dwmitchell61
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Posts posted by dwmitchell61
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Call it paranoia, if you will. But I don't trust anything software-wise that the Chinese have produced. If it is a true Trojan, you'll never know until all your money is gone from your bank account, or your computer gets held for ransom, or worse... They use your computer to do some nastiness, like espionage.
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Yeah, I know. Analyzers can get expensive. Slowly building my shack on a tight budget. I might look into a VNA, but you have to watch what brand if those you are buying, also. The Chinese aren't known for their quality checks, that's for sure.
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The SWR meter could be off, it IS an MFJ product. The BRC HP-500 antenna was advertised as a GMRS antenna. The "Frequency:" range was given as the GMRS, but they also mentioned the "Gain:" as being so much at "2m" and "70cm".
I suggest buying the Comet CA-712EFC antenna before I would buy the BRC HP-500, for GNRS, anyway.
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Heck, if you have a window you could hang the antenna in, that would shorten the cable run and take the absorption of whatever kind of roofing down quite a bit, also. Composition shingles are coated in pebbles, basically.
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Bingo.... Set the priority channel to the channel your club uses or turn it off altogether. I had that issue on my Wouxon amateur handheld.
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Yes. The settings are correct. I double checked. I use the programming software. That way I can use the slots for the normally unused channels 8-14 to put in more repeaters and set it all for wideband operation (among other things). It makes it a lot easier than using the front panel, also.
I replaced a broken Comet CA-712EFC with this one. The performance for a 17 foot antenna compared to the 712 at 10 ft 4 in is abysmal. Internally the BRC HP-500 seems to be just wire antenna elements. The Comet CA-712EFC was a coaxial collinear internally with coaxial stub matching transformers at the base.
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What kind of feedline (RG-58?) do you have to the base station Ed Fong antenna and how long is it (guessing around 40 feet)? Receive will be sensitive to excessive feedline losses. It isn't a big deal at the lower frequencies of CB radio, but when you are operating at GMRS in the UHF spectrum losses build rapidly. Forty feet of RG-58 has 5.4dB of loss at 450MHz (more at 465MHz GMRS). Every 3dB of loss halves the power, 6dB halves that. So you'll end up at about 16.7W at the antenna using RG-58. Forty feet of LMR400 has 1.08dB of loss and with it you'll 30.6W out of your 40W.
In North CACKALACKY (my late wife and love of my life grew up in Havelock) you have humidity and storms. I would suggest N-type connectors and look up how to seal up the connections properly to keep moisture out of your feedlines. I use a connector silicone paste made to seal connections, it goes right in the connection. Then wrap the connection tightly with the silicone rubber "self-amalgamating" tape real good. Over that use the black vinyl electrical tape. And lastly, put a wire-tie (tie-strap) around the vinyl tape to keep it from unwinding on you. I use Times Microwave LMR-400 coax and it will cost you a "Ben Franklin" for 40 feet with N-type connectors. Don't forget a loop just at the antenna in the coax for strain relief (takes cable weight off of antenna connectors and puts it on your mast).
Shhhhhheeeewwww! Did I forget anything? Hope this helps.
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I have a 40W Midland MXT-400. A 1 foot jumper of TM LMR-400 connects the output to an MFJ-842 SWR/POWER meter rated 140MHz-500MHz. A 3 foot RG-8X jumper connected to my window feed through (MFJ-4601N, N connectors). On the outside I have a lightning protector (also N connectors). The feed line is 30 feet of TM LM-400 connecting a BRC HP500 antenna.
The SWR meter indicates 35W output from the radio with approximately 2W reflected power and the needles cross at 1.4SWR.
A call to an individual I hear booming in from a repeater loud and clear with only two bars on my signal meter tells me that my signal is staticky and broken. So it appears that the receive is a LOT better than my transmission.
I suspect that I have an antenna marketed as a GMRS antenna that is in fact a UHF antenna trimmed for SWR, but not necessarily a GMRS resonant antenna. The ad says it is 3 5/8-wave on 2m and 7 5/8-wave on 70cm, and the frequency is 460-470MHz (GMRS) and "C-loaded" (ceramic capacitor at the bottom, probably?).
Any thoughts on this?
Thank you,
Dave KJ7WUZ/WRHW845
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On 2/23/2018 at 9:23 AM, n4gix said:
The loop serves as an RF choke, and acts to reduce common mode current. This will assist in reducing the tendency of the coax to act as an active part of the antenna, which affects both transmission and reception.
If you really want to get into the technical explanation, see this PDF article: http://audiosystemsgroup.com/NCDXACoaxChokesPPT.pdf
As I use 1/2" heliax, I can't create a loop, but then heliax obviates the need for a common mode choke anyway.
To see many images of such coax chokes in action, see here:
I am curious as to how the heliax obviates any common mode current on the outer skin of the shield.
Maybe I am misunderstanding the cause of common mode current on the feedlines?
I thought it was due to imbalance in the antenna system.
The PPT presentation you linked to above, on Page 6, states"
"– Coax is not a part of these imbalances"
So, I am wondering how your expensive heliax transmission line solves the issue. I have a lot to learn and don't know it all and am open to some mentoring from an "Elmer"
It would seem that using ferrite beads of a proper mix rather than the old, trusty "ugly balun" method would be more effective at higher frequencies like GMRS.
Thank you and 73
Dave, KJ7WUZ/WRHW845
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Ed Fong, PhD is an electronics engineer that is reputable and knows what he is doing. He developed these antennas from a request that he design an antenna given explicit criteria for a corporation in the communications business. There is no need to criticize unless you are willing to back your critique with explicit engineering facts. You don't have to buy Doctor Fong's products, but the proceeds do go to supporting the college students in his college courses.
As for the big brand name antennas, I would suggest you take the time to look inside the next one you buy before you put it on your tower or mast. You might just be shocked by what you find, and maybe even a bit disappointed if you know anything about soldering and antenna theory.
I intend to purchase his antennas for my use when I go portable. I just don't want to have to carry around some 10 foot to 17 foot fiberglassed fragile antenna that could be broken, then spend another $200-300 replacing it.
Stay well, see you on the air, stay well and try to stay positive
73
Dave, KJ7WUZ/WRHW845
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On 3/28/2023 at 5:54 PM, tcp2525 said:
Doesn't anyone solder any more? I'm old school and still solder.
I don't have an appropriate soldering station for the shielding. I tried to build a coaxial collinear antenna with a 25W iron on RG-8X and it was a mess. Even tried a butane soldering iron.
If it's just the center pin, then that is manageable.
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This sounds like it may get expensive...
Windstorm brought down mast & destroyed my base antenna. So's I buys a new antenna. The XYL says radios have to leave the bedroom, son has moved out, I now have a radio shack (and XYL used to manage Radio Shack here, LoL).
Make a long story short. New mast, new antenna, new location, in the air, all guyed up, cables awaiting window feedthrough...
I look over and find my Welsh terrier hanging from the GMRS coax and she's having a great time.
I look and there are holes all the through the external insulation. Now I get reports I am "loud and clear but scratchy".
Looks like I am going to lose some length in the cable...
About how much is a crimper set for doing N-type connectors on LM-400?
Maybe someone at the club will graciously let me borrow theirs?
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On 3/20/2023 at 7:24 AM, Lscott said:
Since this is just "theoretical post and for speculation" and Ham related. For GMRS I'm sure you're well aware of the rules so it's up to you what you do.
I'm not aware of any "Ham" single or dual band radios for VHF/UHF that will do 100 watts. The most common power levels are 40 to 50 watts, with UHF generally being the lower of the two. Now for commercial mobile radios there are some that will do 100 watts. You'll likely end up spending a huge pile of shinny coins to get one.
You might be better off getting something in the 15 to 25 watt range. You can find these at relativity affordable prices. The following is an example of one I have. While it's an analog/digital radio I didn't complain about the price, It was free, pulled out of service after a short while, never reused, and scraped off the books by the original agency that had it.
https://forums.mygmrs.com/gallery/image/250-nx-820ghjpg/
The lower power radio you can later add the amplifier if you find it necessary. If your operations will be primarily through repeaters that's likely all you'll need. When I first got licensed I used a dual band HT on low power running into a Mirage dual band FM amplifier, around 35 to 45 watts depending if it was UHF or VHF. Never seem to need more for repeater use operating mobile. Later I had an Icom IC-706MKIIG. I almost never ran more than 20 to 25 watts on it either.
Generating the kind of power you want at UHF isn't that easy and it's not going to be cheap.
https://www.dxengineering.com/search/part-type/vhf-uhf-amplifiers/rf-output-maximum-power/100-watts
Most people coming to GMRS from a CB background are hung up on the power output myth, the more the better. At VHF and more so at UHF the communications are LOS, line of sight, the radio waves don't bend around obstructions in the path very well.
To give you an idea of just how far you can reasonably expect is look at a mobile antenna on a Jeep for example up maybe 6 feet. The range to the radio horizon, square root of antenna height above ground in feet times 1.4 gives range in miles.
sqrt(6)*1.4 = 3.4 miles
https://www.hamuniverse.com/lineofsightcalculator.html
If the other vehicle is about the same then it's the combination of both, about 6.8 miles. Running a huge amount of power won't extend this much. Some of the other posters here have done the experiments and have come to about the same conclusion.
The words he speaks are true... I have a repeater 8 miles out on my HT ham radio. I can reach it using 1W loud and clear.
My "base station" putting out 40W cannot reach a repeater 26 miles out, due to a mountain between us. I can, however, reach another about the same distance because there are no hills between us.
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On channel 1 I am receiving a constant beep. I thought I heard some family chat in the distant background.
One of the neighborhood kids must have set his radio down with an emergency beacon or something turned on.
No channel 1 until the battery runs down, I guess.
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Oregon CIty 575 and Oregon City 575-2 repeaters are not showing in my searches. Repeater owner is WRAS495.
I can however, searh by his call sign and pull them up. But the lack of visibility in the "NEAR ME" and "ADVANCED SEARCHES" is probably limiting the usage on his repeaters.
Thank you,
Dave, WHRW845
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On 3/28/2021 at 3:53 PM, DonErle said:
Click on "Function Setup" in the left sidebar.
Then Fill the "Starting Display" with your GMRS FCC allocated call sign.
73
Dave
It can also be software programmed to do split tones, CTSS and DCS even, on same channel.
You must buy the DBR1 cable from Midland and they give you a limited-life link to the software download when you call them.
I programmed mine to display my call sign on startup
I'd be interested in how you used the Midland MVT400 programing software to display your call sign on startup of your radio. Good idea. Thought I had been to all the corners of the program, but never saw this handy feature
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Is there a way, to age repeater records so entries for repeaters that never made it online or have been taken down are removed from the database. There are like 4 or 5 repeaters listed in my area that have never responded to a transmission in the two years I have been here...., show no activity of the owner and which the owner does not respond when correspondence is sent to them about the repeater.
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18 hours ago, tkruppa said:
So upon further investigation interference is absolutely the issue. With the vehicle completely off (radio running on my auxiliary battery, no power to the truck itself) no noise at all on channel 5. As soon as the vehicle gets power (not engine on, just power on) I get blasted with noise. I've narrowed it down so far to both my head unit and dash cam. Turning the dash cam off will reduce the noise, and turning my head unit to FM radio instead of bluetooth eliminates it. Unfortunately I dont think this is an issue I'll be able to solve, I need my dash cam and radio. So I might just have to deal with it.
If you are lucky, it is in the DC power to the radio, from the car. Get a big CAPACITOR from electronics supply house or auto stereo shop and connect it across the wires
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I did the antenna upgrade to my Wouxon KG-805..... A Nagoya antenna. Works alot better than antenna included in the purchase of the radio. Reaching people 4-5 miles out while in my easy chair. They used to say, "As much wire in the air, as high as possible." I have adapters for the SMA to a SO-238 so I can connect it to the Comet CA-712EFC base antenna.
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On 6/12/2021 at 5:04 PM, OffRoaderX said:
I keep my Roger Beep on - when someone complains about it, I remind them that its my radio and nobody is forcing them to listen to me.
I guess you won't mind if I sit in the chair next to you at the doctors office and pass some gas, then? LMAO..... Sorry, poor analogy but it seemed funny at the moment...
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Deleted due to redundancy...
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Hey Corey, Looking at it from a different viewpoint makes a difference. Other than my own trailer mounted repeater, there are none where I live. Gaining that kind of difference in distance is impressive. Sometimes the Symantecs overwhelms the subject. Then again, I do love a good rant.
It's okay. From what I understand, rants are very much in vogue right now! LMAO...
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I made a home brew antenna today.
I built a 1/4-wave ground plane with 6 ground plane elements today. The SWR is a tad high at the higher repeater channels/frequencies (467MHz). The 462MHz channels/frequencies run a low SWR.
I will try making the angle on the ground plane elements a bit steeper first. Then I will try trimming the element lengths, bit by bit.
This will be one of my "go box" antennas.
I may try a commercial made antenna with a ground plane kit I bought from here. I broke one of the ground plane elements, so will replace them with 12AWG copper wire.
The quagi long-beam I built to use for reaching a distant repeater had very high SWR. It was scaled from a 440MHz antenna design. I need to rework the quad loops on it to match it.
Another project I want to build is a cubical quad "go box" antenna. So many projects, so little time... Trying to fix up our home to sell at the same time.
Huh.... I checked the radiator AFTER soldering it into the center pin on the connector... It is 3mm to long... See what happens tomorrow as I go through teh steps above.
Wouxun KG-805G Stopped RX-ing/TX-ing after using CHIRP.
in Technical Discussion
Posted
Considering the software BTWR supplies, from the manufacturer keeps getting flagged by Windows 11 Security as containing the Trojan:Win32/Wacatac.B!ml, maybe they should supply a download of CHIRP and the factory code plug for CHIRP?
There is a problem when we and the Chinese are in a state of hostility, and they manufacture nearly EVERYTHING we purchase. But our government and the management of the large corporations deem the savings in labor costs are well worth the risk, I guess. "Most Favored Nation."