The forums are retiring and are now closed for new topics and comments. The existing content will remain online and accessible through 2020 to provide everyone the opportunity to save any relevant information. In the spring of 2021, these Community forums will be taken offline.

Search for heavy in Topics


heavy knex weapons

I think we should see more large knex weapons (rocket launchers, turrets, large caliber machine guns (I know perfect duck made one but if you have that many knex WOW and to make 2 WWWOOOWWW)etc.) yeah that probably confused a lot of you im getting confused.?_? P.S.sorry

Topic by woohoo659    |  last reply


Heavy Duty Workbench

Specifications: 60X30 Not attached to any walls Heavy duty (I need to be able to throw a transmission on it and get to work or take out my hammer and do my woodworking stuff and not have holes or any other damage to the work bench) Under $500 I have scoured Instructables and can't seem to find an instructable that suits my needs.  I can get a full metal workbench for $1500, or a metal topped workbench for about $800. I'd like to keep this cheap. I'm all good for scavenging, but I live in the suburbs, so places to scavenge are hard to come by. Regards,  David

Topic by avengingtn    |  last reply


Extract heavy water?

I can't get hold of any heavy water so I want to try extract it from normal water, I only need a drop or two. I was gonna use electrolysis to separate the atoms and increase the concentration if heavy water till it gets to around 70% (min.) but how much of power do I need to pass though the wires to only separate H2O and leave the D2O? (Need the deuterium for a fusor I'm building)

Question by JunaidA44    |  last reply


Your Heavy Hitting Topics

What was your most successful topic? I want to know what people are in to.Mine are: https://www.instructables.com/forum/T9DWQGEF82EU3YX/andhttps://www.instructables.com/forum/TERUXT1F3SYTLW3/You can base it off of just reply number, or quality of replies, rating, etc.

Topic by Spl1nt3rC3ll    |  last reply


knex heavy pistol cannon

This is my heavy pistol cannon should I post?

Topic by Ithaca37    |  last reply


Heavy aerial lift quadcopter?

Hi, I am in a local competition where they are asking for a quadcopter that can lift a box of lead. The box weigh's 25kg. Yes, you read that right 25 kg. The rules state that it must be a quadcopter and it must fit in a meter by meter by meter cube. This limits the prop size to 500mm diameter unless the height of the blades is different so they overlap. I would prefer not to do this. each rotor must lift 7000 grams (payload + weight of quad). I have been using this thrust calculator : http://personal.osi.hu/fuzesisz/strc_eng/ and according to it a 500mm (20") at 4.5" pitch (I just put that as standard) will need to spin at 6000 RPM to produce 7.12 kg of thrust. It also says it will need an 800 Watt motor. I plan on using these motors http://www.hobbyking.com/hobbyking/store/__24433__NTM_Rotor_Drive_450_Series_1700KV_930W.html. They are 930 watts and 1700kv. they run on a 6s lipo. A 6s lipo is 22.2 volts. 22.2 X 1700 = 37,740. 37,740 RPM is the theoretical speed of the motor. I only need 6000 RPM. 37,740 / 6000 = about 6. so the motor has an 8 tooth gear on it and the prop has a 42 tooth gear on it. This makes a roughly 6:1 ratio to slow down and power up the rotor. The motor is 30A constant current, 42A burst. The ESC will be this one http://www.hobbyking.com/hobbyking/store/__25366__Turnigy_Multistar_45_Amp_Multi_rotor_Brushless_ESC_2_6S.html and the battery will be this two of these: http://www.hobbyking.com/hobbyking/store/__9176__Turnigy_5000mAh_6S_20C_Lipo_Pack.html.          When I started writing this I had a question that I answered myself but now I just want to know if you see any faults with this. PS, the winner of the competition is the one who can hover the longest. I also want to do it for as cheap as possible

Question by monty324    |  last reply


weight gain? Answered

This is just one of those strange things that flashed through my mind when I read the other question on Deuterium. Since its just water, and I don't remember ever reading that it is harmful to drink it, I was made to wonder: If a person were to drink enough deuterium over a period of time to replace all the regular water in their body with heavy water, just how much weight would they gain?

Question by Vyger    |  last reply


Bronze Rubiks Cube - Heavy and Functional

This Rubik's Cube is made out of bronze and can be used just like a regular Rubik's Cube even if there's no difference of the faces to try and solve. So even if it's "useless" it's still a lovely item and an impressive build. Link

Topic by fungus amungus    |  last reply


Heavy duty motor controller system

I'm attempting to build a rather large bot using wheelchair motors as it seems many other people have done. However I'm trying to determine the best way to control them. Anyone have any suggestions on a motor shield/motor control board powerful enough to do so or have a recommendation for a specific motor controller or arduino relay board that could work?

Topic by dstech    |  last reply


IAC's Heavy knex Crossbow Review!!

Well here is a review of the cannon so that you know YOU NEED TO BUILD IT. Well here is a video http://www.youtube.com/watch?v=cy9SxI0I3Gc . Next comes the review. PERFORMANCE range: 8/10 75 feet not angled about 90 angled a little. ROF: 5/10 The rate is good for a cannon like thing but for every shot I would say about 7 seconds or less with a lot of practice Reload time: 6/10 about 15 seconds COMFORT Handle: 7/10 good for a cannon but there are better Stock: 8/10 Its a good stock it supportive but not extremely comfortable Second hand placement: 6/10 I feel like my hand is stretched to far when I put it at the way front of the gun and when I put it on the barrel it bends LOOKS AND STRENGTHS Looks: 9/10 well its big so already its amazing and in my opinion it looks pretty good Barrel strength: 8/10 the barrel is really strong for rubberbands but it bends vertically Handle attachment: 10/10 I can lift the gun with only the handle and it is very heavy Bipod: 7/10 Strong but not portable as said by Mr.Muggle Bow: 9/10 Very strong period Overall this gun is like 9/10. That is off my opinion not by calculation Well I'm done so now you need to go build it.

Topic by sprout_less    |  last reply


how to make boxing heavy Punching Bag?

If somebody cen make video about making bag

Question    |  last reply


Is whipping cream and heavy cream the same thing?

In recipes I keep seeing "heavy cream" but when I go to the store the only cream I am finding is "whipping cream" and I am wondering it they are the same thing and/or interchangeable.

Question by KMOM14    |  last reply


heavy gauge metal tubing shaping question Answered

You know the "heavy" gauge metal tubing you see on swings and roundabouts in the public play parks? What is that called and how would I bend and shape it without having to go to an expensive, specialist shop, please? Pretty much I want to have a straight part about 3 metres followed by a curve of radius approx 1 metre and another 1m straight after the curve. Thank you for reading me and your time to reply.

Question by kevinhannan    |  last reply


How to make a block Xkg heavy vibrate?

Any else see that new "magic" excercise machine?http://www.realtechnews.com/posts/3286I was thinking about a diy version and it would be pretty easy, I'm just not sure about how to get the fast vibrations needed.Any ideas?

Topic by greendude    |  last reply


Elevator type platform for heavy, CRT monitor

I have to sit sometimes and stand sometimes to use my desktop computer. I use an old, heavy, jumbo-sized CRT type monitor which has a space-saving stand on its top for my printer. Currently, when I stand, I raise the mouse on a box and elevate the keyboard on a piece of foam and I peer downward to look at the monitor. This is not always a good way to see everything on the monitor.  What kind of simple elevating/lowering platform could be constructed so that the monitor can be raised to be level with my head when I stand and lowered when I sit in front of it? I suppose some electrically powered or non-electrical hand-cranked platform would be fine. Remember: both the motor, hardware and platform have to be able to lift, lower, and support a heavy CRT monitor which has a plastic platform holding a printer above the monitor. [Due to severe space limitatons where I live in my ultra-tiny apartment, I can't really use a shelf to hold up the monitor when I stand, and besides, it would be a pain in the neck to frequently lift/lower and set in place the monitor on either the shelf or on the desktop.] Thanks

Topic by blm7    |  last reply


Visible Gas? Answered

I wan't to fill a chamber with hydrogen, have a chamber of the same size linked with it, with a heavy visible gas in it, then as I pump out the hydrogen the heavy gas displaces it and I can see when I need to stop pumping and refill with hydrogen.  What gas can I use,  I know just about any visible gas will work because hydrogen is the lightest, but it would be nice if it was heavier than average air so I could allow air to flow into my heavy gas chamber to displace it.  Or can I just die the air with some kind of smoke from my smoke machine. Yes hydrogen is extremely explosive, so this would be on a very, very small scale with hopefully 0 oxygen.

Question by jj.inc    |  last reply


What is the best way to move a 170 lb. television off of a four foot high shelf it is sitting on?

We have a big Sony Trinitron that is sitting above the fire place in a recessed area that is about four feet off of the floor.  The TV is 42" screen and is extremely front end heavy.  I know that we could always just push it off and let it crash, but we'd like to keep it if possible. 

Question by russ and the pups    |  last reply


What should I re-build next?

I just recently build both the K'nexsayer and the K'nex heavy cannon.Both of the didn't work out for me. I know what I did wrong for the cannon (I didn't make one of the barrels big enough, and the trigger was a little different)And I don't know (yet) what happend to the K'nexsayer.( I think i didn't build the pump right. )So, Witch one do You think I should build? I kinda want to build I_A_C's cannon, but I want to see what you guys think. :-[D

Topic by Owenmon    |  last reply


World's Heaviest Motorcycle

Monster bike is world's heaviestA giant motorbike powered by a Russian tank engine has been recognised as the heaviest in the world.It's been dubbed the Led Zeppelin by creator Tilo Nieber, 39, who said: "You don't get much more heavy metal than this."The four-and-a-half tonne machine has driven into the Guinness Book of Records as the heaviest motorbike in the world.It is 17ft 4ins long and 7ft 6ins tall and the engine alone weighs 1.8 tonnes after the armour plating tank cover has been stripped off.The bike, which took a team of welders and mechanics almost a year to build at the Harzer Bike Schmiede in Zilly, Germany, is now hoping for a licence to travel on the road.But in the meantime Guinness Book of Records spokesman Amarilis Espinoza confirmed it was the world's heaviest motorbike.

Topic by ewilhelm    |  last reply


Knex Heavy Crossbow VS. Knex Tank Bow

Okay. Two really new guns. Both of equal awesomeness. A perfect match in a war. What do YOU think? Who's gun would win?  kNeXFreek's Tank bow? Or IAC's Knex Heavy Crossbow?

Topic by Seleziona    |  last reply


Knex War idea

This is a new knex war idea it is called IT IS CALLED THE  CANNON KNEX WAR SETUP: THERE IS A KNEX CANNON IN THE MIDDLE OF YOUR PLAYING FEILD THE CANNON MUST SHOOT OVER 60 FT FOR IT TO BE USED THE PLAYERS CAN ONLY HAVE KNEX ASSAULT RIFLES EXCEPT FOR 2 PEOPLE WHO CAN HAVE A SHOTGUN AND A PISTOL. THERE IS A 12IN BY12IN CARDBOARDBOX 4FT OFF THE GROUND ON BOTH SIDES YOUR SIDE AND YOUR OPPONENTS SIDE. IMPORTANT: ONE PERSON MAY HAVE A KNEX SNIPER OF HIS/HER CHOICE THE GOAL: IS TOO HIT THE TARGET WITH THE KNEX CANNON.   IMPORTANT:ONLY ONE PERSON MAY OPPERATE THE CANNON AT A TIME IF YOU ARE HIT WHEN OPPERATING THE CANNON YOU MUST GIVE THE CANNON THE PLAYER WHO HIT AND YOU MUST RETURN TO YOUR SIDE AND HAVE TO WAIT FOR 5 SECENDS BEFORE RETURNING TO THE GAME. IMPORTANT: THE TARGET CAN ONLY BE HIT BY THE CANNON NO OTHER  WEAPONS CAN HIT IT I WANT YOU OPPINION ON IF THIS IS A GOOD IDEA OR IF IT ISNT. BOTH NICE AND MEAN CONSTRUCTIVE CRITICISM IS WELCOME

Topic by superbestknex    |  last reply


how many yellow cons are in knex heavy cannon? Answered

Yeh its alot but ill sub and 5* all ibles (if not all ready done)

Question by knexsuperbuilderfreak    |  last reply


Knex Heavy Cannon v5 - Handheld (TGKT entery)

This is going to be by entry for the TGKT. It is alike my other cannons in many ways. A few things to point out... Fires same ammo as the Micro No wheels or stand, a handle on top makes it handheld True trigger Very Piece efficient Fires about 70 feet Easy to load Cool looking (I guess thats subjective, so whatever) Thats it! I hope you like it. EDIT: Posted!

Topic by I_am_Canadian    |  last reply


Who's Cannon Rules----------I_AM_CANADIAN's heavy cannon rules!!

Its official, and i accept my defeat, IAC's was rated better and more people prefer it. How will it compare to my newest instructable, my HIGH POWER CROSSBOW. Whose cannon is better, My Light Cannon V2.2, or I_AM_CANADIAN's Heavy cannon V5. They are both special in their own ways. His is more powerful and flies 80 feet. It loads in over 30 seconds. Mine is a little less powerful but flies almost 150 feet. Mine loads in under 15 seconds. Also, Mine uses 8 rubber bands and his uses 16. Here is the puncturing using the same front on the ammo. Try to build them before you decide. WHOSE IS BETTER. Note-I did not fake these pictures. Try them yourself and the results will be the same. I am not trying to start a fight I just want to see whose you think is better. Note. The Video was shot with IAC's V5 and my V2.3. I just built V3.0 but did not post it yet.

Topic by Electroinnovation    |  last reply


Which is better, Knex Heavy Crossbow or Tank Bow? Answered

I really want to build one of them, but I don't know which is better. Can someone give me the stats, or pros/cons, or piece list or both of them?

Question by Pizzapie500    |  last reply


Can't Find my Instructable after heavy searching

Hello, I made a recent instuctable(photo) and after heavy searching I can't find it in "Explore". Please Help. The link for the instructable is https://www.instructables.com/id/Batch-Game-Noughts-and-Crosses-using-a-save-folder/ Please help me. Than you in advance. p.s. I've looked at other similar questions in the forums, but none of them work for me [ : ( ]

Topic by Monacraft    |  last reply


heavy duty snap source for making leather bracelets?

Hi,   Have been looking at the tutorials for making leather bracelets.  Purchased a snap setter from a craft store but the snaps aren't deep enough.  The leather is too thick for the snaps, it barely gets through the leather.   There's no way it could make the connection to attach the snaps to the leather.  The leather I'm using is about 1/8" or 3mm thick; about the thickness of a belt.  Suggestions for sources? Thanks!

Question by justkim    |  last reply


The K'nexecutioner - Perfect Duck's premiere super-heavy gatling.

Here for the topic on Moloro0's forum.

Topic by Perfect Duck    |  last reply


WHAT'S A BETTER WAY TO MOVE SUCH A HEAVY ITEM UPSTAIRS?

Isn't moving a ~300 lb refrigerator up flights of such stairs very DANGEROUS? .. I know of catastrophic resulting injuries.. I'm thinking of a few design improvements; and wonder if others are too.. Besides the obvious (pictured) need to add good ratchet straps, and a larger dolly, my designs range from better muscular force use, to mechanization....  Also,  can anyone please inform here about gripping, one-way, or ratcheting pulleys?.. Thanks good thinkers.

Question by micit2    |  last reply


Can heavy duty plastic be sealed to make an inflatable object? Answered

I'm interested in making bumpers for a super long slip and slide.

Question by BoondockSaint    |  last reply


SRV-2, Sipriani Rifle, Heavy Cannon, Vivisector, or what?

I actually got kind of bored. I don't have enough time to make all the guns that I want to make, so I want you guys to choose one for me. Choices are SRV-2, Sipriani Rifle v3, Heavy Cannon v1, vivisector,or you can decide. I have enough pieces to make almost anything on instructables. Oh and BTW I forgot to mention before that I want to make a gun w/o broken pieces! But you can tell me any gun that has broken pieces because I might have them. (Just remember to tell me what kind of broken pieces is needed). Thanks!

Question by Pizzapie500    |  last reply


reusing scanner lamp w/o heavy duty adapter?

I've been trying to do something similar to these https://www.instructables.com/id/Scanner-Parts---Desk-Lamp/https://www.instructables.com/id/Recycled-Scanner-Hack!/I want the lamp to work without a heavy duty ac to dc adapter, but it looks like there's no practical power cord that has low enough voltage. I've tried using a basic voltage converter ( http://www.amazon.com/VX-79NP-MULTI-PURPOSE-CONVERTER-MULTIPLE/dp/B0014JUGTQ/ref=sr_1_20?ie=UTF8&s;=electronics&qid;=1209273618&sr;=1-20 ) set at 12 volts, but the bulbs don't light.Does anyone know if there's a way to do this without the giant adapter, or if there's a way to light the bulbs using a USB connection? I've looked online, and the only thing I've seen is this: http://www.danielandrade.net/2005/12/27/howto-using-the-scanner-light-inside-your-computer/ but they're using a male molex connection. I'm just looking for a plug that's a little more practical: an electrical outlet being my first choice, a usb port being my second.Thanks!

Topic by seebrown    |  last reply


Seeking engineering advice on mounting heavy weight in concrete ceiling

Hi all, I am designing/building a prop ceiling-mounted surgical arm (see reference photos attached) into a 15" concrete slab ceiling for a hospital room set for a tv show. I'm also attaching two sketches of the two different arms I plan on making and I'm hoping some of you clever engineering-types may be able to identify flaws in my schematics before I go too far with the design. If you see something that could pose a danger to the actors or have and alternative suggestion I would be grateful!!! Here are my concerns: 1) what are acceptable stresses on all joints due to weight distribution and actors moving the parts around? 2) the heavy duty industrial casters that tapcon into the ceiling: would they get pried apart as weight is applied gravitationally? 3) can the concrete ceiling handle the live stresses of actors moving the arms? 4) can the horizontal PVC arms handle the weight or do they require a welded metal skeleton? --------------------------------------------------------------------------------------------------------------------- Any feedback would be greatly appreciated; I'm in my research phase of this build now so please let me know your thoughts!!! Thanks, Damian

Question by damianzuch    |  last reply


The Map of Metal (music)

I forget whether I'll actually get this to post, but here goes: Takes a while to load but is worth it. http://mapofmetal.com/#/home

Topic by lemonie    |  last reply


leg and arm weights

Will someone write up the plans for a HEAVY-DUTY ankle and wrist weight. I have been searching online for a company that will make custom weighted wrist and ankle weights but there aren't any. I'm wanting to make a 50 lb for the arms and 100 lb for the legs. I'm thinking along the lines of several iron or lead bars strapped together with a nylon fiber or other strong material. I've only ever done projects in high-school, where materials were provided, so I don't really know where to get the materials needed. Please help.

Topic by dhill16    |  last reply


Names for K'nex guns

Hey, I've decided to name my weapons, like the heavy does in TF2. They are as follows (and they will NOT work without the Russian accent):Storm 220 V1 = SaschaStorm 221 V1 = GertieStorm 222 V1 = UrsulaStorm 223 V1 = BerthaStorm 220 V2 = NataschaStorm 221 V2 = RosmertaStorm 222 V2 = Nikita(postage after we've moved house) TJ-ASTR V1 = LucyJamassault pistol = HannahTJ-SR-V4 = BarberaStorm 22 Pistol = NathaliaI'll be referring to them by name from now on, so you better learn these!

Topic by The Jamalam    |  last reply


What combinations of ammo go the furthest and with how heavy a firing pin?

What combination of Ross go furthest e.g. Oodammo, Oodammo with a blue rod instead of white, Oodammo with a yellow rod etc. and which pure knex ammo goes the furthest.  I would also like to know how heavy a firing pin I should use for different sizes of ammo e.g. Should a red rod have a heavier pin to fire it further? Or should all ammos have the 'standard pin' (black rod with tan clip and orange connecter all taped up)?

Question by I.E.    |  last reply


NEW GRENADE LAUNCHER: H.S.S.P. V3 (Heavy Support Splodie Pistol)

Hello everyone, I yesterday builded this modification of the HSSR, the advantages: - smaller - easier to load and cock - more reliable (less barrel, so less drag) - easier to build disadvantages: - looks less cool (my opinion:P) - less accuracy So I think this gun is better than the rifle version, but also check it (It's an instructable). grtz Infinnion, EXTRA: you can add some grey connectors to the side of the gun to hold splodies. WARNING: I'm not responsible for any damage to urself, your house, your cat. So plz dont shoot at animals or people (or expensive windows:P:P:P).

Topic by Infinnion    |  last reply


According to physics, does driving with a heavy load increase traction in winter?

Many Canadians enjoy adding weight to their vehicles over the winter to increase traction. How does it work? Since friction is force normal times mu, thus having a greater force normal means more friction. However since mu is usually so small, the increase in friction is negligible as compared to momentum. The momentum from added weight, mass times velocity would be dramatically increases, meaning longer distances to stop and easier fish tails around corners. Therefore less weight is more benficial. This is my logic, and I may be wrong. I don't know, thats why I'm asking...

Question by VentingIntrovert    |  last reply


Help with a design for a totally bruttle key ring for a heavy metal fan.?

I just got a new car but the keys didn't come with a key ring. Now, since I am a metal fan I was looking for a keyring that was totally bruttle and cool. Currerntly I can't think of any cool ideas so can anyone help me out? One idea I had was to conceal a taser, that I will be custom making, and possibly a usb flash drive inside. Only issue is that it needs to be light enough as to not damage the key barrel and stearing column. Thanks in advance.

Question by one_fake_user    |  last reply



(newsletter) Cylon Teddy Bear, Heavy Duty Alarm Clock, Media Projector

Cylon Teddy Bear Heavy Sleeper Alarm Clock Simple Media Projector Fingerless Glove Mittens Entwined Aluminum Hearts Funny Personalized Notepad Fold a T-shirt Quickly Make a Companion Cube Create Your Own Keypad Guides Laptop Stands Plastic Bags Fun Science Green Jewelry Instructables.com - 82 2nd St. - San Francisco, CA

Topic by fungus amungus  


Do you think this structure will be able to support a 100kg+ (220lbs+) heavy bag? Answered

I want to hang a 180cm (6ft) 100kg+ heavy bag from this structure in my backyard for Muay Thai (kickboxing).  It's made of hollow steel beams which are set in concrete and welding together at the center.  I know that it can support the weight (My brother and I used a ladder to hang off the center beam, together we're 130kg+) but I'm unsure of whether movement from the bag will be an issue. Thoughts?

Question by YiChen    |  last reply


How can I hang something heavy from the underside of my desk? Answered

I have a sit/stand desk and I would like to screw down or attach everything to the desk I can so that it doesnt move or slide. I have a heavy (20lb) UPS and a small RAID array that currently sit on top of my desk. I would like to hang them from the bottom of the desk instead. I thought of a few ways to do this but I want to KISS and do it good enough.  The two main ways I came up with was to create a simple 4-sided rectangle shelf and screw it to the underside of the desk and slide the heavy stuff into it, one on each side like saddle bags on a bike or motorcycle. Alternately they could slide into place using some kind of track of french cleat though I have not found anything suitable to do that.  The quick and easy was was to use "plumbers tape" which is basically thin steel strips with holes in it, to quickly create a U bracket to attach the items to the bottom of the desk.  Here is a mockup of my desk showing the shelf idea. Ideally I would like these to be removable so that I can disassemble and reassemble the desk easily in the future. So if anyone has an idea or knows of a bracket or sliding rail system that would work that would be awesome!

Question by pcmofo    |  last reply


how can I make a removable mural using heavy MDF shapes?

Hi there, I'm trying to make a mural for our school, using MDF shapes that will be painted by the children. The mural needs to be removable for when the wall needs repainting. Somebody suggested adhesive magnets, because they show no marks. Are they strong enough to hold pieces that are around 1,80m high and weigh over 6 kilos? I was hoping to use 1 or 2 screws on the bigger pieces, just in case they slide. Anyone has some experience on this? Any other ideas for holding these pieces on to the wall?

Question    |  last reply



how can I make a removable mural with heavy MDF shapes, using magnets?

Hi there, I'm trying to make a mural for our school, using MDF shapes that will be painted by the children. The mural needs to be removable for when the wall needs repainting. Somebody suggested adhesive magnets. Are they strong enough to hold pieces that are around 1,80m high and weigh over 6 kilos? I was hoping to use 1 or 2 screws on the bigger pieces, just in case they slide. Anyone has some experience on this?

Question    |  last reply


Can i increase my carrying capacity if i install heavy duty coils?

I have a 2002 Toyota Sequoia and it has coil springs all the way around. I was wondering if i merely installed some variable rate coil springs (so it still isn't like driving a rock) that have a heavier weight rating if i could load my SUV heavier. On vacation I carry 4 people, their luggage, and a small 14 foot pop-up camper. I'm using a weight equalizer hitch, and as it stands, i am maxed on the back axle and could carry 200 lbs more on the front. If i installed heavier suspension, can i expect my axle and chassis to be able to handle the extra weight? and how much more?

Question by red9er    |  last reply


Heavy duty UHF CB radio antennas and why cheap can be much better....

If you not a fan of normal road cars then you might get some 4WD and go off road every now and then.There are even those doing trips to remote locations that take a few weeks.An essential piece of equippment these days is a UHF radio.In a convoy you might get away with a handheld one if the cars are not too far apart and the terrain suitable.Most peole however opt for a permanent installation in the dash or roof console.After that decision comes the hardest and often costly part: What antenna to use....If you trust certain online reviews and manufacturer claims then one thing becomes quickly obvious.If you need a sturdy and powerful antenna then you have to pay top dollar.Some come with heavy spring bases claiming to protect the heavy fibreglass rod if you hit a bush or trees branch.There is always a compromise between weight and stability.And trust me, on the right corrugations you prefer not to look at your antenna....So how are these expensive antennas made?As I don't have any own pictures and don't want to steal them from the net: Please search for the terms used if you don't know them already.To answer this let me go to the other types of antennas you can get for your UHF radio.There is the famous rubber ducky - a stubby antenna best suited for short range on difficult terrian.Then we have the fibreglass whip antennas that have more or less coils integrated or even consist of one single coil with different spacings in sections.Good for normal road use, not so much off road as they won't tolerate too much vibration, they often snap off the base screw.Most people now just ignore the short whip antennas of 15 to 30cm length as they usually only come with a gain of around 4.5-6db.I will explain later why that might be a misconception.The last ones are those steel whips with one or two "loading" coils.These coils electrically shorten the antenna.They also provide a matching to the 50 Ohm required for most transmitters and antenna cables.Usually they are designed to be 5/8 Lambda antennas.A good antenna for just receiving, like when using a scanner is not critical in length.Transmitting however means you need a proper Standing Wave Reflection or SWR ratio.For this the antenna needs to be tuned.To be of any good use your antenna needs to match the transmitting frequency.This works best if the antenna length is at 1/2, 1/4 or 5/8 of the corresponging frequencies wavelength.Also called Lambda if you look for antennas.In the good old 27-MHz days we were used to quite long antennas in our backyard, for the car we then opted for 1/4 of this - usually around 2m in length.For UHF however 1/4 wavelength already means you are down to about 16cm...Going for 1/2 is a good thing here as it is still quite short at about 34cm.Real difference when it comes to these Lambda factors is the radion angle produced.You can imagine a 1/4 to look like a huge donut with no hole, about 25° for the radiation angle.At 1/2 this will be flattened out to around 20°.A 5/8 Lambda ntenna can get as low as 16°.Imagine it like a flashligh that has adjustable focus.The light source is of fixed output as your transmitter.The lens does the job of the antenna.If you make the beam more narrow then the light intensity of a certain areas at a certain distance will increase.Means for the radio you get a longer distance your signal can travel with enough energy.This however comes at a price!Imagine you are at the bottom of quite stepp mountain and your mate is up on the top about 2km above you.A high gain antenna with a narrow radion pattern might not even reach up there, while a short stubbie with just 3db still has a chance due to the more spherical radiation.Also explain why low gain and with that short antennas work best in hilly terrain...Back to the thick ones...As you can see you can basically hide any type of whip antenna into a fibreglass rod.But most of the are as said "ground independent", means unlike your normal whip they don't need the spring or foot to be of low resistance to your car's body.How does that work?Well, exactly like these ground independent whip antennas with a spring base or metal pole base work.You know the earliest antenna was a dipol - look it up on Wiki ;)For our CB radios that means you have a metal rod or spring that is about 1/4 or in some cases 1/4 of the wavelenght long.This is connected to the shielding of the coax cable and provides the required ground for the mounted antenna.The big difference is that only too often a dirt cheap dipol is hiding in your expensive fibreglass rod ;)The complete antenna might bring over 2kg on a scale, but the actual thing allowing you to receive and transmit is a few grams of coax cable...HOLD ON A MINUTE!! Some will say now...My whip is 70cm long and my expensive heavy duty one with 9db is 2m long - how does that work with your wavelength theory??Well, it is not my theory, just a fact ;)Imagine a 1/4 Lambda dipol, then it would be all up around 35cm long.And funny enough, that is about the length of a $180 heavy duty stubby if you just tak the rod itself.Go 1/2 of Lambda and you get an overall length of the dipol of around 65cm - add the metal rod making the crew that holds the fibreglass rod and you have the common 70-75cm heavy duty antenna...Anything above this length usually is either just a long rod with noting above the 75cm mark or simple has the 75cm long dipol made from the coax cable at the top with the antenna cable going down the otherwise empty rod.Ok, I got it, either 1/2 of the wavelength or 1/4, so about 35 or 16cm long.Ground independent we add either 1/4 for the spring base and rod or 1/2 for the longer ones.And how again does it work with the gain of an antenna?If you trust Wiki then it comes down to the radiation pattern.These heavy duty antennas usually come with around 6 or 9db, the short ones with 3-4.5db.These values might give you an indication about the theoretically possible distance you can transmit but nothing about the terrain it is suited for.Common rules of thumb created by those selling antennas and radios is that you a high gain antenna on flat terrain and a low gain antenna in a hilly area.Around 4.5-6db seems to be the golden ratio here as these anteannas are equally bad for both extremes in terms of terrain options.What you really would need to know is the actual radiation patterns in a three dimensional plane.A straight whip or dipol as a more or less donut shapead radiation pattern.However, location affects this!Mounted in the middle of the roof it is closest to perfect, while at the corner of your bumper bar you will distord the donut and also block parts out with the body of your car.This is why for this type of mounting elevated antennas are prefered.Makes no sense to have a 16cm long stubbie mounted so the top is still lower than your bonnet...Any antenna with a loading coil (or several) or top load will have a distinctively different pattern.We speak of so called "lobes".If you see it in 2D then for example a 1/2 lambda straight whip will look a bit like the infinity symbol.A 1/4 Lambda of the same style looks more like two ping pong bats joined without the handles.Those with loading coils or linear arrays made from coax cable however can produce multiple, prefered lobes.Usually they are in the 4-6db range and claim to be "universal" or as "allrounder".Here you get a quite narrow main lobe of 12-16° with one or more but much shorter lobes going upwards at about 10-30° depending on the configuration.At short range, like in hilly terrain both lobes overlap while you get a dead area at greater distances.You can sometimes notice that when you are on a low level talking to someone up high.There are cases when with a bit more difference in angle to each other (in terms of height and distance) the signal jumps up a few numbers.You just went from the dead zone into the lobe ;)With just a db value for the anteanna but no details about the actual design, heavy duty antennas can fool you badly.In mayn cases a 1/2 Lambda straight whip on the roof will outperform a costly, heavy duty antenna mounted to your bullbar.This is the reason why the expensive ones are the biggest cheat - they just elevate a quite small antenna above your roof line.And since it is heavy it needs a big spring and you hope it will not break if you hit something on a narrow track.All while the thin stainless stell whip with the cheap magnetic base just flexes under all obstacles with no damage at all.Plus, if you really get into the thick jungle you can just take the magnet off until you are through LOLWhy is a SWR and power meter still an important tool to invest into?Those remembering or still using 27-MHz radios only know too well why you need a proper SWR and power meter.With the lenght of the antenna at these low frequencies and affecting factors new the antenna proper tuning is a must.The bandwidth of the channels also means you have to tune the lowest and highest channel so the are basically even, anything else and the old guys would scream "UNACCEPTABLE!" ;)Especially it you want to get the last out of your system without going illegal.For some reason we accepted the claims that an SWR reading of around 1:2 is fine and acceptable.Most of the radios lower the power output to protect the transmitter if the SWR goes to far out.Allows for simple mass production of antennas with fixed cable lengths that are usually well overpriced.The most expensive bit is the cable itself here...I had no time to build an analog SWR and pwoer meter that works properly on 27 and 470MHz, so I ordered cheap SW30 from China.With that I first checked my little collection of antennas then those of some of my friends.This includes everything from short rubber duckies over loaded and straight whips to heavy duty models.One thing that was obvious right away: most are far away from an SWR readin anyone with a 27MHz groundplane antenna on a long mast would accept.And only one heavy duty antenna had a SWR readin of below 1:1.6 for channel 1 AND channel 40!That one was relatively cheap noname brand.With that sorted I decided to tune at least my steel whip antennas.To my utter disappointment they were all just a tiny bit too short - a thing that would have caused a proper 27MHz antenna manufacturer to to keep a large stockpile of his antennas...I had one though that was longer than needed.And before you ask: Yes, I tested them on both my elevated bullbar mount AND a direct mount on the roof rack.Did not change much for the bad ones so I ignored the mounting position for the tuning.I checked the power once for both channels on my prefered antenna and got 4.4W.Mind you that one has a SWR reading of 1:2.2 and will no longer be used as I can't be bothered to make it longer.For some reason I thought I check the SWR and power everytime I cut a bit off the antenna instead of just watching the SWR reading.At original length I had a SWR of 1:1.9 on ch40 and 1:1.75 on ch1 with 4.6W.I kept trimming down by about 2mm increments until I got an even readin of 1:1.07 on both channels.And with every trim the power went up a little bit.I have a friend that is or better, was just at the brink of being unable to reach from my driveway when he is parked in front of his house.A radio check after the tuning revealed that instead of coming with a lot of static noise and sometimes cut out I got a solid reading of 2 on his end with a much more acceptable level of noise.However, I still struggles as badly to hear him...Funny thing is that test was with just a plain and straight whip of 1/2 Lambda, in my case the tuning resulted in a length of 38cm from the base of antenna screw to the tip.My fancy 9db high gain antenna that is just over 70cm long did not even reach him while I could hear him slightly better than on my tuned one.Changing the mounting to the roof rack gave me a clear reception and a signal strength of 4 at my friends end with no noise.Elevation and nothing around the antenna does matter...After all this, would I still bother to buy a ready to go antenna for 470MHz?Only if I had to.Getting some RG58 cable or re-using it from on old antenna is cheap enough.A standard screw mount with a grub screw to hold a steel whip sets you back less than 10 bucks, from China even cheaper.And most will find a soldered on connector on the other end of an old antenna to be salvaged if required.If you don't have any sring steel wire of about 40cm length then think out of the box ;)The packing of pillows and such often come with a sring steel wire to make the plasitc floil keep its shape, some old suitaces have thicker wire doing the same.And if you ask nicely you might get a bristle or two for free from a street sweeping machine at your councils depot ;)After all we only need a maximum of 40cm to have enough left to trim and tune down.What is left to do?Of course some distance tests to check how well such a simple antenna really really works in comparison to commercial models.I only have one 9db antenna and will check it first to see if on flat terrain there is much difference in distance for transmitting.Unless this difference is well above one kilometer I will not bother with a high gain antenna like this anymore and instead opt for a longer mast and 1/2 Lambda.Another thing on the to do list to try a ground plane antenna with topload to squeeze the radion lobe down to under 15°.The resulting antenna would be quite short here and using an elevated mast is a must have to get over roof level with at leat a few wavelengths of distance to the roof.I guesstimate that an optimised antenna of this style should result in a distance increase of about 10-15km of flat terrain while being utterly useless in a hilly areas.Plus, such a design is not really suited for a vehicle going fast on a freeway, so it will go on my house instead.

Topic by Downunder35m  


Wanted: 8"-10" STRONG Lazy-Susan type bearing

Hello Community! I'm in need of a strong/heavy-duty Lazy Susan-type bearing.  Looking for about 8" - 10", and a bearing capable of handling 100 - 150 lbs.  Smooth movement is a requirement.  If you have one in your junk pile that's not being used, let me know!   Thanks! huck

Topic by huck alexander    |  last reply