Lscott
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Everything posted by Lscott
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Only quick way to find out is test it with an SWR meter. Some of these multi band antennas show oscillation in the SWR across a range of frequencies. You might get lucky where the GMRS frequencies falls into one of the low SWR valley. The link below is a test I did of a favorite wide band mobile antenna. Usable. https://forums.mygmrs.com/gallery/image/268-ca-2x4sr/?context=new And this link is for a test on a Ham dual band mobile antenna to see if it was usable. Doesn't look good. https://forums.mygmrs.com/gallery/image/283-sg7500a-swr-scans-2jpg/
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The belly fat one gets from the beer sticks around a lot longer.
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From the album: Misc. Radio Gear
These are a couple of Kenwood speaker microphones. I believe both of these maybe discontinued models. You can find these used, and maybe some NOS, new old stock, available on various auction sites. The "D" in the model name signifies the microphone has the additional filtering to function properly when used with a DMR type radio. Of course they can be used just fine with an FM only type. The non "D" model type should not be used on DMR, but is fine for regular FM work. The two-pin plug on the KMC-45D is the Kenwood type "K1." This is very commonly found on most, if not all, of the Chinese radios. The KMC-51D connector is the Kenwood specific "universal" connector found on many of their higher end radio models. The KMC-45D is a very simple design employing a speaker element, mic element and a switch. https://manuals.repeater-builder.com/Kenwood/kmc/KMC-45_B51-8845-00.pdf The KMC-51D is a very sophisticated design employing a builtin DSP processing core for noise reduction and audio filtering. There is a KMC-52D which is the same electrical design but has the better IP67 environmental rating. https://www.wirelessvoicedata.com/downloads/kenwood/kenwood-kmc-51-52-brochure.pdf https://manuals.repeater-builder.com/Kenwood/kmc/KMC-51_B53-7014-00.pdf https://manuals.repeater-builder.com/Kenwood/kmc/KMC-52D_B5B-7122-00.pdf -
I have a few Motorola radios. The XPR6550 is a good choice. You can buy them for reasonable prices. They also use a standard SMA type antenna connector. The XPR7550 is a better radio, but they are expensive used and have a funky stud type antenna port. So, if you need to use an external antenna you want the XPR6550.
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Well that's how the regulations work. Myself if a family member, non resident, wants to use GMRS I would "suggest" they get their own license. Legally they could use mine, but if they had their own any issue with the FCC would be their problem not mine.
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As I mentioned it doesn't have to be unique. Using some made-up ID works, which defeats the purpose of having a DMR database in the radio. I've done the later accidentally, used the wrong ID when programming my radios. That happened when a guy on an out of area repeater noticed my call sign didn't match the call sign that showed up on their radio. Oops.
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Yes I know. That's one reason I got it because I can use it on the Ham band. The other is to see if I can get it to communicate with a couple of Icom dPMR radios. Doing the experimentation on 70cm is legal so long as i properly ID. There are a few differences between dPMR446 and the full featured dPMR. 1. dPMR446 uses the concept of a "common ID", whereas dPMR uses a "dialing" address, 24 bits, that functions as a Talkgroup and user ID depending on the range set for the ID. The remainder of the range is interpreted as the Talkgroup. You want a larger range for ID's, you have less range for Talkgroups. 2. The CC, channel code, for dPMR446 is a fixed value depending on the channel frequency. There are only 16 unique codes, listed in a table in the dPMR446 standard document, that would be used. For dPMR the CC is calculated based on an algorithm that uses the frequency, and there could be up to 64 unique codes. Using that algorithm for dPMR with the dPMR446 frequencies you don't get the values listed in the table for the dPMR446 standard. Otherwise the two are the same protocol. Number 1 I did some calculations and can generate the required bit pattern for the "common ID" using the dPMR Talkgroup/ID. However I can only generate a valid Talkgroup/ID for about 222 out of the 255 "common ID codes" Number 2 I think is going to screw things up where the communications will fail. I suspect this was done to prevent someone, like me, from attempting to use a commercial grade dPMR radio on dPMR446. I guess that's why there are two standards. Mathcad - dPMR446 Common ID Cod.pdf Channel Codes Edited ETSI TS 102 658 V2.6.1 (2019-01).pdf
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That's OK. One other point to make. You don't really need a unique DMR ID to use DMR. FCC doesn't require it, and it's not a substitute for ID'ing using your call sign. So if you're not in the official database all anyone sees is garbage. Not to mention spoofing DMR ID's. Yeah people do that and since it's not illegal the FCC couldn't care less. For those than want to register and get a DMR ID this is the place. https://radioid.net/ I also have a NXDN ID too BTW through this site. I also believe people use their DMR ID as the digital ID for P25.
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I have two D878UV's with it. Don't really use the feature. The problem is when scanning, which is what I usually do, when it stops it's so brief of a time that when I pick up the radio the info is gone. https://forums.mygmrs.com/gallery/image/270-d878uv-model-1/ If I really want to read it I have to use the camera on the phone to catch it. Sort of misses the point.
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My Kenwood commercial DMR radios can't download any digital ID data base, that's not their market goal, Amateur use. I don't miss it one bit. When one is running around with the radio in a pocket or on a belt, using a headset or speaker mic, I doubt anyone is going to yank it out to look at the display every time they hear something. That makes the builtin DMR database feature sort of pointless.
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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
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looking for a good kenwood style 2pin mic/speaker for HT while mobile
Lscott replied to WSES772's topic in Equipment Reviews
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 -
looking for a good kenwood style 2pin mic/speaker for HT while mobile
Lscott replied to WSES772's topic in Equipment Reviews
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 -
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.
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From the album: Misc. Radio Gear
This is a special radio I've added to my collection. 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. 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. 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 two standards for reference are the document names below. 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 electrically. -
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
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looking for a good kenwood style 2pin mic/speaker for HT while mobile
Lscott replied to WSES772's topic in Equipment Reviews
Correct. The difference is the -45D has additional internal filtering for use on DMR radios. Otherwise they are basically the same. -
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
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That's good. The engineer in me would like to know a bit more about the "how and why" that is the case.
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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
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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
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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
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You might want to look at the Diamond SRH320A. Not exactly cheap. SRH320A Triband HT Antenna.pdf
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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.
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I'm north of Line A and just made a big mistake!
Lscott replied to NWHov's topic in FCC Rules Discussion
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.
