KAF6045
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Posts posted by KAF6045
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1 hour ago, Lscott said:
Well in a way I don’t agree in the general sense. A lot of people own various Chinese manufactured digital radios. I have a D878 and a D578. Who can guarantee there isn’t some secret back door code to disable the radios or bypass the built in encryption feature?
Unless the radio is connected to the internet (WiFi?) the only way for mainland China to disable the radio is via... radio. And what, other than maybe GPS positioning, are these radios carrying that is going to be of interest to China. At least for Amateur, MURS, and GMRS, encryption is not an option. For those entities for which encryption is legal, they likely are using Kenwood/Motorola class radios (and for business entities, again are unlikely to be using internet links, local company repeater at best if not ~2W job-site HTs only -- a statewide government trunked system may be using internet, but unlikely to be using low-cost Chinese radios).
The 878 (and many DMR, if not DMR/P25/NXDN) already has a means to disable radios -- the only needed backdoor is for that option to be "on" for some specific (unknown) radio ID regardless of the status in Optional Setting: Digital Functions: Digital Remote Stun&Kill Normally that requires code(s) to be preset for stun and kill on each radio, and a private call to the radio ID. Again, this is an over-the-air function, so anyone trying to kill the radios has to be within range of the units being killed. Okay, that signals intelligence balloon might have enough transmit power to cover a wide-area with one kill burst. But does such a kill survive a radio technician with the programming software for the radio? Especially if they can flush and reload both the firmware and programming.
Laptops, tablets, cellphones, and maybe desktops are the big prizes for "phone home" schemes. They have things like user accounts, documents, etc. that may contain proprietary (at least, if not actual classified information -- though my 25 years on a "black" program would make "phone home" futile; our desktops had NO connection to the internet, only to an internal LAN, even the unclassified telephones had to be some 4-5 feet from the computer to avoid picking up RF, cellphones [this was some 15 years ago] had to have batteries removed before bringing into the facility [that was after the Loma Prieta earthquake... when they finally acknowledged that cellphones were going to non-removable batteries, they changed to "complete power-off, not just standby, and black tape over the camera lens(es)], and calculators with programmable features were not permitted... Laptops&tablets? Didn't exist as far as that facility was concerned).
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The upper loop is meant to be an RF choke, blocking RF from travelling down the outside of the coax shield. A drip loop is just a down below entrance point, U up and then across through entrance point. The goal is for the lowest part of the U to be outside and where you don't mind have rain water dripping off the coax.
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20 minutes ago, 73blazer said:
I had a 2015 Lenovo business laptop (mobile workstation really) I bought new and did notice while it's turned off, a spurious MAC that wasn't the normal network cards MAC would connect to my open wifi guest network for a few seconds every few hours. I could remove the battery and those connections wouldn't happen. Bloomberg then published an explosive story about embedded spy chips in many laptops, desktops and servers whose boards had pre-assembled parts by one company for various computer manufacturers, Lenovo included. Lenovo quickly issued a bios update to stop said "spying" . I I would consider it a direct attack on 'merican companies. But the point is, it does happen.
A former employer used to issue IBM Thinkpad (?) laptops. About three months after IBM sold the line to Lenovo the company started to phase out Thinkpads for Dell laptops.
I wouldn't be too surprised if my Nook tablet was phoning home. Barnes&Noble dropped the Samsung Nook for a Lenovo product... Which has the worst battery life around -- even with WiFi & Bluetooth turned off, and the display off, sitting on a shelf, it loses some 50% of charge in a week (while a Samsung Nook in the same condition goes two or three weeks).
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56 minutes ago, Sshannon said:
Another thought is that there are antenna systems where you swap out the element to concentrate on a single band at a time. They are available for 80 meters through 6 meters and can even be combined for greater versatility. They're sometimes called Ham Sticks. Shark is one of the vendors carried by Gigaparts:
The Outbacker series uses movable taps to change bands... Probably less messy than hauling a golf-bag full of HamSticks. Unfortunately the Perth Plus appears to have been discontinued (I have one, along with the Alpha Delta OutPost tripod mount -- for years it was the only way I could get on the air from my apartment in Sunnyvale). The regular Perth only runs up to 10m -- the Plus included 6m and 2m. Some of the rest of the series have options that go up to 6m.
Random searching...
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1 hour ago, WRVG593 said:
I'm testing using a power meter. I use my cheap Chinese one and I've used my friends actually good power meter and the my read pretty much the same on SWR, Power, Fwd, Reflected, etc. My feed line (I could be wrong as I bought it probably over a year ago) is RG8X if I'm not mistaken. I've tested it in my mobile and from 50 watts(MXT500), it seemed to only lose about a watt or so.
Are you testing power AT THE ANTENNA, or just off the back of the transmitter?
How long is that coax?
https://kv5r.com/ham-radio/coax-loss-calculator/
50 feet of Belden RG-8X, with a 50W transmitter, at 465MHz, with an antenna SWR of 1.25:1, LOSES 63% of your power (50W transmitter -> 18.7W at antenna)
Replacing the Belden with LMR-240 (an RG-8X equivalent) only loses 47% (26.7W at antenna).
Belden 9913 (low-loss RG-8) nets 29% loss (35.6W at antenna); LMR-400 (RG-8 equivalent) 27% loss (36.3W at antenna)
Don't even consider RG-8X for 100ft cable runs at UHF. You would need an antenna with 9dB of gain to counter the coax loss.
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5 hours ago, WRWS304 said:
What I am attempting to do is have a home base station and mobile station that has the ability to cover (TX/RX) the following bands with only reasonable performance: 6m, 10m, 11m (CB), 2m (including MURS), 1.25m, 70m (including GMRS frequencies). With that said, I’m trying to figure out what the antenna situation would end up looking like if I am able to achieve this. I have a little-to-no interest in having my log cabin cluttered with unsightly antennas, or my vehicle looking like some Ham-Clampett wagon going down the road.
Vehicle: Do you need multiple bands available at one time? Without diplexers (wide frequency separation, 2m vs 70cm, HF vs VHF) and/or duplexers (narrow frequency separation -- typically same band) you will only get one active band at a time.
A screw-driver type antenna may be suitable (unfortunately most seem to be mid-HF up to 6m) https://www.tarheelantennas.com/baby_tarheel
Yaesu has the ATAS-120 which covers mid-HF up to 2m/70cm [not 70m!] (2m/70cm is covered with the antenna all the way down) Problem: I don't think it works with generic up/down controllers, it was designed for a series of mobiles that contained built-in control logic [press menu TUNE, radio reduces power, goes into transmit mode, radio runs antenna up/down for minimum SWR]. I used one with an FT-100 (actually, started with predecessor ATAS-100 [rubber accordion boot handled length changes], changed to ATAS-120 [plastic outer tube slides over inner tube] when I moved to MI) on my Jeep Cherokee for 20 years -- until I rolled the Jeep two years ago.
Very few multi-band antennas exist, even Amateur-only, that include 1.25m. Heck, it is common for HTs that include 1.25m to run at reduced power (~1W on a 5W HT) due, I suspect, to the difficulty in tuning the antenna for 2m/1.25m/70cm at the same time. Kenwood seems to be the exception -- their (discontinued) HTs that had 1.25m ran it at full power (D74A, F6A). Yaesu VX-8DR "Tri-bander" (6m, 2m, 70cm) included 1.25m in the US version -- with max power 1.5W.
Home: Same question: multiple bands at once? Some off-center-fed-dipoles (OCFD) cover 40m/20m/10m/6m (but is going to be 66 feet long). The VHF/UHF bands are heavily mobile/HT oriented, and it is best to use vertical polarized antennas for those. HF/6m tends more to use horizontal polarization since signals bouncing off the ionosphere tend to be randomly polarized at the destination -- horizontal antennas being easier to support (consider, with the bottom at 35ft, that OCFD top would be at 100ft, and needs to be away from metal that it could couple to). Consider "stealth wire" -- https://www.dxengineering.com/search/part-type/wire/product-line/dx-engineering-stealth-antenna-wire for dipoles and similar. https://www.electronics-notes.com/articles/antennas-propagation/dipole-antenna/hf-multiband-fan-parallel-dipole.php Note the caution about harmonics -- 2m and 70cm are harmonic, MURS and GMRS are near harmonic -- but 2m and GMRS is not.
OTOH: a quarter-wave ground-plane whip for GMRS is only 6.3 INCHES, and about the same for the ground-plane radial wires. The low-loss coax will be more noticeable than the antenna itself.
FYI: MURS is NOT "2m" -> 1.9m, nor is GMRS "70cm" -> 64cm. And 2m/70cm antenna would have to a wide-band antenna, and that likely means antennas that don't have ideal SWR on any frequency... 1.5:1 would be great.
5 hours ago, WRWS304 said:I digress. As I was doing research on the topic, I came back across the concept of using an antenna tuner to ‘tune’ your antenna to the frequency using. This reminded me of the stories of Elmers using an antenna tuner to tune a lawn chair for TX/RX on the 6m band.
Wouldn’t that ability to tune an antenna mean that I could get 1, 2 to 3 quality antennas mounted for my home base station and then with a combination of antenna switch and an antenna tuner, tune the antennas to whatever band I was using at the time?
The main purpose of an Antenna Tuner is to present a low SWR to the RADIO. It does not really change the behavior of the antenna.
Back in the days of power output TUBES tuning an antenna was not quite as critical. However, the power FETs used in modern radios can only absorb so much power which converts to heat before failing. The tuner lets the radio "see" a matched transmission line which allows the FETs to put out their full rated power (the better radios have safety circuits -- they /reduce/ power when the mismatch is higher than some level to keep the forward&reflected power under the ratiing). Radios with built-in tuners often can only tune a 3.0:1 ratio down closer to 1.0:1. External tuners (many of the LDG boxes) can handle 10.0:1 mismatches.
Note that tuners located at the radio end don't affect the SWR on the coax. High SWR in the coax can cause decomposition of the dielectric/insulator which could cause it to short-out (center conductor "melts" its way to the shield -- especially on bends/curves in the coax). Remote control tuners mitigate that, but... Tuners may also be "tuned" internally for specific frequency bands and might not even operate outside of those bands -- depends on the circuitry.
Most antenna switches are really meant for selecting different antennas for one radio. If you are trying to use the switch with one antenna and multiple radios, you will need one with very high isolation between ports. Otherwise you will have some power from the active transmitter leaking into the connection of an inactive radio, risking the receive circuits. You might have to operate at reduced power to counteract leakage.
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18 hours ago, WRVG593 said:
So now I'm about 34 feet off tbe ground. I have about 10 more feet of coax to use.
Better check the zoning regulations for your area. For my area, antennas are limited to 35ft height (I suspect based on 60s-70s horizontally polarized log-periodic TV antennas) -- EXCEPT for LICENSED AMATEUR who are permitted 70ft height.
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I would just comment that the letter, and FCC database are using the term "Dismissed", not "Cancelled". That should have signalled that the license that had been granted was still in effect and that something else was being processed at the time.
Dating that letter/action for April 1 sure doesn't help (though I could understand it as "start of next month")
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22 minutes ago, WRWE744 said:
I know this is probably a lot to ask, but I am a new ham, with GMRS contacts I would like to keep in touch with. What is the best mobile (car) antenna for 2 meter/70cm and GMRS?
A diplexer (presuming you are trying to use a dual-band radio) splitting VHF from UHF, a 2m whip, and a commercial wide-band UHF whip spanning ~400-470MHz (and that probably doesn't get any better than 1.5:1 SWR mid-range).
Pretty much any dual-band Amateur antenna is going to be narrow-band with terrible SWR on GMRS frequencies. 440MHz is ~3x 146MHz, so is a harmonic frequency. 465MHz comes in at 3.2x 146MHz, not harmonically related (though 465MHz is close match for MURS 4&5 -- coming at at 155MHz when MURS is 154MHz on the high channels, around 152 on the lower three). https://www.rfwireless-world.com/calculators/RF-Harmonics-Calculator.html
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1 hour ago, aapaws said:
The 4505 says to cut the length to roughly 11". At that size it still was over 8 swr as it is now its cut down to 7.25" which is way to small.
I order a new whip for the 4505 and we will see with the NanoVNA before I start cutting again.
I haven't seen the manual to comment -- when I looked yesterday, there were something like three or four different companies selling "4505" antennas, and all looked the same. The only one that mentioned "field tuning" also looked like it should have been close enough that just loosening set screws and moving the elements up/down.
1 hour ago, aapaws said:Also thinking about ordering another gauge this time maybe something better.
Most would refer to that as a meter -- it measures things; in some industries "gauges" only provide go/no-go results (the gauge either fits or doesn't fit the item being checked -- setting spark plug gaps for instance is done with gauges; too large a gap and the gauge for the desired size will be sloppy, too small and gauge won't even go into the gap).
I suspect the next step up, for VHF/UHF (125-525MHz) only, in SWR/Watt-meters might be the MFJ-847. It only displays forward (output) power, reflected power, and resultant SWR. No frequency counter. Just two switches: meter on/off, backlight on/off. Prime reading is forward power, reflected/SWR are smaller characters below that.
SWR meters that cover the UHF range tend to be sort of specialized -- most meters are HF up to maybe VHF (my Diamond SX-200 is 1.8-200MHz, and is not an instant read design; to determine SWR you have to set a switch to "CAL", transmit while rotating a dial on the meter to set the needle to full-scale, then flip the switch to "SWR" to get the ratio).
1 hour ago, aapaws said:
Have you been trimming from BOTH halves of the unit? That black "torpedo" in the middle is a phasing system; the antenna operates as two phased antennas one above the other, fed from the base. Oh, and the spring unit probably counts as part of the length for the lower section. {Personally, I'd want to get it further away from the hood too -- either raised to the height of the hood top, or out to the side; between the spring and the loading coil I'd be worried about coupling detuning the lower section).
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11 hours ago, WRVG593 said:
The idea with that being IF I needed to hear others I should hear most of the transmissions from the bottom of the mountain. (the second home is in the mountains of Appalachia).
The ONLY THING you can control that affects how well you can hear others is your ANTENNA system.
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6 minutes ago, WRVG593 said:
I appreciate the feedback. It actually would be for simplex. I hit repeaters for all 8 repeater channels/frequencies. I have family where we can barely hear each other when using a 25 watt mobile as a base. We both have roof antennas and both like the idea of simplexing, as repeaters could not work at any moment. There are some days where I can pick him up for a few seconds at a time, and his power generally reads 15W. My 50W mobile can make it to where he hears me for almost the entire tike with sporadic intererference. I feel woth the additional 50W it would almost never have drops in signal. My other idea is to get a 460-470 amplifier. The reason I choose gmrs is any people have cheap frs walkie talkies and could hear or talk back. I am aware of the 50 watt limit, but in a situation where I need to get ahold of my family I would like the additional power for guaranteed communication.
Getting high-gain antennas would likely be cheaper and remain legal. {the typos make it a bit difficult to figure out your meaning: is "tike" supposed to be "hike" or "time"?).
You mention using a radio as a "base station" and "roof antennas" -- to me this means fixed locations and non-mobile usage. Either install high-gain YAGI antennas (which will have to be pointed at each other as they are directional -- but easier to achieve the gain needed) or a (more costly) omni-directional vertical.
A 10dB gain would make those 25W units transmit as 250W ERP. {note: a dipole measures 2.15dBi/0.0dBd, so if the antenna lists 10dBi gain, that would be 7.85dBd}
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17 hours ago, aapaws said:
I will try again tomorrow to see if the connections are loose on the Allen heads if not I am hesitant with cutting it because of the original good swr reading. I don’s understand how it could have that big of a swing unless the antenna moved or went bad somehow or the surecom is bad? I never ever got a reading that high on any of my original test. The radio does work great with the smaller 4503 antenna tried out at home with some friends but I figured I would use the larger one for more range and switched when I hit the first rest area gas station. Glad I did not use it if the swr is true.
A comment: don't test SWR at full power unless you already know you are in a good (<3.0:1) range.
Note your bottom line: 35W going out and 25W coming back in... That's putting 60W on the transmitter final/power transistors (unless that is a 50W rig and automatically rolled back the output power to compensate -- but that is still a rather high loading: 60W on 50W finals?)
You'd be better off with an antenna analyzer or VNA that takes the transmitter out of the system and sends signals in the mW range (for one thing, you won't be annoying anyone listening on the frequency you are testing, and both make sweeping the frequencies easier).
FYI: the Laird 4505 variant has a datasheet that shows the BEST SWR at 1.6:1, and that is just under the GMRS simplex frequencies; the antenna should have had enough "give" to be tuned without cutting the whip(s).
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39 minutes ago, aapaws said:
Just got home and rechecked like suggested and the cable is bad. The rfmax cable gives the high swr but the larsen gives the best signal. Also thought is was funny that the ghost antenna is giving me a better swr over the almost 31" antenna. larsen and laird trab4503 for the win.
Which may just mean that the "long" antenna is not yet tuned for the range you are testing. You really need to sweep the frequency to find out where the best SWR is located (if below 462Mhz, antenna is too long; above 467MHz it is too short -- 465MHz is in the middle of the Simplex/Repeater Output and Repeater Input groups).
Or it is coupling to something nearby (metal siding on a house -- don't try to tune it inside a garage).
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3 hours ago, gortex2 said:
DPL is the same as DCS. Motorola used the term DPL.
The misleading term [D]PL with PL short for "Private Line", when there is nothing private about it. The use of tones does not make one's transmissions "private", it only allows one to filter out others -- they can still hear one's transmissions all they want.
You'd need to enable encryption in radios equipped with that feature to get privacy. Of course, encryption is against the regulations of practically all services except some Part 90 LMR (law enforcement, mostly).
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54 minutes ago, WRWT868 said:
Yep, had it bounce on the floor, roll under the couch. Anyone know what size and pitch it is, I'll just get a couple and keep one in the door and another in the cable otherwise that screw isn't going to last 24 hours... What a hooky set up..
Just match to the screw you still have in the dust cover -- after all, a generic match may be too long and cause damage to the radio internals.
Personally, I'm a bit surprised it just slipped out of the programming cable connector. I /think/ the radios I have using that style cover have screws with a blank section under the head, and have to be threaded through the cover (the blank section is undersized enough to let the screw continue turning, so one can make the attachment).
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2 hours ago, WRVR303 said:
Since a lot (most?) GMRS radios don't show what frequency a given channel is on, consider adding in the channel number to the above logo.
The consolidated channel number is the 3 in the 307. Though 85.4 is tone #8 in at least one table of common assignments https://www.buytwowayradios.com/blog/2022/10/chart-of-standard-ctcss-tones.html
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6 hours ago, WRVE426 said:
But I can live with a dark screen. What I don't understand is how the Wouxun UV-9GX scans. I read that on the display's top row ALL the channels are scanned whereas on the bottom display row only VHF/UHF channels are scanned (though I don't understand why channels 15 through 22 are not scannable unless I change that manually).
If the radio has 23-30 set as repeater channels AND it is scanning those, then they duplicate 15-22 (the repeater output is the same as 15-22 simplex).
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3 hours ago, Sshannon said:
On the Rino the repeater channels don’t appear by default, but once you enable it for repeater use they do. They are excellent. I don’t have the 750, but I have one a bit older. 675 maybe? No camera built in, but it does have the ability to send and receive pictures. It’s rugged, super visible in bright sunshine, and very easy to change tones.
Of course, if one enables repeater channels, one has to be aware of the FCC regulations regarding digital data...
Quote§ 95.1773 GMRS authorized bandwidths.
Each GMRS transmitter type must be designed such that the occupied bandwidth does not exceed the authorized bandwidth for the channels used. Operation of GMRS stations must also be in compliance with these requirements.
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(c) Digital data transmissions. Digital data transmissions are limited to the 462 MHz main channels and interstitial channels in the 462 MHz and 467 MHz bands.
IE; digital is NOT permitted on the repeater input frequencies (aka: 467MHz main channels).
Quote§ 95.1731 Permissible GMRS uses.
The operator of a GMRS station may use that station for two-way plain language voice communications with other GMRS stations and with FRS units concerning personal or business activities.
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(d) Digital data. GMRS hand-held portable units may transmit digital data containing location information, or requesting location information from one or more other GMRS or FRS units, or containing a brief text message to another specific GMRS or FRS unit.
Implication is simplex-only
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IGNORE - DUPLICATE
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For the ARRL /book/ on the subject, I don't think one needs to be an ARRL member to hit the store...
Grounding and Bonding for the Radio Amateur 2nd Edition
https://home.arrl.org/action/Store/Product-Details/productId/133989
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3 hours ago, DanW said:
It looks like it also wirelessly pairs with the box. The power cord looks like just a USB. Interesting.
Both the handset and the box need a power connection (the box provides a USB port for the handset). The box has traditional fused wire for vehicle battery. But, yeah... since the handset can be powered from any /other/ USB port (including via the lighter socket adapter) it must be using some other (bluetooth or ISM) signal to get to the box.
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Based on the images at Cobra's web site, this new version puts a lot more into the "interface box". The old 75 did have pretty much everything in the handset, and just a small box with the power, antenna, and handset connections (and maybe the final amp taking a low power signal from handset to the 4W allowed power). The new one looks to have most of the circuitry in somewhat larger box, and just put the speaker/microphone, controls/display into the handset -- looking more like my antique Standard Radio [Marantz period, pre-merger with Vertex, then Yaesu, then Motorola -- Vertex seems to jump more than fleas on a dog] 2m/70cm dual-band.
The "wireless" is that it has BlueTooth which supports pairing with headset or a wrist (or steering wheel?) worn PTT button.
Avoiding FRS channels
in General Discussion
Posted
As already stated, 23-30 (aka rp15-rp22) are repeater only channels. No normal GMRS radio can receive those frequencies (repeaters listen on 467.xxx, and transmit on 462.xxx).
Prior to the 2017 reorganization by the FCC, the only purely FRS frequencies were those now designated as channels 8-14 -- the 0.5W ERP NFM channels. Channels 1-7 were GMRS interstitials (allowed 5W FM) years before FRS was created, and original FRS was permitted them using 0.5W NFM. Channels 15-22 were GMRS MAIN channels (and in the old days, one was allowed to specify just /two/ [pairs: simplex and repeater] of them on their license), allowed up to 50W FM.
With the 2017 changes, FRS is allowed to access channels 1-22, with 2W on 1-7/15-22 (ie; what had been the "GMRS" limits on the pre-reorganization bubble packs sold as FRS/GMRS). FRS is restricted to NFM on all channels. GMRS HTs, in return, gained access to 8-14 -- with the limits of 0.5W ERP NFM, same as FRS. GMRS retained 5W FM for 1-7, and 50W FMS for 15-22.