[Repeater-Builder] (unknown)
The CH751 key is a generic cabinet key used by many manufacturers including Square D, Soundolier, and other non-radio manufacturers. The 2135 and 2553 are pure Motorola, reserved by Chicago Lock (the manufacturer) for only Motorola. The BF-10A key is pure GE as is the GE1000 key. THere are others for some of the other radio folks, but all of them used variations depending on the purchaser (Fed Govt was sometime different keying). All in all, a tech neeeds a very large key ring to open everything.
[Repeater-Builder] RE AGM batteries
Just to clarify what was said before about AGM batteries, when an AGM battery vents, it's because something is wrong. Either it was charged too fast or discharged too fast or it is in a condition called thermal runaway, which occurs when a battery is overheated. In an ordinary scenario, it is just fine. I would place it in a cabinet in most cases. In some instances though, it would make sense to have a separate container vented to the outside. It all depends on your appetite for risk, and how you are using and controlling the battery. Cell carriers will place them in the same cabinet as some very expensive electronics, When there is need for a lot of them (AGM batteries), and a separate cabinet makes sense.
[Repeater-Builder] Re: Repeaters for CERT Use?
Re CERT licensing - If the organization is an association or a corporation, like a club or a public service group, you can license on a commercial frequency. You will have to go with Narrowband though. Wideband channels just are not available on Vashon Island since you are near the Canadian border zone (north of line A). If you are a unit of the local government, then you need to have that local government agency apply for the channel you use. Who is the sponsoring entity? In any case, get with me off-line and I will be happy to point you in the right direction for licensing. Doug Dickinson APCO Local Frequency Advisor
[Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
Hi John How's it going? I remember the Biocom. We tried one out in Palm Beach County way back when. I recall it used GE PE series radios in it. We took it apart to see. It's about 45 degrees up here now in Seatttle. We got almost record snow this year - about 18 inches where I am. 20 miles east they have over 6 feet in the mountains. I could use some sun for a while! Doug Dickinson KC0SDQ
[Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
There were two basic repeat modes used in the Medical Telemetry systems. The Med 1 through 8 and the two dispatch channels (now known as Med 9 and 10) are duplex channels. The Orange Box and the Apcor (both Motorola) and some others were duplex hand carried units. I will focus first on the Orange Box and The Apcor. Both units were duplex and transmitted to the base on the traditional mobile higher frequency. The orange Box had a repeat function that would retransmit the base TX freq through the mobile freq. The base station ran in duplex mode, not repeated. This way, a portable radio (like a COR HT220 model) would transmoit through the Orange Box to the base and the base would transmit through the Orange Box to the portable. The portable was also configured like a base station channel-wise. It worked! The 12W APCOR worked the same way. The EMD mobile repeater was a duplex Micor 10 channel radio with a separate Pac_rt radio receiver. The mobile would transmit on the mobile freq and would receive on both the Base channel and a 458MHz channel (there are 4 of them) simultaniously and repeate the audio back out through the mobile freq. The base would operate in non-repeated mode. The would allow a full-duplex conversation, although it isn't technically full duplex - it just works that way. The porable unit talking to the Mobile was a 1 watt APCOR radio that talked on the 458 channel and listened on the 468 channel, thereby giving the entire conversation duplex functionality. So - that's how all this worked. The Mobile and APCOR portable combined cost almost $5K in the mid-late 70s. That was more than a car cost! Motorola has lots of bells and whistles on it. The mobile was SP all the way and the APCOR was a costly device. Doug in Seattle now, Florida then
[Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
I do remember a little about the radios they used on the series. The Orange Box duplex paramedic radio was the original Motorola adventure into the medical telemetry function. It consisted of (all inside the orange box case) an HT220 used as an exciter, and a PA out of a micor mobile low power unit and a duplexer from a mobile phone (I think from a Mocom 70 series radio). The receiver was straight out of the micor also. It had a limited production VCO that is fed from a differential amplifier that amplifies the typical 50mv signal retreived from the skin surface from heart activity and the amplified voltage feeds the variable VCO which modulates the EKG signal acrosss the air. It also has what we called micky mouse mux so that the audio from the ekg and from the voice were transmitted simultaniously and separated at the ekg console at the hospital to give both ekg and duplex voice simultaniously. It was an interesting radio and it worked fairly well. The next version was the APCOR series, but that is another story. The portables they used started out as HT200 radios with the telescoping antenna which were accurate at one time for LA County FD. I also saw an HT220 on a later show. I never saw an MT500 that I recall. It was mostly older equipment they used. The Defib was a PhysioControl Lifepack 3 if I remember correctly. They were big and heavy, but they did get the job done. I don't remember the mobile radio. I would have to watch an episode to know the mobile radio. It was probably a Mocom 70, but I won't bet on it. So - that's what I remember. Doug Seattle now Florida back then EMT for 29 years
[Repeater-Builder] Re: OT: Radios and Coms in TV and Movies
I do remember a little about the radios they used on the series. The Orange Box duplex radio was the original Motorola adventure into the medical telemetry function. It consisted of an HT220 used as an exciter, and a PA out of a micor mobile low power unit. The receiver was straight out of the micor also. It has a limited production VCO that is fed from a differential amplifier that amplifies the typical 50mv signal retreived from the skin surface from heart activity and the amplified voltage feeds the variable VCO which modulates the EKG signal acrosss the air. It also has what we called micky mouse mux so that the audio from the ekg AND FROM VOICE (LESS THE 400 TO 500 hZ)
[Repeater-Builder] Re: Unknow Radio - Anyone can help?
That appears to be a Mocom 70 dash mount radio. They did manufacture some and they were often found in things like Cement Trucks and other large heavy machinery with space to put a big radio up front. They had to have everything torqued down inside very tightly as the shaking in that environment would throw a lot of the insides out of tune. In the UHF units, the variactor was a bear to keep running in that environment.
[Repeater-Builder] Re: So I watched it NBC Dateline story on Tower Climbers
I too saw the show and a couple of comments: 1) Hard Hats are required by OSHA - no way around that. 2) $14/hr is common for non-union climbers. Double that for Union. Also, these small contractors (and most of them are ) do not provide health insurance and often they don't even keep up with the required workers comp payments. They are fly-by-night for the most part. Of course, there are many legitimate operators - one needs to find the right one! 3) Prevailing wage rates (government jobs) are the ones the big operators usually get beause they play by all the rules. 4) Many companies that act as prime contractors for these jobs don't have any crews at all - they sub all the work out to the little operators. 5) There are several thousand cell phone type towers for each broadcast type tower. Trying to find one that needds work would be a realistic impossibility. 6) 100% tie-off is the only way I allow tower workers to work on any tower I deal with. One infraction and the job is over. 7) In my 6 years of practicing as the Senior Safety Manager for a large cellular company, we experienced 3 deaths and 2 major injuries. This is considered a very low death and accident rate for tower work. 100% tie-off would have prevented the deaths and injuries. No question about that. Enforcement is nearly impossible though. I have not seen a death or injury that was not caused directly by the affected individual. (BTW - we had around 35,000 cell sites). 8) NATE, as an organization (IMHO) is a joke. They charge for everything they provide, and the costs are very, very high. They seem more interested in acting like a private sector company that provides training rather than a place that promotes safety standards. We would not join due to the rediculous rates for membership. You have to be a member to get the materials. It is clearly aimed at the small operators - the ones that usually won't do the training anyway. That is why 100% tie-off isn't the rule of the land (OSHA). 9) As to fluff - what did you expect? it is a commercial TV show and if they really got into detail, most of the viewers would be lost. 10) The amount of drinking that goes on is unusually high for most folks, but normal among people that deal with these trades and live on the road all the time. personally, I feel this contributes to the fatilities! Sad byt very real. Have a safe day Doug KC0SDQ
[Repeater-Builder] Re: Stop the Madness
I still don't understand why people object to two repeaters - properly designed - cannot share the same channel? With separate PL tones and limited hand time, they can complement each other. The use of a coordinator that assigns a channel based on antiquated criteria is still providing exclusive use of a channel to an amateur repeater. As such, I think it could be challenged. In reality, two properly designed and implemented repeaters with PL tones can share the same electromagnetic space and live nicely together - they just get used one at a time based on the initiator's communications need at that time. IMHO Doug KC0SDQ
[Repeater-Builder] Re: UHF Radio recommendations ??
I like the idea of using some of the old brick outhouse type radios. The MasterII and Micor are about as bulletproof as a radio can get. Another idea that I saw on the web is to use a couple of portable radios (i.e. MT1000 or P200 Motorola) radios as the Receiver and the exciter and then use a commercial PA of your choosing. If you add some of the mechanical folters from an old Micor, you could have a programmable, multi-channel device for not too much money. It will take a lot more time, than the modified mobile. My $0.02 worth. Good luck. This could be a fun project.
[Repeater-Builder] Re:Motorola repeaters
I vote for doing either - whatever works for you! The Micos is a fine radio - no doubt. It is also a very old radio. The only way to get parts is to scrap an old micor. Just about the same for the SRA series syntor. Both have mechanical frontends and can do a great job, but the syntors DO require two radios to make a repeater. This is not all bat though - you can swap the RX and TX radios and get a station back on the air on no time with no real radio modification. The Micor's require surgery and don't reert easily back to mobiles if needed. One good thing - the cables and control head for up to a 12 channel micor also work directlywith an SRA series syntor. A syntor 9000 is another animal.
[Repeater-Builder] Re: MICOR BASE OR REPEATER ON BATTERIES?
You CAN run a Micor base station on 12VDC, but you have to arrange a switchover from the 12V supply to the regulator board in the Micor power supply. As was said, you need 9.7 or so volts to run much of the control and logic functions and the power supply derives that from 12V. You need to make that cutover at the pre-regulator board in the PS
[Repeater-Builder] Re: Battery backup
Try this link: http://www.westmountainradio.com/SuperPWRgate.htm Doug
[Repeater-Builder] Re: Battery backup
The best arrangement I have seen so far is the Powergate PW40S which has the built-in 3 stage charger. I have used them and they are really good with a zero time switchover so none of the little electrons in the controller get confused and reset or worse, lockup the controller. It also charges the battery the RIGHT way, with a 3 stage charger. It can be duplicated I am sure, but at the price, I just would buy it and spend the time tinkering with the RF for a good repeater. IMHO Doug KC0SDQ
[Repeater-Builder] Re: FYI: FCc officially issues RO dropping code requirement today
You know, there is no requirement to kil code from the airways. Some people are talking like this is the end of things. NOTHING says there won't be any more code, it is just relegated to the other obsolete and dusty vestages of the amateur radio world. I know there are a lot of folks that enjoy code operation. To them, I say - have a great time with it! It is yours to use and enjoy. There are dozens of other operating modes that are in greater use and are more relevant to today's amateur radio licensee. Why saddle people with learning an obsolete operating mechanism? The FCC acted properly this time. The dooms day sayers are in full foce - but without any facts to back them up. It's time to move the art and science forward - not backward. IMHO Doug KC0SDQ
