Radio Communications of Charleston, Inc.

Radio Communications of Charleston, Inc.
Your Professional Wireless Solutions Provider

Tuesday, October 3, 2017

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Saturday, April 21, 2012

Towers and their associated pluses and minuses !

Oh well, you now have this new tower site.   And, to add insult to injury, you're expecting it to be the save all or fix all of your communications system.........Yeah....Right !

I've written on this subject previously, so this information isn't new from my perspective.   But, it deserves repeating to those that wish to invest in or have already invested in a "new" tower site.

There are basically three physical characteristics of importance when designing or otherwise using a tower site.   In order to get maximum advantage, one must consider location, height and transmitter power, in that order.

Location ~
   This the most basic of all physical attributes and sometimes the most overlooked.   If your tower isn't near your area of need, why even consider it?   Makes sense doesn't it.   Well, you'd be surprised how many people purchase a tower or decide to use one that just isn't near their area of need.  

Height ~
   Ironically, this parameter is more important than high power output of your transmitter.   It also serves a high purpose in developing better receiver sensitivity.   Both of those needs are very important.   But, you just won't get them until you have some height, adequate height.   It's worth considering what type of antennas you plan to install on the new higher tower at the correct location.   Some antennas are 20ft long or, you should consider that and how many more of them you plan to install on the tower.   Vertical separation is a must, so just do the measurement math and see what you get.   Keep in mind that the lowest antenna on your tower is your new height.....hmmm.

Power ~
   After the above attributes are available, power is an important issue.   But, I must say, if you have a lot of power and neither of the above attributes, you're sunk.
  2-way radio power for a repeater is typically 100 watts.   So if you want it to perform properly, you will need the first two properties plus the appropriate power output....100 watts.

Tower sites nowadays must have a lot of issues solved in order to be constructed properly and legally.   Like it or not, this mechanism is an environmental issue, at least if you consider the opinions of those that want to protect you from the ferns, birds, swamps, and probably yourself.

So plan for this or you'll never make it in the tower business.   You will never even get the permits to carve out the road thru the woods to get to your prospective tower site.   That's a lot of data for another conversation.

Good luck with your new antenna site...

Till next time, happy radio range.

Saturday, April 7, 2012

PTP and Crooks - Don't get caught in their web.

PTP speeds are growing up.   Those speeds are challenging wired circuits in a big way.   We've seen reliable radio speeds and bandwidths upwards of 600mbs......and growing.

Unfortunately, there are unscrupulous vendors out there that promise the moon and provide something that is amost just good enough.   What do I mean by that?

We all know that PTP links work best using LOS (line of sight) from one point to another.   In some instances PTP works in a deteriorated capacity in NLOS (non-line of sight) situations.

We have witnessed some vendors offering 300mbs in NLOS situations knowing well that speed would not be achieved.   Instead, they elected to argue down the system owner that they didn't need that amount of bandwidth and encouraging them to settle for less.   The customer ends up settling for the lesser amount with some sort of compromise on expense as a method of paying less for less.   In some situations the customer can't check it ..... or even know what they are viewing if they did.

This is a bait and switch routine in its finest form.

Don't get caught settling for less.   If your new PTP doesn't do exactly as expected, yank it out.   There are vendors out there that give you what is expected.   You nust need to hold the line on expectations and you'll get it.   And, remember.......sometimes the cheapest isn't always the best deal.

Till next time.....happy computing (radio-ing ?)

MOTOTRBO operation DMR

MOTOTRBO is real cool.   It is an experience into a greater radio experience and cause us to believe that radio has been "re-invented."   2 slot digital radio, (DMR standard) is starting to become standard knowledge in the radio industry.

I wanted to post a comment on the analog operation of a MOTOTRBO radio.

While using the MOTOTRBO radio in the analog mode I noted a substantial increase in performance even while in the analog mode.   After researching and studying that un-expected benefit for a while, I surmised that the performanc increase was coming from the digital processing of the analog signal.

So,, if you want a better analog radio, with digital operation performance, then get a MOTOTRBO (DMR) radio.   You'll be pleasantly surprised at the un-expected performance characteristics.

Public safety and business are experiencing this benefit today.

Good luck with your radio operation.

Lightning Strike ! (Fact or Fiction ?) we go. 
We have had the warmest winter in years.   And, that signals we will most likely experience more summer weather events such as lightning storms, high temperatures and strange weather.  

The radio business must have their tower sites and antenna systems ready to tolerate a lightning strike experience.   These lightning strikes can be devasting.   And, sometimes we can tolerate those events and sometimes we cannot.   Just why is it that we can sometimes tolerate the lightning strikes?

For those in the know, Motorola's R56 grounding standard brings several, if not most, electrical standards under one compiled document.   This doucment provides guidance for grounding tower sites and their associated equipment to allow for lightning strike tolerance.   Wow, what a document!

I have read that the average lightning strike is 26k amps.   So, using basic electrical math, if one has 5 ohms of resistance in their tower ground system, you could experience 130k volts of electrical potential across equpment in your shelter.    That can and probably will be devasting to most solid state equipment.   Conversely, if you have 1 ohm of resistance it would be possible to develop 26k volts across your ground system.   Even though 26k volts is high, it's a lot smaller than 130k volts.   Either can be harmful to your electronic equipment.

Needless to say, grounding and protecting equipment at a tower site is important.   But, the further point I wish to make is, it's more than important.   You need a great ground and great ground system conductivity....and should have much less than 5 ohms of resistance in your ground system.   Your equipment survival depends upon it.

And, as a last safety comment, don't be at a tower site during an electrical storm.   It could cost your life.

Till next time....keep yourself grounded !

Sunday, November 27, 2011

P25 phase two - TDMA, fate or consequence?

Did you know that phase one of P25 is FDMA and that phase two of P25 is TDMA?   Ironic isn't it.
Motorola's MOTOTRBO radio is 2 slot TDMA now....and really cool.
If you haven't seen one and demo'd one, you're missing out.   Don't buy another radio until you do.
Even more cool is the MOTOTRBO radio when operating with a repeater, or a multi-site repeater system.  It just gets better and better.
Happy Radio-ing...........10-4?
Till next time......

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