Lscott
-
Posts
3569 -
Joined
-
Last visited
-
Days Won
105
Content Type
Profiles
Forums
Events
Gallery
Classifieds
Posts posted by Lscott
-
-
7 minutes ago, WRYZ926 said:
know some old curmudgeons say that digital modes aren't for real radio operators, but I ignore them.
You hear the same crap about CW too. If you can't "beep" at 25 WPM you're not a real Ham.
- SteveShannon and WRQC527
-
2
-
I would be VERY careful taking a two-way radio to most countries. While it's "safer" to take Ham gear you can still run into issues. You get stopped for inspection the custom agent is going to ask a lot of questions about why you have it. Without proper documentation you might end up getting your radio confiscated on the spot. In some countries it's not even legal to "monitor" communications you're not licensed to use! One example is the UK.
https://www.monitoringtimes.com/html/mtlaws_may04.html
I wouldn't even consider taking a radio to Mexico. The police might think you're a cartel member. Any cartel member seeing your two-way radio might think you're an under cover cop or rival cartel member. Either way you could get shot.
- WRXB215 and SteveShannon
-
2
-
54 minutes ago, GreggInFL said:
Probably 100' total.
You might want to consider up-sizing the coax to LMR-600 for that long length.
- WSAA254, SteveShannon, WRUU653 and 1 other
-
4
-
-
24 minutes ago, WRUW493 said:
Not sure why you would rule out roof pillars though???
They are going to be close to the antenna and in what is known as the "near field" so it couples into the driven element. That can booger up the impedance match, SWR issues, and the radiation pattern. It's not a guarantee you'll have problems but keeping the antenna away from from structures like that will at least avoid the potential for them. You read through the past comments over time here and you'll see this mentioned from various people.
- WRUW493 and SteveShannon
-
2
-
On 4/5/2024 at 11:33 AM, WRZT411 said:
Also, is there a real difference between a 5/8 and a 1/2 wave antenna?
If you don't have a GOOD ground plane for a 5/8 wave antenna, they really need it, don't waste your money on one.
If it's a true 1/2 wave they don't need a ground plane so you can mount them just about anywhere so long as you keep it away from nearby vertical metal supports, like roof pillars.
-
50 minutes ago, WRUW493 said:
Same as above, plus: keep in mind that aluminum is non-ferrous, meaning that is actually repels magnetic fields. Sure it's thin, but there might be a risk of deteriorating the magnet if left on the aluminum long term. Consider a large steel washer below the magnet to "capture" the magnetic fields, then place that combo on the aluminum foil.
The aluminum foil won't hurt the magnet at all. Don't worry about it.
Sticking something magnetic on the back side of the foil the magnet can be attracted to is a good idea to hold the foil in place. The foil needs to be a rough square at lest 6 inches on a side or a circle about 12 inches in diameter. Put the magnet mount in the center.
- SteveShannon and WRXB215
-
2
-
19 minutes ago, Sshannon said:
Eventually you’ll have every combination of adapter
!
I can verify that.
https://forums.mygmrs.com/gallery/image/427-adapters-connectorsjpeg/?context=new
-
5 minutes ago, Sshannon said:
That might be true for some of the technician class hams, but most of the people I know who progress to General (and all of the ones who progress to Amateur Extra) work hard at understanding how everything works, propagation, etc.
Good. I know a few who don't, and they are Extra's too. Sad.
-
36 minutes ago, nokones said:
What did you study on your own? Did you study the actual aspects of radio theories and practices to be an entry-level Amateur Radio Operator, what about the operation of the equipment and test instruments, systems and networks, rules and regulations, and ethics, or did you just study to memorize the answers to the potential exam questions?
Wouldn't a person benefit and learn more from an in-person class with inter-action with other class attendees and have hands-on exercises and participate with class discussions? I guess that type of learning is no longer available these days and people just don't want to inter-act with others and would rather stay home watch a video and could care less on the possibility of learning a lot more on the subject than watching a video.
Good points. Most Hams are "appliance operators" these days.
Still the value is learning the rules. At least memorizing them is about all you can do so that part isn't any different. As for the rest, well, I guess experience is the real teacher. Maybe then the rest of it might start to make some sense.
-
2 hours ago, gortex2 said:
The local club near me still offers an in person class.
You can ask questions with an in-person class. Can't do that with a YouTube video and get instant feedback.
- SteveShannon and WRUU653
-
2
-
1 hour ago, WSCF738 said:
My radios when haywire. I live outside of Austin and the lights on the radios just kept flashing. Couldn't turn the radios on or off and there was nothing on the display. After the eclipse passed everything returned to normal.
You sure it wasn't due to a temporary "climate change"?
-
2 hours ago, WSAA254 said:
I think I will echo what everyone else has pretty much been saying. Quality coax (lmr400) and antenna height. My own personal setup was driven by hi windy conditions here. We can have weeks of 20-30 mph winds. So antenna size was important. Fortunately gmrs frequencys lend themselves to small antennas. I use a compactenna scan - III since I also use the same antenna with a SDR. There are probably better gmrs specific antennas that are less expensive, however I can hit a repeater 50 miles away at 5 watts, but this would not be possible without the elevations involved. Other folks around here have also hit the same repeater with a hand held at 5 watts, this just re-enforces the idea of height being king. My antenna is only about 10ft, and has survived 70 mph winds, the antenna is consistanly hit with 30 mph winds. Hope this helps, best of luck... All info is good info.... regards
You need a few more zip-ties on the cable. I imagine that's to try and take the weight off the cable connector at the base of the antenna.
- SteveShannon and WSAA254
-
2
-
On 4/3/2024 at 4:36 PM, WSAK691 said:
There’s no spot on VHF that is even usable for this antenna. SWR is like 6+. Even on 70cm the numbers are on the high side of the usable slope. So if you bought this antenna for those purposes, it is bad. But fortunately and luckily for GMRS users, this antenna lands resonant (by dumb luck?) at the GMRS region.
My experience with a similar type I picked up cheap at a Ham swap. On the Ham 70cm band it wasn't too bad. On VHF it was VERY narrow banded to the point of being mostly useless. The SWR on GMRS put it out of the running. Oh well I got a decent magnet mount out of the deal.
-
I think today will be one where Ham, GMRS and CB radio is going to get a bit of a workout. People driving around trying to beat out the traffic to find a good location to view the eclipse. With the weather forecast being crummy in some areas getting up to date viewing conditions is going to cause a lot of last minute scrambling to get to a better site.
- WRXB215 and SteveShannon
-
2
-
11 minutes ago, tcp2525 said:
I only use Transco switches. No fake specs and extremely low insertion loss.
It's not really a switch, but a coax relay. Plus it uses a 28VDC coil voltage. Not something easily available in a motor vehicle. I have a couple of coax relays but they use SMA connectors. Picked these up a long time ago for a project, but never got used.
-
6 hours ago, Webslinger said:
I've seen a few comments on the Internet that a 6m band on an HT is not really that great.
That's mostly true. An effective antenna needs to be at least a 1/4 wavelength long so on 6M that would be around 57 inches long at mid band. The short helical antennas used on the radios are so inefficient that most of your power is wasted. It's the same story with those old "full power" 11M CB radio HT's. The range on them was poor.
The only thing that comes close to a useful 1/4 wave antenna on an HT is on the UHF band, Ham 70cm or GMRS. On those bands a 1/4 wave antenna is only about 6 inches long, about what the usual HT antenna size is on an UHF HT.
The antennas for 2M and 1.25M on an HT are also inefficient, but nowhere as bad as 6M.
One other point. The 6M band usually doesn't see much activity unless there is a band opening. And when it does it's typically on sideband where you'll find most of the people.
Some people claim that propagation on 1.25M is better than on 2M. I'm guessing it's due to a sort of a compromise between 2M VHF and 70CM UHF. Activity on the band ranges from nil to active depending on location. Not many people have equipment for 1.25M as it is.
If you're into Ham digital voice modes there are currently only three radios I know of that can do a digital voice mode on 2M, 1.25M and 70cm bands. Two are Kenwood, TH-D74A and the TH-D75A, which only does D-Star. The other is the Anytone D578 series, which does DMR.
-
Here are a few more models. These antennas are a bit less common. The worse one to build and model was the 11 turn helix. I was looking at that for a satellite UHF down link. In the end I went with an 11 element Yagi from M2 Antennas. It was smaller, far easier to aim and the gain was about the same. The only thing lost was the circular polarization.
https://antenna-theory.com/antennas/travelling/helix.php
https://www.m2inc.com/categories/commercial/antennas/helical.html
The rest are a bit more common.
Corner Reflector:
https://www.arrowantennas.com/solid/cr4501.html
Eggbeater:
http://146970.com/PDFs/Antenna Eggbeater-Revisited-English.pdf
Turnstile:
http://www.on5au.be/Cebik-2/SomeNotesOnTurnstileAntennaProperties.pdf
https://www.qsl.net/g4hbt/dipole.htm
The Turnstile model doesn't use the "typical" dipole phasing cable setup.
Turnstile.EZ Eggebeater Rev 8C.EZ 90 deg 70cm Corner Reflector Rev 2.EZ 11 Turn Helix.EZ
-
If anyone is interested in messing around with antenna simulations the software is now freely available.
I've attached some models I've played around with in the past.
Magnet Mount - Rev 2.EZ Magnet Mount Ham and MURS.EZ Ham and GMRS Magnet Mount.EZ GMRS J-Pole Rev 3.EZ GMRS 11 Element Yagi Rev 2.EZ FRS-GMRS Gnd Plane With Radials.EZ 4 Bay Anetnna MURS.EZ
-
OK.
I simulated a simple magnet mount 1/4 wave MURS antenna. The frequency was selected to be about in the middle of the band. The results looks good. The match and radiation pattern look like what I would expect.
The exact same antenna was then run at a frequency about in the middle of the GMRS band, between the simplex and repeater input frequencies.
As you can see the match short of looks OK on GMRS, however most of the RF power shoots up at a very high angle uselessly into space. I guess if GMRS has satellites in low earth orbit it might be a good antenna. For normal ground work most of the power is wasted.
This is what I was getting at in my prior post comments.
-
2 hours ago, WRYZ926 said:
Using power poles does make things easy and simpler. I will buy the actual Anderson brand and the correct crimper when I start switching things over. My plans are to use them for a go box.
@WRDJ205 I am going to suggest to just use the connector that came with the KG-XS20G since it is water resistant. I also suggest running the positive lead to the battery and the ground to chassis ground of your vehicle. Here is where ring terminals that are crimped and soldered is better.
For "under the hood" and exposure to weather that's a good idea. On the inside of the passenger cabin, a home setting or a sealed enclosure the power poles are a good idea.
-
2 hours ago, WRUU653 said:
Is there much loss through a switch?
If you look at the photo and the specifications at the link the insertion loss is about 0.1db up to 500MHz for the example switch. That's only about 2.3 percent power loss, basically nothing to worry about.
-
12 hours ago, WRDJ205 said:
To monitor the draw I bought a pretty nice watt meter. Unfortunately it only came with power poles. Guess I’ll have to either cut them off or make some adapters.
Anderson Power Poles are commonly used. I have just about everything I use outfitted with them. There is sort of a semi official configuration for them.
Anderson Powerpoles - Standard for ARES and RACES.pdf ARES - RACES Standard 12 VDC Power Connector.pdf INSERTION - EXTRACTION TOOL FOR PP15-45.pdf
-
31 minutes ago, Borage257 said:
Cut it for MURS (153 MHz) and it will be pretty good on GMRS too!
If he does that it will may look OK from an SWR standpoint but the pattern will look bad with multiple lobes likely giving crummy coverage. I wouldn't recommend it other than as an experiment.
Keeping tones private
in Technical Discussion
Posted
Simple answer you can't can't.
Some people have toyed with the idea of using a single frequency "trunked" repeater where every radio has to be registered with the ESN, by using the internal Electronic Serial Number, to authorized access. As far as I know there isn't a way to change the radio's ESN.
The typical analog system is known as LTR, Logical Trunked Radio, and the variation using the radio's ESN called Passport.
Some people have bumped into used radios with the special Passport firmware loaded. When they try to reprogram the radio using the "normal" software the display shows SJ-180 and fails to load the code plug. I even had a used Kenwood TK-3180 HT with that firmware loaded. I managed to load the normal LTR firmware so I could use the regular radio programming software. I do have a copy of the special SJ-180 programming software too.
This is also fairly common on digital voice mode repeaters. The process to get a radio on one of those is a bit more complex requiring a "system key" file, licenses etc. just to program the radio. Normally with those radios you can't even read the radio without the system key file. There are hacked versions of the radio programming software out there that will read the radio and save the contents as a ".srv" service file without it. See attached screen shots of a used NXDN trunked radio I read with that software.
Understanding Passport Radio Systems App Note.pdf