I found this article on Antenna dBd Vs dBi that explains why some
antennas show more gain than others. This is because the gain used in
measuring some antennas is 2.15 dB more when expressed in dBi.
http://www.maxstream.net/support/knowledgebase/article.php?kb=146
Antenna Gain: dBi vs. dBd
Tony L. wrote:
My Diamond NR73BNMO stopped working on 70cm. Tx rx are both fine on
2 meters, but the antenna will not tx or rx on 70 cm.
I swapped the antenna with a spare, and everything works fine with the
replacement antenna.
Any ideas?
Take it apart and look to see if water
Eric,
I think the reason antenna manufactures use dbi over dbd is dbi is
higher...the higher the spec the more impressed is the customer.
Most Hams probably do not know how to read the spec reference, dbi or
dbd. They see db.
When a Ringo-Ranger is advertised in Ham magazines it has 6 db
Gary,
Most of the commerical guys do have test ranges and some very
detailed and well engineered.
Most common below 1 GHz antennas were around long before computers
like the PC were avialable and their technology, although sound and
good, are old, go back into the 50s.
Some of the broadcast
Mark,
Right on the Diamond package is dbd, not dbi. However, I do not
believe if in dbi.
73, ron, n9ee/r
--- In Repeater-Builder@yahoogroups.com, N9WYS [EMAIL PROTECTED] wrote:
I believe Diamond uses gain over **isotropic** (dBi) for their
rating
specs... which might account for the
Ben,
The Phelps Dodge/Cel Wave and now Cel Wave/? had 8 Mhz.
One thing to keep in mind. The 150-160 version had 6 dbd gain, but due
to the fiber glass enclosure being only so long one element had to be
removed in the 140-150 MHz Ham version so gain was rated at 5.1 dbd.
This was from long
Mike,
I read the e-mails on the board and do not send to my personal
account. This board gets a lot of them and I have found with yahoo
by the 3rd reply the subject has gone away.
Starts like what is a good repeater antenna for 2 meters
reply #1 well in Atlanta, GA we used a DB224 side
Keep in mind that there are two (or more) ways to measure antenna band
width. One being swr band width and another being gain band width. One
doesn't necessarily follow the other.
What is advertised mostly is swr band width.
73
Gary K4FMX
-Original Message-
From:
Ok... So I've tuned this duplexer as a notch device. Put a 2 watt
handheld into a dummy load and watt meter (not in that order mind you)
and it seems to reject the corresponding frequencies. My question now
is... Why did my swr jump from 1:1.3 to 1:3. Do I need to re-tweek
it? Also I'm
At 06:49 AM 2/20/2007, you wrote:
Ok... So I've tuned this duplexer as a notch device. Put a 2 watt
handheld into a dummy load and watt meter (not in that order mind you)
and it seems to reject the corresponding frequencies. My question now
is... Why did my swr jump from 1:1.3 to 1:3. Do I need
Mike Morris WA6ILQ wrote:
And as of today we have 3402 members
Mike WA6ILQ
Wow...pretty impressive!
You guys all deserve a lot of congrats for putting this together and
making it the resource it is!
I remember Kevin making comments about how the list just passed 500,
800, then 1000...my
Paul Holm wrote:
Reading the replies that mentioned gain specs, I can't help but think of our
last ham club meeting. An older member persuaded the club to replace the
VHF repeater antenna with a Diamond X500HNA rather than a DB-224 because the
Diamond has 8.3 dB gain.
And even worse is
Can you name any of the two way antenna manufacturers that do?
73
Gary K4FMX
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Ron Wright, Skywarn Coodinator
Sent: Tuesday, February 20, 2007 8:52 AM
To:
Gary Schafer wrote:
Measured on their range-they used to be based in Cleveland, and my
father was one of the designers.
(anybody here remember the PRO-27JR 27Mhz antenna? Or the original 4BTV?)
--
Jim Barbour
WD8CHL
With all due respect to your father Jim, I think that 4 db of gain is
Jeff DePolo wrote:
There are a lot of unknown variables here, including, but not limited to the
size of the ground plane the antennas were mounted on, their heights above
the ground plane, the method of coupling to the ground plane (direct, mag
mount, etc.), matching networks' efficiencies,
Crud... I already shipped it out, with the promise that a manual would
follow shortly. I'm pretty sure it was 55 watts, though.
I suspect that I may have sent the full manual along with another Moxy I
sold a couple of years ago, though I thought I kept a copy of the alignment
procedure
I'm presently setting up 4 Delta SX UHF Transceivers as Tx'ters for a
repeater system. I have completed the mod and am presently trying to
tune radios. The problem I'm having is that my dev is up to about 9.8
kHz. My service manual says to adjust R237 (Dev Adj). The radio that I
am working on
Well, keep me posted on your findings with these things... I have a
few laying around that I already have Xtals for and want to get going.
I'll let you know if I find anything new.
-Jordan
--- In Repeater-Builder@yahoogroups.com, ka3hsw [EMAIL PROTECTED] wrote:
--- In
Oh, and 'mag mounts' didn't really exist much then...you
either mounted
the antenna in a hole, or you didn't have an antenna.
Ah, the gold old days, when men armed with a drill and Greenlee punch
thought nothing of putting holes in their roofs, fearing not the Wrath of
Wife.
Jeff DePolo wrote:
Oh, and 'mag mounts' didn't really exist much then...you
either mounted
the antenna in a hole, or you didn't have an antenna.
Ah, the gold old days, when men armed with a drill and Greenlee punch
thought nothing of putting holes in their roofs, fearing not the Wrath of
Like Ken said; all 3 ports need to be terminated in 50 ohms when tuning. A
signal generator is usually fairly close to 50 ohms, a receiver may or may
not be, usually not. The unused port at the time needs a 50 ohm load.
The best way is to use a 6 db pad on gen and rec sides while tuning.
But
I'm presently setting up 4 Delta SX UHF Transceivers as Tx'ters for a
repeater system. I have completed the mod and am presently trying to
tune radios. The problem I'm having is that my dev is up to about 9.8
kHz. My service manual says to adjust R237 (Dev Adj). The
radio that I
am
At 07:29 AM 2/20/2007, you wrote:
Ah, the gold old days, when men armed with a drill and Greenlee punch
thought nothing of putting holes in their roofs, fearing not the Wrath of
Wife.
---When I bought my new Mustang last year, within 24 hours of
bringing it home, I installed a genuine NMO
Good article Jim.
Beware of some things that you read on the web though. For example an
article on antennas in wikipida says that by using a folded dipole rather
than a regular dipole increases the radiation resistance by a factor of 4.
While the folded dipole does provide for a higher feed point
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Eric Lemmon
Sent: Tuesday, February 20, 2007 1:21 AM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Antenna Gain Specification - dBi versus dBd
The
There is also a pot for modulating the VCO ...
Sorry. That should have been a pot for modulating the reference
oscillator.
Now that dBi Vs dBd seems to have been settled, perhaps there is someone who
cares to explain if antenna manufacturers express their antenna gain with
voltage dB's or in power dB's. There is a difference.
Allan Crites
WA9ZZU
Gary Schafer [EMAIL PROTECTED] wrote:
At 08:40 AM 2/20/2007, you wrote:
Now that dBi Vs dBd seems to have been settled, perhaps there is
someone who cares to explain if antenna manufacturers express their
antenna gain with voltage dB's or in power dB's. There is a difference.
---Not really. Decibels describe performance
Hi Allan,
Here is a way to look at it that may help:
A 6 db increase in voltage doubles the voltage.
A 3 db increase in power doubles the power.
A 6 db increase in power quadruples power (4x). (An easy way to do that
is.. 2x power = 3 db. 2x power again = 6 db).
Now if we do it by
Hello,
I did those Mods before there was a Repeater Builder website, like I said in
the other email they are great little radios and make great inexpensive low
power repeaters, if you call 15 to 20 watts low power!
Paul
-Original Message-
From: Repeater-Builder@yahoogroups.com
Jordan,
Are you duplexing the radio to make a remote receiver with a UHF link,
something like that? Are you sure you have made all the mods? How close is
the transmit to the receive frequency if duplexing.
You do need to make that mod, if it's the UHF version you need to shield the
bottom of
Hello,
Anyone remember Ed Juge? I worked for him back when he had his electronics
shop on the South Freeway in Fort Worth. His wife got a new car, a little
Porsche 911 and she wanted a Ham radio installed so she could use the local
.94/10-4 repeater, Ed knew better than to try and install it on
A number of years ago... an installer I knew drilled a cell phone
mount into the transmission hump of a Jag... caught the Jag's wire
harness and shorted/burned the entire car out when he hit the key.
T'was a $4,000 + cost dealer fix...
cheers,
skipp
Paul Finch [EMAIL PROTECTED] wrote:
Can anyone tell me which Celwave model a Motorola TDN7407A is, or provide the
specs on it?
George, KA3HSW / WQGJ413
Hi All,
I'm pretty inexperienced but find myself in charge of a nice repeater
operation, 145.170 - N6FRG in Angels Camp, CA. This is a GE Mastr II
mobil unit that has been in service for many, many years. We just
replaced the 1980s era SC-1 controller with an Arcom RC210 and have a
poping
At 2/20/2007 07:11 AM, you wrote:
Paul Holm wrote:
Reading the replies that mentioned gain specs, I can't help but think
of our
last ham club meeting. An older member persuaded the club to replace the
VHF repeater antenna with a Diamond X500HNA rather than a DB-224
because the
Diamond
At 12:56 PM 2/20/2007, you wrote:
Hi All,
I'm pretty inexperienced but find myself in charge of a nice repeater
operation, 145.170 - N6FRG in Angels Camp, CA. This is a GE Mastr II
mobil unit that has been in service for many, many years. We just
replaced the 1980s era SC-1 controller with an
When it comes to gain, the Diamond probably really has 8.3 dBi.
That's probably true Bob. And the grapes to grapes comparison would
suggest that a DB224 also has ~8.3dbi of gain.
The real
difference between the two antennas is pattern shape (DB224 has a
cleaner
pattern; the
What I don't understand is how at times the DB224 is rated at 4.5 dBd, then 6
dBd, and the DB304 (twice as much aluminum) rated at 6.1 dBd. over a span of
30 years...de nu5d
There could be a number of reasons. You are going to have to be a
little more specific as Poping a really vague term. If possible try
recording it and post it as a .WAV or .MP3.
This could be anything from a loose wire to desence caused by the
oscillators in the controller.
My research says:
Is the speaker connected to the MASTR II? If you disconnected the speaker,
the AF amp can oscillate, which could make this noise...
Jeff
At 05:33 PM 2/20/2007, you wrote:
There could be a number of reasons. You are going to have to be a
little more specific as Poping a really vague term. If
Check your deviation, maybe you are exceeding the bandwidth of your
receiver.
Adam Kb2jpd
On 2/20/07, Shorty Stouffer [EMAIL PROTECTED] wrote:
Ken Sanders - AE6LA wrote...
We just replaced the 1980s era SC-1 controller with an Arcom RC210 and
have a
poping noise when repeating but not during
--- In Repeater-Builder@yahoogroups.com, Steven Samuel Bosshard
\(NU5D\) [EMAIL PROTECTED] wrote:
What I don't understand is how at times the DB224 is rated at 4.5
dBd, then 6 dBd,
H that's a new one. Where/when and what frequency range have
you seen the DB224 rated at 4.5dbd?
and
But don't mount it upside down. The base is not waterproof when
inverted -
I learned that the hard way!
73 - Jim W5ZIT
-Original Message-
From: [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Tue, 20 Feb 2007 3:19 PM
Subject: [Repeater-Builder] Re: Antenna gain specs
-Original Message-
From: Repeater-Builder@yahoogroups.com [mailto:Repeater-
[EMAIL PROTECTED] On Behalf Of Laryn Lohman
Sent: Tuesday, February 20, 2007 5:59 PM
To: Repeater-Builder@yahoogroups.com
Subject: [Repeater-Builder] Re: Antenna gain specs
--- In
Well, I've been playing with GE MVP's, Exec II's and Mastr II's for years
and never had a casting develop whiskers... until now. This was a VHF high
band MVP and when I took it apart, there was one whisker that had to go an
inch long. That particular helical section was completely dead to
I belive the double dipole (304) was supposed to have a more omni-directional
pattern (the books show a 'normalized' pattern) - I will have to dig out some
old DB Products catalogs, or call Lloyd Alcorn in Waco (he designed the 224 for
DB before he and Kit Parsons and Larry Bush started Wacom
Ken,
I, too, used a Greenlee hole punch before I discovered the Ripley HSK-19
Antenna Hole Saw. The description in the catalog states: Ripley hole saw
for installing permanent mount antennas. Makes 3/4 hole and limits depth
to 1/8... It is sold by Tessco as catalog number 14023. It's a lot
--- In Repeater-Builder@yahoogroups.com, Ken Arck [EMAIL PROTECTED] wrote:
At 07:29 AM 2/20/2007, you wrote:
I have friends That think drilling a hole in a car or truck new or
even a used one is a sin . I try not to but if necessary to get
Antenna on ill go for the drill and Greenlee punch
Is 900 Mhz still useable for repeater linking, or is it so full of
garbage that there would be problems? How about 440 Mhz?
Thanks, Al KB2AYU
Yes, the Vatican does have a lot of influence around the world.
Sorry, couldn't resist.
73,
Al, K9SI
I suggest checking with your local frequency coordination group(s) for
the bands. Linking in the 440Mhz band is generally not acceptible
however the 420-430Mhz portion of the amateur 70cm band is used for
linking in some regions.
Gary
let_cyber wrote:
Is 900 Mhz still useable for repeater
Dear Colleagues,
I've laid out the big bucks and purchased an HP 8753C network
analyzer so my previous and trusty HP 8505A system is now offered for
sale. Using a network analyzer provides the fastest and most
accurate means of tuning duplexers. Here are the details.
It's completely
On 2/20/07, Jim Cicirello [EMAIL PROTECTED] wrote:
It is important to note that antenna gain is different than amplifier
gain. Antennas do not have a power source that allows the antenna to
create additional energy to boost the signal. An antenna is similar to
a reflective lens in principle -
On 2/20/07, Ron Wright, Skywarn Coodinator [EMAIL PROTECTED] wrote:
When a Ringo-Ranger is advertised in Ham magazines it has 6 db gain.
When advertised in commerical publications/catalogs it has 4.5 db
gain...same antenna, same part number.
Even getting 4.5dB gain out of a Ringo Resistor is
On 2/20/07, Chuck Kelsey [EMAIL PROTECTED] wrote:
Well, I've been playing with GE MVP's, Exec II's and Mastr II's for years
and never had a casting develop whiskers... until now. This was a VHF high
band MVP and when I took it apart, there was one whisker that had to go an
inch long. That
At 2/20/2007 05:39, you wrote:
Could never understand why a Diamond long 18 ft dual band antenna has
about 8 dbd on VHF/11 dbd on UHF when a commerical antenna like the
Super Station Master or DB224 has 6 db. Think the commerical people
know why, not, hi.
The Diamond specs are actually dBi, not
At 2/20/2007 16:20, you wrote:
Well, I've been playing with GE MVP's, Exec II's and Mastr II's for years
and never had a casting develop whiskers... until now. This was a VHF high
band MVP and when I took it apart, there was one whisker that had to go an
inch long. That particular helical section
At 2/20/2007 18:08, you wrote:
Ken,
I, too, used a Greenlee hole punch before I discovered the Ripley HSK-19
Antenna Hole Saw. The description in the catalog states: Ripley hole saw
for installing permanent mount antennas. Makes 3/4 hole and limits depth
to 1/8... It is sold by Tessco as
At 2/20/2007 21:51, you wrote:
On 2/20/07, Ron Wright, Skywarn Coodinator [EMAIL PROTECTED] wrote:
When a Ringo-Ranger is advertised in Ham magazines it has 6 db gain.
When advertised in commerical publications/catalogs it has 4.5 db
gain...same antenna, same part number.
Even getting
At 2/20/2007 20:05, you wrote:
I suggest checking with your local frequency coordination group(s) for
the bands. Linking in the 440Mhz band is generally not acceptible
... in California. However, I understand that some other parts of the
country have used 440-442 paired with 445-447 MHz for
Yes, The short answer is yes. The power supply ground and battery supply
ground were not tied together but are now. And both the digital and analog
grounds are connected to the power supply ground.
73, Ken Sanders - AE6LA
BRBRBR**BR Check out free AOL at
I have uploaded the schematic for a 556-based version of the Simple
Repeater Fan Controller (original 555-based version by Bob Shepard, KA9FLX)
to the Pix folder in the file area on Yahoo. I left out the LED's (you
can all figure out where to put them if you want them) and added a diode
anyone know where i could find a power cable for a signal group
suitcase repeater. this has a 50 watt amp, battery and two bendix king
portables inside. I need the power cable... a 7 pin military type
plug for the repeater unknown what would be on the other end..
thanks... allen...
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