Jump to content

Lscott

Members
 View Profile  See their activity

  • Posts

    3724

  • Joined

  • Last visited

  • Days Won

    107

 Content Type 

Everything posted by Lscott

  1. Lscott
    I would do a bit more research before sending it back. Checking the match on an HT antenna is a difficult exorcise. Lot's of ways to do it wrong and get crappy results. I've tried it myself and had trouble getting results that looked reasonable. Read the comments about antenna testing and what the guy observed. I did some simple tests using an older MFJ antenna analyzer. Check out the results for the Diamond SRH320A. The results for 2M are particularly weird. WGP - With Ground Plane WOGP - Without Ground plane. Then I ran some SWR sweeps of the SRH320A using my RigExpert AA-1000 antenna analyzer with a special MFJ magnet mount using an SMA connector for HT antennas. The mount was placed on a large 36 inch by 40 inch flat sheet metal sheet for a ground plane. https://mfjenterprises.com/products/mfj-332s?srsltid=AfmBOoq7AleI5bQc6eePGbJ4paGCA-ZK7sBSZWARn6VL0pTjEjIYgUTy https://old.rigexpert.com/products/antenna-analyzers/aa-1000/ Apparently, I assume, something else must be going on to get a good match on 2M when the antenna is on an HT, held in the hand and close to the body, that the testing I did does not duplicate. https://www.diamondantenna.net/srh320a.html HT-Antenna-Testing.pdf HT Antenna Tests Results.pdf Antenna Scan Results (SRH320A 1.25M GP).pdf Antenna Scan Results (SRH320A 2M GP).pdf Antenna Scan Results (SRH320A UHF GP).pdf
  2. Lscott
    The attached files are a couple of the simple Kenwood 2-pin plug, "K1" connector, worthy to look for. I've used the KMC-17 on some CCR radios and got good audio reports. The main issue with used mic's is the cord. The outer material has a tenancy to crack and peel off. If buying used look VERY carefully at the cord condition. KMC-17 Revised.pdf KMC-21.pdf
  3. Lscott
    That makes sense. I have the service manual for the -45. So far can't find one for the -45D. A few of the DMR radio recommended Kenwood mic's had a few extra ceramic cap's installed verses the non DMR recommended models. The really fancy one is the KMC-52D. That one has a full builtin DSP processor core, and it's own programming software. The big pit fall with the various digital voice modes is the CODEC is HIGHLY optimized for voice only. Things like wind noise, sirens etc. will bugger up the conversion from analog to digital. The DSP based speaker mic does all the filtering and noise cancellation in the mic itself before the audio is passed to the radio. By comparison the -45 is very simple. Just a mic element, speaker and some switches. KMC-45.pdf KMC-52D.pdf
  4. Lscott
    M$ screwed up with forcing a move to a tablet type interface on newer versions of Windows. Win10 is "tolerable", have it on the work computer, company laptop and home PC. I needed it on the home PC because the Kenwood license manager for their feature license installation won't work on Win7, which I would still be using otherwise, it was close to the look and feel of Win XP. The Win11 I have in a VM for experimentation sucks. It's slow and and nothing more more than a advertising delivery system for M$ garbage. I've flipped every "switch" I could find and researched on-line, but I sill get annoying reminders, here and there, to get M$ Office 365 and cloud services. Win11 is the new Vista, and much more annoying.
  5. Lscott

    TK-3701D.jpg

    Lscott posted a gallery image in Members Albums Category

    TK-3701D.jpg

    From the album: Misc. Radio Gear

    This is a special radio I've added to my collection from a seller in the UK. The price was fairly cheap, GBP 90, about $120 USD at the exchange rate at the time of purchase. Most sellers want about $175 to over $250 for the radio. The price didn’t include Michigan sales tax or eBay’s international shipping. The radio included a battery pack and charger base (220VAC plug on the wall wart). Have to find a side cover plate for the programming/remote mic port and a belt clip since these were missing. It's a combo FM/digital radio. The digital mode is dPMR446. Both FM and digital use fixed frequencies that lie within the US Ham 70cm band so it's usable there ONLY. The radio has no FCC ID or certification to be used anywhere else. I went back and purchased a second one, from the same UK seller, just so I have at least two that are guaranteed to communicate with each other. The seller in the UK had the lowest price I could find on a used model. Just can’t find these for sale from a US seller, unless it’s imported. https://bhvtotaal.nl/media/productdownloads//b/r/brochure_kenwood_tk-3701d.pdf https://kenwoodcommunications.co.uk/files/file/comms/uk/brochures/TK-3701D_20191030_LR.pdf The radio requires KPG-202D to do the programming. I found the software on line with the install key to download. The programming cable is the same one used on my NX-1300 radios, and many of the cheap Chinese radios. I know how to hex edit the code plug so it’s possible to operate the radio outside of the normal EU PMR446, dPMR446 band if required. This radio is a replacement for the older TK-3401D, which apparently there are V1, V2 and V3 versions. https://kenwoodcommunications.co.uk/files/file/comms/uk/brochures/nx/TK-3401D-Brochure-LR.pdf Also seems there is another model type, TK-3601D, with a display. It look more suitable for light use, like restaurant, hotel etc. use, not a more industrial environment. https://kenwoodcommunications.co.uk/files/file/comms/uk/brochures/nx/TK3601D_0425_final-separate_UK_lr2.pdf The radio is designed for license free use in the EU zone. The dPMR446 mode is very slightly different from the full featured dPMR mode used commercially in the EU. The dPMR446 version has a simpler programming model compared to the full featured dPMR mode. The two standards for reference are the document names below. There is just enough of a difference than it would very likely prevent the two modes from communicating with each other, thus a higher power dPMR mode radio won't work with a low power dMPR446 mode radio on digital. For dPMR446 : ETSI TS 102 490 V1.9.1 (2016-08) For dPMR : ETSI TS 102 658 V2.6.1 (2019-01) https://kenwoodcommunications.co.uk/files/file/comms/uk/pmr446/PMR446-White-Paper-V6_18AUG2016_JT_KB.pdf I should point out the TK-3701D is really an NX-1300 series radio loaded with the special dPMR446 firmware, instead of the usual DMR or NXDN one. Looking at the service manual for both I can't really see any differences from a general schematic layout, but I didn’t check for any component value differences. In case anybody is thinking can an NX-1300 be converted to a TK-3701D? From my research the answer is no. Can’t force the dPMR446 firmware on the radio according to a few people I asked. The programming software has a "Tune" mode for service. The procedure is outlined in the service manual for the radio. I might be able to pump up the default power from about 0.5 watts to maybe 1 to 2 watts. That would be nice.
  6. Lscott
    This radio was a bit more expensive, GBP 90. I had it shipped from the UK through eBay's international system. https://www.ebay.com/itm/126800820122?var=427899179724 I had to get it before the "de minimus" tariff exception for goods under $800 disappears on 8/29/2025. Otherwise it would be a ridiculous price with the minimum tariff required. No more shopping for stuff outside the USA on eBay anymore. https://www.avalara.com/blog/en/north-america/2024/11/de-minimis-exemption-changes-coming.html
  7. Lscott
    Correct. The difference is the -45D has additional internal filtering for use on DMR radios. Otherwise they are basically the same.
  8. Lscott
    Yeah, works on the Ham band. Would be a novelty. Without another compatible radio, or decoder for an SDR, good luck monitoring the digital voice traffic. Almost as good as encryption but since it’s publicly documented the FCC can’t really complain it’s a “secret code” thus illegal on the Ham band. The point to remember is the modulation used is exactly the same as the low data rate NXDN mode. The later the FCC has emission designators for that. You can’t tell the difference with a spectrum analyzer. What’s different is the CAI, common air interface a.k.a. the digital protocol used. Note the radio is restricted to just the official dPMR446 frequencies in self programming mode. The radio programming software is also locked to the same frequencies. My main objective was to do some testing to see if it will communicate with a full feature dPMR radio. I have some Icom dPMR radios. There are a few “slight” differences which might bigger that up. There are in fact two different ETSI standards, one each, for the two, dPMR446 verses dPMR. https://forums.mygmrs.com/gallery/image/500-ic-f3162dt-front-and-back-sidepng/?context=new
  9. Lscott
    That's good. The engineer in me would like to know a bit more about the "how and why" that is the case.
  10. Lscott
    Well I just got a clean looking license free TK-3701D dPMR446 radio, NOT DMR446, which is the other allowed digital mode. The idea is to run some tests between it and the Icom's I have with the more functional dPMR digital voice mode. I want to see if they will communicate. There are some slight differences that might bugger it up. I won't know until I can get around to running some tests. Other thing there radios are the functional equivalent of FRS here, but in the EU where it's license free, 0.5 watts, and digital voice is allowed. I'll bet some Ding-Dong will bring their radios here on vacation and try to use it while at some major tourist attraction like Disneyland, Yellowstone etc. The radios only work from 446.0000 to 446.2000, the Ham 70cm band. Anyone ever bump into something like this on the air? If one has a spectrum analyzer, or SDR, it would look like the ultra narrow band NXDN mode, the modulation is the same but the digital protocol is different. https://kenwoodcommunications.co.uk/files/file/comms/uk/brochures/TK-3701D_20191030_LR.pdf https://kenwoodcommunications.co.uk/files/file/comms/uk/pmr446/PMR446-White-Paper-V6_18AUG2016_JT_KB.pdf
  11. Lscott
    A definitive test, or comparison, should be done with a field strength meter and a uniform standardized test stand. That removes any personal bias and different physical antenna setups. Any changes in the far field has to be due to gain and pattern variations. Qualitative comments about hitting a repeater with one antenna and not another doesn't revel any insight on why that might be the case. Too many variables to control, any one or combination, can affect the results. I've tried this just for antenna matching. It's much more difficult to do than one realizes. I found just slight changes in orientation and ground plane made a big difference. https://www.hamradio.me/antennas/ht-antenna-comparisons.html https://reflector.sota.org.uk/t/antenna-testing-jig-swr/14791 Antenna Testing W9MDB.pdf
  12. Lscott
    A 5/8 wave requires a good ground plane. The reason it has a slightly better gain is the reflection off of the ground. Without that reflection it's basically no better than a 1/2 wave. And for an HT antenna you have crap for a ground plane. https://www.w8ji.com/VHF mobile vertical.htm
  13. Lscott
    You might want to look at the Diamond SRH320A. Not exactly cheap. SRH320A Triband HT Antenna.pdf
  14. Lscott
    Normally you have to be sure the group is enabled for scan too. I know on various Kenwood HT’s I can enable, or disable, an entire group for scanning even if all the channels in a group are always marked for scan.
  15. Lscott
    Thanks. I just tried it. downloaded a reference copy. Nothing is listed under Waivers/Conditions. Looks like I'll have to make a few code plug edit changes for my radios. Oh-well, more busy work.
  16. Lscott
    Now this is a legal question. There are those of us that have it specifically stated on our license we can't use those frequencies, so is it perfectly fine to disregard that? I'm thinking if it's a special restriction on our license, above and beyond the current rules, it would still apply until we get it officially removed from our license. One could argue the restriction is there to serve some other purpose than rule compliance.
  17. Lscott
    I was looking through the ad listings on eBay and found one for a very sophisticated microphone. It has a DSP chip builtin for background noise, wind noise, siren etc. elimination. Some of my radios also have some basic DSP builtin. For example my TK-D74A has a basic 5 band audio equalizer for TX and RX. Other commercial grade radios have selections for audio filtering, high/normal/low pass, and audio leveling, on TX and RX for digital modes. This is something I haven't seen on the cheap CCR's. So any cheap CCR's out there that has user configurable DSP features?
  18. Lscott
    I was in our electronics lab once working on a project. Some mention was made about drunks on the street. I referred to them as "Stumble Bums." Well I got one of those "WTF is that" looks. Makes you feel old.
  19. Lscott
    If a deaf person can't hear you some would say it's OK.
  20. Lscott
    That's a nice neat installation! I like it when people post stuff like this. Good material to reference for ideas.
  21. Lscott
    Except for the people a mile or so away using their 0.5 watt FRS radios that’s getting hammered by your 5 watts. You can’t hear them, but they’re very likely can hear you. Does that still make it OK? You didn’t hear it. Given equal radio receiver sensitivity then range can be limited by the square root of the ratios of the transmitter powers. So 5 watts verses 0.5 watts could result in a range increase of 3.16 to 1 in favor of the 5 watt radio.
  22. Lscott
    I have fun running various OS's in a VM. I haven't had any luck getting Mac OS X Sequoia VM to work yet, kernel panics. Sierra seems to run OK. I use Tumbleweed when on the Internet, like now.
  23. Lscott
    Every once in a while you may stumble across an "odd split" repeater frequency, rare but they are out there. If you end up getting some commercial grade radios the programming is a bit different. For those they don't assume any kind of offset. You have to enter in BOTH the discrete transmit and receive frequencies. None of mine have any entries for an "assumed" offset, unlike many Ham grade radios. https://wiki.radioreference.com/index.php/Offset
  24. Lscott
    Understandable. The goal was finding a spot where those that want to use digital voice have a "home", and not impact those who are happy with analog FM. The proposed changes allows those who want to continue to use FM won't notice a difference. The manufactures would have a choice which grade of radio they want to provide. For example right now in the EU one can buy cheap simple analog only PMR446 radios, or spend more money and buy one with digital functions too. There isn't any reason to force manufacturers to sell only the more expensive combo analog/digital models. The market place will take care of that if the demand is there.
  25. Lscott
    Yes I did. Yeah, it's not the best written paper I've ever done. Just tried to get my ideas down in some coherent fashion. I'm not an English major. It's easier to just attach it to a post rather than try to convey my ideas a few lines at a time over dozens of separate posts. No. The only reason for any kind of registration on Ham is for the user ID's. That's to prevent duplication. However you can use whatever ID you want, but for those that depend on the radio's builtin database it will, of course, show the wrong info. I had accidentally did that programming one of my DMR based NX-1300's. When I used it one of the Hams on the repeater noticed and asked about it. Didn't impede the QSO any however.
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use and Guidelines.

  I accept