Transmission1

I recently aquired a job-lot of aerials and amongst them was the above aerial. It looks like one I've seen on a Youtube video by someone beginning with 108****.

What I'm after is the length of the short, adjustable stainless whip piece at the tip of it, the bit that slides up and down for SWR'ing in.

I've cut down a bit of spare whip to about 6 inches which slots in lovely, but would like to know exactly what length it's supposed to be, rather than having to find a magmount, stick it on the car, sort out a swr meter etc and find out that long-winded way

So, if anyone happens to have one, could they kindly pop the whip out and measure it for me please? You can put a bit of insulation tape on where it sits inside, so you don't lose your set SWR

Thanks in advance!

SWR is less important antenna parameter.

Picture added. I've found a liitle rubber tip for the whip to stick on once it's at the right length:

Original top whip is only 110mm if this will help....Enjoy

highvoltageuk wrote: ↑16 Apr 2022, 18:04 Original top whip is only 110mm if this will help....Enjoy

That's exactly what I need. I can now cut it to length and fit it properly - thanks

ch25 wrote: ↑14 Apr 2022, 20:58 SWR is less important antenna parameter.

I don't really agree with that. It sets a bad precedent for CB and ham new ops. They should take care of SWR and can
give you a lot of information about antenna problems. If you start off accepting poor SWR it is a slippery slope to
lose dB's.

Take care of it like all other details.

It'll be up for sale on ebay at some point so I just wanted to ensure the tip was as it's supposed to be from new.
I could have just left it longer and let the new owner cut it down to its best SWR, but if I can do it beforehand I might as well Thanks all.

Measuring SWR just says, that antenna impedance is matched to transmitter impedance. So is dummy load, but it doesn't make it good antenna, right?
There are more important, I would say critical parameters making antenna good or bad performer.
Some reading attached.

Rather than dump a statement into a forum with users of differing levels of experience maybe you can qualify you
statement at the time you post so it appears less.. "I know, you don't so there."

Thanks for trawling out the dummy load analogy and assuming we are all dumb. Let's assume people have the awareness
to understand they have an antenna and not a dummy load attached cause they have eyes in their head. In fact it is even highly likey
a commercial antenna, ready made. Ok, a sensible starting point.

Here is some reading material for you.

Often people only have an SWR meter. As such it is the most important data, not least.

Whilst it is trendy in ham circles to pretend SWR is not worth worrying about.. laziness, happy with compromises, pretending to show how relaxed you are.... throw it out there without explanation etc. it is worth putting it into context.

I don't think it benefits a CBer or hams to have the same attitude as it leads onto other "I don't need to worry about that" thoughts. I will assume 97pct of people are using coax for cb and ham in 2022.

Whilst SWR does not represent the efficiency or lack thereof of an antenna system.. as in its radiation resistance, it does give you an indication of if your coax may have a problem or the antenna itself has some connectivity issue or metal is close by, sometimes unseen metal.Maybe the antenna length needs a tweak or something has collapsed or bent, a connector has corroded or centre pin is lost or it is just not quite set up optimally.

Let's say you have a brick wall 5 feet from your antenna with some metal work in it, or a pipe, some metal in a concrete fence post you cannot see. SWR @ 3:1 is going to most likely let you know your antenna is not going to be working very well (pattern will be screwed also)... So actually it can have a value especially for getting an idea if an antenna is working ok or not as a beginner in radio. Maybe a CBer or foundation licence holder. So actually SWR is important.

As a ham maybe you are fine with a 3:1 - sure it won't stop you transmitting with your tuner and some coaxial losses added on top.

But is that the goal, the low bar for which to aim ? Losses are dB's and dB's can matter... very easy to lose and hard to find !

http://www.firestik.com/Tech_Docs/SWRLOSS.htm

So if you are ok with a 3:1 SWR, maybe you are also ok with RG58, and an internal ATU (wrong end for reduced losses) and an antenna which is 2 or 4 x the wavelength with the ridiculously poor pattern it will have on higher bands etc. etc. And maybe you don't mind you antenna a bit lower down to the ground and you protect your output stage running 80w instead of 100W, and you don't mind using a 25mm ferrite in a balun / un un instead of a 60mm one, very thin wire instead of something thicker, cheap PL-259's and so the list goes on.

Before you know your DX gain is knocked back 6dB. To throw signal away that you can do something about seems careless to me.

SWR is something we should all take care of and minimize. I think it is a poor precedent to suggest high SWR is fine. It can lead on to other
precious signal losing bad habits.

InTheClouds wrote: ↑18 Apr 2022, 10:59Let's say you have a brick wall 5 feet from your antenna with some metal work in it, or a pipe, some metal in a concrete fence post you cannot see. SWR @ 3:1 is going to most likely let you know your antenna is not going to be working very well (pattern will be screwed also)...

That is pretty obvious even before placing antenna there.

InTheClouds wrote: ↑18 Apr 2022, 10:59I think it is a poor precedent to suggest high SWR is fine.

Where I said that? I said, that it is least important parameter of the antenna system.
You can have SWR 1:1 100W output, but antenna will radiate 0.1W.

You would be surprised where people put antennas.

You implied SWR is not a primary concern, down the list somewhere compared to I guess resonance or efficiency
..... you might be right but only if the SWR is low on something that would be reasonably be assumed as a sensible wire
antenna of some kind.

"You can have SWR 1:1 100W output, but antenna will radiate 0.1W."

This is very far from any known antenna in common usage. Ok maybe on some 472kHz, who is there ?

Straw man argument IMO. No one uses 50 Ohm resistor as an antenna. No one typically
makes a loading coil and put 3cms of wire as the radiating element.

To present highly unusual antennas is not a legitimate ways of discrediting SWR as a very useful RF measurement.
We should consider this in context of as popular, common DIY or commercially available antennas.... not fantasy land.

SWR is primary, irrelevant of cool trends and internet parroting.

InTheClouds wrote: ↑18 Apr 2022, 13:24You would be surprised where people put antennas.

I know, there is many fans of wiping ass with glass, some keep doing that while others evolve.

...I only asked how long a bit of whip should be?...

Sorry if I've caused an argument

Anyhow, I have the length, a hacksaw and a file so job done. Ta.

We all make mistakes in pursuit of RF based pleasure. I have put antennas on fences of concrete and wondered why the SWR was sky high. A lot of concrete has metal in the middle.

Glad your antenna works The Collector.. it did well in the tests 104 did.(104 not 108!)