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Lscott

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Everything posted by Lscott

  1. Lscott
    Actually the antennas respond to the "E" field. Look at the sensitivity rating of a radio's receiver. It's specified in microvolts. To get a ruff idea the power density varies as the inverse square of the distance since the same power is spread out over a larger surface area of the sphere around the isotropic source. So if the power density is: PD=(watts)/(sphere's surface area) Expressing sphere's surface area as a function of the radius: sphere's surface area=Pi*radius^2 PD=(watts)/(Pi*radius^2) And watts can be expressed as: watts = (Volts^2)/(Resistance of free space), which is about 120*Pi, or 377 ohms. So your power density becomes: PD=[(Volts^2)/(377 ohms)]/[(Pi*radius^2)] Or after a bit of rearrangement: PD=[(volts/radius)^2/[(Pi*377 ohms)] That will vary as the surface area of the sphere, or the inverse square of the distance. If the radius is in meters then you have the "E" field intensity in Volts/Meter. PD=(E^2)/(Pi*377 ohms) Note that antenna simulation software will specify the antenna's "E" field in volts per meter. Also be careful you want the "Far Field" number. This also leads to another topic about "path loss" and how there is is a difference between VHF verses UHF for signal strength given antennas of equal gain. It turns out you need much more power at UHF to get the same signal strength you would see on VHF for the same power. Part of the gain you get on VHF is ruined due to the short stubby VHF antenna gains on HT's, reportedly around -5 to -6 db, which almost cancels out the reduction in path loss reduction. Just can't win.
  2. Lscott
    IC-F3162DT Front and Back Side.png

    From the album: Misc. Radio Gear

    This is another "specialty" radio. It's an Icom IC-F3162DT FM/Digital. The digital mode is dPMR, a close relative to NXDN, but not compatible with it. Now I have a radio in my collection for dPMR. The two photos on the left are from the US seller’s ad. The one on the far right is the one I took when the radio arrived. The radio is only going to be legal for use on the Ham bands since it doesn't even have an FCC ID tag! Based on the frequency showing on the display the original owner was messing around with it on MURS. https://pdf.nauticexpo.com/pdf/icom/ic-f3162dt-ds-ic-f4162dt-ds/21749-73295.html https://adradiocoms.com/files/icom/files/DOC-IDAS-dPMR-angl.pdf Of course Icom has to use their own weird antenna port connector. I found a place to order the antenna port adapter from, to female BNC. I didn't get raped too bad on the price. https://www.ruggedradios.com/products/bnc-antenna-adapter-for-icom-handheld-radios?_pos=1&_sid=51449eb2d&_ss=r I’m have a UHF version I just purchased from a seller in the Middle East, IC-F4162DT. Just so I have at least two identical radios to experiment with I ordered a second one from the same seller. dPMR is basically a European centric digital voice mode. It seems to be popular there and a competitor to NXDN. I haven't stumbled across anyone else using dPMR here, at least in the US. For more info about dPMR look here. https://dpmrassociation.org/dpmr-downloads-technical.html In the EU they have a license free service called "dPMR446". It like our FRS but allows digital voice modes. https://kenwoodcommunications.co.uk/files/file/comms/uk/pmr446/PMR446-White-Paper-V6_18AUG2016_JT_KB.pdf
  3. Lscott
    Maybe you could start one by you and announce one of those touchy topics as the focus.
  4. Lscott
    If you don't have your Ham license yet, well now might be a good time to consider get it.
  5. Lscott
    Nothing radical was discussed. More along the lines of what kind of food stuffs are good for long term storage, emergency power, go-bags etc. Nothing about guns or crazy government conspiracies.
  6. Lscott
    Given the frequent questions about people wanting to setup their own private repeater maybe now is a good time to go shopping for equipment.
  7. Lscott
    If the net has a specific topic it could be interesting. For a while the original wide area local GMRS repeater held a "Prepper's Net" on a Tuesday night once or twice a month at 7PM. They stopped because a few had an issue with it, and some infrequent jamming I believe. Some of the topics were informative when the net was active.
  8. Lscott
    But you can hold it's head under the water until it's ready to drink.
  9. Lscott
    That about what this attached chart shows. IC-706MKIIG Freqequency Mod Power Output.pdf
  10. Lscott
    We never got that spectrum back either.
  11. Lscott
    A buddy picked up some cheap XTS5000’s at a few swaps. Used some utility to create a fake authentication file for the radio. He says he uses them to monitor his local 700/800 MHz public safety frequencies.
  12. Lscott
    I don't think people in general understand this point. The 10-codes aren't that universal. PLUS when you have a bunch of volunteers I'll bet most have no idea what those codes are, unless they are specifically trained. Its far better to communicate as clearly as possible without obfuscating things with various codes. That's the general recommendations I've read from other groups.
  13. Lscott
    At least people aren't using silly CB lingo, 10-codes and echo-mics yet.
  14. Lscott
    What kind of antenna do you use on the truck?
  15. Lscott
    I don't think the FCC would agree. https://www.law.cornell.edu/cfr/text/47/95.303 The definition of "Base station" makes NO assumptions about the manufacture's classification of the radio. It would seem the definition is not the label slapped on it by the manufacture but the actual usage of the station independent of the manufactures targeted usage. The prime example is a radio with a nominal 13.8VDC power supply input but connected to a wall powered converter and never leaves the house.
  16. Lscott
    You can put these on the Ham 33cm band with a software hack for the radio programming CPS. See attached file MOTOTRBO too 927MHz Code Plug Mod.pdf
  17. Lscott
    If you have a digital multi-meter you can check the contact on the back side of the battery pack for voltage. A freshly charged battery pack should read about 7.5VDC. I wouldn't be surprised if the battery pack is toast. Not uncommon for used radios. XPR6380_6580 Service Manual.pdf
  18. Lscott
    Like 11m CB radio, FRS and MURS. Big difference is none of the later requires an FCC license, limited to 4 watts or less, unlike GMRS.
  19. Lscott
    You only have 22 channels. Using CTCSS/DCS you just have more choices on blocking what you don't want to hear on those 22 channels.
  20. Lscott
    I learn many years ago one thing. If something isn't broke, and you start screwing with it, it soon will be, BROKEN.
  21. Lscott
    Oops, I guess they didn't learn. They added FM to the service now. So how many people would trash their old obsolete 40 channel AM only CB to get one with AM/FM?
  22. Lscott
    1. The majority of digital voice modes are on Ham UHF. 2. Ham UHF has a satellite sub band for FM operation, and some birds have linear translators for SSB, which can accommodate multiples stations at a time. 3. Fast scan TV. 4. Some have high power EME, moon bounce, stations using digital or analog modes. 5. World wide linked repeaters, using different types of digital voice modes. There’s more but the above is what comes to mind.
  23. Lscott
    Thanks. That has to be the first one I’ve ever seen.
  24. Lscott
    Sad but true. I've heard recommendations to just put up the tower/antenna and not even connect it to radio. Then wait a few weeks to see who complains about malfunctioning appliances, radios, TV, stereos, automatic garage doors openers etc. Then you show them there is NO RADIO.
  25. Lscott
    No, I think you get it. Maybe some just don't get your brand of humor.
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