Leaderboard
Popular Content
Showing content with the highest reputation on 03/08/23 in all areas
-
RF Spurious Emissions (aka Spurs) Example.
AdmiralCochrane and 5 others reacted to marcspaz for a topic
Hey folks... I have discussed receive and transmit quality with many of you in the past. Especially focused around the quality of the transmit signal with regard to spurious emissions, commonly known as Spurs. I wanted to share this info because with the introduction of the TinySA, some YouTubers are using these in their tech reviews, but really don't understand what they are looking at and end up giving out bad information. Our friend NotARubicon recently reviewed the BTech GMRS 50V2 and did a great job of showing/explaining what is known as a harmonic spur. Harmonics are a subset of Spurious signals found at integer multiples of the fundamental frequency of the signal. If you haven't seen the review, I highly recommend it. BTech GMRS 50V2 - Review & Power Test - Is BTech's New GMRS 50V2 Better Than The GMRS 50X1? I got a couple of pictures I wanted to share, that relate directly to this. These images may help understand the references when you see/hear reviewers discuss this topic. I have a friend of mine who's repeater was not behaving well and upon testing with a tool called a Spectrum Analyzer, he found Spurs every 100 KHz above and below the carrier at 462.675 MHz. In the GMRS world, that translates to the signal being transmitted over and over again, every 4th channel. Below are the images he sent from both prior to the repair, and after it was fixed. Broken... Fixed.... There are many, many types of spurs that can occur. You are looking at the effects of noise generated by the exciter circuits (VCO for those familiar), known both as sideband spurs and Baseband Harmonic Images. If this doesn't make sense, its okay. Just know that if someone is doing a tech review and shows pictures or video like this, the radio is broken... not that it was designed poorly. The next two pictures are of two of my radio's signals on a TinySA. These images are great example of Phase Noise spurs. The first picture, the issues seem pretty obvious to me. The second picture shows one small spur. It's not terrible, but it really shouldn't be there. Warning... Geek Alert! Phase Noise spurs are unwanted signals that occur due to the random fluctuations in the phase of the carrier signal. Phase noise spurs can degrade the quality of the transmitted signal. Think audio and signal quality. This is a symptom of poorly/cheaply designed radios and use of low-quality parts; not something that is malfunctioning. This was by no means meant to be technical. It is just samples to help know whats broken vs. poorly designed, and a conversation starter. Let me know if there are any questions. Either myself or one of the smart people in the room will answer them the best we can.6 points -
Signal stalk tuning.
pcradio and 3 others reacted to SteveShannon for a topic
Plus Signal Sticks are made in the USA by the guy who also runs HamStudy.4 points -
Man, I have to be honest, I feel like the internet and my cellphone/smartphone has made me dumber. Like so much so, that I'm not sure I even spelled 'dumber' correctly, but I don't want to look it up because that perpetuates the problem. LoL3 points
-
Uh...MY father had a GMRS license when I was a kid. Thats 40+ years ago. GMRS is way not a new service. I think you need to do some reading.3 points
-
Petitioning to get a few VHF frequencies added to GMRS
TOM47 and one other reacted to SteveShannon for a topic
2 points -
Yep, went back and reviewed his other posts. 6 to 8 lines max and then all of a sudden this stuff. Personally I think we need to put a stop to this nonsense right now. If you want to get on here and write a novel about a topic, then YOU need to be writing it, not ChatGPT. Because screen scraping someone or someTHING else's work and calling it your own is still plagiarism and BS. Is this what the world is coming to that people refuse to have an actual thought or opinion and instead ask some AI thing on the Internet to form an opinion for them? We just gonna forgo free thinking and jump on the InterWeb bandwagon of BS and allow others thoughts to be combined by some computer system and just go with that? Ok, how about we just forgo voice communications of any kind, run some voice recognition program on our computers and and then connect that to our radios and let the computers talk on the radio and not bother to actually communicate with each other any more. Personally I think this stuff is getting out of hand. And we are only beginning to scratch the surface of the coming dumb. The WORST is yet to come.2 points
-
2023 mobile unit pick
wayoverthere and one other reacted to PartsMan for a topic
I like my RA-25 (DB-20 AT-779 are the same). Nice simple GMRS mobile. Plus In an emergency It can be unlocked to other frequencies.2 points -
Signal stalk tuning.
SteveShannon and one other reacted to WRUU653 for a topic
I have been considering this as I always feel like I’m not giving recognition where it’s deserved. back to signal stalk tuning2 points -
2 points
-
Signal stalk tuning.
marcspaz and one other reacted to SteveShannon for a topic
It’ll reset during the day. It is an odd limitation. Paying for premium membership was almost worth it just for that!2 points -
GMRS Travel Channel (rant 2 of 3) Frequency choice criteria
WRVX846 and one other reacted to SteveShannon for a topic
@kirk5056 I enjoyed reading your post. It was well written and you did a nice job of summarizing the issues. Unfortunately, I agree with @WRUU653 that it probably won’t make any difference.2 points -
GMRS 10-Codes
SteveShannon reacted to WQAI363 for a topic
Last year when I was working at MS 150 City to Shore, I was assigned to working Dispatch / Net Control. I did receive some slack from a fellow Amateur Radio for using 10 codes on the 2m repeater and GMRS repeater. Of course, I understand what that person saying, you don't want to heard, that's a BIG 10-4 GOOD BUDDY. After all, the 11 meter dwellers have really made a mockery of what started in the public safety. Sometimes have problems with my speech, but I figured using Ten Codes help me conveying information that I need to get out. There's nothing wrong with using Ten Codes on GMRS or Amateur Radio, as long as the group that you're working are on board with the protocol.1 point -
RF Spurious Emissions (aka Spurs) Example.
SteveShannon reacted to marcspaz for a topic
I believe you are correct in that my phase noise comes from unwanted digital oscillations in the VCO circuit of the Exciter or between the VCO and neighboring circuits. SA manufacturers have a feature to remove this from the results, referring to it as a "mirror spur". I don't like suppressing them, because I want to know if there is a quality issue. I haven't built a transmitter in a long time, but knowing if my gear is any good is a plus.1 point -
2023 mobile unit pick
wayoverthere reacted to Borage257 for a topic
Second or third the AT779UV for value/dollar. great for car use, base station or “man pack”.1 point -
Signal stalk tuning.
wayoverthere reacted to kidphc for a topic
Yeah mine had a glow in the dark tip. But 3d printed base. Nice to know they are making changes. Especially, with the warranty if something happens you get a replacement. Lifetime warranty doesn't apply to the stalk antenna. But he sells replacement parts. Sent from my SM-S901U using Tapatalk1 point -
Signal stalk tuning.
kidphc reacted to wayoverthere for a topic
Theyve moved over to an injection molded base on the signal sticks within the last couple of batches (bought a sma male one in black around black Friday last year), it's a nicer finish now. They also appear to be using glow in the dark tips on all of them, irrespective of color, which is a nice touch.1 point -
Welcome to my Ignore User list. Have a look around. Introduce yourself.1 point
-
Signal stalk tuning.
wayoverthere reacted to kidphc for a topic
Well minus the price. For $40 vs the usual 80-100 Sent from my SM-S901U using Tapatalk1 point -
People learn the most from their mistakes. It's like the little kid in the kitchen. Tell them don't touch that, it's hot. Turn your back and a few seconds later you hear the scream. Time to get the band aids out. Next time you tell them something is hot they'll believe you and leave it alone.1 point
-
Not much different than the Sti Co Super flex whips.1 point
-
GMRS Travel Channel (rant 2 of 3) Frequency choice criteria
blastco2 reacted to SteveShannon for a topic
If any kind of officiality is desired for things like this, GMRS users should first establish some kind of users group. Perhaps one even exists in stealth mode. Clearly the FCC intends GMRS to be used to provide traveler assistance: § 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. (a)Emergency communications.Any GMRS channel may be used for emergency communications or for traveler assistance. Operators of GMRS stations must, at all times and on all channels, give priority to emergency communications. (b)One-way communications.The operator of a GMRS station may use that station to transmit one-way communications: (1)To call for help or transmit other emergency communications; (2)To provide warnings of hazardous road conditions to travelers; or, (3)To make brief test transmissions. (c)Travelers assistance.The operator of a GMRS station may transmit communications necessary to assist a traveler to reach a destination or to receive necessary services. (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 unit1 point -
Yeah, this plot is not very good... However, it was into a 50 Ohm load. A better measure in practice would be to do the same plot using the HT factory antenna, and measuring the same parameters using the off air antenna on the service monitor. A/B more complete characterization. Performance my be worse at 2nd or 3rd..., or could be better. Best I have ever heard is these radios are exactly what you pay for. They do have a giant upside though as people get in cheap with little downside $ risk. Oh, and was the one test sample random? How many were there? Just one won't do. Perhaps some are made that perform better?1 point
-
Well... Yes. That one would never have occurred to me as rock bands are not on my radar at all. There are a few other codes used on this site I have no idea what they mean, and when I see them again I will ask. I had seen the CCR code enough that I used a google query with "radio" and "hobby radio" and that is how I found it.1 point
-
Unfortunately, at work. So I"ll just do the signal test as I use it normally. Thanks though1 point
-
Likely they could, and it would be manufactured in China anyway to keep the cost down.1 point
-
Well you learned it doesn't stand for the old rock band " Creedence Clearwater Revival" ? https://en.wikipedia.org/wiki/Creedence_Clearwater_Revival1 point
-
The attached file, found on the Internet, is a test done on the often recommended UV-5R radio. This is the FCC section dealing with emissions on the Ham bands. https://www.law.cornell.edu/cfr/text/47/97.307 Section "e" is worth reading. Particularly about transmitters of 25 watts or less. That would include portable radios. UV-5R VHF Harmonics Test.pdf1 point
-
No. Signal reports as of today, just got it installed. Btw. Don't run out and buy one just yet. It is a 2m 1/4 wave and 3/4 wave 70cm antenna. 3/4 have a weird radiation pattern and a take off angle of about 60‐70 degrees. So who knows, how this will work in the real world. I should of have taken 2m sweeps but failed to. I really wanted an antenna taller than the 1/4 for 70cm p25 and gmrs, i was also hitting the 1/4 wave in some garages. 2m was not a consideration, so I didn't even bother. Because of the garage/tree thing I started searching for nintinol antennas. 2 came up signal stalk and sti flexi ( about 2x the price). The sti was ruled out for the first round due to the cost and the cut chart would of had it back at 1/4 wave for gmrs/70cm. Might still try it in the future. Going to look at my buddy Seth's sti antenna to see if it is more flexible. ** the signal stalk is flexible. But no where near a signal stick. You will not be able to loop a signal stalk like a signal stick. I think you can loop the Sti (will check when I get the chance). *** DO NOT try to trim with cutters. I recommend a bolt cutter or cut off wheel. Even my pneumatic cutting off wheel at the shop took some time to cut through it. On the order of 5-10 seconds. Usually, it will go through a steel whip in 2 seconds. Sent from my SM-S901U using Tapatalk1 point
-
Ah! Cool. I'm looking on my phone and my near vision isn't great, even with glasses. New picture looks great! I can't like anything else today. Such an odd limitation.1 point
-
Sadly hidden and blened in with the telephone pole. Retaking the photo.1 point
-
Uncut Laird b4505cns. Swr sweep. Always impressed with this antenna. It was mounted in the same place the signal stalk was located. Sent from my SM-S901U using Tapatalk1 point
-
I didn't mention the radios because the images of spurs are not radio specific, they are symptom specific. Meaning any radio can have those spur types. Also, none of the test were conducted with coax or antennas connected. For the one that was damaged, it was a QUANTAR repeater. As mentioned in the original post, the VCO in the exciter had gone bad. It was repaired with a card swap, placing a new exciter in the radio. After 26 or 27 years in use... I'm sure some silicon-based part went Tango Uniform. The other images, from the TinySA, are from my BaoFeng BF-F8HP handheld and my Yaesu FT3DR.1 point
-
In my book, superhet beats non-superhet, and since I listen a lot more than I transmit, that's important to me. My choice was between the Midland units and the Wouxun, and because I wanted superheterodyne, I chose the Wouxun. I also like the features and the programmability. I don't regret that purchase at all! It also sent me on a Wouxun buying spree, for some reason. Seems like every HT they came out with, I bought.1 point
-
@WRQC527, the FT-70 chews up batteries. I sold mine within a few weeks of getting it. The FT-3D and FT-5D have much better battery use and standby times. I used my FT-3DR as a remote net control operator (via my xband repeater in the truck) for a Marine Corps Marathon event. I was non-stop slammed for 5 hours, 50% duty cycle, at 5w. It also has about 6 weeks standby, with the battery in the radio, before the voltage drops to 7.2vdc. With the battery disconnected from the radio, I have no idea how long the storage time is, but I know it's more than 6 months, because that is the longest I ever went between charges on my spares. Even then, they were above 7.2vdc, and I just charged them for an event.1 point
-
Baofeng Radios
CentralFloridaGMRS reacted to marcspaz for a topic
100% anecdotal, I personally have had great luck with the handhelds, especially my BF-F8HP. The mobiles, not so much. Though the BTech brand seems to be making moves in the right direction, based on some recent reviews I've seen on newer HTs and mobiles. For the most part, if you are trying to save money, it's hard to be the price for what you're getting.1 point -
Linked Home Repeater / Car Hotspot
kerstuff reacted to SteveShannon for a question
I’m not sure it matters. See the bold portion of the preceding quote. It says “or any other network…“ That seems pretty clear but I’d like to point out that the actual wording in the regulations are not phrased that way.1 point -
I use said flashlight to take the dog out at night ?? ?1 point
-
That is alot of words. I may have skipped reading one or two as i really only use it for family comms. My official travel channel is whichever one we agree on ahead of a trip.1 point
-
GMRS Travel Channel (rant 2 of 3) Frequency choice criteria
gortex2 reacted to Radioguy7268 for a topic
Someone has discovered the joy of using ChatGPT to pose wordy ramblings. Congrats.1 point -
I'm just wondering... And anyone feel free to chime in here. Who, exactly, is monitoring my GMRS communications for hidden meanings, and more importantly, am I going to get busted for asking my wife to "Rendezvous at Location Sierra Bravo" instead of saying "Meet me at Sonic Burger"?1 point
-
GMRS Travel Channel (rant 2 of 3) Frequency choice criteria
gortex2 reacted to OffRoaderX for a topic
I approve this message.1 point -
Radios unavialable due to chip shortages?
kerstuff reacted to SteveShannon for a topic
I have a friend with a 400 who’s disappointed because it has had some problems. I don’t know exactly what they are. If a person doesn’t need C4FM, the ftm6000 looks like a decent radio.1 point -
A friend of mine who has several 400s bought a 300 and as far as he's concerned it's a disappointment in comparison. I think he was spoiled by the touch screen. I'm cheap, I went with a pair of 7250s before they got the axe.1 point
-
I would add you have a cell phone. It’s okay to use your cell phone. I mean seriously if you want a private conversation radio isn’t it. Sure there’s encrypted radios but that’s not GMRS. Op is looking for a solution where there is no problem. I’m 10-98 ?1 point
-
The problem is not the price of ham gear, it is the horrible user experience. Why pay $600 for a radio that has 0 product management? Terrible software, silly menu structures, cheap materials. You don't get much for your dollar. Yaesu's rugged radio design (VX-6R) is almost 20 years old now with what, like six characters to name your channel? Come on man! Because the big three quit caring & trying.1 point
-
Again we are beating a dead horse. If you want to use some 10 code use it. I can say in Public Safety world very little of the 10 code system is still in play. Other than 10-4 you wont hear it much in public safety. In SAR we have a few "CODES" for critical information but to be honest just go to encryption if we need to discuss that.1 point
-
For your application I'd go with the Midland. Many in the off road world are using them and it will be simple to use. The MTX575 has the handheld head but cannot be programmed via PC. The MTXT500 will allow you a few custom channels in addition to the standard.1 point
-
Midland MXT575 Drops Next Week.
DeoVindice reacted to Hoppyjr for a topic
I picked up this one. By filing down the sides it fits perfectly into an empty switch blank in my 4Runner. Mic / control head plugs right into the dash and looks factory. CERRXIAN RJ45 Male to Female LAN... https://www.amazon.com/dp/B01MRZAN3R?ref=ppx_pop_mob_ap_share Using a ProClip console phone mount, angled wedge, and MagneticMic holder. Here’s a shot of the dual NMO antennas; one for the Midland and one for the Wilson WeBoost. Both head units mounted under driver & passenger seats. Both work great! Controlled power for both through the SwitchPro. Top left is the Wilson, bottom left the Midland. Semi-related, but the other coiled cord visible in a prior photo is for the phone. Here’s my DIY dash mount for iPhone. …….and a random glamour shot in its element. In this photo I was trying a Wilson whip antenna, but it broke (and didn’t work too well anyway).1 point