Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: New Upgrade Kit for Zero Five 43' Verticals???  (Read 1606 times)
N3OX
Member

Posts: 8847


WWW

Ignore
« Reply #15 on: June 09, 2009, 07:54:32 PM »

"I thought that perhaps I could put up a 1/4 wave that covered 40 and just use the ground rods as I do not have room for radials."

The thing is that you should try to use them even if they can only cover a very small area.  The area right around the base of the vertical does a LOT of the work, so putting down 10 or 20 short radials in a small side yard or something can be fairly effective.

The problem with ground rods is that RF doesn't penetrate the ground very deeply, so it's only the first few inches to a couple feet of the ground rod that's transferring all the RF current from the earth to the coax shield.  I'd bet, but have not checked, that even a dozen 5 foot long radials would be measurably better than a few ground rods.

"perhaps a PAR end fed 40M antenna would be a better choice. "  

A voltage fed antenna like that is a good way to get around earth losses.  It's still possibly useful to install a small ground system connected at the shield point just to keep the coax from radiating.



"One of them told me not to even bother when he heard I was going to try working them with my R5! "

That's the silly flip side of this business.  The thing is, a lot of antenna advice comes from people who are using pretty bad antennas.  I try to convince people that if they're going to strongly recommend some antenna system with potential pitfalls to someone else, they should try to understand its strengths and weaknesses in comparison to antennas with almost no pitfalls.

It's hard to screw up the radiating efficiency of a simple resonant dipole or elevated ground plane antenna.  That makes them good comparison antennas.  

I've seen all kinds of "new ideas" around the internet which are antennas that probably work worse than a dipole but are touted as being better by people who've never actually done a decent comparison.  Advising someone to use a potentially lossy antenna system without actually having estimated or compared in any way is, I think, bad for the hobby.  It would be nice if new hams were able to find lots of high quality technical information coming from the hams around them, and I don't think that's what's happening most of the time.  There's a lot of folklore and guessing.

But the flip side is also bad for the hobby.  Anyone who tries to discourage someone from making contacts with any particular antenna system is also guilty of making a serious technical error, no matter how bad they think the antenna is!

When I worked 3Y0X (my Peter I contacts) I was living in an apartment and using 100W to a magnet wire doublet with a remote tuner at the feedpoint.  3Y0X had excellent signals, and I was able to work them on 30m and 20m CW and even 40m SSB.  They were probably a real S9 on 20m.

S9 on my radio is a huge amount over the natural noise floor of the radio.  It's probably in the vicinity of 60dB higher than the noise floor.  

Remote islands in cold climates like Peter I. are probably the quietest places to install a radio station on Earth.  

Let's say 3Y0X is running 1kW to to a good antenna and coming in S9 in Maryland on 20m.  The minimum requirement for them to hear me is that I make it over their receiver noise floor.   Let's say I need to be 10dB out of their noise floor, and their noise floor is only 10dB above the internal receiver noise.  And let's say their internal receiver noise is 60dB down from S9 on our exact same radios.

So I need to run at least -40dB down from a kilowatt in effective radiated power.

-40dBkW is 100mW :-)

If I can find a quiet spot to call, like maybe I hunt them hard and get them the second they call CQ on a clear frequency, I only need to radiate 100mW.  If I'm running 100W that means my antenna needs to have a better gain than -30dBd or so (given that a dipole radiates almost everything you apply to it) ;-)  It's actually pretty hard to build a -30dBd antenna without adding intentional resistors.

It's likely that I could have worked 3Y0X with one of those "apartment antennas" that's just a loaded whip clamped to my railing.   I could have worked them with a hamstick dipole or a TakTenna or a random wire on a fishing pole with no ground or a magnetic loop or by loading up my window frame.

So it's really missing the point in a technical sense to tell someone they *shouldn't even try* to work some DX with any given antenna system.  That is a dumb thing for someone to have told you, and it's the reason why I say that all antenna systems "work" to a certain extent.  It has to be really,  horrifically, absurdly bad to make it impossible for you to contact a DX station on a strong path when you have a good combination of luck and skill to go along with it.

The problem is, though, 3Y0PI ***is*** an easy path compared to some paths you might want to work DX on, and this is where antennas can start to show whether they're good or bad.  Polar paths to Southeast Asia from W3 have weak enough openings that I can only sometimes get through with 100W to a two element beam antenna at 30 feet, *even if there are no other callers.*  I've had YB and HL and HS stations CQ in my face, and not come back to anyone at all when I called them several times.

And those cases where I *can* make it through would turn into ones where I *didn't* if I had 5dB or 6dB or 10dB less signal!

So on one hand, it's absurd for someone to tell you not to try even if your antenna was a poor -10dBd, or maybe -20dB on a decent beam, but on the other hand, your antenna being -10dBd could totally preclude working some very long haul difficult DX.

- - - - - - -

In short: even if I suspect I've got a bad antenna, I'm gonna jump in that pileup and call my brains out.  There's a good chance I can get through.

But when I can't, I will be quick to recognize that my antenna might be BAD even if I've worked 200 DXCC on it.  That's the big deal thing here, that I can work a LOT of DX on a terrible antenna, but to work the harder stuff, the guys that CQ in my face, I may just need more radiated power than what I've got, and I should look at all my options...

And most of all, I should be careful what I try to convince new hams to build or buy based only on my logbook entries, because they might not paint the whole picture of how well or poorly my antenna is working.

73
Dan
Logged

73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
K0OD
Member

Posts: 2557




Ignore
« Reply #16 on: June 10, 2009, 12:10:30 AM »

Dan, I'm still scratching my head over this 5/5 review for the tak-tenna that was just posted.

. "I`ve made several contacts [in a month]
. in the states on 40m and also 20m, have not
. yet been able to pick up any thing DXing
. but have not really tried hard enough.
. Great reception..."


I'm doing my product reviews the wrong way. My 43 footer was up for a year before I reported on its performance, thru heat and snow and high winds. Used on all bands... phone, cw, digital... 5 or 6 contests and a full weekend of the CQWW on all bands. It was tested in hundreds of sizable pileups.
Logged
AA4PB
Member

Posts: 12856




Ignore
« Reply #17 on: June 10, 2009, 05:55:28 AM »

Humm. I've made several contacts with a 100W light bulb sitting on my desk. I guess that makes it as good as a TAK :-)
Logged
WB2WIK
Member

Posts: 20603




Ignore
« Reply #18 on: June 10, 2009, 09:21:02 AM »

>RE: New Upgrade Kit for Zero Five 43' Verticals???       Reply
by AA4PB on June 10, 2009    Mail this to a friend!
Humm. I've made several contacts with a 100W light bulb sitting on my desk. I guess that makes it as good as a TAK :-)<

::Better, if you run a carrier mode like RTTY, AM or FM because while making contacts you can use the light to read by...
Logged
K0OD
Member

Posts: 2557




Ignore
« Reply #19 on: June 10, 2009, 09:38:05 AM »

"I`ve made several contacts [in a month] in the states on 40m and also 20m"


Apparently the 40 meter monoband tak reviewed works about the same on 20. Is that good?

It would be fun and probably very educational for Eham to sponsor a "bad antenna" category within next years CQWW... Light bulbs, dummy loads, bed springs. Limited to the height of a 6-foot step ladder. The ultimate level playing field.

Seems I've heard of such a competition years ago.
Logged
N3OX
Member

Posts: 8847


WWW

Ignore
« Reply #20 on: June 10, 2009, 12:04:25 PM »

"It would be fun and probably very educational for Eham to sponsor a "bad antenna" category within next years CQWW.."

I would overall encourage anyone who's in an educational mood to make some contacts with intentionally bad antennas and post results, including how bad the antenna is relatively.

I try to do it every once and a while but it's so easy to get bored and switch back to good antenna...

I compared my 60 foot vertical on 40m using the proper matching network at the base vs. the indoor tuner with direct coax feed, measured the difference at about -10dB, and proceeded to bust a pile on C57R with the "bad" config.  But after that and a couple other contacts, I just wanted to switch back and do some hamming :-)

The more of us that do this, the bigger the database of "bad antenna success reports" gets without any one of us having to be extremely dedicated to always using one ;-)

73
Dan
Logged

73,
Dan
http://www.n3ox.net

Monkey/silicon cyborg, beeping at rocks since 1995.
W6TGE
Member

Posts: 154




Ignore
« Reply #21 on: June 10, 2009, 02:10:56 PM »

OK, I thank everyone for their reply(s). I did use this R5 at another location and know that my 3Y0PI was not a 1 time dx contact. I made many and almost became "one of them" who only cared about DX. :-)

At any rate, I have the R5 and have no downside to just trying it.

Since I believe this is now way OT, I think that I should not continue in this thread.

Great idea, BTW, about starting a thread about the worst antenna we ever used...that worked. As a Novice, my 40M dipole was at about 15'...if that...and I worked so much DX when I loaded it on 15M!
Logged
K0OD
Member

Posts: 2557




Ignore
« Reply #22 on: September 19, 2009, 01:48:22 PM »

The "MKII Upgrade Kit" to improve low-angle high-band performance has been out for many months now. ZeroFive must have sold many of them. But their site still provides no info on what the kit consists of. Google shows no discussion of this product elsewhere on the web. (zerofive owners must be too busy "busting pileups on the first call")

Maybe it's just a hack saw to chop off the top of the vertical Smiley

Let's hear from all those ZeroFive 5/5 reviewers about this.
Logged
K0CWO
Member

Posts: 418




Ignore
« Reply #23 on: September 20, 2009, 06:13:32 PM »

Looks like a stub to me.

http://viewmorepics.myspace.com/index.cfm?fuseaction=viewImage&friendID=159960568&albumID=510679&imageID=43644979#a=510679&i=43644974
Logged
K0OD
Member

Posts: 2557




Ignore
« Reply #24 on: September 20, 2009, 07:40:13 PM »

Thanks!

That's what I figured the kit would be, a short parallel radiator. I tried modeling something like that but couldn't find a length that would work on all the higher bands. Any vertical experts want to figure out how long that stub is?

http://c4.ac-images.myspacecdn.com/images02/35/l_9566a733d2864ec89356d5d3d8cbc9f7.jpg


I can see why N9ZV likes ground mounted verticals. His horizon must be on another continent! Very pretty ZeroFive installations.
Logged
K0OD
Member

Posts: 2557




Ignore
« Reply #25 on: September 20, 2009, 07:40:30 PM »

Thanks!

That's what I figured the kit would be, a short parallel radiator. I tried modeling something like that but couldn't find a length that would work on all the higher bands. Any vertical experts want to figure out how long that stub is?

http://c4.ac-images.myspacecdn.com/images02/35/l_9566a733d2864ec89356d5d3d8cbc9f7.jpg


I can see why N9ZV likes ground mounted verticals. His horizon must be on another continent! Very pretty ZeroFive installations.
Logged
K0OD
Member

Posts: 2557




Ignore
« Reply #26 on: September 20, 2009, 07:42:28 PM »

Thanks!

That's what I figured the kit would be, a short parallel radiator. I tried modeling something like that but couldn't find a length that would work on all the higher bands. Any vertical experts want to figure out how long that stub is?

http://c4.ac-images.myspacecdn.com/images02/35/l_9566a733d2864ec89356d5d3d8cbc9f7.jpg


I can see why N9ZV likes ground mounted verticals. His horizon must be on another continent! Very pretty ZeroFive installations.
Logged
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!