I have a battery question one of you might be able to answer.

I have 3 40Ah batteries connected in parallel for 120 Ah. These are for back-up power in the shack.

We'll call the batteries #1, #2 and #3. Battery #2 is in the middle and the power lead to the radios comes off #3.

I have acquired a 1.5 amp automatic charger, which I plan to use to keep the batteries topped off. I have a question about hooking it up.

Can I hook the positive and negative leads from the charger to the positive and negative posts of #3 (the battery from which the radio power lead extends), or do I have to hook the charger to #1 so the charge is able to pass through all 3?

On the Battery Tender website http://batterytender.com/resources/connecting-batteries-chargers.htm, the suggestion is made to connect to positive to battery #3 and the negative to battery #1 "to balance the voltage drop evenly across both batteries and each wire during charging." But it mentions that this is not critical for low-amperage chargers.

Do any of you have experience with this? Should I follow the website's instructions?

I will probably run the shack off the batteries for a few hours each month to keep the lead acid in motion to extend the life of the batteries. Can I run the the shack off the batteries while keeping them on the charger?

Thanks,

Teak
KD0KVV

With all the good suggestions, I have been rethinking this a little. How about this:

I ordered a copper grounding bar from Georgia Copper: http://www.gacopper.com/GroundBars.html.

This will be used outside the home at the point of coax entry. I will mount to it the lightning protection (I chose the Alpha Delta ATT3G50, based on reading reviews). It will be bonded to a ground rod at the entrance

I will get a second grounding bar to put in the shack, to which I will ground station equipment. The bar could be grounded to the house ground, which is at the service entrance for the water supply (it's an older house, that's how they did it then and my electrician has signed off on it as being OK by code, due to the age of house) or I can ground it to another rod just outside the shack. Getting through the wall with a short section of 4 or 6 gauge copper will be easy.

I can pass the coax through the floor/baseboard, reducing strain on the feed line. I can run the lines directly to the radios (scrapping the in-wall box, which is unnecessary) or I can attach the feed line to a second surge protector mounted on the bar in the shack.

This, in theory, would give me secondary protection and bond the equipment coax grounds together. It is would be more money (worth it if it provides more protection), perhaps overkill.

Would this really add more protection? Would it potentially cause more problem to have the coax grounded twice and grounded to the same as the equipment? I think I've read that a common ground is preferred.

Thanks again for all the suggestions. You've all been helpful.

Teak
KD0KVV

K1CJS:  Good points. Thank you.

Unfortunately, the coax must enter the house on the west wide, and the shack is on the east side. This is due to a power line dropping on the east side without enough clearance to safely route the RF coax.

Going through the floor is possible, and I'm not opposed to it -- I was just thinking that a box with connectors would be a little nicer. If it's all behind a desk it shouldn't matter. and you make a good point about causing too much of a bend/kink in the coax if I route it through a wall and a box.
Teak

Great tips, thank you all for taking the time to reply.

I doubt I'll do much UHF work beyond local repeaters. But having the four connections through a 2-gang box will give me options for growth.

Access to the wall and crawlspace below is pretty easy, so I think I'll start with a single box and two UHF connectors on it. I can add a second box in the future if I need.

@W6RMK: Good suggestion for the disconnect box. I am going to probably going to use one at the coax entrance to add a little more protection for the lightning arrestors. A flush-mount box in the shack might work, too.

I like the idea of an auto antenna switch. That would be easy to deal with if I add antennas.

A remote antenna switch would be fine, except that I will be using multiple radios, probably 2 or 3, so each radio will still need a connection to the appropriate antenna.

I really don't need the four connections now; two would suffice but I am thinking I'd do four in the event of expansion.

So two on the wall -- one leading to a VHF/UHF antenna and another to an HF antenna -- would suffice. The HF antenna connection could be replaced by the remote switch if and when it is necessary.

So that still leaves me with the issue of the two coax cables entering the shack. Maybe a single-gang box with the home-brew plate would work.

Thanks for the suggestion. This makes it easier.

Have you seen this?

http://www.youtube.com/watch?v=gmnnf0xUWNM&playnext=1&list=PL1E9D2DE0C5586022

The video summary includes links to some pages that diagram the full setup and ways to buy the panels.

It's not exactly what you describe, with the remote heads in the lid, but it is pretty slick and might give you and idea for your set up.

How about the power supply and main radio unit below the panel and the remote head on top?

Teak
KD0KVV

I would like to have a panel of UHF (SO239) connectors on the wall of my shack. Each connector would have its own coax line to an antenna. I will have no more than 4 antennas.

I prefer a panel because the shack is a shared family room and is also my home office. I'm trying to keep it fairly tidy.

My plan is to cut a hole in the sheet rock wall and install a 2-gang old-work electrical box, through which the coax would be run. I would put PL259 connectors on the ends of the coax.

The PL259s will attach to 1" SO239 bulkhead connectors that will be fastened to a metal 2-gang blank plate, through which I will have drilled 4 5/8" holes to mount the bulkhead connectors.

I can then connect my radios to up to 4 different antennas by connecting a jumper from the radio to the connector on the wall. The wall plate also keeps the system fairly clean, so that if I need to move furniture I don't have just a bunch of cable running through the wall.

Imagine this wall plate, but with UHF connectors, not XML connectors:  http://ecx.images-amazon.com/images/I/31KtRHeYSwL.jpg

Here is the bulkhead connector:  http://www.universal-radio.com/catalog/parts/ug363.html

My questions are:

1: Is this a good idea? It seems good in my head, but I know that the more connectors I have the more likely I am to experience RF loss. The total run of coax is fairly short, 50' or less. I can't think of any reason why mounting the bulkhead connector to a metal plate would affect performance, since that what MFJ pass-through panels do.

3: Has anybody else done this?

2: Does anybody know of a commercially-available 4-uhf connection wall plate? Making one would be easy, but it might be easier to buy one instead of buying 4 1" bulkhead connectors.

Leviton makes a single-gang wall plate that will accommodate the SO239, but I cannot find a two-gang plate with four holes.  http://www.leviton.com/OA_HTML/ibeCCtpItmDspRte.jsp?item=9354&section=10996&minisite=10026

Thanks

Teak
KD0KVV

OK, thanks for the feedback.

Right now I have just a Yaesu FT1900, and I don't believe that has a TX Monitor. I can attach a recorder to a scanner tuned to a VHF repeater and accomplish the recording.

I am still weighing my options for an HF rig. I am not in a big hurry, but I am not likely to spend $1,000 or more on a radio. I am looking at the Icom IC-718 or Yaesu FT-857D. They are very different, I just have not yet decided what i want out of a radio yet.

Perhaps I'll put the TX Monitor on the list of desirable features. I'm not sure which radios have that feature.

I'll probably use either and MP3 recorder.

Thanks

Teak

Does anybody know of a good way to make audio recordings of QSOs, beyond putting a recorder near the speaker?

Specifically, I'd like to record both the RX and TX directly into a VOX activated recorder.

The RX is not much of a problem, as I can just run the sound into the recording device and the speaker out the recorder. Patching the mic into the recorder to capture the TX is the issue.

Some radios have a port for this type of function, but I don't own one.

Thanks

Teak
KD0KVV

The ARRL books are designed so that learning is in a logical order. Each section and chapter builds on the information previously covered. The test pool questions are not ordered with the same logic (there appears to be no specific reason for the numerical order of the pool questions), so writing a book to follow the numeric order of the test questions would be impractical and illogical.

The end of each section within a chapter of the ARRL book suggests reviewing the questions related to the material covered in the section. This is so you can do exactly what you describe: as your son completes a section or chapter, quiz him on the questions specified by the book.

It's accomplishing the same thing, just not in sequential order.

The Gordon West books address each question independently, but they are also not in numerical sequence but are arranged by topic.

The questions in the official test are not given in numerical order, they are random. Studying them in numerical order would be of little -- or perhaps no -- advantage.

I understand the concept and mission of MARS, but I am wondering, what does MARS do, realistically?

This is from the mission statement:  "Handle morale and quasi-official record and voice communications traffic for Armed Forces and authorized U.S. Government civilian personnel stationed throughout the world."

I see that there are numerous nets, and I know that emergency communications is a part of the mission. So, outside of the EmComm part, what are MARS operators doing? Are the nets any different than the standard amateur radio nets, where operators often just rag chew? Are operators actually passing traffic to oversees personnel?

From the description, MARS appears to be a good service to belong to, but I can't help but think it ends up being not much more than many ARES groups, where they always prepare but seldom "deploy." Are the armed forces really using MARS for morale and "quasi-official" communications?

Perhaps one of the operators can help clarify the day-to-day reality of MARS.

Thank you all.

Thanks, all, for the tips. I'm now considering going with a ground plane vertical or j-pole on an outside mast. It will be easy and won't be noticed by neighbors.

KD0KVV

OK, great, thanks for the tips.

I'll likely go with the GP-1.

KD0KVV

I have a an attic that is easily accessible and sort of finished -- enough to be a useful utility space. I am considering putting a vhf/uhf antenna in it.

I am split between a J-pole, such as Arrow's open stub j-pole: http://www.arrowantennas.com/osj/j-pole.html and a a vertical, such as Comet's GP-1 or GP-3: http://www.cometantenna.com/products.php?CatID=1&famID=5&childID=4. All three would fit easily in the space.

I could put them outside on a conduit mast (I'm not in a restricted area) but I am interested in them in the attic for stealth -- more aesthetics -- and accessibility. Keeping them under a roof is nice, too, both for longevity and lightning protection. The minimal loss due to the roof is not a concern to me. There's almost no wiring or other metal to cause problems.

My home is situated on one of the highest points of the metro area and I can already hit most repeaters with 20 miles with less than 10 watts and a mag mount on top of a cabinet in the shack. I'm just looking to get a little more elevation and a little more gain.

Any thoughts on the merits of the vertical vs. j-pole? Any good way to figure out which would give more effective gain? All three antennas have had good reviews.

Thanks

KD0KVV

Hey, all, this has been a great thread. Thanks for all the great information. This has greatly helped my understanding of battery power for radios.

I have a 10Ah AGM battery that I use for a portable kit of an HT and 35-watt amp. The battery is charged with a 1 amp wall wart charger that does pretty well at keeping the thing topped off.

For my home shack, I just acquired 3 40-Ah 12V AGM batteries from a friend who managed to score a bunch of these from a company that needed to replace their UPS for servers (great tip, K1CJS!) These things are in top shape and had over 12.5V of charge in each.

I have them connected in parallel to provide 120 Ah of battery, which really is more than I need but is enough to ensure plenty of coverage in the event of a long-term outage.

I have two questions regarding charging:

Do I add the total Ah of the batteries to figure my charging rate? The ARRL EmComm book recommends charging at a rate no higher than 1/3 of the battery Ah rating. At 40 Ah, that suggests I could charge at 13 amps; at 120 39 amps, which is quite high.  I plan to put West Mountain Radio PowerGate between my power supply and the batteries to keep them topped off. WMR suggests charging at 7 amps for up to 50Ah and 10 amps over 51 Ah. (I think these rates sound more reasonable). Again, the key is do I charge based on the sum of the Ah ratings? It seems as though I should, but perhaps I am not considering this properly.

Secondly: If I charge these batteries with a solar panel, would I be able to get by with the 45 watt panel described above? I'd need a charge controller for it, and that's when I start getting confused about the relationship among watts, volts and amps. Using P=IxE, I figure a 45 watt panel will give me up to 3.75 amps at 12 volts with a regulator. Is that right? I guess that would be plenty of current to keeping the batteries topped off if I'm not using them aggressively.

Thanks

Teak
KD0KVV