KAF6045

If someone with a service manual tweaked various inductors and potentiometers, they may have shifted the optimal transmit frequency down to 70cm. It's only a 30MHz change to go from centered on 470MHz to centered on 440MHz.

As mentioned, there are the digital tones (these somehow send a numeric value). If you see something like DN999 (or D999N -- N could also be a I for inverted) it is a digital tone. CTCSS => Continuous Tone Coded Squelch System (AKA: PL => Motorola's name: Private Line, though there is nothing private about it -- anyone set for "no tone" can hear the traffic, it only means the unit /with/ a receive tone set does not hear traffic that does not match). Confusingly some rigs in their settings use "Tone"/"T" for transmit only, no-tone receive, and reserve "CTCSS"/"CT" for when both transmit and receive tones are being used. (And similar options for digital tones.)

Sounds like your browser is blocking location requests. Don't use the "near me" button (difficult to tell if it is selected)... Use the advanced search. (I should have trimmed that in Word or such before pasting it...)

Not putting out the full advertised power still doesn't mean that the rigs won't draw 2-2.5 times the direct (watts-out/voltage) for amperage. 50% loss in heat isn't unusual -- at the price most of these rigs cost I wouldn't be surprised if they waste 66-75% as heat. Though at 2.5X I'm still coming in at 9A, call it 10A -- which is the limit for most lighter sockets (though my former Jeep had a standard lighter socket [no lighter] on the left, and a 20A power socket on the right). I don't think the problem is fusing (probably a 15A fuse on the 10A socket) so much as how cheaply made those sockets (and plugs) are -- really high sustained current draws might cause heating in the thin contact surfaces used (ever compare the center contact of a real cigarette light plug to most utility power plugs? And the former is a deliberate heat producing resistor with some insulation).

Per the Manual https://cdn.accentuate.io/6946947694769/1644868577928/MXT500-Owners-Manual-05-27-21.pdf?v=0 and Programming Guide https://cdn.shopify.com/s/files/1/0531/2856/0817/files/MXT500_Programming_Guide.pdf?v=1640104635 for the MXT500, you are locked into the GMRS frequencies. The 0.5W NFM 467MHz frequencies are not available at all (in the unified FRS/GMRS numbering scheme, these are channels 8-14. The programming guide indicates that you CAN program 8-14, but only with frequencies from the 8 GMRS MAIN channels (guide says 16, but that's only because they treat simplex and duplex [repeater] as separate channels, you can not duplicate the interstitials [1-7] with different tones). So... If you have a number of repeaters on the same frequency using different tones, you can program them into the 7 empty slots instead of having to change tones as you move from one to another. NO SCANNING or selection of frequencies outside of those predefined channels GMRS channels. The KG-1000G manual https://www.buytwowayradios.com/downloads/dl/file/id/1411/product/5287/wouxun_kg_1000g_owners_manual.pdf specifically lists wide receive capability (including AM Air band, and 6m Amateur). They didn't spend much money on images in the manual -- page 26 shows a rig set for 2m and 70cm bands. Manual also implies you have receive-only for the 0.5W NFM (8-14) (which are not available at all on the MXT500). It has just short of 1000 slots available for specific repeater configurations, or receive only non-GMRS frequencies.

For receive, the main criteria is length -- longer antenna "captures" more input signal; tuning for frequency/SWR is less critical unless you are really into weak-signal work. Transmit, OTOH...

I'd have expected it to be a reference to CW/Morse -- in which the carrier is all that is transmitted, and it is cycled on-off. If CW were permitted, I'd expect to see it in the list of emission types. However, a portion of the rules that was NOT quoted above is: From which I'd interpret it to mean: can not use it as a broadcast station; one must pause to receive... CW would be A1A, F1A (or G1A -- frequency modulation vs phase modulation tend to both be decoded the same way). So that too could be a prohibited mode as it is not listed.

Ever consider that the radio may, somehow, not even have those memory slots? That is, the firmware may have something like "if channel# >14, memory# = channel# - 7"

But Class A of the Citizens Radio Service did... GMRS is essentially a renaming of that "Class" system. The renaming took place in 1987... FRS is a mishmash promulgated by RatShack in 1994, originally using only the interstitial channels (and creating 467 interstitials). I no longer have the paper, but my original GMRS license (not labeled Class A) had the two frequency authorization. I'd have to dig up the Maxon radio to find which two...

If you are really close together, you might overload the receiver front-end circuits (consider the worst case -- using a coax jumper to connect the two radios together... Receiver is looking for microvolt signal levels and you just pumped multiple volts into it). Desense is just a case of trying to filter out out-of-band (467 vs 462) signals that are stronger than the desired in-band signal. A wide coverage front-end may apply AGC to the input to reduce the undesired signal to a level it can process -- but that makes the desired signal even weaker. As for "zero noise" -- did you try pushing the MONITOR button? That forces the squelch to open letting any signal through. Having too high a squelch setting will block all but the strongest signals.` Can't help much more -- my BTech V2 doesn't have the specified power (don't think it makes it to 3.5W, while the "2W" V1 registered nearer to 2.5W), but otherwise operates okay. Hearing signals while the antenna is partway off makes me suspect a cold-solder joint on the antenna socket and radio circuit board, where fully attaching the antenna is pulling the socket away from the board, breaking connection. (Note: SMA connectors are rated for 500 cycles, you don't want to be doing too many antenna swaps)

In my opinion the (entry level) Technician license is the hardest one. At Technician, the FCC is more concerned that one knows the regulations: what parts of each band each license class is allowed to use, what transmission modes on those bands, what types of activity are legal (the 3rd-party communication rules still plague me), etc. They want to make sure that when you get on the air, you do not cause problems. The General and Amateur Extra, in contrast, ARE more focused on electronics and technical theory. I went some 20 years as (No-Code) Technician -- no HF privileges. When they finally dropped the Morse requirement, I dug up the General study guide, spent two weeks of lunches reading it. Then found an online practice exam site and verified that I was passing every test I took (since they randomize the questions each time). On a whim, I then tried the Extra practice tests, and was passing three out of every four WITHOUT studying. Two days later I went to the nearest VE test session and signed up for both tests; if I didn't pass Extra I had two weeks to study before the next session closer to home. I passed Extra by one question. By definition, ARES is Amateur Radio (and RACES is even stricter). An ARES group /might/ include some GMRS users with someone designated to handle the relay from GMRS to Amateur traffic handling -- more likely is Skywarn, since that's associated with the weather service and members are not likely to be asked to pack up and report to some out-of-state disaster. The GMRS users would have to undergo the same training as the ARES and/or Skywarn members. "friends and family" (or small business) IS the original purpose of GMRS (back when it was known as Class A Citizens Radio Service [CB was Class D; Class B was reassigned; Class C is radio control]). Base stations were NOT allowed to contact other base stations, one was licensed for only TWO of the eight primary frequencies. The "immediate family" clause carried the additional restriction that said family had to RESIDE in the same home as the license holder! Think large family farm: base station at house, HTs for family members working the fields -- maybe a mobile mounted on tractors and trucks. Given the 2 of 8 frequency limit, it is possible the next farm over had no frequencies in common (unless one followed the guidance of making one of the two frequencies the national emergency channel -- yes, there used to be an FCC defined GMRS channel for emergency/traveller assistance, usable by anyone for E/TA but only if it was on one's license could one use it for general chat).

In the old days, a GMRS license only authorized two frequencies, and most radios only had a "A"/"B" toggle to select the channel. The channels had to be programmed by a shop in accordance with the license. Referring to the frequency (or, at least, the kHz section) would have been common practice as what one had in "A" might have been programmed as "B" on the other radio. And note how many repeaters name themselves with the kHz section... (I just looked at the repeater list, with no search criteria, and six of the first ten are named AAA 999 where the 999 is the kHz part of the frequency). (When the interstitials were introduced, some radios expanded the number of channels to include those -- the Maxon GMRS 210+3 used channels 1-7 for interstitials, channel 8 for the FCC defined emergency frequency ".675" [usable by any license for emergencies, general use only if it was one of the two authorized frequencies], and channel 9&10 were the programmable slot for license frequencies; 675 is the 6th of the 8 primary frequencies). Many modern radios allow one to NAME the channel slots. Using names makes the absolute numbering of the 2017 reorganization unnecessary. Especially if one has reason to use CTCSS codes as one could enter the same frequency in different slots each having their own specific tone configuration. The OP's imported list shows that -- having /named/ the first 22 slots as "FRS xx", and then using "GMRS xx" for the same frequencies in (W)FM (And using frequency in naming the default repeater slots). AS FOR THE OP: from the excerpt image, it appears that it loaded pure FRS -- NFM -- definitions first, then started with the GMRS (W)FM definitions. Unless one really needs the NFM mode, I'd just delete the FRS specific entries and move the others up to fill the space. The "preprogrammed" radios don't have the FRS/GMRS duplication, they are either FRS-only or GMRS-only.

How theoretical did you want. As mentioned, the ARRL Antenna Book is probably a first resource. You just have to rescale things for 465MHz as most UHF example antennas will be sized for 440MHz. The overall concepts of gain, etc. would be covered. Real theory? Antenna Physics: An Introduction gets rather crunchy. For designing/optimizing: Antenna Modeling for Beginners (covers usage of EZNEC), An Introduction to Antenna Modelling (focuses on MMANA-GAL). And, if you end up creating some serious gain antennas RF Exposure and You covers the safety aspects, calculating safe distances from the antenna to "controlled environment" (those who know there is a transmitter in operation and can take actions to minimize exposure) and "uncontrolled environment" (neighbors, people on the street, etc. who don't know about and can not control their exposure to your transmitter). While all the above are available from the ARRL, the MMANA-GAL book is actually from RSGB. For software: the creator of EZNEC has retired, and made EZNEC PRO v7 a free download but offers no support https://www.eznec.com/ . The RSGB book DVD provides a version of MMANA-GAL the current version is http://gal-ana.de/basicmm/en/ (the Pro version is 140Euro for personal use license). 4NEC2 https://www.qsl.net/4nec2/ is a somewhat cruder package -- it explicitly uses external NEC-2 executables built for different memory usages (number of wires/segments). I believe it basically started as an Excel macro package for editing NEC-2 command cards and grew into a stand-alone GUI for NEC-2 (if you are a glutton for punishment, you can download the NEC-2 manual and hand edit the Hollerith card type input deck it uses -- EZNEC and 4NEC2 both use the NEC-2 engine for number crunching [unless you fork over a fortune for a license to NEC-4 from Lawrence Livermore National Labs -- hmm, there is now a NEC-5, wonder if it would be compatible with EZNEC]). Given that EZNEC Pro is now free, I'd probably start with it as the books that include datasets for models probably use EZNEC input files.

I don't think I'd trust Surecom for precision... Even the MFJ-847 costs twice as much, and MFJ is often considered a lower-grade product (many items are built into what can be called "hobby" project boxes, rather than engineering a custom case, but this is an exception) https://mfjenterprises.com/collections/mfj/products/mfj-847?_pos=4&_sid=b976da1f8&_ss=r The fact that it shows some variation when you jump 5 MHz at least proves some function. Note that SWR is computed from comparing forward power to reflected power... If the power measurement circuits are "sloppy" (a very low reflected power may not even be detected) then 1.0:1 is a reasonable display, even if false (any reflected power will raise SWR, but if the meter can't detect it...). The spec for the Surecom states 0.5W minimum (with 5% accuracy -- so 0.475-0.525 to my mind). Given that "channels" 8-14 are 0.5W ERP maximum, you wouldn't expect to detect any reflected voltage unless the antenna is pretty much unusable -- send 0.5W out, and have 0.5W reflected!). Even on 5W output, you'd need a 1.9:1 to have 0.5W reflected https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiMj_39_e_5AhUPlGoFHUGxBQkQFnoECAkQAQ&url=https%3A%2F%2Fwww.arrl.org%2Ffiles%2Ffile%2FTechnology%2Ftis%2Finfo%2Fpdf%2Fq1106037.pdf&usg=AOvVaw3UXQaeDbAlSg1tPOEUuz0Z Ugly Google tracking garbage.... Even 1.3:1 implies only 0.1W reflected, so getting that measurement almost seems a miracle. I can only hope the spec is for /forward/ power, and sensitivity for /reflected/ is better: 0.05-60W perhaps ADDENDUM: Also -- any non-exact match at the antenna may show different SWR depending on the length of the coax. There are points where the forward&reflected will add together, and others where they subtract. Just adding a foot extension between meter and antenna coax could change your results.

No.. That qualifies as an "in band" duplexer... vs what I was describing (HRO seems to catalog them as duplexers, but I've seen diplexer used for the cross-band systems) https://www.hamradio.com/detail.cfm?pid=H0-001449 (HF & VHF/UHF) https://www.hamradio.com/detail.cfm?pid=H0-001446 (2m & 70cm)

Well, that does put you in the same range as an HT on high power, so... Any reasonable straight freeways... "Mile" was just a suggestion -- mostly I was thinking of increased range than normal "convoy", IF you were running higher powers. Narrow band for GMRS is 12.5kHz using an 11kHz modulation width, deviation [how much the FM signal swings around the nominal frequency] is even less. Normal GMRS is a 20kHz band (some rigs don't support 20kHz and are actually 25kHz, commonly using a 16kHz modulation. The deviation tends to track "volume" while the rate of deviation indicates the audio frequency (high pitches "vibrate" +/- the stated radio frequency faster than lower pitches). So... 11k modulation doesn't swing as far as 16k modulation -- on a radio configured for GMRS (20kHz), the smaller swing translates to quieter audio. Going the other direction, the wider swing may be clipped, causing distortion in the audio, and will sound louder/compressed [less volume variation relating to actual voice changes]. For true GMRS, only the channels 8-14 (in the 2017 combined numbering scheme) are NFM. ALL true FRS radios are NFM on all channels. You may still want to evaluate line noise at the battery. Do you sound different if you disconnect the charger and rely ONLY on the isolated battery? It will be lower voltage, so your output power might be lower, but if you were running on a 5W channel, probably not much change.

You can't have mine -- even if they are museum exhibits? Think I've stopped hitting Batteries Plus to get new rechargeables for them, since they just die from lack of use. (I think I have one set still in the original box -- they were cheap enough to have two sets of the larger model (6-digit "address/hop scheme"), and gave my brother/father sets of the smaller (3-digit) models). At the time they were a interesting variation on "bubble-pack" radios. Pretty sure they used their own hopping system with no attempt at compatibility with commercial systems. Last purchased Jan 2011 from Fry's Electronics: eXRS 300 pair @ $80, eXRS 100 pair @ $60. A pair of 300s @ $90 in Mar 2010. A pair of 100s @ $75 in April 2010 (alongside Midland 1050s at $75!)

Apologies, the subject did wander off the trail in the last week or so.

How much current does that "battery charger" handle. If it is essentially a "float" charger to keep the battery topped off, the radio drain when transmitting -- especially on high power -- could result in you operating at less than battery-full levels, or get charging fluctuations on the power cable as the charger tries to keep up with the drain (analog VOM or oscilloscope would show noise when transmitting; digital DVM won't respond fast enough to show voltage swings). If this is a situation, you may need to add filter capacitors of enough capacity to level out the radio draw. What power is the mobile set at -- obviously a 5W HT is fine; a 50W mobile at those distances may be causing some overload on receiving units (do you sound better if vehicles are a mile apart vs a few car lengths?). Reduce power to the lowest level that reaches the length of the convoy [an overall FCC requirement for most services is to run the lowest power that achieves ones results]. As others have stated. Check bandwidth (though NFM heard on FM is usually going to be "quieter", less modulation; I'd expect clipping if FM received on NFM as the signal exceeds the input filters). Try holding the microphone differently -- further away from your mouth, and possibly a bit to the side of your mouth (which should reduce any "plosives" -- the air burst from P, B, V, for example -- it's why studio recording artists often have a mesh screen in front of the microphone). The only microphones I know of that require really close positioning are noise-cancelling types that were a rage for CBs in the 70s-80s. Some of those had rubber "mustache" bars to set position -- since they work by taking environment noise on both sides of the diaphragm [hence cancelling the impulse] and need the voice to come only from the front. Maybe set up an HT with a recorder -- at a fixed location -- while you make (and announce as such for FCC purposes) test transmissions with both the mobile and another HT from varying locations. Then review the recording (turn off any AGC on the recorder before making the test, set the recording level by hand first -- you don't want it leveling out signal variations). A coupling cable from HT earphone jack to recorder ext-in would be useful; one: no feedback when making test transmissions from the other HT while setting record level.

Remove the "no longer in use" TV Yagi [not quite -- Yagi's have one driven element tuned for a single frequency range, TV booms have multiple drivers each tuned for a different TV band (VHF LOW, VHF HIGH, UHF)] antenna from the mast, clamp GMRS antenna to said mast, run coax (the old TV antenna probably uses 300-ohm twin-lead)

If you are configuring repeaters, then your radios are not "talking to each other" -- they are "talking to" the repeater, and the repeater "talks to" the others. For testing, you should maybe start with SIMPLEX channels (no repeaters) and ensure your radios can "talk to each other". Channels 8-14 are low power, so you should be able to get away with a few feet distance between units. Pick one from the factory configuration and play with the CTCSS codes (DO NOT modify frequencies, or bandwidth -- 8-14 are former FRS-only restricted to 0.5W NFM mode to reduce interference with repeater inputs). Tx CTCSS means the radio will send the tone. Rx CTCSS means the radio expects to hear the tone. Rx None means it doesn't care if there is a tone or not on the received signal. Your radios, for repeater access, will Tx 5MHz higher than the Rx frequency (467.xxx Tx for 462.xxx Rx). Presuming the page shown for your GEM 700 is correct, the configuration should look like: {I'm a bit wary of those tones. 254.1 is the highest CTCSS tone available, and 250.3 is one tone below it -- almost like someone's mouse slipped when selecting from a list of tones -- if those don't seem to work [set Rx tone to NONE to ensure you receive anything coming back] you may need to try setting both to 254.1 OR 250.3. If you can hear other traffic with Rx tone NONE, try activating the KG-935 "tone scan" -- I set PF2-ShortPress to CTC-SCAN as you have to activate the scan while traffic is active -- it should, after a few moments of received traffic, lock onto the actual repeater output tone} As for the RT-97... The key thing is that it will Tx on 462.xxx and Rx on 467.xxx (eg: swapped frequencies from what you program into the HT). There are only 8 GMRS repeater channels, so one will be duplicating some frequencies if filling the 16 channels the RT-97 supports. I set mine with 8 CTCSS variants, and 8 DCS variants -- between 8 frequencies, 8 varying CTCSS tones, and 8 varying DCS, it should be possible to find a combination in the field that doesn't interfere with "common" (FRS kiddies) channels and minimize interference from those that still are on the frequency.

Just for my education -- do you have a link to one (or more) of those units? The closest things I've seen to "flat pack" are the /diplexers/ used to combine separate VHF&UHF sources into one (my TS-2000 has dual-HF, separate VHF & UHF -- needs a diplexer to combine the VHF&UHF to feed a dual band; my previous vehicle rig [FT-100] had combined VHF/UHF and separate HF -- needed a different diplexer to combine for the ATAS-100 screwdriver antenna).

Which process is pretty much SOP for anyone programming a DMR radio -- except for DMR (digital) channels one has to first populate the TalkGroup/Contacts table(s). Then one can go to the Channel table (or list, as many pop-up a dialog in which to edit the parameters rather than a spread-sheet format) to define a channel name, Tx/Rx frequencies, Time outs, Tones for analog channels, or talkgroup/contact for digital. If one uses scan lists, one can create an empty first, then specify the empty list in the channel definition. After the channels, one can go back and populate the scan list, along with creating/populating the "zone" lists with channels.

Unfortunately, the tabular formatting from the manual itself is lost in the copy&paste. I haven't found much use for the so-called APRS modes on DMR radios. Having to specify a separate channel on which to send digital position reports is rather meaningless as most repeaters likely won't carry it, and I've not seen if analog APRS is compatible with common APRS digipeaters on 144.390 (for one thing it appears tied to PTT; does that mean one would have to ON 144.390 and hit PTT to send a position report?) At least D-STAR rigs embed the position in with the voice data on the same channel. (Okay, the programmer seems to imply a fixed interval ability, but one still has to configure an active channel for which APRS data will be sent -- using a defined frequency setting... Nothing like what I consider APRS with checks for channel clear, beacon timing variable with vehicle speed and turning, etc., and using a dedicated channel/VFO, not tied to some voice channel settings).

I've already gone a year past when the oncologists would have estimated when the cancer was first discovered... Though it does seem to be migrating to lymph nodes... so who knows where treatment goes next... I do need to get off the Internet and inventory my crud in preparation of having a will made (I'm aiming for a trust -- especially with all the firearms, followed by all the musical instruments -- one may not care about what happens to a $350 flat-top mandolin, but a $2400 Taylor NS-72 is a different matter, along with all the radio gear [which is why I gave my nieces the Tech study guides, and as incentive Yaesu starter HTs]).