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kidphc

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Posts posted by kidphc

  4. MRI causes interference

    in General Discussion

    Posted

    As I approached a hospital today, GMRS 17 started buzzing loudly, in some pretty distinct sequences. This started about 3/4ths mile from the hospital. I was on my way to an MRI appointment. And when in the machine I quickly realized what I had been hearing on GMRS 17 was the MRI sequences. For anyone who has had one, the sequences are unmistakable and probably unforgettable.
     
    I just found it interesting that the interference started so far away from the hospital, and was so reliably attenuated to channel 17. I didn't hear it on 16 or 18. And the sound my radio made was just like what I was hearing inside the apparatus. And it was an intense level of interference.
     
    I don't have a question, just reflecting on the situation.
    I have had several head mri's. Couldn't tell you what they sound like. Was wearing ear plugs, still defeaning. When people ask I don't know, like putting you head next to a jet engine with rocks in it?!



    Sent from my SM-S901U using Tapatalk

  7. Getting a signal through metal walls?

    in General Discussion

    Posted

    You could build a low power repeater. Problem will be you will need an indoor and outdoor antenna. When the repeater transmitting. You will lose half of the power to each antenna. Plus a mess of other things that could go wrong.

    I had looked at passive repeaters/antennas. But the usefulness of them are low. In your case. I would investigate this an option. Don't expect much, but to spend money. You could try to build a dipole indoors connected to a yagi outside pointed at the area of intrest. But again passive repeaters aren't in high use for a reason.

    Another option is to get a kg100g, or any radio with a Bluetooth option. With a Bluetooth mic and connect the kg to an external antenna.

    For hams, I have contemplated buy a uv578 with Bluetooth head control mic. But always just walk over to one of my digital radios and use the hotspot. Haven't seen a gmrs (tuned) hotspot yet. Guess that will be on a to do list.

    Sent from my SM-S901U using Tapatalk

  11. PL-259 through the firewall.

    in Technical Discussion

    Posted

    Most can't be passed through without leaving a big hole and requiring a grommet to seal said hole.

    I have used a coax that had an fme connector (barely larger then rg58). Came with a fme to pl259 adapter. It was pretty slick if you ask me.

    Most of the time you need to snip off the connector to get it through tight spaces and crimp on a new connector.

    Contact the vendor to see if it can be disassembled for installation with instructions.

    Sent from my SM-S901U using Tapatalk

  12. Mobile radio issues

    in Technical Discussion

    Posted

    I'd also be curious about antenna location, and what might be close by.
    I get a ton of RFI from some Amazon special LED headlight bulbs, to the point of 2m being near unusable. It wasn't an issue previously, with the antenna on the roof, but once I moved the antenna to the front fender, major RFI.
    I've read of using copper scouring pads to shield noisy LED/HID ballasts, but keep forgetting to track some down to test with.
    I had a fender mount that was introducing a lot of rfi in the middle of the gmrs band. 2m/70cm cap modded radio.

    Installed a dedicated gmrs radio and antenna (back 1/3rd of roof). Noise was manageable with just a hair of squelch.

    Turns out the rfi noise was caused by a failing brake accumulator, and hydraulic leak into the abs computer. My generation landcruiser and some 4runners use a electric motor to build brake pedal pressure. God awful expensive part. The rfi went away when the brake module was replaced.

    When I find leds that make rfi noise that is noticeable, in the trash it goes. It's the driver, lots of leds you can't replace the driver.

    A neighbor of mine has decent inverters on his solar panels. Only really made noise when at peek power, sunlight going full tilt on the panels. My noise floor goes from s3 to almost s6-s8, usually not home at those times. His plasma screen was terrible also, thank God he upgrade the tv. A lot of rfi comes from cheap electronics and poor shielding, sigh.

    Sent from my SM-S901U using Tapatalk


  13. Mobile radio issues

    in Technical Discussion

    Posted

    Rfi, or installation issue from the electronics running on the car.

    Seems like the shielding is kinda crappy on alot of Chrysler products. Turn off the car and rfi is gone. Some times the delayed accesories can still introduce noise till about 5minutes after shut off.

    Your coax can act as a big antenna, routing can make a difference. Generally, a good practice in mobile installs is to keep the coax ad far away from power and canbus lines as possible. Cross those lines if possible at 90 degrees with the coax.



    Sent from my SM-S901U using Tapatalk

  14. 15Watts? Good for mobile?

    in Technical Discussion

    Posted

    On my truck I have a Laird BB4503 (NMO) on a mag mount.  It is a 5/8λ ground plane required.  Each time I use it I am impressed with its quality and performance.  It does need to be cut for proper tuning, and they provide the center frequency and length, so you're not guessing.  I'm only running 14-18w into it, and for repeaters with a 250-300' AGL receive antenna I can hold the repeater, and talk out to 50 miles or so, as long as I have a good line-of-sight.
    For the car I am considering getting the Laird BB4502 (1/2λ) which is a no-ground plane required, since I don't have a good mounting location.  It won't perform as well as the BB4503, but should be pretty close, and probably not enough of a difference for me to notice.
    Only difference between the "B" and the "BB" models is that the base is black, instead of stainless.
    Try the 4505. The 5/8 over 5/8, other then the size it is a very, very impressive antenna. Did I say impressive.

    I am running a 4503 right now. It's not bad, just a bit more deaf than the 4505.

    Crap i might be selling mine. Even uncut it was about 1.2 to 1.3 in gmrs repeater frequencies. Still have not cut the 4505 or the 4503 just really no need to.

    Sent from my SM-S901U using Tapatalk

  16. 15Watts? Good for mobile?

    in Technical Discussion

    Posted

    Personally, depending on location. Ie mountains and repeater availability.

    Usually, 20 watts or so are nice and adequate. Most will let you trim the power back some even enough to get on the frs interants and still be close to inbounds according to some rules. Plus most are economical compared to a 50 watt model.

    Most 40/50 watt radios can't turn the power down enough to play with the entire allocation. Hence some channels are blocked etc. But it is always nice to bump up the power when at the fringes of a repeater or in the woods.

    With uhf and vhf. Gmrs is uhf. Focus on the antenna setup more then the radio. 15w with a properly setup 5/8 antenna gets you out further and cleaner then a 50w with unity gain antenna with no groundplane and crap coax.




    Sent from my SM-S901U using Tapatalk



  18. Inline Booster

    in Technical Discussion

    Posted

    Yes, but mainly for hand helds. Btech makes one. The input voltage is usually set to 1 watt or less.

    For mobiles, yes they sell amplifiers. But the radio needs to put out about the same wattage as handheld and most radios that put out more then 20watts can't be lowered enough

    Normally, it is easier to get a more powerful mobile. Gmrs is already limited to 50 watts, which really is enough. Hell with a good antenna system you could get away with about 20 watts 80-90% of the time.

    The question I want answered is why are you asking?





  20. L3Harris XG-100M

    in Amateur Radio (Ham)

    Posted

    Wiring and Accessories

    • Canbus Terminator

    Unlike the Motorola Canbus like on the XTL series and newer. The Harris radio wasn't self terminating. Think old fire ring/token ring networks where you had to terminate connections or the ring would fail. So we need a couple of terminators.

    • Original Part# CD-014027-0001
      • These were supplied with the radio when new. Most are long gone, or in a box somewhere in a radio shop.
    • Substitute Part# MACDOS0010
      • These were originally XG-75m, 7300m, and 5300m series radios
      • About $11 a piece
    • Generally, most radio setups will need 1-2, but if you add multiple heads then you may need several extras
    • Microphones
      • DTMF
        • MC-103334-040
        • MC-103334-041 Included with MAMW-NMC9C
      • Standard
        • MC-101616-040
        • MC-101616-041 Included with MAMW0NMC72
      • Noise cancelling
        • MC 103334-050 
        • MC 103334-051 Included with MAMW-NMCSD
      • Avg $20-100 depending on stock and condition
    • Speaker and cable
      • Speaker Cable
        • Part # 1000005812-0001-REVB
        • I plan on using my speaker from the XTL. The speaker cable is basically that 4 prong box connector that Motorola uses.
          • Originally part of the installation kit.
        • Avg $18-23
        • Again carry over from XG-75m, 7300m, and 5300m series radios. SEE A TREND YET?
      • Speaker If you have to have your speaker have Harris on it. 
        • Part# LS102824V10
        • Avg $20 new
        • Again carry over from XG-75m, 7300m, and 5300m series radios. SEE A TREND YET?
    • Canbus Cable
      • Part# ca-009562-030
      • Supplied with original installation kit
      • I am using a new/old stock Macom cable. Again carry over from XG-75m, 7300m, and 5300m series radios. SEE A TREND YET?
      •  Abg $25 ebay $98 new
    • Power Cable
    • Programming cable
      • It is a Rs232 9pin Straight serial cable. I opted for an FTDI usb to rs232
      • NO rib box necessary
      • Rs232 female on the head and back of the radio.
      • Avg $20-40
    • Antenna connectors
      • VHF HIgh, UHF and 7/800
        • TNC female on the radio brick.
        • So you will need a Male TNC to your chosen antenna connector.
      • VHF Low
        • BNC female on the radio brick
        • Again adapter if necessary.
      • GPS port... 
        • I am not utilizing the GPS
        • From my understanding the radio will provide NMEA formatted data.
          • this will be on several pins on the 44 pin serial port.

     

    Reference photo of back of radio on page 18 Figure 3-2

  21. Toy to play with Harris XG-100P

    in Amateur Radio (Ham)

    Posted


    Unfortunately, I don't know how to mod older harris 900mhz radios.

    From what I get, the public service usage is below and above the frequencies we hams get to use. So it might be possible to get what you are looking for in a single band radio.

    I had looked at an old motorola, think it was an Mc series, sorry can't recall. They were about $100 on ebay. But the usage of 900mhz was so low in my area that I abandoned the idea. Plus, the whole 23cm/13cm opposite link nailed the coffin shut for me.

    If it really something you want to play with there are some cheap 900mhz single band mobiles both from harris and motorola to play with.

    Or play with the big boys with an icom ic9700, which lacks 900. Think it was more for the satellite boys.

    Sent from my SM-S901U using Tapatalk

  22. L3Harris XG-100M

    in Amateur Radio (Ham)

    Posted

    Page 21-30 contains a part list

    Page 52-53 has a diagram that includes the part numbers to aid the search.

    The radio body or complete system can be found on ebay ranging from $300 (brick) only to $1000-$3000 depending on the head style for a complete system.

    I chose to buy the bricks and components separately. You can buy an older complete 7300m/5300m/75M for about $120-150. Double check the part numbers from those radios, to verify what parts carry over.

    THE HEADS and Mounting Refer to page 18 of attached manual from first post for pictures of the styles.

    CH721 Head- Avg about $60-80 on ebay.

    • Part# CU23218-004 (system head)
    • Part# CU23218-002 (scan head)
    • This part can be a carry over from a 7300, 5300, XG-75M
    • CH721 Head Remote Mounting Bracket
      • I opted for the  remote head bracket, which may be changed to the ram style home brew mount copying the Harris mountU Shaped bracket
      • Remote Head U bracket
        • Part# KT008608
        • Avg Price new on ebay $10 + shipping
      • CH721 Head Remote Pedestal Mount
        • Part# MACDOS0012
        • Would love to find one but haven't, probably will have to DIY something similar
      • CH721 Catalog numbers
        • Ch721 scan head remote # XMCP9E
          • console mount # XMCP9G
        • CH721 system head remote # XMCP9F
          • console mount # XMCP9H
        • Ch100  remote mount # XMCP9H
          • console mount # XMCP9Q

    CH100 Touch screen, bluetooth head

    • Part# 120991200-01
    • Avg $1000-$2000 (new)
    • Highly sought after but crazy priced.
      • allows for bluetooth programming
      • allows for system/configuration changes that are unavailable on any of the other heads.,
    • CH100 Head Remote Mounting Bracket
    • Part# 12099-1500-01
    • Avg $60 new on ebay
    • CH100 Head Remote Pedestal Mount
      • Part# 12099-1501-01
      • not sure if you need the above as well as the CH721 Pedestal mount.
      • Refer to Fig 8-9 on page 59 to understand what I am saying.
    •  
    •  

    Remote Brick Bracket

    • Part# KT23117
    • I chose to use part# fm103111v1
      • We will see if it works fine. Probably won't have the screws, but it is the part number that is included with the kit
      • I couldn't find the kit
      • AVG $18.99 for a beat up one

    Console Install bracket

    • Part# KT101533V1
    • Avg $15-40

    You can do multiple head setups. A pair of CH721s, a pair of CH100s. You can not mix and match a CH100, with a CH721 head on the same system. This is much like trying to use and 03 head with a 05 head on an XTL series Motorola radio.

    XG-100M00-1470305.pdf

  23. L3Harris XG-100M

    in Amateur Radio (Ham)

    Posted

    Trying to compile a list of parts necessary to build out an XG-100M. Nothing more at this point.

    The Radio: XG100M

    • VHF low band 30-50 MHz
      • 9 miliwatts
        • Some agencies around DC suburbs still use VHF low
          • Shenandoah PD
          • Maryland state on the western handle of MD
          • couple of others
        • It CAN NOT transmit on the ham bands
          • Filters are to tight
    • VHF High 136-174 Wide/narrow
      • 5-50w
    • UHF  380-520 MHz Wide/narrow
      • 5-50w
    • UHF 700-800 MHz 
      • 2-30 w 700 MHz
      • 2-35 w 800 Mhz
    • P25 Conv., Trunked, 
    • 12.5/20/25  kHz spacing
    • Modulation
      • Phase 1 TX: C4FM, RX: C4FM & WCQPSK
      • Phase 2 TX: HCPM, RX: WCQPSK
    • DVRS (digital vehicle repeater) available for 700/800 Mhz only

  24. Toy to play with Harris XG-100P

    in Amateur Radio (Ham)

    Posted

    16 hours ago, Lscott said:

    Are the filters too tight to try and get it on the Ham 33cm band?

    At least the XPR6580's with a CPS in memory hack you can do it with no mod's to the radio.

    Should add. Yeah, I know about some of the memory/cps hacks to get some models to open up.

    Prime example is my XTL5000 it is an R2 "s" model. That was cps reconfigured to a quasi "Q" spec. With a CPS hack/hexedit.

    The older harris radios some could be reconfigured "opened up" to transmit outside of their original band, using "sc" files. Initial research is showing not possible with the XG-100M/P series. 

  25. Which band for digital voice modes?

    in General Discussion

    Posted

    Yeah, I've noticed that frequently many of the commercial digital mode Ham repeaters are using the Mi5 network in Michigan.
    https://w8cmn.net/dmr/
    https://w8cmn.net/p25/
    There is nothing for NXDN on their network. In fact there is only one repeater for the whole state listed in RepeaterBook.com that does NXDN.
    There is a nice linked NXDN network in west central Florida however.
    https://ni4ce.org/nxdn-digital-communications/
     
    Yeah, mxdn is pretty much unavailable in Washington DC area.

    One repeater in Arlington.

    Wonder if that repeater is as dead (little to no traffic) as a majority of the p25 repeaters in the area.

    Really wish repeaterbook wouldn't list some of these tiny repeaters (1 mile coverage) for personal use. You know the hotspots with a high gain outside vertical. I feel it kinda misrepresents the actual digital coverage.

    Sent from my SM-S901U using Tapatalk

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