WRUE951
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Posts posted by WRUE951
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33 minutes ago, SteveShannon said:
Once upon a time aluminum was used for house wiring but there were fires in some places. It’s a little trickier to work with aluminum because aluminum oxidizes very quickly and aluminum oxide is a pretty good insulator. We still use aluminum for utility conductors but with quite a bit of extra training to do it right when joining copper and aluminum. Gil @WRUU653 would be much more likely to understand the process than me.
But that’s at DC and and 60 hz. RF travels through molecular thin oxide layers pretty well and I agree with you that stainless steel and aluminum don’t appear to bother Comet.
I just got currious about anti-seize and pulled mine out of the cabinet to read. It's a copper base antisize recommend for electrical connections. I wonder if Comet recommends a copper base anti-seize to enhance the electrical connection with their antennas?
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3 hours ago, WRTC928 said:
As I said, I've seen houses wired with aluminum wire and secured with steel screws without any significant corrosion. Granted, they aren't exposed to the weather, but they carry a lot of current. I'm not saying it doesn't happen and I'm not going to start randomly screwing dissimilar bits of metal together, but if Comet uses stainless steel radials screwed into an aluminum base, they must not be too concerned.
Yea, i have as well.. Water and moisture surelty contribute to the corrosion factor. About 10 years ago i restored a 1970 Yamaha 250 Enduro Motorcycle. It sat in my dads back yard for over 30 years. Many of the steel bolt used for the aluminum casing were seized with some destroying the threaded casing. The bolts that were steel to steel cam out with ease.
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On 5/19/2025 at 12:47 PM, WRTC928 said:
TBH, I'm not sure. It has that dull sheen like aluminum, but that could just be the finish. I don't have a magnet handy, but a lot of stainless steel isn't very magnetic anyway. I think the whole "dissimilar metals" things is a bit overblown anyway. Cars and motorcycles bolt aluminum to steel all the time. If it were a part that carries a current, it might be different, but I've seen lots of aluminum wire secured to an outlet with steel screws for decades without any issue, so maybe not even then.
Cars and motorcycles do use dissimilar metals for fasteners and they also advise use of anti-seize. Also, dissimilar metals for fastening use does not promote the corrasion effect as much as it does when electrical current flows through the dissimilar metal.
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On 5/19/2025 at 8:48 PM, WRKC935 said:
Maybe YOU should read what you wrote. I never implied that 30Mhz and below would NOT reflect. I did say that about anything over 100 would NOT reflect off the ionosphere however.
Which is basically what this post says. And is correct. You said that VHF maritime radio would reflect, you never mentioned HF marine radio.
If you ever operated Sporadic-E you know that it opens for a few minutes at the longest and then fades. It's not a consistent method of communications. Yes, this is an exception to the normal rule that frequencies above 100 Mhz pass through the ionosphere. Just like there were 10 meter (29Mhz) downlinks on some ham satellites. Of course they worked better when the sun spot cycle was in a null and the MUF for DX never got above the 15 meter band.
I posted your quotes..
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4 minutes ago, LeoG said:
The aluminum tube that hides the coax and mounts to their 2 struts is aluminum, so are the struts. The U bolts that secure the antenna to the mast are SS also. I assume most masts are some sort of steel but there are aluminum masts out there. So there can be some dissimilar metal issues over time between the aluminum and SS components. SS is much better over time in the weather than aluminum is. Time will tell.
most antennas i'm aware of use aluminum for the radials and it's mouting and use SS for the actual antenna mouting hardwae, wo what you report makes sense.
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21 minutes ago, tcp2525 said:
The stainless steel radials aren't screwing into aluminum. Even if it were, it's a non-issue anyway. Nothing to worry about. Just buy the antenna, assemble, mount and enjoy for many years.
no arguments on the quality or performance of the Comet Antenna..in fact im a bit impressed they arent taking shortcuts in material quality...
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15 minutes ago, WRKC935 said:
OK, Marine VHF is at 160Mhz. I said that hams use 145 Mhz which talks right through the Ionosphere to satellites. No reflection. Try to be nice,
Nope. Ain't your BUD, so here it is straight.
Anything ABOVE 100 Mhz for certain and most anything above 30 Mhz will NOT reflect off the Ionosphere. Which is what you said, which is incorrect.
SO VHF TV on any of the upper channels and mostly on the lower VHF channels doesn't skip, reflect, DX or whatever you were referencing.
Marine VHF also doesn't do that. Hence the reason that HF comms were required on ships over a certain tonnage by maritime regulation. And the reason that we had MORSE CODE requirements in ham radio for the amount of tie we did.
Now that GPS and satellite systems are in place and required on ships, the HF radio requirement is gone.
And BTW. When TV went digital, it quit being VHF all together. There are no VHF (below 300Mhz) TV channel allocations any more.
https://www.antennasdirect.com/hdtv-station-list.html
Look at the list and it will show the station channels are NOT where the claim to be and instead have moved to the UHF band and only claim to be on the original analog channel position.
Bud
You should spend a little time and google this topic and possibly re-read my comment. Yes VHF marine radio is significantly affected byt the inoosphere, is it common, No but yes it does happen just as it does with Broadcast TV. Is it common at UHF NO.. You may want to go back and retract your statement, "30 Mhz will NOT reflect off the ionosphere". That my friend is defiantly incorrect. BTW, i wasn't calling you Bud. I was more currious if you were drinking BUD.
Meanwhile here is a little bit you may find on a Google Search:
How the Ionosphere Affects Marine Radio:-
Marine radio communication often uses HF bands, which are susceptible to ionospheric effects. The ionosphere can reflect HF radio waves, allowing them to travel long distances, sometimes even around the world.
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Ionospheric Disturbances:Solar activity, such as solar flares and coronal mass ejections, can disrupt the ionosphere, leading to reduced or even blackouts of HF radio signals.
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Absorption and Refraction:The ionosphere can absorb radio signals, especially during periods of increased ionization density, and it can also refract (bend) radio waves, altering their path.
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Long-Range Communication:The ionosphere's ability to reflect HF radio waves is crucial for long-range communication, as it allows signals to be transmitted over distances beyond the line of sight.
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Daytime vs. Nighttime:The ionosphere's characteristics vary during the day and night. At night, the ionosphere can be thinner, allowing for more efficient reflection of radio waves, which can enhance long-distance communication.
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VHF and Higher Frequencies:While HF radio is strongly influenced by the ionosphere, VHF and higher frequencies usually penetrate the ionosphere and are more commonly used for ground-to-space communications. However, there can be exceptions, such as Sporadic E (E-skip) propagation, where VHF signals can be reflected by the ionosphere during certain seasons.
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18 minutes ago, wayoverthere said:
I'll have to listen for those. Thinking either DMR/Trbo, or P25 as likely possibilities.
I'll be traviling to from that area in two weeks.. I'll keep my ears open too. Yes, either DMR or TRBO
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2 minutes ago, WRTC928 said:
That's true, but the Comet radials are stainless steel, and so are my temporary substitutes. Comet apparently doesn't think the stainless steel/aluminum interface is a problem. It may be a slightly different composition of stainless steel, but I doubt it's enough to cause problems before Comet sends me some. Meanwhile, I'm doing some testing and trial runs. At any rate, Comet isn't kidding when they say "pre-tuned". SWR < 1.2:1 across the entire GMRS band.
I have never used a Comet antenna so i can't attest to their product. I have read good things though. I do find it odd they would use stainless steel radials compared to aluminum, mostly because of cost difference of material and the low cost Comet sells at. Is Comet also using a stainless steel base for the radial? if so, there wouldn't be an issue with dissimilar metals.
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33 minutes ago, SteveShannon said:
He didn’t initially bring broadcast TV up; you did. All he did was reply to your comment from Saturday:
I get that.. I brought up 'Broadcast TV' in my comment as a reference to Marine VHF because Broadcast TV is VHF. Most of us know VHF Broadcast TV reacts to skip off the ionosphere like VHF Marine radio and UHF TV does not, so it was a reference. His first line comment 'Not Sure Thats Right' and the rambling after was a bit boggling.. Thats all.
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4 hours ago, WSHF732 said:
I can’t find a Kenwood TK-890H that has been fully tested or is fully intact.
This is the 110 watt radio.
If someone could point me in the right direction it would be greatly appreciated.I am trying to acquire all the items I want for my portable/home base setup and this is the radio for me.
Check Ebay,, they have a few advertised as fully tested and ready to shop.. Some are a bit pricey.. Check Surplus Two Way Radios as well.
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8 hours ago, WRKC935 said:
Not sure that's right.
Part of analog VHF TV was below 100Mhz, but went as high as 210 Mhz.
https://en.wikipedia.org/wiki/Television_channel_frequencies
But, satellite communications are done, at least with ham radio, at 145Mhz. Now, there isn't much satellite happening below that, and the reason is the reflection. But low powered handheld radios with modest gain antenna's are used with great success at 145Mhz. So there isn't much 'skip' happening on the upper portions of VHF.
TV signals are NOT a good measure of coverage distance, reason being is thousand foot towers and 100KW plus ERP's. You can't sit and have a discussion of GMRS or ANY type of non-broadcast radio and compare it to TV or even AM /FM radio. The antenna heights and power levels are so much greater with commercial radio and TV stations that it's not even apples and oranges. Its apples and steak, or beer, NOTHING is similar when it comes to coverage.
And broadcast anything is just that, broadcast. It's all one way. Now if you operate simplex (without a repeater) it's at least one way at a time RF, unlike a repeater that's listening to something and transmitting it somewhere else.
what the hell are you saying there? sounds like 'Bud' talking. 99.9% of us would not argue that broadcast TV is oneway transmission and no way compares to a GMRS signal. We know that, why do you bring that up. Sorry, but i cant wrap my head around your comment. 'Bud' will do that sometimes.
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1 hour ago, WRYZ926 said:
Either way, bad things can happen when dissimilar metals are put together and exposed to the environment over time.
exactly what i was thinking
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10 hours ago, LeoG said:
The originals are stainless steel. Always stinks to have delays. But... do it right, do it once.
Hmmm. As cheap as they sell the Comet i'm thinking the radias are made of threaded aluminium rod or tube.
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10 hours ago, SteveShannon said:
Nope, no stars between us and Voyager. Voyager is 15 billion miles away. The nearest star (other than our sun) is 23 Trillion miles away.
Amazing to think about.. Here is a neat video, long but very interestig about communications to and from space
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9 hours ago, WSHH887 said:
And it takes a while for the signal to be received after it is sent. Get's longer every minute. Still, it is pretty cool that we can still communicate. I'm waiting for someone to respond on that frequency. Could be interesting.
takes 20 hours to receive a signal from Voyager and the same amount of time for Voyager to receive a signal from earth.
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19 minutes ago, WRTC928 said:
There aren't any buildings in the way.
But a hell many of stars.
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1 hour ago, marcspaz said:
The numbers I provided are the RF horizon. But, yes, typically the RF horizon is about 15% further than the visual horizon.
what amazes me is how far we can communicate into space.. For example Voyager 1 is some 15 billion miles into space and we are communicating with that spacecraft to and from with ease.
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4 minutes ago, LeoG said:
I made a clock bit by bit using machine language. That was fun. Saved as a .com file.
the good ole days.
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21 hours ago, OffRoaderX said:
i'm old enough to remember when they were all real.
Real ones were so much better, it never entered your mind that the ones you were playing with could have been made in 'China'
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9 minutes ago, tcp2525 said:
Rubbish, that only points out the bare minimum requirements, but not what is optimal and yields a higher degree of safety and functionality. I look at the NEC the same way, a guide to get by with minimal effort. I've seen way too much substandard abominations the "met" code, but is an embarrassment to the trade. Plus, not all inspectors are created equal..
I wouldn't consider the NEC a 'bare minimum' but more so of a 'standard' Some manufactures of electrical equipment may 'suggest' additional steps or recommendations beyond the 'standard' but defiantly not required.. However some manufacture may require their recommendations for warranty purposes but i dont know if any manufactures that do.
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2 minutes ago, WRXL702 said:
Wrong Again - No Lesson - A Mis Read On Your Part - Again.....
NFPA 70 Is The Standard For The Nation Electrical Code.
There is a very slight difference, one protects the welfare of workers while doing installations and includes certain electrical guidlines, whiel the other outlines the actual electrical guidelines.. One of these guidelines came before the other. I actually attended a class on this in 1986 and i still remember.. Do you know whichy guideline came before the other than adopted the one before? You might have to do some studing on that one. Carrry on
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1 minute ago, WRXL702 said:
NFPA 70 Is The National Electrical Code Sir.....
or the National Electric code is NFPA.. Read.. Carry on I told you at the end of the day we would agree, but stubborn you wanted to keep on arguing
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15 minutes ago, WRXL702 said:
No, Not Really - You Did Not.
When You Take The Time To Read NFPA 70 - Attempt To Understand It - Get Back To Me.
I eally cant leave you without giving you another lesson. However, this one will require you some excersise of reading.. Carry on.. Get back to me.
https://alliedmoulded.com/nfpa-vs-nec-understanding-the-key-distinctions/
Bridgecom Repeaters
in Technical Discussion
Posted
Bridgecom software is different (slightly) but Maxons software will still make changes.