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Lscott

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Everything posted by Lscott

  1. Lscott

    First HT.png

    Lscott posted a gallery image in Members Albums Category

    First HT.png

    From the album: Misc. Radio Gear

  2. Lscott
    2117323252_BatteryPackTesting.JPG
    Battery pack testing using a lab grade electronic load. Battery pack is discharged using constant current mode. Rate is set at 0.2 times the rated battery pack capacity. This is one of the typical rates used for capacity rating by manufacturers. The Kenwood Lithium Ion battery packs have a rated output voltage of 7.2/7.4 VDC. There is a protection circuit in them, over charge and over discharge, which shuts the pack down if the charge voltage goes too high or discharge voltage too low, around 5.7 VDC more or less. The HT's typically will alarm out/shut down around 6 VDC so that's my discharge cutoff voltage. Data sheet: https://siglentna.com//wp-content/uploads/dlm_uploads/2019/04/SDL1000X_DataSheet_DS0801X-E01E.pdf
  3. Lscott

    NX-300.JPG

    Lscott commented on Lscott's gallery image in Members Albums Category

    NX-300.JPG
    This is one of the NX-300 400-470 band split radios. Just got it back from service and testing it out at the office by letting it scan. The 450 MHz to 520 MHz band split models have Part 95 certification so they can be used on GMRS FM mode only. I also have the NX-200 VHF versions too. This radio is easily setup for railroad monitoring if you are into that. The railroads use either FM or NXDN digital so the NX-200 is perfect for that. These are very nice radios. Detailed spec's: https://comms.kenwood.com/common/pdf/download/02_NX-200G&300GBrochure.pdf Depending on the generation of the radio they can be reprogrammed over the air remotely. You just need the master base radio connected to a computer running the application. For these radios the KPG-150AP package is required. https://comms.kenwood.com/common/pdf/download/905_KPG-150APBrochure.pdf
  4. Lscott

    NX-300.JPG

    Lscott posted a gallery image in Members Albums Category

    NX-300.JPG

    From the album: Misc. Radio Gear

  5. Lscott

    NX-820GH.jpg

    Lscott commented on Lscott's gallery image in Members Albums Category

    NX-820GH.jpg
    I got this NX-820GH mobile radio free from a buddy. Had to clean it up a bit. It's the 400-470 MHz band split version. Detailed spec's: https://comms.kenwood.com/common/pdf/download/10_NX-720HG&820HGBrochure.pdf
  6. Lscott

    NX-820GH.jpg

    Lscott posted a gallery image in Members Albums Category

    NX-820GH.jpg

    From the album: Misc. Radio Gear

  7. Lscott
    My Radio Collection
    I collect mainly Kenwood HT's. Some of the models I own several units of them, multiple units per box and several boxes for the larger numbers. The storage boxes are sorted by model type. Many of the radios are UHF since that seems to be where the majority of the Ham digital voice activity is found. Not so much on VHF. I'm currently looking for a good deal on a few NX-1200DUK2 radios in like new, or new, condition to add to my collection. I'm also considering an Air Band radio. While some VHF radios have air band receive a special purpose radio would also include the transmit function too. I'm looking at an Icom IC-A16 series radio, but even used these are more expensive than most of the digital mode radios I have! I just recently purchased some Icom radios that do FM and dPMR digital, not to be confused with DMR, for the VHF and UHF bands. I now have radios for the following digital modes: D-Star, DMR, P25, NXDN and dPMR. Nothing for System Fusion yet. I was hoping to program the dPMR radios for dPMR446, BUT there are some differences between dPMR446 and dPMR that seems to render the two modes incompatible. This is based on my reading for the two ETSI standards. Looks like I might have to pay up and get an official dPMR446 radio even if they're limited to only 0.5 watts. I would like to get a Kenwood TK-3701D in that case. The radio appears to be based on the NX-1300 series radio. That means I likely can modify the radio and replace the crummy fixed antenna with a removable one by replacing the fixed antenna with the original design SMA socket the regular NX-1300's use. Then using the external antenna port I can use an external power amplifier to boost the power up to around 4 to 5 watts, more like a regular HT. I have a spreadsheet I put together so I can remember which programming software is used for which radio. I also have separate folders for each radio model, and sub folders if more than one band split is available, for the code plugs for each one. When I receive a used radio I try to save the original code plug. Part of the fun collecting these is trying to figure out who, or where, they were originally owned by or came from. One I figured out was used by the maintenance staff at a nuclear power station on the east coast. Fairly current list of models I have: Tri Band: TH-D74A analog/D-Star Digital (With MARS/CAP Mod) UV-5X3 TH-350 Dual Band: TH-G71A (With MARS/CAP mod) TH-79A UV-5R D878UV analog/DMR Digital (ARC4 40 bit enhanced encryption, AES 256 bit encryption, both enabled) KG-UVD1P Multi Band: FT817 HF/VHF/UHF AM/FM/SSB (With MARS/CAP mod) VHF: TK-270G TK-2000 TK-2170 TK-2140 TK-2160 TK-2360 TK-2180 TK-D200E analog/DMR Digital TK-D200GE analog/DMR Digital (GPS enabled) NX-200 analog/NXDN Digital NX-200G analog/NXDN Digital (GPS enabled) XPR6550 analog/DMR Digital TK-5220 analog/P25 Digital IC-F3162DT analog/dPMR Digital (Not to be confused with DMR) IC-A16 analog AM Air Band TX-RX / FM Weather RX only UHF: TK-370 TK-370G BF-888S TK-3170 TK-3212L TK-3212 TK-3173 TK-3160 TK-3200 TK-3360 TK-3140 TK-3180 NX-340U analog/NXDN Digital NX-300 analog/NXDN Digital NX-300G analog/NXDN Digital (GPS enabled) NX-320 analog/NXDN Digital NX-411 analog/NXDN Digital (Setup for Ham 33cm band) NX-1300DUK5 analog/DMR Digital (ARC4 {RC4} 40 bit enhanced encryption enabled) TK-D340U analog/DMR Digital TK-D300E analog/DMR Digital TK-5320 analog/P25 Digital XPR6550 analog/DMR Digital (RC4 40 bit enhanced encryption enabled) XPR6580 analog/DMR Digital (Setup for Ham 33cm band) IC-F4162DT analog/dPMR Digital (Not to be confused with DMR) T5720 (Motorola FRS Radio)
  8. Lscott
    My Radio Collection

    From the album: Misc. Radio Gear

  9. Lscott

    Misc. Radio Gear

    Lscott commented on Lscott's gallery album in Members Albums Category

    IC-A16 Air Band Radio.jpg
    Battery pack testing using lab grade electronic load in "constant current" mode. Discharge rate is set for 0.2 times the battery pack rating.
  10. Lscott
    2117323252_BatteryPackTesting.JPG

    From the album: Misc. Radio Gear

  11. Lscott
    Yeah, for that purpose it's likely just fine.
  12. Lscott
    That's all nice but do you have anyway to at least calibrate the clocks in the frequency counter and NVA's? Some use cheap crystals as the time base and can be seriously in error or show large drifts over time and temperature. I have a used Rubidium atomic clock, haven't used it yet since it was pulled from an old cell site and I don't know how much life is left on the Rubidium lamp. What I do use is a GPSDO to calibrate the frequency counters against. They aren't horribly expensive. When I got mine I paid about $150 before taxes and shipping.
  13. Lscott
    Good reason NOT to go to your door. That's really scary stuff.
  14. Lscott
    That will be one of the issues with trying to get the FCC to approve the idea. There is an existing group of FM only users and how would allowing digital affect them? Many, I would guess, likely wouldn't have any need or interest in getting digital enabled radios. The current FM only radios fits their needs as is. The FCC would need to balance any proposed rule changes against the interest of those users. That will be the tricky part.
  15. Lscott
    Do you have the service manual for the radios? Manufactures can and do change versions because of hardware design changes. That could apply to the display too. You simply might have a different, electrically, LCD display verses the other radio where they are not compatible. The service manual might show the differences.
  16. Lscott
    Some of the above sounds like a rehash of topics discussed before. I'm surprised more haven't downloaded a file I posted on 7/25, 3 so far and I was one of them to test it, in this thread detailing my thoughts on the topic along with a lot of links to prior background material. In there I go over some points where a couple of modes might be a good choice even if they are not the current favorite and why. The idea is what could be proposed in a filling with the FCC they will seriously consider. Before that happens there has to be sound arguments why it can and should be done.
  17. Lscott
    I wouldn't be concerned about FRS. It's a different service, and effectively unlicensed at that. If an FRS user wants to use digital voice, well let them pay for a license. It's another perk of getting licensed besides using higher power and access to repeater operation. The repeater idea has merit. I believe that dual mode equipment is available, which will automatically switch between analog and digital modes. The negative aspect is too many non-technical GMRS users have trouble figuring out what offsets and tones are judging by the frequent posts on the forum asking for help. Now throw in color codes, slots, talk-groups and user ID's, well even some experienced radio buffs have a bit of a problem with those.
  18. Lscott
    So, given the current regulations, and assuming the FCC would change it's mind, what do you think has the best change of getting serious consideration? We have to be realistic here. The FCC isn't likely to make major changes that could have negative impacts on existing users. They made a mess of things previously by allowing the marketing of dual service radios, GMRS/FRS, and tried to clean it up with the 2017 changes. This is the conversion we need to have and have an open mind about it.
  19. Lscott
    The spec's for the 2730A are hard to compare to the 2821D since the sensitivity units are different. You need to convert the 2730A to uV units. -10dbuV -> 0.32uV -5dbuV -> 0.56uV https://static.dxengineering.com/global/images/technicalarticles/ico-ic-2730a_sn.pdf file:///C:/Users/kcs/Downloads/IC-2730A-brochure-12-01-17.pdf
  20. Lscott
    So far no. The programming software seems to set all of the “unused” channels frequencies to zeros if I switch between 8 to 2 channel models. It also sets those channel options to default values too. That’s VERY inconvenient. I had hoped it wouldn’t so I could do most of the channel setups through the software and just manually hex edit the code plug for the custom frequencies. I need to experiment and see if hex editing the code plug for just the frequencies and load it into the programming software if it leaves them alone for the extra memory channels so I can write it to the radio. If it does I’ll have to reverse engineer the code plug structure for a memory channel completely to figure out where the options are set, bandwidth, power, scan etc. and hex edit those for each one. If that works maybe I can write a utility to read in the code plug and make the changes, then save it. Right now the frequencies are stored as packed BCD in little endian format in 4 bytes. The tones are stored as a 16 bit unsigned integer in 2 bytes, also in little endian format. Why the difference? Beats me. I didn’t write the radio programming software. Some of Kenwood’s other radios the code plugs are encrypted using a simple XOR method. The key is stored in the code plug in a fixed location and might be different from one code plug to the next for the same exact model radio. I’ve seen the install key in the code plug along with radio serial numbers too for some models. I think this is done so Kenwood can trace where the code plug came from.
  21. Lscott
    The issue was looking at the range limit due to problems when the radios can't sync the time slots from signal delays. If the time slots overlap then communications basically fails. That was the focus of the mentioned section in the ESTI standard. I was curious if anyone has experienced this, or at least can be reasonably sure that was the cause. The second issue was clock drift in the radios. Unless one is using extremely accurate clocks, like synchronized to an atomic standard, they will drift over time. BTW old cell sites used Rubidium atomic clocks but now use GPS disciplined clocks to maintain sync. https://www.thinksrs.com/products/prs10.html https://en.wikipedia.org/wiki/GPS_disciplined_oscillator The clock would be the internal master oscillator reference used for the frequency reference. After some period of time, likely just seconds, after the initial slot synchronization for a transmission the slot timing may overlap between slots 1 and 2. Remember the frequency drift is for both radios at each end. Again communications fail. That seems to place a piratical limit on the transmission time length too. If you look closely at the cheaper DMR radios, compared to the more expensive commercial versions, they have sort of crappy oscillator accuracy and drift spec's. For example the few Motorola XPR-6550's I have spec at +/- 0.5PPM, my Kenwood TK-D340's are +/- 1.0 PPM. The popular D878UV is +/-2.5PPM ! Ouch. Some base radios, and or repeaters, could be using OCXO, oven controlled crystal oscillators, to maintain frequency accuracy and very low drift rates. The best hand held radios only have TCXO, temperature compensated crystal oscillators, because the power drain for the oven heater is far to high for battery pack powered radios. http://www.realhamradio.com/GPS-oven-journey.htm https://www.electronics-notes.com/articles/electronic_components/quartz-crystal-xtal/tcxo-temperature-compensated-crystal-xtal-oscillator.php
  22. Lscott
    I've read about there being range limitations when using TDMA digital modes, like DMR, due to clock drift in the base and mobile stations. The issue seems to be the slot timing verses distance and length of transmissions. See section 10.2.3.1.3 on page 112 in the following link to one of the ESTI DMR standards. https://www.etsi.org/deliver/etsi_ts/102300_102399/10236101/02.03.01_60/ts_10236101v020301p.pdf Anybody have any experience with this or did the detailed calculations for their installation? I've seen comments where some have gone to FDMA type modes to avoid this issue.
  23. Lscott
    You can try enabling through the option menu window.
  24. Lscott
    If "N" connectors are too big and you need something small that can be weather proofed, good luck with BNC's, and high frequency rated have a look at the RG8 mini UHF type. https://www.everythingrf.com/tech-resources/connectors https://www.amphenolrf.com/connectors/mini-uhf-connectors.html
  25. Lscott
    If you check you'll see just about every radio that says it's "wide-band" really is spec'd for 16K0F3E, not the FCC authorized 20K0F3E for GMRS. The 16K0F3E was the old business wide-band specification. Just about every GMRS repeater on the air is build using old Part 90, business band, equipment with the 16K0 spec. Many of the currently sold GMRS radios are old repurposed business radio designs, or amateur gear, with tweaked firmware to make them compliant with the FCC rules. The 16K0F3E spec seems to be particularly true of the new Chinese manufactured GMRS specific radios. One would have a difficult time telling the two apart, 16K0 verses 20K0, on the air. I suspect the FCC could have changed the rules to make 16K0 the "official" FM standard for GMRS and likely nobody would notice.
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