Marconi discussing the 102" whip with a suitable ground plane for 11 meters.
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- Опубліковано 5 кві 2011
- These models are using Eznec5 to study the 1/4 wave whip and how it works with a suitable ground plane and when not.
I also present a 1/4 wave with a top hat for you guys wanting some evidence that a shortened antenna with a top hat of appreciable size may work just as good as a full length 1/4 wave radiator with a suitable ground plane. This is not intended to apply to mobile installations. - Наука та технологія
Dear Lord this information is wonderful😃😃I've been looking for a channel such as this for many many months!! bless you sir for your knowledge and freely sharing with us people..
One of the simplest and best explanations that I've seen. Your comparison of the chart and graphics is great! You're a good teacher. Thank you!
Yep the 102" whip is very hard to beat
Well this here comment is about 10 years late but EXCELLENT EXCELLENT EXCELLENT VIDEO.
Thanks and ten years later is GOOD with me!
good info, like the graphics..👍
Great info . I will tell you all my setup an old Homer told me and I've used it every time I set one up on a truck or trunk lid . On a truck , don't bother mounting to the bumper . The tailgate kills your signal . Buy an aluminum toolbox, mount dead center /on a car , dead center of the trunk lid , yes I know it's not beautiful to everyone . Drill your hole , mount the ball or stud , stainless steel , the heavy duty stainless steel spring approximately 4 inches , then screw in your 102 inch antenna and use a 3/8 stainless washer between the antenna and stud or ball mount . Use 21 feet and 6 inches of coax and you will have nearly a flat swr across the 11 meter and about 1.1:4 on 28.300-28.500 . I've done this over and over . It works
Coax length only tricks your meter and gives you a false reading. Coax length only matters if you want a correct reading while tuning antenna. Only way to do that is use multiples of a 1/2
wave for the frequency you are tuning the antenna for.
Had a friend tell me he used a 102 with no ground plane and said it worked great with good SWR, Told him that couldn't be the case since it needs something on the other end. Then I realized what happened. He had the bracket mounted on a 9 foot piece of pipe. AHA! You have a half wave center fed dipole.
Hahahahaha
Is that all I have to do? I have mine on a 12.5 foot metal pole... but i have a 10 foot one...
@@andrewmcallister4151 Well, technically, that's what it is. Put it on and try it. Might work depending on what you mount the pole to. I don't think his was mounted to anything metal. Might have been an eave mount connected to wood. I've already strung a 9 foot piece of copper wire down from the bracket for another friend of mine to get the SWR down. He had a truck mirror bracket bolted directly to the side of his trailer.
@@billyjoejimbob75 im mounted to a 12 foot metal pole, that is attached to the wood work around my chimney, so the metal mast is not connected to an metal, but the metal mast runs near the aluminum chimney flashing.
I think the mast is too long and I need to add a spring to make it 108 inches. Trim the mast to 108 inches... maybe that will get it down some... trying to refrain from radials because of hoa...
Any antennas that don't require radials to get swr down. I'm over 3 to1
@@andrewmcallister4151 Yeah, cutting one of your masts down to 9 feet sounds like a plan. Try it out before you buy the spring. Might be close enough.
Great video
GREAT Video, TNX OM. Hope many of the guys will study enough to understand the readings. Many that use antennas don't study any electronics at all and just go by CB myths.
The 102 inch whip is not going to be any different on output unless you can increase the Q of the antenna. But it is what it is, a 102" radiator. """You have to build an antenna to talk where you want and no one antenna is good for everything"""!
73 Jimmy, WX9DX
I used a black beauty 98.2 with a 4 inch spring got good results for 11 m on mobile in 1964 CB.TN.SWR one to one
my friend made me a 4 element yagi beam with no gama match n it rocks n solid as a rock
i use one of these in the loft seems to work well. im going to make a t2lt antenna similar to a bazooka will this out perforn the quarter wave ????
A coat hanger will out perform a 1/4 wave...lol
@@thevacuumtubejunky9774 102 is a 1/4wave
Great video!! I am going to look into this Eznec5? I run a 102" whip about 17ft. to the base for 11meters. I have a 12" diameter sheet metal disc that has three radials @ about 115" long angled down @ 45degrees. The SWR is very good although I don't know what the reactance or actual resistance is?
It seems like my ground plane which is about 121" and works well, very broadbanded from 26.515-27.855 very flat on my meter.
Thanks keep up the great work!
Never heard of this type of radial needing to be 5% longer than radiators... This isn't a beam/reflector setup, so why that need? Theres only ONE "perfect" resonant length for quarter-wave elements at any frequency - alter either and the match inevitably isnt as good in some way. Altering radial angle alters feed-point impedance - "match" or "mismatch" that seems to result isnt the same as with right or wrong frequency:element lengths. See about "top-hat" capacitive effects. 73 G0TDE
In part you are right Richard.
So, when I talked about the 5% idea I had in mind these EZNEC models were based what I remembered the real StarDuster dimensions showed as (98.5"/107" = 8% longer radials compared to the radiator in my notes on the SD'r antenna.
I also show the resulting matchs as the dimensions changed. So, I did not try and match all these models to their best results on changing the dimensions. That for sure has to be considered, but back in those days I was limited to about 10 minutes for the time of my videos.
These models showed the radials (of varying lengths) based mostly on what the talk I was hearing about 102" SS Whips being too short for 11 meters and such.
I appreciate the good eye you put to task in checking my video out. Good Job!
Eddie - Marconi
Bull shit,skip the figures,you're only killing time,the 102 whip is the best if installed properly.the coax cable must be correct to get 1.1swr..
Do you need a spring ?
Spring yes.but youll loose 00.372
@@Fox250R I used a 6" spacer in the models as an example of setting a 102" whip to 108" inches as if it was on a spring. The difference here is I did not use a mobile object as the ground plane. Of course that makes differences...but understand I did not have the time for all situations.
When I ran mobile years earlier, I never use a spring, maybe a ball mount at times and mostly stud-mounts on my vehicles that were not very long.
How much coax would you need? 18 feet?