Like you said Steve, they're everywhere, and they're still considered
acceptable even in aviation. Critical locations though will use better
locking hardware.

I wouldn't want to rely on split ring washers on anything mounted at
the top of the tower where it cannot be easily periodically inspected.
Now that I think of it I should have used drilled head bolts and
lockwire on the bolts that secure my Hy-Gain Ham IV rotator. Not many
amateurs that I've met lockwire hardware.

Ron VE8RT

On Sun, 02 Jan 2022 08:06:40 -0800
"Steven Greenfield AE7HD via groups.io"
<alienrelics@...> wrote:

--
Ron VE8RT <ve8rt@...>

Lots of info.. bit ott..its a wellbrock on a mast..

Blue locktight, plus nylock locking nut against a plain washer..job done..( on just about anything on land.) only thing that can be an issue is too much of above, (if not using stainless bolts and nuts) that the head is not “ get atable” ie “ bugger” the bolt in a plastic housing is spinning, never tighten or loosen them now.. and we do all use stainless for non safety/stess related stuff ie wellbrock to mast outside in all weather conditions don’t we.

Ok not for an aircraft of spacecraft..or submarine etc..

Simon

You could use a jam nut that way but you risk moving both nuts
together and have little or no locking. When applying a jam
nut you use both hands and two wrenches. The procedure and detailed
explanation are here:

Using a jam nut is also a good way of removing or installing studs.
There is a lot of information online about this.

You may already have everything you need to do this on hand.

Ron VE8RT

On Sun, 2 Jan 2022 08:04:52 -0800
"Dick Bingham" <dick.bingham@...> wrote:

Greetings

Once you tighten things up, how about running another nut against the nut holding everything in place. Tighten it it so it jams against the original nut.

Dick/W7wkr. CN97uj

--
Ron VE8RT <ve8rt@...>

--
Ron VE8RT <ve8rt@...>

I posted on StackExchange about split-ring lockwashers, including a link to the NASA Fastener Design Manual.

https://diy.stackexchange.com/a/242093/129807

--
Steve Greenfield AE7HD

Thanks Steve

I've snipped out most of this to get to one point of interest:


On Sun, 02 Jan 2022 07:47:00 -0800
"Steven Greenfield AE7HD via groups.io"
<alienrelics@...> wrote:

If, =if= you use another method to lock the parts in place, for
instance the fiber locking nuts Ron mentions, a split ring washer can
act like a spring and keep things a little more snug if the parts
become loose, but temperature change or a stretched bolt is the only
reasonable situation I can picture that being an issue.

Thermal cycling is not mentioned on the wikipedia site
but I thought that
thermal cycling may have been the reason that Belleville washers were
used on the link hardware of aircraft Nickel Cadmium batteries.

Ron VE8RT

--
Ron VE8RT <ve8rt@...>

Greetings

Once you tighten things up, how about running another nut against the nut holding everything in place. Tighten it it so it jams against the original nut.

Dick/W7wkr. CN97uj

Hi,

I understand that :-) yesterday around this time it was -42 C with
a wind chill of -54 C. Other than going out to take a few photos and
to clear the build up of ice on the furnace and water heater exhausts,
I wasn't up to any other work. Its warmed up today, currently we're at
-31 C with snow, with an overnight forecast low of -41C

With the alternatives I've listed you do not rely on compressing a
lock washer, reducing the risk of crushing what you've mounted, and
where there may be allowance for thermal expansion and contration (+30C
extreme max in summer to -45C extreme minimum in winter).

Ron VE8RT

On Sun, 02 Jan 2022 07:23:56 -0800
"Oyster Town (G0IFS) via groups.io"
<nigel_clayton@...> wrote:

--
Ron VE8RT <ve8rt@...>

Did everyone notice that the one thing Ron did not mention was split-ring "lock" washers?

That's because they are worse than no lock washer at all when it comes to being the only thing used to prevent loosening.

From a NASA study:
“The? typical? helical? spring? washer? …serves as? a? spring? while? the? bolt? is? being? tightened.? However,? the? washer? is? normally? flat? by? the? time? the? bolt? is? fully? torqued.? ?At? this? time? it? is equivalent? to? a? solid? flat? washer,? and? its? locking? ability? is? nonexistent.? ?In? summary,? a lockwasher? of? this? type? is? useless? for? locking.”

I've gotten in arguments with engineers over this, and sadly they continue to be used where they serve no purpose.

If, =if= you use another method to lock the parts in place, for instance the fiber locking nuts Ron mentions, a split ring washer can act like a spring and keep things a little more snug if the parts become loose, but temperature change or a stretched bolt is the only reasonable situation I can picture that being an issue. Everything I work on has a split ring washer on top of a regular washer, and blue Loctite on the threads. In that case, they are there purely to prevent the device from vibrating excessively due to temperature caused temporary loosening. The fact that every single commercial product I've seen has the lock washer on top of a regular washer proves that it is NOT providing a locking function by digging into the surface.

Absent any other method to lock the parts in place, split-ring lockwashers can actually hasten loosening under vibration and temperature changes. See the graph on the last page in the PDF I linked to below.

Let's see if I can link to the PDF:
http://hillcountryengineering.com/wp-content/uploads/2011/10/Split-Lockwashers-Separating-Myth-from-Truth.pdf

Sadly, there are a lot, a LOT of websites, mechanics, and even mechanical engineers giving out bad advice about split-ring lockwashers.

--
Steve Greenfield AE7HD

Thank you Ron, good suggestions to be employed when the weather calms down!

Thank you Andrew, I feel happier about pulling them up tighter.

Hi,

I work in avionics and deal with vibration related problems. Three
suggestions suggestions wrt to dealing with hardware working loose.

You could keep the plain nut and star washer hardware but use (blue,
as it is removable) locktight on the threads, alternatively replace the
nuts and star washers with fibre lock nuts and flat washers. The
third, and likely most affordable method is to use jam nuts
( ) .There are other ways (pal
nuts but you
may find a good quality fibre lock nut, or nuts to use as jam nuts, in
a local hardware store.

Ron VE8RT

On Sun, 02 Jan 2022 05:10:22 -0800
"Oyster Town (G0IFS) via groups.io"
<nigel_clayton@...> wrote:

--
Ron VE8RT <ve8rt@...>

开云体育

EZNEC runs just fine using Wine on my Linux Mint machine too.

Gazing up at my Wellbrook ALA 1530 loop which has served me well as one of my receive solutions I noticed a slight tilt from the vertical. On further examination I found that the clamps that secure the mounting spigot to the TV type rotator had loosened (even with star washers). In addition the two long screws that secure the amplifier and loop to the mounting flange were also loose. I am reluctant to pull those screws up very tight as they go through the plastic housing and may damage it it some way.

It may be worth checking your own installation, I can only assume vibration from the strong winds here on the Kent coast have caused this problem. I always turn the loop to reduce action of prevailing winds.

I built the amplifier referenced in the Australian document.

Be aware that the output is not temperature compensated. In northern climates the output transistor bias will drift far enough to cause major IMD.? Mine had decent performance until the temperature outside dropped below about -5 to -10C (basically all winter in Canada), at which point it would have harmonic and intermodulation products across the whole LW-SW spectrum from my local MW flamethrowers.? The author obviously only tested it in a warm climate.
Tom

On Sat, Jan 1, 2022 at 08:00 PM, Jeff Green wrote:

MAXIMUM loss that you can have due to this mismatch (an SWR of 1.5:1) is 0.18 dB for ANY length of cable! These equations are also displayed in the Handbook as graphs."

I'm not sure that I entirely agree with that figure, but it does highlight a difference between a transmission system, where the transmitter is the signal source and the antenna is the load, and a reception system where the antenna is the signal source and the receiver is the load.

As the receiver presents a constant impedance load at the far end of the transmission line, and if the characteristic impedance of the transmission line is similar to that of the load, even though the antenna source impedance may vary considerably, the SWR and line losses are constant and the only variable is the mismatch loss between the antenna and it's connection to the transmission line.

However in a transmission system, the transmitter is a constant impedance source and the antenna becomes the load at the far end of the transmission line. As the antenna load impedance is likely to vary with frequency, this is often not of the same value as the characteristic impedance of the transmission line, so the SWR varies considerably and there are two lots of mismatch losses, one at the interface between the transmitter and transmission line and another at the other end of the transmission line where it connects to the antenna. Plus there are additional lines losses due to the increase in SWR, but these can also partially offset the source to line mismatch loss and reduce the losses across this interface, so things are not quite as bad as they could be.

Regards,

Martin

On Sat, Jan 1, 2022 at 08:00 PM, Jeff Green wrote:

One of my coworkers gave me this link to study, more as "This is how a professional designs a project" then for me to attempt to construct: "A High Performance Active Antenna for the High Frequency Band" at

https://www.dst.defence.gov.au/sites/default/files/publications/documents/DST-Group-TR-3522.pdf

It is a good reference documents as it covers the majority of the design criteria for such an antenna.

Interesting the performance of the final design is pretty close to that of the popular PA0RDT and the slightly better PA3FWM E-Probe antennas, both of which are much simpler circuits.





Regards,

Martin

Historically in the early days of coax, 50 Ohms was preferred for better power handling and 75 Ohms for lower loss.

Over time 50 Ohms became the de-facto standard for transmitters and 75 Ohms for domestic receivers and baseband video distribution.

The technologies were often developed and maintained by independent sets of engineers, possessing contrasting skills and training, which partially explains why this difference has perpetuated to this day.

Regards,

Martin

Hello Simon,

Saturday, January 1, 2022

Who is Mary and will your wife mind, that is what I want to know? ;) Happy New Year. The divorce courts are backlogged so you will have time to hide some of the expensive stuff..... ;)


Best regards,
Chris mailto:chris@...


S> Quote

S> “Whilst I realize there's no such thing as perfection in an imperfect world,”

S> I beg to different..my Wife is allowing me to put up a top band
S> 20m vertical with all its associated stuff, plus all the rx
S> antennas etc at our new location in Cornwall when we move there this year..
S> This makes her perfect..( plus Mary will be helping, though she does not know this yet.)

S> Simon

S>

Quote

“Whilst I realize there's no such thing as perfection in an imperfect world,”

I beg to different..my Wife is allowing me to put up a top band 20m vertical with all its associated stuff, plus all the rx antennas etc at our new location in Cornwall when we move there this year..
This makes her perfect..( plus Mary will be helping, though she does not know this yet.)

Simon