Hayden. Anything that is stainless steel, no matter if it is 316 or 308 grade needs anti-seize paste (Res-Q-Steel) applied to any threads or parts that may seize up. Stainless steel is one of them metals that once moisture migrates into the threads, they have a tendency to seize and can't be undone. As long as you get hot-dipped galvanised hardware and use anti-seize paste on all of your fasteners, it should be all good. We look after 2 repeaters here on top of Mount Hutt and we had numerous issues with corrosion of U-bolts and the like, we upgraded everything to 316 stainless and we've not had a problem since.
Wow, never in my wildest dreams would I have thought a bit of rust on polls or chains would cause RF issues. Very much opened my eyes and mind, thank you.
Very interesting video Hayden. The rust issue's were something I have often thought about, and they will effect more than just a VHF repeater setup. I remember back in the 1980's in my CB days, taking my Megatron 27MHZ vertical down and changing the bolts when they rusted, I dropped my static noise floor by a good two S points just doing this simple maintenance, and the intermittent wind crackling was solved completely. I understand it's slightly more difficult on a tower with multiple antenna's mounted to it, but the result is the same. Any metal to metal contact that can move even slightly will introduce a level of noise in the RF at some point. Silicon, rubber grommets, liquid electrical tape, etc. can be life saving material...
Good tips on repeater specific issues Hayden. About your indoor lightning protection, the green/yellow ground wires will work for static discharge but poorly for lightning. Those bends are inductive to lightning's high frequency components and thus not the low Z you want. Dead straight is the way to go. Wide copper strap even better.
It sounds stupid, but it is a very practicable and important video. Thanks so much again Hayden for all your effort you put into Ham Radio DX channel and HAM. HAM radio is fun :-). Anyone else going to Shepp ham radio fest????
If you stop using the good stuff and use cheap chinesium nuts and bolts instead you won't have this loose hardware problem. They'll rust solid within a year or two. Guaranteed not to come off. 😁
You missed probably the No 1 issue. Plastic cable ties used to dress the feed line. UV rated or not they will all eventually fail allowing the feeder to flap in the wind leading to fatigue breakages. Commercially available coax standoffs are available for tower attachment. Use stainless steel ties for general usage. Clamp on earthing systems for LDF are much cheaper than surge protectors and you further save on minimising the need for coax connectors.
I am a retired auto mechanic. Avoiding nuts that back off. That is the easiest thing in the world. "Thread lock". There are two kinds of thread lock. Permanent (don't use this one) and "removable". The removable kind is BLUE. The permanent kind comes in a red bottle. Use the blue stuff. The reason those nuts back off is because of heating and cooling over and over again. The thread lock acts like glue to prevent movement UNTIL YOU WANT IT TO. That simple things seems to be the solution to most of your issues here.
Nice job. Not only wind can loosen bolts and nuts. temptura change can also loosen up hardware. I use lots of nylock nuts. I keep assortments of all sizes on hand. Both SAE and Metric on hand. Also Blue Lock tight sometimes the Red I use. Lots of bonding of grounds . very heavy copper wire running around to keep everything at same potential. Lots of filtering on mains and surge protection as well. We had complaints from a nearby fence from MW (AM station) doing strange things . hearing the station in fence gate and sparks at night. Was like 3 blocks away . metal fence. Turned out rusty hardware caused it. The welding shop down the road sometimes herd station when welding . Also hurd AM station in old fluorescent 8FT lamps when realcold . Changing lamps fixed that . RF can do strange things. 73
Yes tower (metal to metal) contact is a major problems with repeaters often not understood. Way back looking for such on a large tower we fed a weak signal into the repeater's receiver and with H/H in the pocket climbed the tower listening to the repeater's. output. I had some coins in my pocket and would you believe the rubbing of the coins together in my pocket produced crackle noise. Will VK6UU
Hi Will, Yes that doesn't surprise me! All you need to do is rub the shafts of two screwdrivers together near the antenna and you can hear the crackle! I have some PIM hunting to do over the next short while.
propagation antenna then coax ...at the last set...no one I know...hears the difference between an icom yeasu or an oldie a alinco dx 77, my first love but this is my opinion...and who am I...
I have to chuckle whenever I hear "oldie" and "Alinco" used together. I remember when they pushed into the US market around 1990; they were the Baofeng of their day. My first dual band mobile was a DR-510T; I used it mobile until the display backlight died (a common failure mode on these radios), and then it became a dedicated packet rig. (I was first licensed in 1981. Yeah, I'm a old fart.) Fortunately, Alinco stepped up their game over the years, and is now every bit as good as the Other Three.
I have been a HAM for three years, just now realizing that I've had mismeasured antennas this whole time! Now that I'm building newer antennas, these are very good tips!!!
I'm curious as to how your incorrect calculated cut lengths came about. I'm a ham instructor and your experience could be useful to the teaching process.
Excellent video Hayden. I'm sure glad I don't have to deal with snow at my repeater sites, but we sure do get a LOT of wind at times, right off the Southern Ocean. I agree that folded dipoles are the way to go in most situations. Simple and grounded design, not a lot to go wrong with them. My 2m FM repeater does use an RF Industries COL3 collinear antenna which has been giving stellar performance for over 15 years. On the same tower I use RF Industries folded dipoles on 70cm, 2m APRS and a spare that was used for 2m packet radio (now a spare, just in case). All fed with Heliax. Not cheap, but money well spent.
Thanks Michael! The snow is just starting to melt, so should be able to get back up there soon. I've had a COL7? I think which is the UHF version of a COL3 installed on another site and I agree it's performed very well. The large radomes are a must. Thanks again, your repeater videos from years ago inspired me with a lot of stuff! Cheers
Sound advice in here, as for collinears, real cols do work great and can withstand cyclonic winds and last decades, however there is a huge difference between a AU100 dollar diamond antenna, and, say, an RFI col that costs 10-15 times that :) (yep, you do get what you pay for). Not sure I'd have used an insulated nylon mounting for any antenna, most commercial antennas use DC grounding for lightning protection, but again, I doubt a 100 dollar job from any manufacturer - diamond, comet, whoever, is going to have that, might surprise us, but, I'm thinking nah. One other thing, lightning should be kept out of the shack, those terminations to protectors ought be outside (I'm sure polyphaser even say that in some of their literature), if that TV tower next to you has a star point lightning rod, you might be protected by the accidental arch (45deg theory) from a direct strike or even static bleed off. (Whilst on those diamonds, I know of folks using them in repeaters for many years, they loctite/superglue the grub screws, one even fills it with superglue and uses a strip of marine grade heatshrink over it to make damn sure it doesnt move.)
Lubricating stainless steel nuts/bolts can help reduce the galling (binding) you have noticed. For a good electrical connection across the joint, I'd recommend a dialectric compound such as is used to install automobile spark plugs.
Nice video Hayden… Exactly agree on all this stuff… Folded Dipole all the way… Simple and Solid… In fact on many sites we actually have our lightning arresters outside in a wall-box, to not have the lightning enter the building at all.
Thanks mate. We're lucky to not have much lightning here, plus have a 200 foot lightning rod next to our antenna! The arrestors are mainly for surge protection. Since installing repeater systems I've never had any lightning damage - touchwood!
