Resonant Antennas, HF Mobile, MFJ-1668 Screwdriver

[@yifeiwang7383]

Antenna tuner basically does some 'impedance match' to maximise the power transmitted from your radio to antenna, it is not cheating the radio. The most common type of impedance matching network is LC matching, which the microcontroller tries combinations of many different capacitors and inductors to find the lowest SWR. But, maximise power transmitted to the antenna doesn't necessarily mean you have a good antenna. The antenna has its own characteristics which determines how much incoming power is being transmitted to air and how much become heat. This character cannot be changed with external impedance matching circuits. When you shorten an antenna, you use inductors to compensate for the electrical length, while sacrificing efficiency. The efficiency of a typical mobile HF antenna is about 1%, means you need a lot of power to transmit. Receiving is usually not a problem due to relatively high atmosphere noise (about 30db above thermal noise, allows more loss on an inefficient whip without lowering SNR)

[@samscement]

Finally, I’m glad you’ve preached the truth about about what a true resonant antenna really is, love your videos, keep them coming !

[@Laborkei]

A lot of walking back and forth to get it right, but your right... I have a old High Sierra Screwdriver Antenna on a Tripod for POTA with Counterpoise. I just push the up/down button while watching the SWR Meter for the lowest SWR.

[@buckeye5704]

Thank you Eric! I'm considering going mobile HF and now the antenna dilemma is nearing its conclusion. Would like to be multi-banded, but that may be impractical for me. Too many trees, drive-thrus, etc. You brought me back to Ham sticks again. For $25 (ish) just buy the bands I want tune them and store the unused ones in PVC tubes in the (covered) truck bed.

[@NICKGAR7]

I have used an Ampro160 on top band and made 1000-2000 mile Qs BUT every change in the dial needs a visit to the antenna to change length such is the super-narrow bandwidth! You’ll wear the door hinges out! Thanks for informative video.

[@magnetus26]

I live in an HOA community and the mfj-1668 is my main (only hf) antenna I use it with a magnetic base and my tranceiver is in my garage. I have hundreds of QSO in SSB CW and FT8 all over the world

[@joewilson2258]

What your talking about is very old ideas brought to us by the early amateur radio operators . As for the tuners they are good as long as you stay within the resonent frequency of the antenna and within about 100 to 150 khz of the turned frequency .

[@tahlularose9267]

Excellent presentation on both video's, I'm a lic. but non practicing HAM, I really enjoy all the technical aspects but over the years I just assumed the Antenna Tuner was 'tuning the antenna'. You really brought home the idea that a random length wire does not an antenna make! It's clear as a bell now, thanks.

[@cliffbarrett9471]

I'm a new sub and a newcomer to ham. I'm 56 and building my retirement hobby. Learning a lot by listening and vids, enjoy yours a lot. Very informative THANKS!

[@Swoop180]

I currently run a Yaesu ATAS 120A on an 18 wheeler, it is decent enough on 10/12 /15 and you can have sporadic luck on 20. I've actually been lucky enough to have contacts on 40, but nothing to write home about. I am planning on installing a cattle guard on my truck where I plan to deploy a Scorpion 680 or a Texas bugcatcher, I think the counterpoise shouldn't be be an issue. We'll see! I do recall a few drivers having claimed to work 75 and even 160 mobile but I'm a show me kinda guy. We'll see. Take care Eric and 73' Sincerely, John C.

[@kd4kzz]

Depends on where it's mounted and it's ground. Florida to California on 40M. Florida to Belgium and Africa on 20M with my ATAS 120A.

[@eddy4011]

Excellent your video only one question .I am leaving HOA but I will tray to buy this antenna MFJ 1688 and see what happen at home ,let me know your opinion about the antenna móvil in this condition thanks in advance Eddy from West Palm Beach

[@melissacoleman9633]

Great video. I am going for my HF technician ticket because of you. Thank you for doing what you do.

[@daveborchard2019]

How does the mobile HF antenna compare to your base HF antenna? For example, if you moved to a home in a restricted community, where you’d have to stealth your HF antenna. Is there a huge difference between the HF antennas? Maybe you could do a video on stealth antennas. Do you know anyone who uses a stealth HF antenna? Do you know anyone that uses a remotely controlled HF station? I’ve seen commercially shared remote HF stations advertised, but they start at over $5 an hour. Decades ago, when I was on HF, I spent many hours a week on HF, sometimes many hours in a single day. How many hours a week or a month do you spend a week or a month on HF? My goal is to get back on HF in the future after being off HF for decades, but it might be a challenge if my next home is in a restricted community.

[@InternetGoldMiner]

Wow This is the problem with appliance operators today.

[@flatdog691]

Great to see you're good Eric. God Bless You!

[@mark6831]

Hello Eric this is Mark k2csx I want to say about the mfj-1668 I own one of those antennas and yes it's a great antenna for instance I live in an apartment building in New York City at times in the past I was not allowed to have an antenna on the roof so I ordered from mfj one of those antennas It's a Wonderful antenna I had it outside my bedroom window on a window guard on a 45 degree angle I use it on my Yaesu ft 920 and I had great results my counterpoise wire ran for my bedroom window so my fire escape very thin piece of wire that I had left over from the mfj apartment antenna the 1664 work flawlessly so well I have a1661 and a 1664 from 6 meters all the way down to 40 + 75 + 80 m on the 1668 I've also left it tuned on 40m and with the help of my mfj 969 tuner I made several contacts on the 160 meter band so that particular antenna works good and a balcony situation if you live an h o a you can hide it in the bushes or just like me use it window side but I wish mfj produce on antenna like the screwdriver antenna but only in a loop form with like a little gray box underneath with a tuning capacitor something that might handle a hundred or 200 Watts when you live in an apartment like I do you're really compromised and really cannot put up antennas like folks do with their own homes so I just wanted to comment about the 1668 I enjoy all your videos and keep them coming I would like for you to do a video on FRS gmrs and Murs radio there's a lot of that use here in New York 73 from the Bronx k2csx mark

[@JockWilliamsMeteorologist]

I hit active powrlines all the time never any issues

[@recumbentogiro26]

Speaking of screwdriver antennas, have you ever tried the Wolf River Coils antenna? I'm hearing good things about it and the cost is very reasonable

[@jordanjohnson3370]

Great video, gave me a simple but much better understanding of antennas in general.

[@nr01337]

Eric, your videos are fantastic. Thank you for making them!

[@flyboybobio3431]

Well said Eric. I try to tell all the new hams in the area that a tuner doesn’t replace a resonant antenna. Keep up the great videos. I enjoy everyone.

[@izzzzzz6]

A good ground on a vehicle is not that tricky. Just drill a hole in your roof and go big! I have a design for 80M 40M mobile. The idea is to put 4 or 5x 10M antenna on the roof. Then only the 1st one connects with coax to the radio. Then the 1st tip connects to the 2nd tip and the base of the 2nd connects with coax to the base of the 3rd and so on joining all of the antenna in series and tuning with the last two antenna lengths. a bit like the loch ness monster. Ok i'm naming it just that, or Nessy.

[@enginedave]

What's your matching method? Very important

[@user-xj8oh6fo2f]

That’s not just additional length but also inductance. Sliding that tube you add inductor to the antenna. That’s how it works. And having resonant antenna doesn’t mean “100 watts in 100 watts is coming out of the antenna” Absolutely not. Such shortened antennas have very low efficiency.

[@michaeljtalkington7960]

Can you add more mast under the antenna and a whip above to put the major in the middle like center loaded it for more efficient

[@hubercats]

Thanks for sharing this helpful video. It seems that once you choose the band of interest, and have made the antenna resonant for that band, you still need an impedance matching network that matches the antenna to the line characteristic impedance, and that the mismatch is going to be different for each band, thus suggesting that a tuner might make sense between the antenna and feed line. Does this make sense? - Thanks!

[@troydavidson5661]

So I guess its Hexx Beam time ! My 88' end fed is out of style, and I climbed 36' up three trees to mount it.

[@gmcjetpilot]

There is nothing like a good tuned (resonant antenna) with matching impedance.... no substitute.

[@andrewevanoff1192]

I've been preaching this for a long time. Unfortunately many hams think that as long as a tuner can tune, you are good to go. They brag about their new '"super tuner" being able to tune a lawn chair on 80 meters. LOL. They fail to understand that a tuner only matches antenna impedance to the radio's rated antenna impedance. It does not make an antenna more efficient. There is a reason why most reputable radio manufacturers limit their internal tuner to 3:1 SWR. It's because anything outside that limit will have VERY poor efficiency. It all comes to the unfortunate truth that the FCC license tests are a joke. People pass Extra exams but still have no clue about anything ham radio related. BTW, I've had excellent luck with a Tarheel motorized "screwdriver" type antenna on my vehicle. It works very well and requires no tuners, obviously.

[@radionotes9354]

Coil, capacitance, looks like a motorized screwdriver tuner :-)

[@Dennisjp-8318]

Thanks

[@randyjones6225]

With no tuner...how do you manage the low impedances offered for the lower bands? I've seen 75 meter Hamsticks with load impedances under 10 ohms, which really runs your SWR up, regardless of whether or not you're resonant.

[@WallDiver7]

Bought one of these recently.... Was the inductor coil (base matching coil) included with yours? I guess I'll be winding my own; An inductor coil was NOT included with mine.

[@DAVIDGREGORYKERR]

What about using a UNUN to match a transceiver to a vertical pipe antenna of height 500 feet high.

[@rodjava]

Great video. What antenna analyzer would you recommend to tune the MFJ-1668? I'm new to ham and would like a reasonably priced analyzer. Thanks in advance.

[@stevencarey2479]

Great video as always. My question is, how's the ft-450? I'm Still looking for that 10 meter beacon.73's KJ4EIB

[@bruehlt]

OK - I have to ask. What's with the frog painting in the background?

[@HamRadioConcepts]

well, it's like this... I saw that painting and wanted it, the wife bought it for my birthday months ago. I just hung it on my wall, and at this point, I just said screw the green screen and whatever else is in the background, just make the damn video :) Although when I get time (or a real room) I'll use the greenscreen.. But it's pretty much just a cool painting (I thought so)

[@HamRadioConcepts]

I should make a gofund me for a bigger studio for better quality videos :)

[@mattw3406]

You still have the cardboard corner protectors on it my dude - and what looks like the price tag and receipt jammed in one of the corners.

[@stevencarey2479]

I'd fund that!!

[@HamRadioConcepts]

@@mattw3406 Bro, hahaha, yes I have the corners on it. It's not permanent in that location. Just thought it would help when I move it around, not the damage the thing. YOu guys catch everything. LOL..

[@brentjohnson6654]

Another excellent video. I am wondering if a manual screwdriver antenna would be good to try. I am wanting to do mobile and portable HF. You mentioned you no longer do HF mobile. Can you say why? Not a problem, new ham here just figuring this out. All the best! 73 de KI5HXM

[@HamRadioConcepts]

This video was long ago, I do HF mobile every day with my Icom 7100, can’t remember why I said that in this video

[@brentjohnson6654]

@@HamRadioConcepts not a problem. I have always enjoyed your content from radio to solar power. I want to get HF mobile for my future trip to northern Florida. I will wave to you as I cross into Florida. Cheers!

[@ronleblanc9832]

So if you had that antenna in the field on a telescope tripid was uset on a 10 inch telescope would you still need to run a counter poise VE1-BHM

[@RevGunn-jq3cq]

Love your work! Keep it up

[@michaelthees7247]

Great video KD2RVW 73 to add a comment to Dave below I watch a video where they substituted lengths of wire to fit in an attic "folded"

[@lawrence3242]

Are you saying that the coil of the screwdriver radiates?

[@HamRadioConcepts]

It adds to the total length of the antenna It doesn't radiate, it adds electrical length

[@alanread6596]

Excellent video.

[@richardbutterfoss2353]

Thanks for the lesson.

[@ildefonsodomenden7441]

Hi, if your going to use it as a portable antenna how long should be the grounding radial length for the antenna?

[@Coyotethumper5]

It’s funny just yesterday I was thinking about how does a tuner really work and that it just fools your radio to think the antenna is resonant but the antenna still remains nonrsonanted so how can that help your signal. This video cleared that all up thanks Eric. I don’t use a antenna tuner I have using ham sticks for 20 and 40 meters on my truck (one on each side of my truck and a antenna switch in the cab) but started really thinking about getting a little tarheel 2 that way I can do 6-80 without swapping out my antenna’s if I wanted to do other bands besides 20/40 meters just tune and go. It also sounds like the screwdriver antenna will out preform the ham sticks Am I thinking correctly on that? And is it by a lot or just a little? Thanks

[@HamRadioConcepts]

Check out my little tarheel video, man that thing is just awesome in the mobile, a little innefficient on 80/75 but 20 meters 17 meters mobile I have worked hundreds of stations, I can tune it 1.1:1 SWR wherever I want just by running it up or down. Hamsticks are good too but theres only going to be a dip at one spot, and each hamstick for each band...

[@kb6dxn]

I have a Tarheel antenna that I am thinking about using on my truck. What is your feeling about the antenna?

[@TridentMissileTech]

I am new to hobby. What vertical do you like best for portable

[@radionotes9354]

Wouldn't 1/4 wire dipole (or 1/2 end fed) be a way more efficient then such a short vertical for portable operation? Probably, such a short vertical will have efficiency less than 10%?

[@UR4UNV]

Does it tested? Do you have a field test video?

[@Bernoulli-t3d]

The bands are dead

[@cedricvillani8502]

Moving the slider backwards and forwards makes me laugh watching you playing with that pipe.

[@HamRadioConcepts]

unreal, HAHAHAHA