Видео

The value of that test resistor has always fascinated me. I had an idea the other day, and tried out measuring the antenna side of the transformer with my 50 ohm cal std on the "radio" side. The values were close to 2400, but varied a lot over the frequency range. 2.5K ohms at 4Mhz, 2K at 20Mhz, 3.3K at 30Mhz. I even used the S21 serial R measurement method for high values of resistance... As a cross-check for my procedure, I measured a carbon film, 2415 ohm (Agilent 34401A) resistor, and on the Nano it ranged from 2.1 to 2.6Kohms. My method for measuring loss is much, much more primitive than yours. I have about 5 various transformers, and I use one as a "standard" and measured the other 4 against it, took an average of 1/2 of the loss readings, and use that value as the amount for the "standard"... All are various 49:1 z windings, tapped, twisted, cross-over, tight, loose etc. I am within about .5 to 1 db of your values... I'll have to try the two of the same type back to back one day. I also own a DG8 VNWA, which has a super software package that includes math "expressions" that you can plot. Saves you from having to cut and paste readings into spreadsheets, you just plot the formula (expressions) with the live s11 and s21 sweeps within the formula... Its also within .5 to 1 db of your readings.. Interesting stuff, thanks for your work, and attention to detail... 73s

I love your design/approach on this! Great work! N0BBM

Very inspirational! Thanks!

You said you aren't really interested in this antenna for the 10M band because you have better antennas for 10M. Since you clearly know your stuff, what antenna do you use for the 10M band?

I decided to go with the Rig Expert and have never looked back.

What makes an "autotransformer"? Why is the 56:1 a standard transformer and the 49:1 an autotransformer?

Great video,it’s given me a bit of confidence to try and build my own .Is there a shopping list of components?maybe I missed it,thanks,Karl G0SKW

Great video!

why not run a two port (S21) phase shift measurement on the VNA for the frequency you are looking for rather than get tangled up in the math? something you can't do on the RE Zoom........73 from Mike, K1FNX near Boston

Hi Colin whats the final weight of the Hexbeam in total

Thanks for sharing, ssb was same for me, cw definitely the rig, but I've got old ears hi so I always use headphones. Problem here is neighbors use speakers outside all the time, we never get to sit in a quiet garden ever anymore, because of the bloody music.

I last year I had the sale idea as you and I got a huge Bluetooth speaker from Banggood (Blitzwolf bw-wa3 pro 120w) not initially meant for use with HAM radio but have found it to be wonderful for Anytone 878 DMR, X6100 or FT0857d using bluetooth or cable - it has a "voice EQ profile" which makes it even better for HAM use. The one I have isn't cheap but damn good and has a HUGE Lithium battery for running phone/radio from too.

My KX3 is renowned for under powered audio (KX2 is better), after 11 years I use a mixture of plugging in an external speaker, use headphones or run barefoot. KX3 has no BT capability, we all have our crosses to bear 😜 Thanks for posting Colin always good to see useful bits of kit.

Hard to tell on Cw. Definitely better on voice. I have the jbl mentioned above and it’s hit or miss depending on the radio. K3 it works well but sounds like garbage on the kx2. Using just 3.5mm connections. Maybe I’m doing something wrong most likely

Colin i did listen with my headphones on and personally the 705 speaker was crisp and had a better tone , especially on CW. In my opinion absolutely no need for a BT Speaker

JBL go3 Bluetooth works fabulous to.

When you changed the length of the elements, did you also move their position on the spreaders?

Great seeing you build this in a typical garden instead of a wide open field. Glad I'm not the only one with obstacles in the way of my antenna projects. 73 K9WWW

Your hexbeam building videos are fantastic!

So which half of the 80m band do you want? The coil will make it so narrow on 80 you will get about half the band.

It doesn't take long to look at Owen Duffy's notes to see he's clueless about antennas.

I have a question, on your 49:1 toroid video can I use 24g magnet wire? Of course using the 2661102002

Great video Thanks for your time. What capacitor you recommend?

Once you go to the lower band, ie 40m to 80m you have a 1/4wl antenna and you should have a close to 50 Ohm match. Steve Ellington setup his 80m-10m EFHW with a remote switch to direct feed the antenna bypassing the 49:1 autotransformer. He however configured his antennas as an inverted-L.

"In cold weather it really does get stiff." - I have a couple of knees like that.

When the wire is wound without a crossover does the toroids get to disperse the heat evenly or is the heat concentrated where the windings are ?

My garage is messier than your :=)

Colin, first let me say thank you! Your work is amazing! Thank you! I just had a perverse thought while rewatching every video I could find between you, Evil Lair Electronics, and Survival Comms on core testing. What would be the effect of cocentrically nesting a ferrite inside a wound transformer? That is placing a ferrite rod or smaller ferrite bead inside a wound transformer. I've never seen or heard of it being done. They fill university libraries with what I don't know on the subject, but its my understanding that the ferrite has two functions. One is to increase inductance per turn, and to constrain the elrctromagnetic field. I am not even sure how the righthand and lefthand rule applies to transformers wound on ferrite. I can see such an experiment either being amazingly good or amazingly bad. You already have several wound transformers and ferrites, so if its not too much trouble perhaps you would be gracious enough to empirically answer the question.

This is awesome Colin, I must have missed that in the instructions.

Very fine Colin! Love the calculation.

Have you made a second video on Hexbeam ty 10:36

Do you see a difference in the hex vs the moxon for 20m?

Thanks Collin,I m trying an hexbeam using pvc coated wire of 1 square mm of section.12m and 17m bands show roe>2 , and it increases with power.Do you have any tip for this?Regards

Thanks Colin. Really looking forward to seeing your high band version 😊

Great video as usual! Im hoping to have a hex beam one day.

Thamk you. I am thinking hard about getting a hex beam

Excellent! Thanks for this!

Cose HARP start working

Your red-eye shift paid off! Congrats Colin

Thank you for the explanations, what software do you use for the analyses? Good luck, 73 QRO. CN8RED

What is this?

Awesome!

Simply Outstanding!

I can feel the excitement coming through. What more proof do you need? Fantastic Regards Mike

I think he’s on a 7el triband yagi. 2 element on 15. Good to hear you so loud into ky. I’m 40 miles north of Steve in thoroughbred capital. Many 100’ plus towers around. Just guyed really well 😆

Good to see how the other half live hi. A bit bigger gap between your calls would help us old guys hi. Every time tonight I went to call, but realized you were cq again. Good luck. Zl3xdj.

So well thought out and executed Colin. Look forward to the next instalment. Regards Mike

I thought about this, and your modeling assumes a 100% efficient 49:1 UNUN. Which won’t be the case, especially on 12m & 10m with the typical 240-43 based UNUN. They are only ~72% efficient range at higher frequencies . The 1/4 wave MAY be better on those bands? Some of your newer torroids you have wound seem to be much better on 10 & 12m.

I switched to using 2 FT240-43 cores in my 49:1 UNUNs. They seem to work better with lower SWRs than a single core. I only run 100 watts. The primary and secondary windings are separate for no common mode current in the coax.