wrote:
On 7 Feb 2005 21:27:32 -0800, wrote:


I couldn't find anything there that was similar
to this:

http://www.drslick.org/Temp1/yagiplot.jpg

You can lead a horse to water, still can't get it damp.


I would like an H-plane plot, if possible,
and i'm looking for a cardiod pattern, as above,
but with higher dBi if possible.



You'd have to look at the data sheet. All the commercial people
are aware of this and it's accepted practice.

What you missed is a 2 or 4bay dipole is a really nice antenna
that can offer gain and pattern control. The usual use is a 4 bay
vertically oriented with each of the 4 dipoles spaced 90 degrees
around the mast for 5.6db omnidirectional gain. Now, if you want a
directional pattern, such as cartioid then put all four on one side,
also expect slightly higher gain as well. The commercial version are
expensive but are known for their durability but, the good news is
they can be built using copper pipe and will give the same
perfomance. I might add, the gain numbers I gave are not theory,
they are real numbers from proven designs.


2 bays is big and heavy enough! 4 would be
a bit overkill in this situation.



http://dipole.w4zt.com/ look at the plumbers dipole page.
This can be built as a 1/2/4/8 dipole array. The limit is 4


I've tried using an SO-239 attached to the
antenna itself (as they have done here), and it's
a bad idea...pot metal is very weak.



direction. These designs will you get away from theory and use
practical designs.


The theory is close to reality in my case! Except
for the F/B ratio, which seems a bit exaggerated.





A repeater group I work with locally used the DBproducts 4bay and
found it the best antenna they've put on the tower to date. It
wasn't
cheap and it was heavy. Experience at that site was anything less
robust would barely stand a year before the SWR went to unacceptable.
I've built the 4bay for UHF and it's a solid performer. The all
copper design weathers very well, is very cheap to build
and performs just as well as the commercial versions which are welded
up from aluminum.


yeah, but UHF versus VHF is gonna be a huge
difference weight and size wise!



I'm sure your getting results from the Jpole but, I can be certain
from using them myself that your results are part luck and can easily
be attributed to the added height (the 70+inches can really help)
and
placement more than the presumed gain. If you compare a yagi or
dipole to a J-pole the radiating element must be the same height.
Since the J-pole is really an end fed dipole it has a 38 inch
advantage. For a yagi the centerpoint is the boom.. In direct
comparisons the yagi you built would have to be minimally 3ft higher
to compete on fair ground.


The Super J-pole was actually about 5 ft. lower than the
Yagi, so it evened out in the end.


S.

John Smith wrote:
wrote:
Roy Lewallen wrote:

wrote:

My Goodness! I would never break any
FCC rules! How dare you accuse me.
. . .

No need for anyone to accuse you, it's all there on the Web:




http://www.talkaboutradioshows.com/g...ages/7526.html


Don't be silly Roy! I might sell 100 watt
broadcast band transmitters, but i only encourage
people to use them into 50 Ohm non-radiating dummy
loads!

Hehe! Makes a great bed-warmer!


This is an outright lie. On Ebay and at


http://www.talkaboutradioshows.com/g...ages/7526.html

you say:

"...WHETHER 50 OHM DUMMY LOAD OR A

PROPERLY TUNED ANTENNA..."

An antenna is not in the category of "...non-radiating dummy loads!".



But if you read it carefully, you will
note that i only am stating the conditions whereby the
final transistors will not be blown, which is
a 50 Ohm dummy load or a properly tuned antenna.

But I don't encourage anyone to break the law,
heaven forbid!

:^/

S.

On 8 Feb 2005 11:55:02 -0800, wrote:

I would like an H-plane plot, if possible,
and i'm looking for a cardiod pattern, as above,
but with higher dBi if possible.

Try google, or better yet do a little work. I've already done a fair
bit.

2 bays is big and heavy enough! 4 would be
a bit overkill in this situation.

Not likely.

I've tried using an SO-239 attached to the
antenna itself (as they have done here), and it's
a bad idea...pot metal is very weak.

It's a good idea, use a good connector, most of the quality ones are
nickel or siver plated brass. The ratchack ones are garbage. I
prefer Type N connectors as they are easier to waterproof and good
ones are quite solid.

yeah, but UHF versus VHF is gonna be a huge
difference weight and size wise!

Yep, 3:1. Use light metal. Though using 1/2 inch copper is not as
heavy as it may seem as it's also structural. I have built them for
VHF too.

Of course for 100mhz FM use they do grow a bit and may be too obvious
for a stealth operation.

The rules are simple. Want more signal, put up more metal.

Allison

On 07/02/2005 4:52 PM, wrote:
Richard Clark wrote:

On 7 Feb 2005 01:44:10 -0800, wrote:

Come listen for yourself...

????? Volume has nothing to do with this!

You could throw a dead carrier and still
have an idea of how close to full quieting you
are....

Obviously your hearing perception exceeds the characteristics of a
larger part of mankind. This makes any claims for someone ELSE to
listen to the difference even more problematic.

Hearing is the poorest measure second only to "seeing" for one self.
Leave this type of testimonial for the Sunday services.


A good receiver actually gives you
TONS of information. You can hear overmodulation,
sideband "splatter" to adjacent channels,
spurious oscillations on other channels,
dead carrier hum in your signal, the overall
intelligibility of your signal and the audio frequency
response (roughly). No field strength meter can
tell you this information!

Bottom line is, human hearing is
the ultimate destination. It can
be more qualitative that quantity.


However, it is exactly these aspects that make human hearing terrible
for side-by-side comparisons like the one initially described by the OP.

There are plenty examples of double-blind tests that indicate that the
participating observer often makes the worst sort of qualitative judgements.

Human judgement is a useful tool, especially when trying to understand
the hard-to-quantify. However, I find it dubious that anyone has ears
good enough to hear the quality of an audio signal that is the result of
+- 1dB of RF gain presented to the front-end. (This is not to say I
think that the OP only used this method to get his/her results.
Clearly, the OP used some sort of methodology to obtain the +1dB gain
claim. I only suggest that we should be critical of qualitative
results that back up the results we want.)

Results to the contrary from a proper double-blind test backed up by
multiple datasets based on what we /can/ measure would convince me
otherwise.

A better qualitative test would be to simply live with the antenna for a
few weeks, and see what DX one could pull in. Again, totally
unscientific; but this is what average radiopersons (like me, I'm
afraid!) have been doing for decades now.

I look at this sort of thing as an example of the "right tool for the
right job."

wrote:
. . .
But I don't encourage anyone to break the law,
heaven forbid!

Most of these are no longer on the web, but they were on 9-19-03 when I
originally posted them he

From http:http://www.metroactive.com/papers/me...eat-9735.html:

I missed Creech but got to hear a tape of the band's performance two
days later on a micropowered radio station broadcasting at 91.3FM out of
Los Gatos known as Radio Free Lost Gatos. The guys in Creech guest DJed,
heckled callers and played the whole of their set along with some of
their favorite bands. According to RFLG owner/manager/DJ Dr. Slick, the
station has been operating out of a house "buried in the Los Gatos
hills" for three years. "I do it for fun," Slick says. "I don't do it
because I'm an 'anarchist.' I don't go out and say, 'Kill the cops.' I'm
positive with radio."

Slick was mum on the wattage but said that 91.3 reaches all of Los Gatos
and parts of Campbell. Slick plays classic rock, jazz and "a little bit
of Bach" when not turning the controls over to guest DJs like the
members of Creech. The station can be heard Sundays and Wednesdays,
8pm*3am. Meanwhile, the next Gaslighter Theater show stars Monkey, Blue
Beat Stompers, Steadyups, Lucky Strike and Pigs in Space on Friday
(Sept. 5). As always: all ages and five bucks.

From http://www.svcn.com/archives/lgwt/05...PirateCat.html

Monkey Man stepped into the world of microbroadcasting about a year ago,
with his friend Michael Magic at Free-Radio San Jose, 93.7 FM, but had
to leave the station after some of his on-air hi-jinks went too far.
After that, he started working with Dr. Slick, whose station, Free-Radio
Los Gatos, is on 91.3 FM on Sunday and Wednesday nights from 8 p.m. to
11 p.m.

"Then Dr. Slick said I should get my own station, so I went down to
Fry's and got one of those little radio kits for, like, $30." Dr. Slick
gave Monkey Man an old one-watt amplifier, and another friend, Austin
Tatious of KKUD 104.1 in Willow Glen, donated a mixing board. Pirate Cat
was on the air.

------------- end of Web quotes ---------------

At the time, I asked:

"It looks like we can look forward to a bigger signal from Radio Free
Lost Gatos (or is it Free-Radio Los Gatos?). No more 'all of Los Gatos
and parts of Campbell'! Or are you be building FM transmitters and
amplifiers for sale?"

It looks like we now have the answer.

Roy Lewallen, W7EL

clvrmnky wrote:


A good receiver actually gives you
TONS of information. You can hear overmodulation,
sideband "splatter" to adjacent channels,
spurious oscillations on other channels,
dead carrier hum in your signal, the overall
intelligibility of your signal and the audio frequency
response (roughly). No field strength meter can
tell you this information!

Bottom line is, human hearing is
the ultimate destination. It can
be more qualitative that quantity.


However, it is exactly these aspects that make human hearing terrible

for side-by-side comparisons like the one initially described by the
OP.

There are plenty examples of double-blind tests that indicate that
the
participating observer often makes the worst sort of qualitative
judgements.



But any radio broadcaster worth his or her
salt will be able to tell APPROXIMATELY how many
watts a signal is producing (or ERP), especially since
we don't have ionospheric skip in the broadcast
band, all line of sight.



Human judgement is a useful tool, especially when trying to
understand
the hard-to-quantify. However, I find it dubious that anyone has
ears
good enough to hear the quality of an audio signal that is the result
of
+- 1dB of RF gain presented to the front-end.


-1 dB at 100 watts is about 79 watts, so
yeah, most people with a good receiver aren't
going to hear the difference. But some
people very familiar with the signal might
notice the difference.

-2 dB at 100 watts is about 63 watts, which
most people should notice, especially on the
fringe of the service area.

-3 dB is 100 versus 50 watts, and no
**** there's an audible difference!





(This is not to say I
think that the OP only used this method to get his/her results.
Clearly, the OP used some sort of methodology to obtain the +1dB gain

claim. I only suggest that we should be critical of qualitative
results that back up the results we want.)


+1 dB was what our theoretical
difference was, but it may have been more.

Sorry, but we don't have a huge VHF anechoic
chamber, and the proper signal strength meter
to do this properly!





A better qualitative test would be to simply live with the antenna
for a
few weeks, and see what DX one could pull in. Again, totally
unscientific; but this is what average radiopersons (like me, I'm
afraid!) have been doing for decades now.


Like i said, I would love to have a
big VHF anechoic chamber, and place each antenna
on a rotor, and measure every 2 degrees or so,
with the proper uV/meter equipment, but
we don't have the $$ for that. Most people
don't, i don't know anyone who does.

It may be unscientific, but in a certain
way NOT, because you can get field reports from
many people, who all have different receivers,
and different antennas on their cars, etc... so
the results are more of an averaged response.

Bottom line is, is the signal more
intelligible and listenable?


Slick

Roy Lewallen wrote:
wrote:
. . .
But I don't encourage anyone to break the law,
heaven forbid!

Most of these are no longer on the web, but they were on 9-19-03 when
I
originally posted them he

From http:http://www.metroactive.com/papers/me...eat-9735.html:

I missed Creech but got to hear a tape of the band's performance two
days later on a micropowered radio station broadcasting at 91.3FM out
of
Los Gatos known as Radio Free Lost Gatos. The guys in Creech guest
DJed,
heckled callers and played the whole of their set along with some of
their favorite bands. According to RFLG owner/manager/DJ Dr. Slick,
the
station has been operating out of a house "buried in the Los Gatos
hills" for three years. "I do it for fun," Slick says. "I don't do it

because I'm an 'anarchist.' I don't go out and say, 'Kill the cops.'
I'm
positive with radio."

Slick was mum on the wattage but said that 91.3 reaches all of Los
Gatos
and parts of Campbell. Slick plays classic rock, jazz and "a little
bit
of Bach" when not turning the controls over to guest DJs like the
members of Creech. The station can be heard Sundays and Wednesdays,
8pm=AD3am. Meanwhile, the next Gaslighter Theater show stars Monkey,
Blue
Beat Stompers, Steadyups, Lucky Strike and Pigs in Space on Friday
(Sept. 5). As always: all ages and five bucks.

From http://www.svcn.com/archives/lgwt/05...PirateCat.html

Monkey Man stepped into the world of microbroadcasting about a year
ago,
with his friend Michael Magic at Free-Radio San Jose, 93.7 FM, but
had
to leave the station after some of his on-air hi-jinks went too far.
After that, he started working with Dr. Slick, whose station,
Free-Radio
Los Gatos, is on 91.3 FM on Sunday and Wednesday nights from 8 p.m.
to
11 p.m.

"Then Dr. Slick said I should get my own station, so I went down to
Fry's and got one of those little radio kits for, like, $30." Dr.
Slick
gave Monkey Man an old one-watt amplifier, and another friend, Austin

Tatious of KKUD 104.1 in Willow Glen, donated a mixing board. Pirate
Cat
was on the air.


Cool article! Yeah, i remember those days well....sigh.

Great times!





At the time, I asked:

"It looks like we can look forward to a bigger signal from Radio Free

Lost Gatos (or is it Free-Radio Los Gatos?). No more 'all of Los
Gatos
and parts of Campbell'! Or are you be building FM transmitters and
amplifiers for sale?"

It looks like we now have the answer.



Radio Free Los Gatos doesn't exist anymore, but thanks
for bringing up good memories!

We serve the San Jose/Milpitas area now.

Just because i build transmitters, don't mean
i encourage people to use radiating loads with them!
Dummy loads are a wonderful thing, and you can learn
so much about RF circuit design and the phase-locked-loop!


Slick

wrote:


2 bays is big and heavy enough! 4 would be
a bit overkill in this situation.

Not likely.


Definitely! You try putting up a VHF
Super J-pole yourself! You are probably
more used to UHF, so 4 bays doesn't scare
you, but at the broadcast band, you will need
some serious help.

I would love to see what a 4 bay
would do though, but you need serious
bucks to do that, plus alot of manual
labor...




I've tried using an SO-239 attached to the
antenna itself (as they have done here), and it's
a bad idea...pot metal is very weak.

It's a good idea, use a good connector, most of the quality ones are
nickel or siver plated brass. The ratchack ones are garbage. I
prefer Type N connectors as they are easier to waterproof and good
ones are quite solid.


He doesn't explicitely say brass in
his website, and looking at the picture, it
looks like a cheapie SO-239 made of pot metal.

It's a bad idea overall. I would
mount it with 4-40 nuts and bolts on
an aluminum plate, and then attach
that to the antenna.

I've had to take an antenna
down before, just to replace the
broken SO-239 that i used in this
way. Bad idea. You have to make
your antenna very physically strong,
unless you like to spend a lot of time
on your rooftop.



yeah, but UHF versus VHF is gonna be a huge
difference weight and size wise!

Yep, 3:1. Use light metal. Though using 1/2 inch copper is not as
heavy as it may seem as it's also structural. I have built them for
VHF too.


1/2" copper gets heavy with 2 bays, trust me.

Especially for something like the Super J.





The rules are simple. Want more signal, put up more metal.


Or want more ERP, or a lower angle
of radiation, put up more metal.

I would agree.



Slick

wrote:
Radio Free Los Gatos doesn't exist anymore, but thanks
for bringing up good memories!

Remember KFAT? "The Free Mexican Air Force"?
Those were the days.
--
73, Cecil http://www.qsl.net/w5dxp


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On 8 Feb 2005 18:49:05 -0800, wrote:

-3 dB is 100 versus 50 watts, and no
**** there's an audible difference!

Only to a piece of toast.