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lomfs24
06-13-2005, 12:11
I was talking to an old ham the other day about simple cheap repeaters. Let me give you a little background first. I hunt in a remote area where we are very far from a repeater and about 120 miles from a decent hospital. We would be looking at a medivac flight if anything serious were to happen in there. I can hit a repeater that is linked with a large city with a mobile but I cannot hit it with an HT. I can do a crossband repeater with my mobile that kinda helps out a little. But what I was looking for was a simple repeater, run on batteries, that could be quickly and easily dropped off and set up in the early morning hours to cover handy's in a hunting area. Then picked up and night as we returned to our camp. We were using those expensive $30 FRS/GMRS radios from Wally World and they work about as good....well.....as a $30 radio should.

So anyway, I was talking to an old ham and he said you can get a couple handheld radio's and link them together if you can serarate the COS, audio and PTT etc... You would set one at the top end of VHF and one at the bottom end of VHF and get away without having a duplexer. Granted, it wouldn't be the greatest but it would be a simple small area repeater that could be easily carried and set up.
Now, to the question. Does anyone know how to do that? I am not looking for indepth instructions across this message board but rather a website that discusses this.

Thank.
W7DOA
73

Glock Bob
06-14-2005, 00:04
The problem is that HTs aren't designed to RX and TX at the same time. Plus, most HTs max out at about 5 watts (some at 7), so you wouldn't gain any more wattage, just distance. I suppose if you had a ton of money you could rig up a portable repeater or just build a stationary one. You could set it up as a private code-access system and have those who want to access it pay a yearly fee. Then, all you'd have to do is unlock it when you're out and about in the woods and lock it down after you're through. There could be a monthly usage schedule where it could be emergency only on certain days at certain time blocks and open to every other member at all other times. It would be sort of like IRLP nodes that need a DTMF code entered in order to key up.

lomfs24
06-14-2005, 00:17
There are a couple problems with that.
1) The ton of cash part. Seems to be more like an ounce or so rather than a ton.
2) I don't need to increase watts. I need to increase range of HT's in a small area.
3) It would be on state land and I am only there for about 3 or 4 weekends a year through hunting season.
4) I would like it to be extremely mobile so that as we moved from ridge to ridge during the hunt the repeater could easily be moved with us.

As far as HT's not being able to Tx and Rx at the same time. That's why you would have to be able to separate the COS, PTT, audio etc... so that as one started to receive the other one would be prompted to start Tx. Thereby making a reletively cheap extremely portable repeater

Glock Bob
06-14-2005, 12:53
But, if one was prompted to TX while the other keyed up, what would that accomplish? The TXing HT would have to RX at the same time in order to send out any kind of voice TX, otherwise it's just keying up and sending nothing. However, perhaps a manufacturer already makes such a beast. I know Kenwood makes the mobile that can act as a mini repeater, as I believe you already have one. However, that could run down the battery in your vehicle if you're not careful or get stuck out there for a while.

You might want to look into a portable yagi antenna. Arrow Antenna (http://www.arrowantennas.com) makes them commercially, and you can even make your own (http://www.g6lvb.com/HomebrewArrow.htm). Lots of folks use them to get out to satellites with HTs, so it should be a help with hitting a repeater.

lomfs24
06-14-2005, 16:03
You are right Bob, I do have a crossband repeater. It is a Yaesu 8500. I have planned to set that up as a crossband repeater that would get out to a repeater about 55 or more miles away. The idea with the HT repeater was to create a larger cell, if you will, for out HT's between hunting partners not really to get out to a repeater.


I don't know if I explained the HT repeater thing well enough. Basically, when on HT began recieving it would key up the other one to TX. The audio, rather than coming out on a speaker would be passed to the other HT that was keyed up to TX. That's why you would have to separate the COS, PTT and audio wires. There would, of course, be some moding required to do this. Then you would take the whole mess and put it in a project box that was water proof.

Anyway, I was just looking for ideas.

thenewguy
06-14-2005, 22:05
Some of the nicer (read: more expensive) HTs have crossband repeat capability. My good 'ol ADI dual-band HT does, as do the modern Kenwood models. Since we all know the secret to an effective repeater is not power output but *location* (usually on top of hills and such) an HT-based repeater can work quite well. I've used mine a couple times with good results. :)

You probably just don't want to leave a $400-500 Kenwood HT up in a tree somewhere, so you might look for a used ADI dual-bander on EBay that can work just as well.
-Adam

Glock Bob
06-15-2005, 00:50
Ok, if modding is involved then it could work, I suppose, but it would make my head hurt thinking about it ;g . Now a crossband HT, I didn't even think about that. It seems my VX-5R might have that capability.

So, in effect you're just wanting to boost a TX without actually boosting it (ie without pushing more watts). How very interesting. :cool:

Glock Bob
06-15-2005, 00:58
Are you or any of your friends Generals or above? If you all, or at least most of you, had HF privledges it would seem that you would be able to TX farther than VHF/UHF as HF is a longer wave length and requires less wattage to travel the same distance as higher MHz require.

Also, 6m is open to Technicians, which is as close as we (us Techs) can get to HF. I know it's not the best or most popular band, but it would seem that would make it a good alternative to HF, assuming RF interference isn't too bad in the area you wish to operate within, as 6m suffers from it.

lomfs24
06-15-2005, 01:38
Originally posted by Glock Bob
Are you or any of your friends Generals or above? If you all, or at least most of you, had HF privledges it would seem that you would be able to TX farther than VHF/UHF as HF is a longer wave length and requires less wattage to travel the same distance as higher MHz require.

Also, 6m is open to Technicians, which is as close as we (us Techs) can get to HF. I know it's not the best or most popular band, but it would seem that would make it a good alternative to HF, assuming RF interference isn't too bad in the area you wish to operate within, as 6m suffers from it. Unfortunately, NO. I am and everyone else there will be techs. 6M might work, we will have to play around a bit with that. I do have a Yeasu VX5R which has 6M capabilities. But I don't think anyone else has 6M abilities.

thenewguy
06-15-2005, 09:32
Originally posted by Glock Bob
Ok, if modding is involved then it could work, I suppose, but it would make my head hurt thinking about it ;g . Now a crossband HT, I didn't even think about that. It seems my VX-5R might have that capability.

So, in effect you're just wanting to boost a TX without actually boosting it (ie without pushing more watts). How very interesting. :cool:

With a good location for the repeater, you don't need more power than an HT provides. It's all about location, location, location. :)
-Adam

Glock Bob
06-15-2005, 09:47
There's always a catch if you look hard enough. I've found 6m to be quiet on one frequency and overcome with white noise just a few KHz up. Tone Squelch should clear up any unwanted transmittions of white noise, except of course those that happen simultaneously with someone TXing with your same Tone.

lomfs24
06-15-2005, 18:52
Originally posted by Glock Bob
Ok, if modding is involved then it could work, I suppose, but it would make my head hurt thinking about it ;g . Now a crossband HT, I didn't even think about that. It seems my VX-5R might have that capability. I don't think the VX-5R has crossband repeat ability. At least I have not found it on mine.

So, in effect you're just wanting to boost a TX without actually boosting it (ie without pushing more watts). How very interesting. :cool: Now you are getting the picture. For instance, let's say there was a ridge, one hunter is on one side and one is on the other side. Normal HT comms could not happen between the two. But with even a low power repeater in the middle at the top of the ridge it would be possible. That is just one scenario for it. A fast moving Search and Rescue party might also find the extra distance and extreme portability a plus.

Glock Bob
06-15-2005, 21:55
Yeasu makes a portable mobile rig, the model FT-817 (http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=102&encProdID=4muXjWdMWmk%3D&DivisionID=65&isArchived=0). However, it does not seem to have crossband repeat as far as I can tell. If it did it would probably be exactly what you were looking for.

lomfs24
06-15-2005, 22:39
Originally posted by Glock Bob
Yeasu makes a portable mobile rig, the model FT-817 (http://www.yaesu.com/indexVS.cfm?cmd=DisplayProducts&ProdCatID=102&encProdID=4muXjWdMWmk%3D&DivisionID=65&isArchived=0). However, it does not seem to have crossband repeat as far as I can tell. If it did it would probably be exactly what you were looking for. That would be exactly what I was looking for if it had crossband repeat. The downside to crossband repeat is that then everyone has to buy, at least, a dual band rig. The other downside is the $600 price tag. I figure if I can find some plans for this, I can buy a couple older commercial VHF rigs that will go down into the ham bands for about $100 apiece, a couple bucks in solder and wire. And I'll take the other $400 in experience. If I did it that way as well, I could buy older VHF commercial rigs for use too. You can usually find them on eBay for around $100. True they don't have all the bells and whistles that a newer ham radio has but when I am hunting I only need one volume knob, one channel knob and one PTT button and a jack for a headset. That's all I want to deal with. Then I have cheap radios all the way around and I lose one or one get's damaged I am not out a $400-500 Kenwood.

Glock Bob
06-16-2005, 22:34
Ok, this is all starting to come together for me. I've made a diagram, below. It's crude, but I think it will sort of demonstrate what I think will work.



http://webpages.charter.net/netpresence/htRepeater.JPG

HT1 and HT2 are set to two different frequencies that will not interfere with any repeaters in the area and are offset by a considerable amount, say the normal 600 KHz. When someone TXs on HT1 freq, the speaker wires, which would normally power the speaker, now are attached to HT2's PTT and microphone. The power through the wires trips the PTT button (can be accomplished via a relay or something) and the audio is sent to HT2's microphone, thus being TX'd on the second frequency. You could even run a small amplifier to boost HT2 up to 10 to 15 watts to help ensure better coverage.

Does this make any sense at all? It does to me, but it's 11:30 at night and I've had a pretty long day.

lomfs24
06-16-2005, 22:44
OK, now we are getting somewhere. It does make sense, kinda. I think we are missing some caps somewhere. Some other things to think about that I didn't think about earlier is desensing (I don't know if that's how you spell it or not) one radio with another. I think if you used the whole band as a spread (tx at 144.000 plus a little rx on 148.000 minus a little and set a channel on the radios you will carry with an odd repeater split) you could actually get away with a single antenna, say, a J Pole of sorts hung in a tree. If you use two separate antenna's I think you would want to separate them by at least 6 feet but you could use a more conventional repeater split.

I did find a PDF on rough schematics on how to do it with Bendix King VHF radios. Although they operate in commercial bands I think the idea could be used for ham radios as well. Just have to get schematics for what ever radios you wanted to use. I will include the pdf as an attachment to this message.

greenlead
06-17-2005, 03:08
Are you talking about about repeating FRS or Amateur. I think the FCC has some regs limiting the range of FRS a bit.

I do know that there are some premade repeater kits out there that consisit of the circuits necessary to make a quick erpeater out of HTs. I learned this when I was interested in doing one of these a while back via a few Google searches.

How are you planning on taking care of the identificataion and licensing requirements for the repeater?

lomfs24
06-17-2005, 07:55
I don't believe there are restrictions on the distance of an FRS radio. However, there are restrictions on power limits and with the rinky dink antenna's that are put on those radios you just don't get anywhere.

I am planning on repeating ham freq's. I will ID manually, and I will take care of licencing too. No need to worry there.

Do you happen to know where some of these premade kits are? Or what they consisted of. I seems to me there is really nothing more than a couple wires and a cap or two. I suppose people would pay for that if it's in a neat premade package.

EUPHER49
06-17-2005, 08:54
Paragraph 2 of the PDF doc is crucial:

As with any repeater system not incorporating cavity duplexers, self-interference and receiver desensitization must be considered when using the system. Repeaters constructed using this document should be limited to two watts, use CTCSS (CG) receiver decoding, use separate battery packs on each radio, use input and output frequency separation of at least 1 megahertz and maintain an antenna separation of at least six feet. Radio mounted flexible antennas may be used allowing the entire system to be placed on the roof of a vehicle parked at a geographically high location.

Cavity duplexers for 2m are VERY expensive!!!

The transmit timeout feature is also required by FCC rules for remotely operated systems.

Glock Bob
06-17-2005, 22:52
Yeah, it may be a little tricky, mostly with the FCC. Technically you would be making a repeater of sorts, and would, therefore, need to register it as such and pay any fees. However, you are using HTs, which only require you to have an operator lisence. However, I would try it with some cheap HTs first, if only to see if it can be done. I doubt the FCC would really care so long as you keep the wattage down and the frequencies away from other repeaters to avoid interference.

EUPHER49
06-17-2005, 23:20
Just a point of clarification on Glock Bob's post. The FCC doesn't actually register repeaters. The Frequency Coordination Commitee in your area "coordinates" them. Once you have the approval for a frequency pair then nobody can use that pair and cause interference with yours.


Check here for one near you:

http://www.arrl.org/nfcc/coordinators.htm

They actually coordinate commercial stuff too...

greenlead
06-20-2005, 17:19
Originally posted by lomfs24
Do you happen to know where some of these premade kits are? Or what they consisted of. I seems to me there is really nothing more than a couple wires and a cap or two. I suppose people would pay for that if it's in a neat premade package.

I get a lot of results doing a quick Google search for "portable repeater".

Another thought: How much time can the HT handle transmitting for? Rather than transmitting just for the normal duration of one person operating it, it will be transmitting EVERYONE's traffic. It will need to be quality built, have a good heatsink, and will need to disable any transmit-limit menu functions. You will probably also need an external power source, because transmitting will drain the batter relatively quickly.

lomfs24
06-20-2005, 19:46
Originally posted by greenlead
I get a lot of results doing a quick Google search for "portable repeater".

Another thought: How much time can the HT handle transmitting for? Rather than transmitting just for the normal duration of one person operating it, it will be transmitting EVERYONE's traffic. It will need to be quality built, have a good heatsink, and will need to disable any transmit-limit menu functions. You will probably also need an external power source, because transmitting will drain the batter relatively quickly. This will be a unit that will be utilized during hunting. Bowhunting to be more specific. So it would sit idle for the majority of the day. It would only be needed or used to co-ordinate a couple people if something was taken or to give quick directions if someone was lost. Most of the time it would sit idle. I would expect total usage of about 10 mins a day and 30 minutes on the outside if there were a lot of things happening that day.

I will do a google search and see what I can come up with.

Lawfficer
06-23-2005, 19:01
For a battery source I would suggest a Car Jumper Pack from Wal-Mart. They're basicly a car battery with a pair of jumper cables permenatly attached, and a provision for a Cig plug.
120V or 12V rechargeable. Works really well as long as your not trying to run a 100W Syntor off it.

lomfs24
06-23-2005, 19:21
Originally posted by Lawfficer
For a battery source I would suggest a Car Jumper Pack from Wal-Mart. They're basicly a car battery with a pair of jumper cables permenatly attached, and a provision for a Cig plug.
120V or 12V rechargeable. Works really well as long as your not trying to run a 100W Syntor off it. Good idea, great idea actually. There is only one problem that I can see with it. The jumper pack that I have from wally world has a safety shut off switch in it so that you can just touch the two leads together and get a spark. You have to have some amount of power to get it to turn on. This makes me mad because when I use it to jump a dead battery on a car I have to get a set of jumper cables to get it to turn on anyway.


I am sure there are some older models that don't have that saftey feature on them though. I think I am going to have to worry about building it first. I think the power source will take care of itself later.

Lawfficer
06-23-2005, 19:28
Order a pig tig adapter and plug it into the Cig Lighter port. That's what I do.

PRC 74
07-16-2005, 21:53
Here is an idea. If you just want commo between hunting parties you might consider setting up a temporary simplex repeater. It take some getting use to but is cheap and does extend your range. Radio Shack use to make them and I think MFJ makes a version. I guess a more disciptive term for them would be a "parrot". You plug this device into your tranciever placed on a high point between parties set to a simplex freq. When the transceiver hears a signal on the simplex freq. it will record 30-60 seconds of audio. As soon as the signal drops it keys the TX and sends the recording. Remember this is all on a simplex freq. so you don't need duplexers. You have to train your people to keep messages short and not get confused when the hear their previous transmission being repeated. Takes alittle getting use too but is cheap and does work. Will work with any VHF/UHF radio not necessarly amateur. Just a thought for a cheap and dirty system. Your thoughts?
73

Kim W4OSS

lomfs24
07-17-2005, 22:08
I wasn't aware of a "parrot". It sound like it might work the way I would like it to. Except for the voice delay. But that is an acceptable "cost" of they are cheap enough.


As a side note, I do remember someone on eham.net say something about a parrot. But it was said in such a derogatory way in the middle of a bunch of derogatory posts so I didn't even bother to read it. I was really surprised at the level of elmering that happens on eham.net.

PRC 74
07-18-2005, 07:27
Well it is not perfect by anymeans. But is relivly cheap. I did some checking and MFJ does still sell them. It is the model 662 for about $80.00. The unit is about the size of a pack of cigarettes. It is light enought that if you used it with a light transceiver/battery combo you could through a rope over a tree limb and pull it way up.
The way I would set it up:
1)The repeater(parrot) transceiver set to a simplex freq. with tone encode and decode set to a CTCSS tone of your choise.

2) Program channel 1 of the handhelds for the same freq. as the "repeater", but with no tone settings. Just carrier squelch.

3) Program channel 2 of the handhelds for the same freq. as the "repeater", but set to use tone encode and decode the same as CTCSS as the repeater.

This way you could use channel 1 DIRECT when the handhelds are with in range of each other. You can still monitor the repeater since it is on the same freq. so if a unit is out of DIRECT range you will hear him call on the repeater, then switch to channel 2 to work him.

Since channel 2 and the repeater are set for tone encode/decode it will only respond in the repeat mode. With the handhelds on channel 2 they would not hear the weak out of range handhelds on channel 1 but they would hear you and know to go to channel 2 to communicate with you.

Remember channel 1 and 2 are on the same radio FREQUENCY, just one is toned the other is carrier squelch.

Here is an exsample of what can be done.

http://www.qsl.net/kq6xa/repeaterpack/

Let me know if this works out for you.

Kim W4OSS

TaxCop
07-26-2005, 20:46
Something else to think about is using GMRS repeater pairs. The 5 mhz split would allow the use of notch filters rather than duplexers that VHF would allow. Also, the question of coordination would be easier as there are set repeater pairs. There are plans out there to convert old GE MastrII to repeaters. I am not totally familar with all the ins and outs of GMRS so you might want to do a search on it HT's for GMRS are not all that expensive anymore so that also helps.

lomfs24
07-26-2005, 22:15
Originally posted by TaxCop
Something else to think about is using GMRS repeater pairs. The 5 mhz split would allow the use of notch filters rather than duplexers that VHF would allow. Also, the question of coordination would be easier as there are set repeater pairs. There are plans out there to convert old GE MastrII to repeaters. I am not totally familar with all the ins and outs of GMRS so you might want to do a search on it HT's for GMRS are not all that expensive anymore so that also helps. The problem I have had with FRS/GMRS is that with the extremely quality equipment and the quality antenna's that are put on them you can use them about as far as you can spit. I know that the box says 5 miles but real life experience has shown me that about 500 yards in normal terrain is about all you get out of them. I suppose if you were on the salt flats you might get somewhere near 5 miles. Maybe.

lomfs24
07-27-2005, 08:38
Here is a neat bit I found about digital parrots. From a site discussing legallities of repeaters.

As these digital store and repeat devices are not repeaters, they can not be operated under automatic control, if you the control operator is NOT physcially at the control point of the device, it can NOT be used. You can NOT leave one of these systems on 24 hours a day unattended !

While I wouldn't leave it unattended for 24 hours I would not be with it all the time.