, if your crossband repeater retransmits the remote VHF repeater to you, the UHF transmission to you will NOT be identified. This is outright illegal. Why our radio manufacturers keeps selling radios with this feature without the ability to ID themselves, I don't know. This feature has been around a long time.

I've never seen anybody get in trouble with FCC for doing this, but it could easily happen. If your repeater does cause interference, nobody will be able to figure out who it belongs to.

There are still ways around this problem. You could get an outboard ID'er and build some logic to have it key up the UHF transmitter and ID periodically. Another Idea would be build an actual repeater instead of using one of the common mobiles. There are several ways to mate a UHF transceiver to a VHF one, including IDers.

It's also possible on some radios to have the crossband repeater only work in one direction. If you can hear the 2 meter repeater OK direct, but they can't hear you, one of these radios can be set to only retransmit from UHF to VHF.
Then, you can ID both your local HT and the repeater.

The 8800 doesn't seem to have the option of one-way repeat, and frustratingly, Yaesu has a CW IDer built into almost everything they sell, but it only operates in ARTS mode, which is something I'd wager nobody actually uses.

[wb6mmj]

Quote[/b] (kb1oev @ July 30 2007,06:49)]I have recently found out about the cross band repeat function offered by some radios. #I think I am in a situation where it would be very beneficial to have, but I would like some input before I buy anything.

Here is my situation:

I typically carry a Yaesu VX-7R around with me at college. #My roomate also carries one and we use them to communicate with each other as well as the local repeaters. #In some locations, especially within buildings, the HT's are not powerful enough to communicate with. #To hit the closest repeater, I need to be outside, and the signal is still scratchy.

I am thinking that if I put a cross band repeat radio in my room with a good size vertical antenna on the roof, that it will allow much easier communication between the HT's and the repeater. #Does this sound correct?

The other case where I would like to use this is at Boy Scout events. #These usually take place in large wooded summer camps which make the HT's questionable for direct communication, and make repeater communciation out of the question. #If I placed a cross band repeater in my truck and parked it in the camp, I would think that it would improve communications immensely. #Again, does this sound reasonable?

Any suggestions on alternate methods of improving communication are also welcome, as well as discussion of the pros and cons of different rigs for cross band repeat or other functions.

Thanks in advance
-Blake
I forgot one thing Blake. You have my respect for asking questions here before acting. Very smart move. I wish more people would ask questions first before doing things they arn`t sure of.
Good luck.

[k0cmh]

The ID situation is a problem with the 8800. I have one.

The corss band function is limited to both ways, that is, it can only function with running both the links.

Other manufacturers have a choice where only the link from your HT to outbound is activated. This is useful when that is all you need, in other words you only need a boost to get to the repeater, but your HT can receive the repeater output fine. This eliminates any possible problems with getting the return line from your radio to ID properly.

However there is a way to do this with the FT 8800. You need to set your HT so that is transmits simplex on the requency that the FT8800 is listening to for the return to you. Let me make this clearer. You HT is transmitting on 70 cm and the 8800 is repeating that on a 2 meter repeater input frequency. The 8800 is listening on for the reply on the 2 meter output frequency which will be retransmitted to your HT. So you set up the HT so that it will also transmit on the 2 meter frequency that the 8800 is listening to. Then every 10 minutes you can transmit your ID on the 2 meter listening frquency and it will ID back on the 70 cm return to you.

[k9kjm]

"Cross Band Repeat" Is about the neatest thing since sliced bread! And should go a long ways toward solving your communications problems.

A few points to remember:

DO use a dual band hand held, Program in BOTH your crossband input AND output frequencies, Then run your handheld in "scan" mode to monitor BOTH frequences all the time. (Just in case that crossband radio gets "hung up" transmitting! (If you did not monitor both, You would NEVER know it was stuck in transmit!!!!!!

I suggest you experiment on simplex two meter frequencies to get the hang of how it operates Before operating thru some big repeater systems..... #There are a few quirks of squelch settings, etc to resolve BEFORE operating into repeaters.......

The Yaesu FT-8800 is about the best radio on the market right now to get.

Whatever you do, AVOID the real dog Icom 2720H!!!!

[kg4kww]

You need a girl friend not a cross band repeate rig.

[KD6NIG]

I'd suggest simplex.

You have to keep in mind that the 8800 in your truck will be transmitting either when your buddy is accessing it, or you are, or when the repeater is being used. So you'll probably have to provide some kind of external cooling. And its going to eat truck battery fast, you'll probably need another, isolated from the main one, lest you want to be getting jump starts every day. If its a busy repeater, it will be transmitting whenever the repeater is in use!

Another thing to keep in mind is that with crossband, in order to access it right, you have to let the repeater totally drop, so the other side will stop transmitting, so it can receive you. If other users on the repeater don't do this, you won't ever get a break in. The transmit won't drop on the radio till the carrier drops on what its hearing, be it your HT or the repeater.

I'd personally suggest simplex for these reasons. I do have an 8800, I have on occasion used the crossband feature, but only if I was expecting a call from someone. And when I did, at all times, I had another cooling fan strapped to it and turning, and I was running it off a power supply.

It gets warm quick even with the little fan on it.

I'd try to improve your HT's or use simplex, personally.

[W0JBC]

I suggest using ' simplex' on the UHF side .. Encoded ... both enc and dec ...

My UHF side has a CW-ID feature ...

As was stated earlier, the VHF repeater side must drop carrier for you to utilize it's system .... It works .... Do not use a UHF repeater to x-band in full duplex ... Simplex is the word .... I made a mistake by using 446.000 once and got chastised ...I did not know it is the national simplex calling frequency ! Like there is alot of UHFers using that every moment of every day ...

Use your brain .....


JB