But I've seen a lot of recommendations in other threads to use a steel whip for a vertical and 102" wires for the radials in a homemade 1/4 wave GP. And no mention was ever made about using a spring with the whip. Hence my confusion.
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Different Look At 102" Whip Discussion
- Thread starter Wire Weasel
- Start date
That length thingy deals with resonance, not SWR, or impedance matching. Especially with a typical groundplane antenna, varying the angle those radials 'droop' can make a big difference in SWR/impedance matching/input impedance. The formulas for length are always an approximation, never exact. They can certainly get you in the 'ball-park' with resonance though. Those are two different thingys altogether, resonance and SWR, they are not related.
- 'Doc
- 'Doc
Jim, I think you're not reading what the calculator link in the beginning of this thread is showing dimensions for. The explanation for its purpose is right there in the words at the top of the page.
If you are considering a mobile installation this calculator will not be of much help IMO. Who really knows how the antenna sees the car body as the ground plane in a mobile install? Some setups work and some don't in such cases.
The calculator is giving you the dimensions for a base type antenna install using a vertical 1/4 wave radiator, and 3 or more horizontal radials. But, assuming you want resonance and the impedance match to look really good on your meter you will need to slant the radials down 45* degrees or more.
Setting the radials horizontal will also work just about as good, but the match will be off at resonance.
Thanks, 'Doc. I keep forgetting they are two different things.
Thanks, Marconi. I'll learn this stuff someday. By the way, it's good to have you back. I think you went missing about the time I came aboard a few months ago. Glad you've returned.
Thanks, Marconi. I'll learn this stuff someday. By the way, it's good to have you back. I think you went missing about the time I came aboard a few months ago. Glad you've returned.
If you go back in this thread and read my post #11, you will read that I was pretty much saying the same things to Wire Weasel back then too.
Yes sir. Got it.
I don't have room for 7 (or even 4 full-length radials) because of my roof. How will it perform with only 2?
Just kidding! Been there, done that with 4' Firestiks. Worked pretty well and while steel whips would be better, I'm guessing it wouldn't be THAT much better.
Are you sure none of you need a MINT Royce 619? I have it listed in the CB Swap forum for $125 (you can see pics there) but would let any of you have it for $100 as you've all been very helpful to me in many forum threads. Free shipping. The cover has never been off of it (has not been meddled with).
Thanks,
Jim
Old thread, and some inaccurate information. Fiberglass whips are shorter than a 102 due to a lowered velocity factor caused by the fiberglass over the wire.
i don't understand the point of your post.
the post you quoted said the exact same thing you just did.
LC
the post you quoted said the exact same thing you just did.
LC
You use a 6-8 inch long aluminum bar that add's length and moves the antenna horizontally away from the vehicle. Assuming it is being mounted to a metal bumber on a truck this keeps it out of the way of the tail gate, gives you the extra length and keeps the SWR flat from 26-28 and still really good from 29 to 32Mhz . I think I was using 18 feet of LMR 240 or 400. This was used from 1991 to 1998 on 1986 Toyota 4Runner. It is hard to find a spring that is worth a darn most of them have cheap wire, cheap still and cheap other bits that rust.
Somebody throw me the GOLDEN SHOVEL!
Yes this is an old thread but, I am using a very heavy duty barrel spring my Dad bought back in 1967 and it still works perfectly. And, it is very strong. He ran it for yrs and yrs on his 1967 Chevrolet pickup truck and that spring and whip took a beating! As a matter of fact, I'm using his old 102 in whip also.
They talk just as good as the day he bought them.
Yes this is an old thread but, I am using a very heavy duty barrel spring my Dad bought back in 1967 and it still works perfectly. And, it is very strong. He ran it for yrs and yrs on his 1967 Chevrolet pickup truck and that spring and whip took a beating! As a matter of fact, I'm using his old 102 in whip also.
They talk just as good as the day he bought them.
I got a couple of those steel heavy duty barrel springs, antiques. Got a couple of coats of spray paint on them. They say General Electric at the end.
It's a good idea to look at the braid inside the spring, most cheaper chrome plated springs have a low quality braid inside that connects the top and bottom.
Even the Hustler Stainless Steel spring uses a copper braid that overtime will deteriorate.
Especially if you live in a area were the are exposed to salt.
I chased a intermittent SWR problem one time and learned that lesson.
73
Jeff
Even the Hustler Stainless Steel spring uses a copper braid that overtime will deteriorate.
Especially if you live in a area were the are exposed to salt.
I chased a intermittent SWR problem one time and learned that lesson.
73
Jeff
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