Buddistick or Buddipole?

classic Classic list List threaded Threaded
4 messages Options
Reply | Threaded
Open this post in threaded view
|

Buddistick or Buddipole?

Fred (FL)
I've been considering the Buddi antenna, for a while
now.  It seems to be built well.

One thing I've not been able to establish - is how
much HF bandwidth does the antenna exhibit - once one
sets the clips on those 2 coils, and gets resonance?
I just wonder if a constant readjusting is necessary
with this antenna, when we move up and down the
HF bands?   20M CW  then 20M SSB .......

In other words - if antenna was all set up outside,
would a HF user be required to continually adjust
either the clips or the whips - when an operator
goes from SSB to CW portions of the band, etc.?

I tried some years back, to make a "dipole" out of
Hustler mobile elements, with some adjustable whips
- but never was able to get it to resonate very
reliably.   Those were in my no-tuner IC-730 days.

Those are my questions regarding the Buddi line
of dipoles and verticals, with coils and clips.

Fred
N3CSY, FL

Very seriously considering one.

Fred, N3CSY
FL



 
____________________________________________________________________________________
The fish are biting.
Get more visitors on your site using Yahoo! Search Marketing.
http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Reply | Threaded
Open this post in threaded view
|

Re: Buddistick or Buddipole?

n6wg
Hi Fred
Any antenna heavily loaded with coils will show a narrow bandwidth.
In effect, the coils and the capacitance of the antenna elements
across them form a tuned circuit.  The higher the Q of the tuned
circuit (meaning the lower the coil losses) the narrower the
bandwidth, but the higher the efficiency.  If you find a loaded
antenna with a large bandwidth, it is by definition much less
efficient due to the inherent losses.

There really is no free lunch.

Sometimes you can fudge a bit by tuning such an antenna to
the center of a band, and using an autotuner like the Elecraft
T1 at the feedpoint.  Then, once you get away from the resonant
frequency of the antenna, it acts as if it were a simple nonresonant
centerfed piece of wire and the tuner will give you as good a
match as it can.

Good luck and 73
Bob N6WG


----- Original Message -----
From: "Fred (FL)" <[hidden email]>
To: <[hidden email]>
Sent: Friday, April 06, 2007 8:42 AM
Subject: [Elecraft] Buddistick or Buddipole?


> I've been considering the Buddi antenna, for a while
> now.  It seems to be built well.
>
> One thing I've not been able to establish - is how
> much HF bandwidth does the antenna exhibit - once one
> sets the clips on those 2 coils, and gets resonance?
> I just wonder if a constant readjusting is necessary
> with this antenna, when we move up and down the
> HF bands?   20M CW  then 20M SSB .......
>
> In other words - if antenna was all set up outside,
> would a HF user be required to continually adjust
> either the clips or the whips - when an operator
> goes from SSB to CW portions of the band, etc.?
>
> I tried some years back, to make a "dipole" out of
> Hustler mobile elements, with some adjustable whips
> - but never was able to get it to resonate very
> reliably.   Those were in my no-tuner IC-730 days.
>
> Those are my questions regarding the Buddi line
> of dipoles and verticals, with coils and clips.
>
> Fred
> N3CSY, FL
>
> Very seriously considering one.
>
> Fred, N3CSY
> FL
>
>
>
>
>
____________________________________________________________________________
________

> The fish are biting.
> Get more visitors on your site using Yahoo! Search Marketing.
> http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Reply | Threaded
Open this post in threaded view
|

Re: Buddistick or Buddipole?

k6dgw
Bob Tellefsen wrote:
> Hi Fred
> Any antenna heavily loaded with coils will show a narrow bandwidth.
> In effect, the coils and the capacitance of the antenna elements
> across them form a tuned circuit.  The higher the Q of the tuned
> circuit (meaning the lower the coil losses) the narrower the
> bandwidth, but the higher the efficiency.  If you find a loaded
> antenna with a large bandwidth, it is by definition much less
> efficient due to the inherent losses.

My BP is quite narrow-band, and the BW decreases as one goes to lower
bands [more of the equivalent circuit of the overall antenna resides in
the lumped, hi-Q inductance I guess].  It'll cover the nominal CW
portion of the higher bands, 30m --> 10m if I adjust it for the middle
of the sub-band.  On 40, if I adjust it with the MFJ 259 at 7025, it'll
be under 1.5:1 from 7000 to maybe 7040 or so, but the VSWR rises rapidly
above that.  I don't have the 80m coils, but I would suspect it would be
VERY narrow that low in freq.  I'm not sure just how useful an antenna
as small as a BP would be on 80m at QRP levels.

> There really is no free lunch.

The B&W "all band folded dipole" exhibits acceptable VSWR 3-30 MHz,
which sounds like free food.  It also includes a resistor which forms
the major source of the feed impedance [and that eats a chunk of your
power] so the "lunch" turns out not to be quite free after all.  In
fact, it's common for dummy loads to exhibit a phenomenal VSWR bandwidth.
>
> Sometimes you can fudge a bit by tuning such an antenna to
> the center of a band, and using an autotuner like the Elecraft
> T1 at the feedpoint.

Note, Bob says "at the feedpoint," which would be up at the VersaTee.
Using an autotuner in the radio [e.g. KAT2 or KAT100] gives 1.0:1
matches but the losses go up in the coax.

I do make a lot of Q's on my BP with the K2 and KX1.  Biggest thing I've
found is to get the antenna up in the air and away from other objects.
The threads on the BP mast fit painter's poles which is what I use.
This July will be my first FOTBB with the BP.  I'm anxious to see if it
beats the 27' wire in the tree.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2007 CQP Oct 6-7
- www.cqp.org
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

Reply | Threaded
Open this post in threaded view
|

Re: Buddistick or Buddipole?

Bernie Gardner
In reply to this post by Fred (FL)
I had a combined work/vacation trip in February that prompted me to take my
K2/100  along.  I wasn't going to be in a position to put up a dipole, even a
Buddipole, so I bought a Buddistick.  I hoped it would allow me to make a few
contacts without adding unduly to my luggage, and it pretty much met my
expectations.  I didn't have time to operate extensively, but as an example
of the possibilities I had a ~half hour ssb contact from Santa Fe, NM to
Hawaii and later in the trip a brief contact from Hawaii to South Africa.  As
has been mentioned by others, any shortned antenna is a compromise, but as
long as you recognize that, some interesting contacts can be made.  The
Buddistick requires some fiddling with the counterpoise to get a good match.  
I just used the internal K2/100 swr indication to tune the antenna.  

The quality of construction and convenience of the packaging of the Buddistick
are great.  To answer your primary question, I would concur with earlier
comments that you can get most of the 20 meter cw portion without retuning,
and comparable bandwidth on other bands, though maybe a bit less on 40.   I
just mounted the Buddistick on the Balcony of the Condos I was staying in, so
retuning wasn't too much of a problem.  The Buddipole in dipole mode might be
more difficult, though possibly with better performance?

Bernie
W1AZ

On Friday 06 April 2007 11:42, Fred (FL) wrote:

> I've been considering the Buddi antenna, for a while
> now.  It seems to be built well.
>
> One thing I've not been able to establish - is how
> much HF bandwidth does the antenna exhibit - once one
> sets the clips on those 2 coils, and gets resonance?
> I just wonder if a constant readjusting is necessary
> with this antenna, when we move up and down the
> HF bands?   20M CW  then 20M SSB .......
>
> In other words - if antenna was all set up outside,
> would a HF user be required to continually adjust
> either the clips or the whips - when an operator
> goes from SSB to CW portions of the band, etc.?
>
> I tried some years back, to make a "dipole" out of
> Hustler mobile elements, with some adjustable whips
> - but never was able to get it to resonate very
> reliably.   Those were in my no-tuner IC-730 days.
>
> Those are my questions regarding the Buddi line
> of dipoles and verticals, with coils and clips.
>
> Fred
> N3CSY, FL
>
> Very seriously considering one.
>
> Fred, N3CSY
> FL
>
>
>
>
> ___________________________________________________________________________
>_________ The fish are biting.
> Get more visitors on your site using Yahoo! Search Marketing.
> http://searchmarketing.yahoo.com/arp/sponsoredsearch_v2.php
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
> Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
> Help: http://mailman.qth.net/subscribers.htm
> Elecraft web page: http://www.elecraft.com
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com