Batboard

I don't know too much about MW site equipment and costs. One idea that was kicked around was to add MW paths to the PD when we add our receiver sites. Currently we are a one site/tower operation. We are also making the transition over to digital.

Admin really doesn't want to lease lines from the telco companies, but thats most likely what we are going to do.

What would be involved and the general cost in adding two MW paths. Distance would be 5 miles max from the PD site to the other two, and generally would be a clear line of site.

Most likley it would only carry 1 radio channel, but possibly up to 4 other town channels but I would HIGHLY doubt it.

I believe we have access to two sites so we can rule out the extra tower cost. Cost ideal for equipment, licenseing etc? Would we get any long term return on the investment etc?

Just looking for ideals..

First off, if you are a public service agency, you are very wise to consider microwave and bypass telco facilities. The more that's in your own control, the better.

You will need to consider an unlicensed 5.7 GHz product since the FCC has minimum loading requirements for licensed microwave systems that far excced what you will be able to meet. Furthermore, there are minimum path lengths for licensed systems that it looks like you may have trouble meeting as well. (2.4 GHz unlicensed is an option as well, but personally I'd stay away from 2.4 GHz for this application...)

There are a few very reliable unlicensed products available. I'm partial to the Proxim (formally Western Mux) Lynx product ( http://www.proxim.com/products/all/lynx/index.html ), but Adtran and Plessey make similar products. I'm guessing that these radios will cost you about $6000-$7000 per end, maybe a little cheaper if you go to the refurbished market.

You'll also need think about antennas; luckily with such short distances, you probably won't need anything too big or elaborate unless you're in a metropolitan area. I'm guessing that the antenna system will add an additional $1000-$2000 per end. Make sure to consider tower loading issues before adding antennas to your towers. In this case, these antennas would unlikely cause a problem, but if you have lightweight towers, talk to the tower manufacturer or a structural engineer to be sure.

You'll also need a channel bank and DC power source to support this stuff.... There are tons of options here that will vary greatly with personal preference and application. Again, if you go to the refurbished equipment market, you'll be able to save some money here too.

I'm guessing that after considering all the odds and ends, you're looking at $12k-$15k per end and with some some double-duty you can do at the hub, about $45k-$55k for the whole two-path set up. (Remember these are ballpark numbers... They could be high or low.)

This system would be complete overkill for a single a channel to each tower site, but would probably start to make sense if you added those other 4 channels... Additionally, if you could find other agencies or departments (like water dept SCADA, etc.) to share these facilities with, you could better justify the costs...

I don't know what your circuit charges are but with 5 channels per site, I'm guessing it would take 4-5 years to break even compared to telco. However, if you have service issues with the local telco, that should be considered as well.

One word of warning... With microwave, it cannot be "generally line of site"; it must be absolutlely line of site. A path profile should be performed to insure you have line-of-site with suffcient fresnel clearance.

--z

As was stated above, for public safety service, if you can fund it, the MW is the way to go. The more channels you can put in the microwave the better the cost payback will be.

A normal spread spectrum MW radio is design for providing a T1 data channel. This is where the channel bank or mux unit comes in. You have the ability of placing 24 voice or low speed data circuits over a standard T1 path with these radios.

Depending on the channel bank mux unit, you can even place parts of a telephone system over the same MW. In other words, you can have the PBX at say the dispatch point and have remote phones at the other end of the MW link. They would function just like they were in the same building as the dispatch.

Another application would be able to link computers over the MW. Just remember for high speed data it takes more than a normal voice channel. You can expect to do a 56 Kbs data channel with out much problem.

The possibilities are almost unlimited. It just takes planning and money. Some of the newer spread spectrum MW radios can hold up to 4 T1 channels. In this case, you could use one of the T1 circuits for a slow speed Ethernet link at a 1 Mbs data rate.

Jim

For budgetary considerations, figure about $50,000 per hop. 23 GHz, or 28/30 GHz digital microwave radio, with a minimal complement of D4 banks on each end. This will cover path surveys, engineering design, spectrum clearing, licensing and coordinating, other FCC filing requirements, minimal tower costs, installation, and checkout, testing, and final turn-up.

Yes, I know someone will post a reply(s) that you can buy the new digital microwave radios for as little as $5 to $7k per end, so why the $50k? It’s called TOTAL cost!

Telco private line costs have plummeted in competitive parts of the country in the last few years. We currently pay $70/mo for our ASTRO 4-wire 3002, VG-32 Type 5 dedicated circuit (DIU3000 to/from Quantar), whereas we had been quoted almost $300/mo only a bit over a year ago.

As a rough rule of thumb, figure that to be an “economic winner,” your $50k per hop self-owned microwave radio system needs to effectively cost less than 3 years of leasing costs from the Telco to realize an economic push/wash. That equates to nearly $1,400/mo. So, if the Telco charges anything less than $1,400 per month, you are ahead of the game to NOT build your own microwave system. Also, this estimate assumes ZERO MAINTENACE COSTS for your microwave! What do you plan to pay for your maintenance costs? That makes the Telco look even better. With these loaded costs, the results are even more dramatic in terms of NOT building your own microwave radio.

If you are going to recommend self-owned/operated microwave to the Decision Makers/Upper Management, you need to run a Net Present Value (NPV) discounted present value economic evaluator. I highly doubt you can come anywhere close to economically justifying it.

Then, look at reliability. The National Network Telco Reliability Council (NNTRC) was formed post divestiture (1/1/84), and they can provide you with reliability statistics for your particular Telco for local dedicated private line statistics, as filed with the FCC, on a Quarterly basis. Include this information in your recommendation to Upper Management.

Who is going to repair your microwave radio on New Years Eve?

Sounds nice to be independent, especially from an emotional viewpoint. But, run the discounted payback numbers against a first cost of $50k. You can pay a lot to the Telco and still save a helluvalot over your own private microwave.

We've never had an outage yet, as they give great service on their dedicated circuits with the highest priority---it’s not at all like residential service. Albeit, on that last point, when is the last time your home phone went out?

Good luck,

Larry