HAM RADIO: HF MOBILE ANTENNA EFFICIENCY (PART 1 - ANTENNA LENGTH)

[@alzeNL]

For me you are easily the best educator on KZbin - you really draw out and make theoretical concepts relatable and understandable. I like the way you bring in other people’s knowledge (and well cited/credited) and then explain them further. Thanks again Tim, a real credit to the amateur radio community.

[@timg5tm941]

That’s very kind Al, thank you 73

[@WECB640]

This is SUPERB Tim. GREAT job! Far too many hams have become "appliance operators" and forgotten what our previous generation understood as common sense. Please do more videos like this and enlighten those who are willing to listen. 73 OM

[@timg5tm941]

Thank you! 73

[@AmateurRadioUK]

Great work. Looking forward to part 2. Thanks Tim.

[@timg5tm941]

Thank you James! 73

[@G5STU]

Very interesting, thanks for doing the homework and boiling it down into an easily consumable presentation. Looking forward to the next one in the series.

[@timg5tm941]

Appreciate the feedback Stu, 73

[@COASTALWAVESWIRES]

Great video Tim, I think you are definitely the mobile ops source here on KZbin. Thanks for sharing that knowledge my friend.

[@timg5tm941]

Thank you Walt! 73

[@matyos7754]

Hi Tim, The efficiency of the antennas has been my concern and the formula you presented are what I wanted to see and understand. So, thank you creating the is series of videos.

[@timg5tm941]

Thank you for watching them!

[@dennisbauer3315]

Thanks Tim, as a layman, with little knowledge, but some understanding of Physics, and a later learner in life, of math, knowing the great importance of math, this would have to be one of the best, important Antenna videos on KZbin for a very long time. Your ability to make it understood, is greatly appreciated. Thank you.

[@timg5tm941]

That’s very kind Dennis, thank you!

[@joseneves2822]

Hi Tim ... very, very well-sustained and extremely useful information Many thanks for sharing / 73

[@timg5tm941]

My pleasure Jose, thank you. 73

[@arnoldgrubbs2005]

A very good video presentation! I am looking forward to seeing videos on the other parts of the subject. Thank you for taking the time to do these videos.

[@timg5tm941]

Glad it was helpful, 73

[@MikeN2MAK]

Thanks, Tim. I always learn a lot from your videos. I'm looking forward to the next.

[@timg5tm941]

Thank you Mike!

[@MIKROWAVE1]

75M mobile is my favorite mobile band, and I ran a standard stainless 108" CB whip with a base load (tuner in trunk) for years. Yes a few dB down, but it worked great and was indestructible. It really is all about the location of the antenna on the vehicle, especially height and center position, smoothness and size of your ground footprint, and your grounding bond to the vehicle. Using low loss double shielded cable with several beads for decoupling is important for when you are off resonance. These install factors dominate vs the antenna efficiency itself, within the resonant bandwidth. This is why a hamstick in the center of the roof can outperform a bug catcher with a giant top hat in a truck bed.

[@timg5tm941]

Indeed .. the increase in loss resistance is quite marked when you start to mount the antenna below roof height

[@pasjeihobby]

Amazing piece of knowledge passed in very digestible way.

[@timg5tm941]

Thank you that’s very kind!

[@2E0RME]

Hi Tim, thank you for doing this series on antenna efficiency, I look forward to seeing Part 2. Part 1 confirms what I suspected regarding there being a "sweet spot" for convenience vs length, but I didn't know (specifically) that an 8th wave was only 2.5db down on a quarter wave - which let's be honest, is pretty negligible at the receiving end. This level of detail is really useful, so once again thanks.

[@timg5tm941]

Thanks!!

[@bobsaunders3621]

Like that a lot Tim, looking forward to the next. 73 Bob, MØMJA.

[@timg5tm941]

Thank you Bob!

[@stevewheatstone1856]

Nice video Tim, I have been looking at some small compromised antennas for portable handheld ops, great timing. Capacity hat very interesting. Look forward to the next video. Cheers Steve MW0SAW

[@timg5tm941]

Cheers Steve!

[@ssubaihi]

i can't wait for Next Episode

[@timg5tm941]

Thank you Suhail

[@oldpreach]

Wow... Grape 🍇. I live near w8ji. He runs a 2 meter repeater out of his home, and has a tech session every week. It's like an advanced class that sometimes go right over you, but can be extremely helpful.

[@timg5tm941]

I’d like to chat with him some day. A very knowledgeable man.

[@Liam2E0LDQ]

Would be great to see a video with the slidewinder again but this time with different slider positions and what bands etc 😊

[@timg5tm941]

Interesting idea

[@cmiltenberger]

As someone just starting with HF mobile, topic this is very relevant. I'm currently using monoband hamsticks which appear to be a bigger compromise than expected. Please share links to the research you mention. 73 de W5CMM

[@timg5tm941]

Will provide more info on the links in future videos 👍

[@lostinkansasonasunnyday305]

but by adding a hat on a mobile antenna the wind wind resistance a ton.. once you go anything above 20 kph, when you stop the recoil will be dramatic . not only that, while driving the wind resistance with the flexibility of the anten may just rip the antenna off the car I'm assumming a mag mag mount. I'm confused, the wind resistance seems to me will cause many problems. I';m assuming you're driving, the old CB radio days.

[@timg5tm941]

Yep I addressed wind loading in the video

[@bensmith4563]

The more i try to learn the stupider i seem to get

[@timg5tm941]

Me too!