Building a repeater . . .

[Wire Weasel]

The first order of business would seem to be obtaining a coordinated frequency pair. You do NOT even want to consider going on the air "on your own" by picking yourself out a pair that you believe will be "okay" for whatever reasons. These repeaters owners are a tough crowd.

I find it hard to believe that any pairs are available in So. Cal right now. Even in my rural corner-of-the-state backwoods area...all pairs are taken and in use.

I wouldn't spend .10 cents on any equipment until I had the freq. pair in hand.


Good luck

 

[Robb]

The first order of business would seem to be obtaining a coordinated frequency pair. You do NOT even want to consider going on the air "on your own" by picking yourself out a pair that you believe will be "okay" for whatever reasons. These repeaters owners are a tough crowd.

I find it hard to believe that any pairs are available in So. Cal right now. Even in my rural corner-of-the-state backwoods area...all pairs are taken and in use.

I wouldn't spend .10 cents on any equipment until I had the freq. pair in hand.


Good luck

Fair point.
But the nuts and bolts of a repeater aren't that well known. Although there are MANY repeaters out here, there is room for a few more. But for someone living in the more rural areas of the US, this thread might be helpful.

 

[Wire Weasel]

Fair point.
But the nuts and bolts of a repeater aren't that well known. Although there are MANY repeaters out here, there is room for a few more. But for someone living in the more rural areas of the US, this thread might be helpful.

Room for more? How do you know that? Are you guessing?

 

[Robb]

Room for more? How do you know that? Are you guessing?

To answer your question; yes that was a guess. That is beside the real point here; but valid just the same. This thread was primarily written with the concern to go about understanding and possibly build a modest repeater. Perhaps even an emergency mobile repeater can be built and used with an external antenna, and the proposed freq are acceptable to the frequency coordinator. Thank You.

OK. So we understand that a duplexer must be used to keep the receive on the antenna from desensing. Desensing is interference that can adversely affect the received signal when transmitting on the same antenna. Since the same antenna is both receiving and transmitting, the duplexer makes the TX and RX on the same antenna possible.

Building a 5/8 wave 2m GP antenna with an MFJ-259B can be also be done to save on cost - perhaps $5-$10 plus the cost of an N-connector. The Duplexer is $100 plus shipping from eBay (previously noted). I suppose some LMR-400 coax will work if we aren't going to exceed 50 ft working length length - that's about $75 with N-connectors installed. Let's say that I find a couple of older 2m radios with 50 watts output (<7 years old) at the local hamfest tomorrow for $80 for the pair; that would do just fine. Now, we are up to ~$260 in cost. Yes; I'm GUESSING that the duplexer can handle a 10 watt output w/o further desensing the receiver. The radio output heatsink can get beefed to have a greater duty cycle too for that 10 watt continuous duty.

Will the TX and/or RX radio need specific mods?
What do they need?

Now; what is next? Should the computer, sound card, and the Echostation software be considered next? I have enough old computer parts to put together a Windows 95 box for $0. I also have an old laptop that has Win95 already on it; this will keep the system portable too.

What about the IDer/controller? How does this hook up to the radios? Is it simple and comes with an instruction sheet? Is there a template that sheds more light on this? What about the cabling between the radios, the ID controller and the computer? Can the computer/Echostation software take the place of the IDer functions? Ideas/thoughts?

Moleculo said:

A way to ID - use a computer interface or use the ID-O-Matic from hamgagets for $25.

Using the computer as the ID interface running the Echostation software -I'll guess that the TX radio receiving the output from the receive radio thru the computer should have the VOX on so that it will transmit out. So that all that it would need is a cable from the output of the sound card to the mic input of the TX radio and the speaker output of the receive radio into the input of the soundcard. Perhaps an impedance transformer from the speaker output of the RX radio to the input of the sound card? Is that it?
Thoughts?


Here is a standard repeater layout FYI

http://www.eurekaboy.com/electronics/repeaterbuild.htm

 

[Wire Weasel]

Well okay Robb. You did indicate in the first post that you were interested in putting a repeater up.

This is the kind of thing that no one would actually do unless it was going to go on the air.

Why would anyone buy gear and build a repeater system and then not use it?

If you want to redo this as a tutorial....then you can go back and edit your OP to reflect that.

 

[Moleculo]

If you're interested in extending the functionality of newer digital technologies (D-STAR, P25, etc.) then you have a good reason to put up a repeater even in an area with heavy analog coverage. D-Star (for example) still doesn't have very good coverage in many areas.

 

[Robb]

From the help file of EchoStation:

" . . . Welcome to EchoStation

EchoStation is a repeater-control program for Windows 95/98/NT/2000 which makes it easy to set up a complete, fully-functional repeater or "announcement machine" using a personal computer.
Setup is as easy as installing the software, and connecting a transmitter and receiver to the PC's sound card. The transmitter can be controlled by VOX, or connected to the COM port with an interface such as the RIGBlaster from West Mountain Radio.

EchoStation is perfect for portable and emergency use, or for clubs wishing to use a PC instead of specialized hardware to control a repeater. It also makes an excellent store-and-forward simplex repeater when connected to a single transceiver.

The software also lets you set up an "announcement machine" which plays scheduled voice announcements over your club's existing repeater, using a radio at another location, such as a home station.

All standard repeater functions are supported, such as COR, CW ID, voice ID, and courtesy tone.


What Else Do I Need?

The basic requirements for a EchoStation setup are:

Personal computer with sound card
EchoStation software
Transceiver (or separate transmitter and receiver)
Audio connection between sound card and radio(s)
Push-to-talk connection between PC's COM port and transmitter (if transmitter does not have VOX)


These items are also recommended, but not always required:

Carrier-detect connection between receiver and PC's COM port (required for simplex autopatch)
Internal or external modem, connected to a telephone line (for remote-control link)
Internal or external voice modem, connected to a telephone line (for Autopatch support) . . . "

EchoStation license fee is only $19.95.
Anybody use this before?

???

 

[Robb]

If you're interested in extending the functionality of newer digital technologies (D-STAR, P25, etc.) then you have a good reason to put up a repeater even in an area with heavy analog coverage. D-Star (for example) still doesn't have very good coverage in many areas.

Well, that is a thought. I wouldn't know if there are any D-Star repeaters here in the Bay Area. Could be; probably. Presently, I don't run D-Star and don't know anyone that does. It just isn't as popular yet. They will - no doubt - become more popular within 5 years. In the mean time, there are so many well made analog rigs out there still working fine. Who needs to change; why? No one will go with digital - simply due to their present cost at this time - IMO.

These radio mfrs need to get the 'digi-ball' rolling by selling these rigs at a more competitive price. They should really make some intro rigs VERY CHEAP and get enough of them on the market for the interest to arise - IMO. Their marketing isn't working.

Can you see Wouxun or Puxing making a digi-HT and selling them for less than $150? Now; there's a thought. That would push up the need for digipeaters right there. Cheap and abundant can get this happening. But getting two D-Star radios for this project is an expensive proposition at this point.

I was hoping to find a couple of semi-old 2m radios at the hamfest @DeAnza College today. No Joy. If I did; I would have bought that duplexer from eBay and ran it all on a dummy load - just to see if it could be used in an emergency situation if needed. We do live in CA Mole; CA is a catastrophe waiting to happen.

 

[Robb]

BTW - just how does one tune those cavity/duplexers to the appropriate freq pair? I do have an MFJ-259B and a cool DVM. What is the procedure?

 

[Robb]

Here is a diagram on how I think it should work with the EchoStation software as the controller. If anyone is interested, they can download the software and run it on their computer w/o running a radio with it. Just to read the help files and see its many functions. And NO; I am not affiliated with that company in any way, shape nor form. This is just for educational purposes.

If this does work as suggested; then the cost of building an emergency repeater can be quite inexpensive.

 

[Moleculo]

I haven't used Echostation, but see no reason why it won't work just fine. It's similar in concept to what I'm working on with the D-STAR repeater project.

 

[Robb]

This is another easy way too . . .

Radio-Tone Duplex repeater controller - Radioshop888 KG-UVD1P KG-UV6D TG-UV2 ROIP Repeater Controller Speaker Mic Ham Radio KG-669 KG-689 PX-777 PX-888 FT-897 FT-857 VX-177 VXA-300 KG-679 VEV-3288S V-1000 TG-UV FT-817ND FT-60R FT-897 FT-857 VX-7R VX-

 

[Moleculo]

I need to come up with a reason to try that out

 

[Robb]

I need to come up with a reason to try that out

Hehe.
Lemme help you out then. You already have enough HT's - so that they aren't the problem. You are moments away from going to that site and using your paypal account and buy the cables, controller, and the duplexer.

The only problem that exists is that you need to pick a coordinated freq pair, and whether it is going to be set up on the 2m or the 70cm band. The duplexer seller will set it up for any freq pair that you request for no additional charge. Or, you can set them up yourself if need be.

Tick-tock; tick tock . . .

EDIT:
To make this setup truly effective; one would need to use HT's - or any radios - that has a constant supply voltage. Or else it would only work as long as the battery state was usable. Of course; even for a temporary emergency station.

On another note; just what are the FCC reqs concerning use?
The local freq coordinator would need to be consulted just the same - right?