Mobile radios

MT2000 man · Post by **MT2000 man** » Fri Mar 01, 2002 7:17 pm

Hi all, as you can/will tell I am VERY new to mobile radios, (the only time I use them is in the patrol car

Ok, heres my question: I'm going to buy probably an M1225, and my question to you is, I would like to set it up inside my house, not as a repeater, but like a base station. Now, (this may sound like a stupid and easy question BUT) how would I go about hooking the unit up for power? I don't think there is an AC wire in the back. So, what wires if you will, would I need to power the unit up? Thank you for any help!

TexMN · Post by **TexMN** » Fri Mar 01, 2002 7:28 pm

What you need to do is determine how many amps this radio needs when you transmit and then purchase a 12vdc power supply that is rated for a little over that amperage. Hook the same two wires that would provide power in a patrol car to the radio to the connections on the power supply.
I use a similar arangement with one of my Amerature Radios here in the house. In my case the radio required 8 amps so I have a 10 amp power supply.

MT2000 man · Post by **MT2000 man** » Fri Mar 01, 2002 7:33 pm

Ok, thank you for the info. Now, would a power supply be radially available, in .. lets say radio shack?

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Fri Mar 01, 2002 7:55 pm

On 2002-03-01 22:33, MT2000 man wrote:
Ok, thank you for the info. Now, would a power supply be radially available, in .. lets say radio shack?

Well... Yes and No.

Yes, Radio Shack does sell power supplies. BUT, the word on the street is that RS power supplies stink. And, they seem over-priced.

I'd suggest looking at something made by <a href="http://www.astroncorp.com/">Astron</a>. I have a RM-35A, and it suits me just fine for my ham shack. You can buy a power supply through a ham radio store or web-store. Or, your favorite two-way repair shop

Make sure the power supply is rated for continuous duty at the amperage you'll be using. This will help the power supply live a longer life.

I'm sure others have helpful hints, too.

Nand · Post by **Nand** » Fri Mar 01, 2002 8:07 pm

williamh · Post by **williamh** » Fri Mar 01, 2002 8:08 pm

dont forget , youll need a antenna , not a coat hanager ,it would be good to get the ant. outside , or every time you key up the radio youll knock out the t.v.

Josh · Post by **Josh** » Fri Mar 01, 2002 8:15 pm

On 2002-03-01 23:08, williamh wrote:
dont forget , youll need a antenna , not a coat hanager ,it would be good to get the ant. outside , or every time you key up the radio youll knock out the t.v.

Two things. I have a GM300 running 25 watts through about 40ft of LMR-400 cable. The radio itself is about 5 ft from a TV. Even then, the radio still messes it up a bit!

The radio is also hooked up to a Radio Shack 10Amp power supply. I've had it for a couple years and have had no problems, even when transmitting 45Watts. I got it used off of eBay, which might be a good place to look for power supplies at good prices.

I keep my power supply underneath my desk to keep it out of general view. The Motorola's however, will be set-up so that the radio fits into the power supply so it, too, will be in sight on your desk/tabletop.

-Josh

MT2000 man · Post by **MT2000 man** » Fri Mar 01, 2002 8:21 pm

Ok, thank you all for the power supply help

(I'll probably end up getting a 10amp power supply) Ok, now that I got that (almost) figured out, now, any ideas on what kind of antenna I will need? Or do I just "ask the radio shack guy" that question? I know there are TONS of (UHF, since that's the band I'm getting it in) antennas out there, but I'm looking for a small, (no towers or anything:) size antenna. Any ideas on that one? Thanks again, for all that took the time to respond.

[ This Message was edited by: MT2000 man on 2002-03-01 23:22 ]

rfguy67 · Post by **rfguy67** » Fri Mar 01, 2002 8:37 pm

I would avoid "Radio Shack".
Find a 2-way dealer and they will be able to set you up with what you need.
Astron power supplies are reliable and I would recommend a SBS-150/450 base antenna.
They are unity gain and provide decent performance.

Hope this helps.

jim · Post by **jim** » Fri Mar 01, 2002 8:39 pm

For home type use on UHF, I'd suggest something small such as a regular 3dB gain mobile antenna with a "base conversion" kit installed. The base conversion mounts the mobile antenna to a pipe mast which can be mounted on a vent pipe or chimney and provides the proper "ground plane" to help tune the antenna. For the cable, you can run RG-8X "mini-foam" without much loss at under 100' cable length.

visit Antenex- they have what you need. Myself and many others on this forum are dealers for them as well.

Part #B4505CN for the antenna in the 450-470 range.
Part #MBCN for the mount/adapter
Part #PT8X50NP for the 50' cable with connectors on it. A "mini-UHF male to SO-239 UHF female" adapter is required to connect this cable to the radio.

A 10 amp power supply is enough to operate the M1225 radio. TESSCO and others have a nice power supply that also contains a mount for this specific radio to make for a neat installation.

http://www.antenex.com

Jonathan KC8RYW · Post by **Jonathan KC8RYW** » Fri Mar 01, 2002 8:42 pm

On 2002-03-01 23:21, MT2000 man wrote:
...Or do I just "ask the radio shack guy" that question?...

I've always tried to talk with RS employees as little as possible. I'm afraid of their answers.

Plus, the employees seem to really want me to subscribe to SprintPCS through them. Every time I come in, they ask. I come in to buy some resistors, and they pop the question about SprintPCS. Argh. Get a clue: I wouldn't get SprintPCS if it was growing on my ass.

Sorry for ranting, I think it's past my bedtime!

Monty · Post by **Monty** » Fri Mar 01, 2002 8:46 pm

Hi:

BE CARFULL

The Motorola 40/45 watt radios require
a ample Power supply capable of delivering
15 Amps of Continious Current @ 13.8VDC or less and 7.5 Amps for 25 Watt Radios.

So, make sure any power supply you purchase
has at least these ratings !!

Some power supplies " Say " they will do
10 Amps, but if you look at the small print
it may be a Surge or only for a minute or
two.

Also, sometimes you will see ( 2 ) ratings...One is a surge amount ( which
is sometimes 4-5 amps ) higher than what its
trully rated for....So if you see a 10 Amp
Power supply, make sure the rating is in
the continious mode. I have seen 5-6 Amp power supplies rated this way.

10 AMP ( 5-6 Amp ) Continious...So beware

Play it safe, Get a good Astron, or find
a original Motorola Power Supply ( as they
already have the cable installed ) and since
you are new, its highly recommended you consider that.

It is possible to damage the radio, not to mention the power supply if they are not compatable with each other.

Also, if you desire optimum performance, you
also need good transmission line, and a good
antenna.

Trying to use anything less could spell
a major service bill. If you are not able
to find anyone in your area to supply the
materials, I am more than willing to help.

Monty

MT2000 man · Post by **MT2000 man** » Fri Mar 01, 2002 8:51 pm

Hi Monty, thank you for offering the help, for further advice, I'll go to my local radio shop. However, I will be in touch with you if I need and additional help.

Thanks to all again

Mike

Will · Post by **Will** » Sat Mar 02, 2002 2:37 pm

A good antenna for UHF 450 to 470mhz for "base" use would be a Comtelco BS450UC at 97 dollars retail. It is about 30" tall and is real profesional quality. This is a unity gain, three and five db gains are also available.

http://www.comtelco.net

Josh · Post by **Josh** » Sat Mar 02, 2002 2:44 pm

On 2002-03-01 23:39, jim wrote:
For the cable, you can run RG-8X "mini-foam" without much loss at under 100' cable length.

At UHF frequencies, RG-8X is extremely lossy. RG-8 at runs even at 50' is too lossy! For any run longer than 12', I'd run nothing less than double shielded cable. Times Microwave LMR-400 cable at UHF frequencies works far better than RG-8 cable.

I'd reccomend getting the best cable possible as UHF can escape cheaper co-ax easily leaving you with degraded performance!

-Josh

raymond345 · Post by **raymond345** » Sat Mar 02, 2002 3:37 pm

Hi there what are you transmitting
on simplex or repeaters.If u are
on a repeater only or on simplex for only
a couple of miles or just listening then
a mobile zero ground plane antenna inside the house beside the radio is just fine.
No metal is needed to run this radio
off the mobile ant.Been setting up
emergency radio equipment for 15 years with no trouble like this.Fast to set-up and goes anywhere.My two pennies from Canada.Raymond

Tom in D.C. · Post by **Tom in D.C.** » Sat Mar 02, 2002 3:52 pm

An individual who is not a thorough "techie" sure can get a lot of confusing, conflicting information here on our Board. Let's try to keep things simple for him, okay?

To start with, if I'm running a radio which has an output of 40/45 watts with a 13.8VDC supply, and I buy a 15 Ampere, REGULATED, CONTINUOUS DUTY power supply then I have about 200+ watts of power available, which is nice to have but is probably overkill.
A power supply with meters is NOT required, and a transformer supply rather than a switching supply will save some money in first cost and may even work more reliably in the long run.

As far as antennas are concerned, a person who is not thoroughly familiar with what is needed, and safe, should get help in this kind of installation from someone who does know what is safe and what will work. As far as feedlines are concerned, it obviously depends on repeater vs. simplex operation, distance from nearest receive site, etc., the object being to get into the site with a DFQ signal, that's all.

And as far as who is the best person to help, of course forget Radio Shack as there is usually no one there who knows much, if anything, about professional communications.
Rather, if I were a law enforcement professional and needed help I'd consult with the service manager of the shop which maintains the department's radios.

As some say, "My 2-cents, FWIW."

Tom, W2NJS
...in D.C.

MT2000 man · Post by **MT2000 man** » Sat Mar 02, 2002 3:54 pm

Ok, I like your idea about the in-house anntena, where can I find one? and how much does one cost?

Thanks

MT2000 man · Post by **MT2000 man** » Sat Mar 02, 2002 3:59 pm

Hi Tom, thanks for your input, I think I'll take your advise and go to the local radio shop for the antenna selection. I recently am buying a GM300 UHF, and the seller made a deal with me to throw in a power supply for an extra $50. So I'm taking it. Also, he'll throw in some cables as well. So all I'll need is an antenna.

Any more comments?

Mike

[ This Message was edited by: MT2000 man on 2002-03-02 19:00 ]

W1WWJ · Post by **W1WWJ** » Sat Mar 02, 2002 5:35 pm

Does license matter??? As a patrol man you might look into it.

[ This Message was edited by: W1WWJ on 2002-03-02 20:36 ]

PCSAR 4x4 652 · Post by **PCSAR 4x4 652** » Sat Mar 02, 2002 6:19 pm

you should be covered under your departments license as a mobile since there are never the total licensed mobiles operating at one time. But do check wih your Comm Shop to make sure.

W1WWJ · Post by **W1WWJ** » Sat Mar 02, 2002 6:28 pm

Not if he is setup as a base.

CHEFA2001 · Post by **CHEFA2001** » Sat Mar 02, 2002 9:25 pm

Don't think that it would matter since he would likely be using it to monitor his Dispatch when he's o/d or on meal.

I mean, in a legal standpoint, he cannot use a base radio unless it's listed on the ticket, but for monitoring purposes and the occasional 10-4 or 10-80 (yes- and responding) are far from something that would land you a fine.
Only my 1/2 cent....

Nickdap · Post by **Nickdap** » Sat Mar 02, 2002 10:26 pm

I agree with the last post. In Australia, the ACA licence commercial tickets for 50 watt repeaters and unlimited units; base, mobile or portable. I'm sure there is some reason why the fcc isnt the same but i assume its and old and out dated one or just to keep things fairly neat by having a list of units. A mobile set up as a base doing the same power as it would be if it where in a car is the same as a mobile, at least down here it is. The only thing that would be different is the fact its always going to be right next to the neghibours tv antenna...or not.
Nick

edit:
The base being of the same spec as a mobile just at a fixed location

[ This Message was edited by: Nickdap on 2002-03-03 01:32 ]

jim · Post by **jim** » Sun Mar 03, 2002 8:30 am

For an "occasional use" UHF rig at home, RG-8X is just fine. It may have some loss, but with under 100' run and also for home use to communicate with a local PD's repeater, it will be just fine. You wouldn't want to use this cable or antenna for a commercial installation, but for at home to do a low-buck installation, it's slight loss at UHF frequencies is meaningless.
You might not be able to receive a mobile that's 55 miles away, but that's not the intent purpose of this cheapie home install- which is why I also said to use a mobile antenna with a base conversion. It will work just fine for home use. I have an M1225 with this exact cable and antenna and I can talk point-to point with another station in Ligonier, Pa. (about 38 miles from me) with no problem at all and there's hills to deal with. I think if it is capable of doing this, it should be QUITE capable of monitoring or accessing a local PD repeater that's in town!
Home or ham use has a slightly different requirement than a commercial installation that you would sell to somebody's public safety organization or business. Sure, it's nice to use all of the big $$$$ items at home, but is it really necessary for this type of use? If an HT works fine in the house, I'm sure that a mobile antenna with base conversion ans 8X will work with a 25+ watt radio much better!

wb6fly · Post by **wb6fly** » Thu Mar 28, 2002 12:46 pm

The ideal power supply for the M1225 radio, in my opinion, is an Astron switching power supply equipped with the Radius cover. For the 10-25 watt radio, use the Astron SS-10-RA, about $80 from Tessco. The 25-40 watt radio should use the Astron SS-18-RA, about $100 from Tessco. I currently have a half-dozen of these Astron switchers in service, and they are trouble-free. The custon cover exactly fits the radio, and makes a clean and compact base station. I have never had any RFI from them, and they weigh just over three pounds. I can't imagine going back to linear power supplies!

Will · Post by **Will** » Thu Mar 28, 2002 4:44 pm

Have you tried a DuraComm switcher?
The are made better and we have yet to have a failure. They also have a battery revert oprion.

http://www.duracomm.com

jim · Post by **jim** » Thu Mar 28, 2002 8:59 pm

I just used the Duracom switcher for the first time last week. It's a nice unit! I just had to open it and it seems to be built better than the Astron- everything's heavier built and no SM components like the newer Astrons.