Beacons

[W3WN]

In view of a recent comment in Decon about a lack of amateur radio threads here on an amateur radio forum...

My club has sponsored a 10 meter beacon in the US Virgin Islands, NP2SH/B 28.275 MHz, for a good many years now. Don't bother listening for it right now, it's all dead... about the only thing you can do with that transmitter is go through it's clothes and look for loose change.

A club member, Mike N3BSQ, has offered to resurrect the beacon, either by repairing the existing unit or building a new one.

The original beacon transmitter was a Uniden 2600, followed up by a RadShack HTX 100. Or was it the other way around? Anyway, the drive on both was lowered to about 1 Watt, but time still took it's toll.

Any suggestions on Version 3?

I should mention that Mike just put a 10 meter beacon on from his home, N3BSQ/B on 28.2535 MHz. He's using the "Little Joe" transmitter kit that was featured in QST back in 1981. (You can find it in QRP Classics and Solid State Design) Cost for the unit is about $20 plus crystal. My concern is that, well, if something goes wrong with Mike's unit, it's right there in his house to fix. But NP2SH/b is a bit further away, and even though Paul NP2JF is kind enough to host it, we can't ask or expect him to fix it if it breaks.

Steve W3SRL, who built the original beacon and it's replacement, is up to his eyeballs in school, work and home, so we're trying not to burden him with this. That said, he is taking time to look for an old commercial unit (VHF LOW ex-public safety I'd presume) that we can adapt. Same problems, though, plus if it's an older unit, we have to figure out how to safely ship it... and so forth.

Any technical suggestions appreciated!

Keep in mind that I'm just the conductor (since I'm club president this year and most likely next as well), Mike N3BSQ will be the actual head of the project...

73, ron w3wn

[KC2UGV]

How about this kit: http://qrp.kd4ab.org/2000/001030/0001.html

[W3WN]

That's a parts list, but it doesn't say much about the kit itself.

[KC2UGV]

That's a parts list, but it doesn't say much about the kit itself.

It's the Iowa QRP-10 (That's what I know of it). Can't seem to find anything except this:

http://www.norcalqrp.org/files/K8IQYIowaQRP10.pdf
http://www.norcalqrp.org/files/K8IQYIowaQRP10Sch.pdf

Hope it helps :)

[ab1ga]

A couple of questions:
Am I right in assuming it's a CW beacon?
You're satisfied with 1 Watt or so output?
Is there a price limit?

Although you said you can't expect your host to fix the beacon, would he be able to just replace the whole thing and mail you the dead one? That way you could keep shelf spares at the site, and fix them at your leisure without downtime.

This could be a nice homebrew project rather than just a kit.
The Parallax propeller chip has an on-chip programmable oscillator that will go that high, and is programmable in a high-level language called Spin. It can delivered a keyed carrier, which would need filtering and squaring, which could then drive a Class E amplifier.

[N8YX]

Convert a mobile AM-only CB rig.

Use one with an MB8718, 8734 or PLL02A PLL chip. A re-crystal and realignment is usually all that's necessary.

Then reduce its power to 1w. A small ball-bearing fan blowing on the rear of the case will provide adequate cooling.

A BASIC Stamp would make an ideal keyer for this project. If you really want to get crafty, there are a couple Ethernet adapter boards available for use with a Stamp, Rabbit and similar microcontrollers. These utilize Java code to provide a web interface. One can use transmitted commands to manage devices behind the front end; you could remotely control the transmitter (or check on its operating parameters) from your browser.

[W3WN]

A couple of questions:
Am I right in assuming it's a CW beacon?
You're satisfied with 1 Watt or so output?
Is there a price limit?

Although you said you can't expect your host to fix the beacon, would he be able to just replace the whole thing and mail you the dead one? That way you could keep shelf spares at the site, and fix them at your leisure without downtime.

This could be a nice homebrew project rather than just a kit.
The Parallax propeller chip has an on-chip programmable oscillator that will go that high, and is programmable in a high-level language called Spin. It can delivered a keyed carrier, which would need filtering and squaring, which could then drive a Class E amplifier.

To answer the questions in order:

Yes, it's a CW beacon. (Has to be on that part of the band)

I don't know the technical reasons why 1 Watt output was chosen; that may be the nature of the beacon network itself, I will have to find out. Certainly QRP power level.

Price limit? Well, the club is a little flush in cash right now, but we're not about to spend a couple of thousand on a custom made unit... reasonable costs are acceptable.

Actually, if we can find something reasonable, I am in favor of having an "off the shelf" backup available. Since we're talking about the US Virgin Islands, postage back & forth will be reasonable. Delivery times will be an issue... overnights under most circumstances won't be practical, but down time of a few days is acceptable. What the heck, it's already been QRT for a few months now.

But first priority is to get the system back on the air.

[W3WN]

Convert a mobile AM-only CB rig.

Use one with an MB8718, 8734 or PLL02A PLL chip. A re-crystal and realignment is usually all that's necessary.

Then reduce its power to 1w. A small ball-bearing fan blowing on the rear of the case will provide adequate cooling.

A BASIC Stamp would make an ideal keyer for this project. If you really want to get crafty, there are a couple Ethernet adapter boards available for use with a Stamp, Rabbit and similar microcontrollers. These utilize Java code to provide a web interface. One can use transmitted commands to manage devices behind the front end; you could remotely control the transmitter (or check on its operating parameters) from your browser.

That will be up to the ad-hoc committee working on the project. Considering the two rigs already smoked, I wonder if another conversion project is worth it.

Now if this was my project, and I could get my hands on a working crystal controlled CB from the 23 channel era, I might consider this the way to go.

As far as the controller... I understand the existing one is functional. Again, I'm going to defer to the committee on this, and there are some nice things out there. But remote controlling via the web? Not an option, not unless NP2JF lets us know that they have full internet access available on St. John.

Again, first things first. Since the first two units smoked after several years in service (each), Phase 3 is to get something back on.

[N8YX]

The original beacon transmitter was a Uniden 2600, followed up by a RadShack HTX 100. Or was it the other way around? Anyway, the drive on both was lowered to about 1 Watt, but time still took it's toll.

Considering the two rigs already smoked, I wonder if another conversion project is worth it.

I would start by doing a root-cause failure analysis. Something's just not right at the transmitter site.

When I had node BARBER on the air, one of its radio ports used an HR2510 and an HR2600, alternatively. These were set up on 28.195 and ran 1200 baud. The antenna was a 3-el yagi, fixed towards the southwest. AZSE was the node at the other end of the "pipe". When Sporadic E or just plain ol' F-layer skip set up and the path opened, my 10M port saw as much as 16 hours use per day running an output power of ~20w on LSB. Day in, day out...all summer long...year long...I had that setup on the air from late 1993 until the fall of 2005 and it never once missed a beat.

Both of those rigs are still hanging 'round the shack - I had them mobile for a couple years until I sold the truck in which they were mounted.

When run with a low (< 1.7:1) SWR, you practically cannot kill them. Both of mine still work great.

Identify the cause of the failure before placing another transmitter in service.

[KC2UGV]

That will be up to the ad-hoc committee working on the project. Considering the two rigs already smoked, I wonder if another conversion project is worth it.

Now if this was my project, and I could get my hands on a working crystal controlled CB from the 23 channel era, I might consider this the way to go.

As far as the controller... I understand the existing one is functional. Again, I'm going to defer to the committee on this, and there are some nice things out there. But remote controlling via the web? Not an option, not unless NP2JF lets us know that they have full internet access available on St. John.

Again, first things first. Since the first two units smoked after several years in service (each), Phase 3 is to get something back on.

I can send you one (A 23-channel crystal CB). I've not used it, since there have been some mods applied (And, I'm not really deft enough to figure out what they were).