Surprised I had missed this one. Very instructive.

@timg5tm941

4 ай бұрын

Thanks!

Thoroughly enjoyed that Tim. Certainly keeping people on the hook for the next installment going further down the rabbit hole. People themselves need to have an understanding or they will never be content in what they have and believe any old marketing nonsense.

@timg5tm941

2 жыл бұрын

Thank you Colin and I totally agree 73

Excellent video TIm. Really appreciate this. Mark, 2E0MSR.

@timg5tm941

2 жыл бұрын

Thank you Mark! 73

@markramsay6399

2 жыл бұрын

Meant to add - with the DX Commander on 40m, the physical pole is about 10m, but the element is longer as there is a fold back. Given that the wire is coated, there is a real "length" extension to perhaps 12/13 m (I cannot recall right now). There is some interesting physics going on , the "length" of the wire is not the same as the desirable actual "height" of a 1/4 vertical, but it certainly does increase efficiency on 40m> Mark, 2E0MSR

Its great having you online as a teacher Tim - I wish we could have you at the club :D

@timg5tm941

2 жыл бұрын

Thanks Al! 73

Hi Tim,I usually ignore the scientific graphs and build an test in my own location! Over the years I’ve found a 1/4 wave mono band antenna with 4elevated radials has allowed me to work dxcc on whatever band I’m working at the time.my own experience is don’t be put off and build and test! Thanks for all your great videos 73s Gm4zji Chris

@timg5tm941

2 жыл бұрын

Yes elevated radials are a game changer. Cheers Chris 73

Very good presentation Tim as always, but I must admit I didn't take anything like that into consideration when I put up my vertical, I simply got a 5m painters pole and some 5m radials and went on 20m, sort of suck it and see, and it's been there for 8 years now working dx Zl to eu every day hi , I just hope the painter doesn't want his pole back hi. Your info is always interesting, but we must remember sometimes ant can be very simple indeed, especially if we just want a quick qso at lunch time, as you demonstrate yourself very effectively whilst your mobile. Keep up the great work Tim 73.

Good stuff! New ham here. I've mostly been focusing on QRM issues so far with my vertical. But lately I've become very aware of its poor efficiency as well, and I'm trying to understand that a bit better. This has been very helpful. Also thanks for crediting your sources.

@timg5tm941

7 ай бұрын

My pleasure and thanks for stopping by!

Excellent description, Thanks Tim!

@timg5tm941

2 жыл бұрын

Thanks!! 73

Well done presentation. You may be surprised where this leads....

@timg5tm941

2 жыл бұрын

We shall see!

Hi Tim, Awesome explanations and visuals. Looking forward to next installment. Stay safe. 73 WJ3U

@timg5tm941

2 жыл бұрын

Thank you Don, friend, you stay safe 73

Very good video 👍👍look forward to the next one

@timg5tm941

2 жыл бұрын

Thank you Andy! 73

I have a 43 ft vertical with 660ft of total radials. (22 x 30ft) Best vertical I ever used.

@timg5tm941

2 жыл бұрын

They work really well Mike

@user-ss6zt2mo1l

Жыл бұрын

@@timg5tm941 instead of using a 4:1 balun, with these 43 foot verticals, could I use a 9:1 balun with the vertical Or could I disconnect the radials and use a 49:1 unun and increase the length of the radiator to an appropriate length ? Food for thought.

Another top vid Tim - keep 'em coming :)

@timg5tm941

Жыл бұрын

Thank you Mark!

Thank You! Very useful information.

@timg5tm941

2 жыл бұрын

Thank you Dave! 73

Very interesting to see!☘️👍

@timg5tm941

2 жыл бұрын

Thanks Donal

It occurs to me that, as a practical matter, there is more to be considered beyond radiation resistance and the sum of antenna losses. With several of these antenna lengths, there will be substantial reactance, the network which provides a reactance of opposite sign and transforms the impedance to that of the transmitter will have losses, too. If this network is distant from the antenna, there are losses associated with the circulating current in the transmission line. Combined, these losses may be greater than antenna inefficiency or radiated power.

@timg5tm941

Жыл бұрын

Yes, where you match them is absolutely vital if the vertical is non resonant

Hi Tim, My copy of the RAE Manual from 1988 (page 57) says "The 'radiation resistance' of an antenna is a fictitious resistance which would dissipate the power radiated by it.". A good reminder that everyone needs to double check their 'facts' from time to time. It's wierd that I remember that, that's in there it's probably because it stuck out as being a bit odd.

@timg5tm941

2 жыл бұрын

I agree, facts are very important. Thankfully we have the work of people such as DJ2YA to support the theory. I was glad to use his data. 73

Excellent

@timg5tm941

2 жыл бұрын

Thank you!

A bit of confusion between Radiation Resistance and feed impedance. A center fed half wave dipole and an end fed half wave antenna have the same radiation resistence and way different feed impedance.

Hallo Tim, thank you for nice video, I'm waiting for the next👏. Only a clarification: in Half Wave configuration impedence is abt 3Kohm, and a tranformer is mandatory: for monoband application best results with 64:1, in multiband configuration 49:1 is using as a compromize.

@timg5tm941

2 жыл бұрын

Hi Franco. I deliberately used the lower end of the radiation resistance figure for the half wave. You are correct that it can often be higher 73

@francoguanziroli7867

2 жыл бұрын

@@timg5tm941 👍

Life begins at 1/2 wavelength!!😏👍

@timg5tm941

2 жыл бұрын

Well for radiation resistance, it could be said so yes! Lol

Hi Tim, interesting series! I was wondering, you're mostly concerned about radiation pressure WRT transmitting, but is it also important for receiving as well?

@timg5tm941

2 жыл бұрын

Hi there its a unit to assess the radiation efficiency therefore TX 73

Super interesting. It’s curious to me how much worse the 1/4 wavelength vertical is as you go down to lower bands (as compared to the higher bands)… since I think the ground system you described is proportionally the same.

@timg5tm941

Жыл бұрын

One of the many mysteries!

Hi Tim, It seems like the 1/2 wave vertical has the best efficiency. Do 1/2 wave verticals need radials and what is the best way to match them? Thanks for another great video. 🙂

@timg5tm941

2 жыл бұрын

Hi Brian, stay tuned for the next video in the series (radials), all will be revealed! 73

Vy good presentation. If I take the 43 foot vertical and turn it 90 degrees... this is my endfed random wire antenna out of my window. Instead of radials a 4:1 UNUN is grounded in a water pipe for the heating (works great for what it is). Suppose all this theory applies.

@timg5tm941

2 жыл бұрын

Yes and a nice antenna you have too

@Tim how to measure radiation resistance? or efficiency? Can it be calculated out of any NanoVNA measurements like power loss?

@timg5tm941

2 жыл бұрын

The few who have, have compared field strengths as well as taking into account overall feedpoint impedance and thus determining loss resistance as part of this. It’s a complicated measure and in most part is based upon the inevitable differences in the feedpoint impedances between say a 1/4 and a 1/2 wave.

So am I understanding this right? Half wave verticals with quarter wave radials have the best radiation resistance?

@timg5tm941

2 жыл бұрын

We cover radials on the next video, but 1/2 wave verticals fed at the base require minimal radial fields and exhibit an appreciably higher radiation resistance compared with a 1/4 wave. 73

@stevet7522

2 жыл бұрын

@@timg5tm941 thanks for the reply and info. Another question: would this only work as mono band verticals? I'm assuming that it would not work well in a fan dipole (DXcommander) since the signal would most likely radiate at the quarter wave radiator, assuming you have something like 20,17,15,10. Or does the signal radiate on the most resonate radiator?

@timg5tm941

2 жыл бұрын

Hi Steve you need to use 1/4 waves in a DX commander configuration owing to their lower impedances. 1/2 waves wouldn’t work. Of course you could also use one vertical and have a tuner near the feedpoint. So for 20-10 a 20 foot plus vertical would do well for example.

@stevet7522

2 жыл бұрын

@@timg5tm941 fantastic. Thank you for all that. Love the video and keep up the good work.

@timg5tm941

2 жыл бұрын

@Steve T that’s very kind Steve thank you for your support

On a completely unrelated note, may I ask is that a West Country accent?

@timg5tm941

2 жыл бұрын

Nearly, it’s South Walian

@45auto

2 жыл бұрын

@@timg5tm941 some definitely sounded Welsh to my American ear but I've been watching an old TV show called Hinterland and was afraid I was projecting.

Can I shorten or lengthen the antenna

@timg5tm941

24 күн бұрын

Yes

Very good presentation Tim as always, but I must admit I didn't take anything like that into consideration when I put up my vertical, I simply got a 5m painters pole and some 5m radials and went on 20m, sort of suck it and see, and it's been there for 8 years now working dx Zl to eu every day hi , I just hope the painter doesn't want his pole back hi. Your info is always interesting, but we must remember sometimes ant can be very simple indeed, especially if we just want a quick qso at lunch time, as you demonstrate yourself very effectively whilst your mobile. Keep up the great work Tim 73.

@timg5tm941

2 жыл бұрын

Wise words Brian. My focus here mainly was on non resonant multiband verticals. It’s amazing how many manufacturers claim great efficiency for very short unloaded verticals!!73