I have had that happen on radios that had been overheated and needed the lead
tabs resoldered on the output transistors to get the power back up. maybe not
your case though. Usually most radios will make more than their rated power
especially at higher input voltages. Sometimes not for long
Bob,
When we as ham use commercial cut antenna in the ham bands that were
designed for 450-470 MHz down at 441 MHz you will have what is called
electrical down tilt. As a result, your reflected power will rise the more
you take the antenna out of band. You can call and ask our friends at
First off you will definitely loose some of the gain from the original
rated specs. About 1.5 - 2 Dbd. is what I'd expect...Maybe a little
worse depending on where the antenna was originally cut for... For
example, If the antenna was originally built for say a 454.xxx freq
(center freq) the
Well said. Thank you Jeff.
Chuck
WB2EDV
- Original Message -
From: Jeff DePolo [EMAIL PROTECTED]
To: Repeater-Builder@yahoogroups.com
Sent: Saturday, June 07, 2008 9:25 AM
Subject: RE: [Repeater-Builder] Re: antenna suggestions for 440mhz
First off you will definitely loose some of
Tom,
It appears that the final transistor Q2740 is dead, and the driver
transistor Q2730 is running wide open. The driver normally provides about
13 watts to the final. Check all solder joints and verify the correct DC
voltages are present during transmit. An RF millivoltmeter can be a great
Cheaper to just buy another UHF MaxTrac or Radius and swap the PA outright. By
the time you figure in the troubleshooting and repair time to replace Q2740,
you'd be better off with another radio and keep the best looking and working
parts.
Bob M.
==
--- On Sat, 6/7/08, Eric Lemmon [EMAIL
In fear of moving off topic... I'd like to ask how one can determine the
electrical downtilt of an antenna?
I just put into service a RSF/Celwave Super StationmasterR Model 10017-6
that is designed for 925-960 MHz on my 927.5250 repeater. The added gain
factor of the antenna (an additional 4dBd
down-tilt is specified when ordering the unit
other than the original paperwork, the only method would be to have it
tested on a test range
and that would probably cost more than ordering a new one
Gary
- Original Message -
From: n9wys
To:
Thanks Gary.
I was looking for more of a generic answer along the lines of, As you
move down in frequency, electrical downtilt . (Enter INCREASES or
DECREASES here as necessary -- if this is the case.)
I am also wondering if 20MHz on the receive is far enough off to cause a
problem.
well, as has been commented, if it was not ordered with down-tilt, there will
be none at any freqency you put into it, as all elements are exactly in-phase
since the method of acheiving down-tilt was to make the feeds to the lower
elements shorter, if it originall had down-tilt I'd venture that
At 6/7/2008 08:22, you wrote:
In fear of moving off topic... I'd like to ask how one can determine the
electrical downtilt of an antenna?
I just put into service a RSF/Celwave Super StationmasterR Model 10017-6
that is designed for 925-960 MHz on my 927.5250 repeater. The added gain
factor of
Maybe you're already hearing as well as you're going to at that site.
A given user signal is only going to be so strong compared to the
noise level no matter what you do.
Jeff
--- In Repeater-Builder@yahoogroups.com, n9wys [EMAIL PROTECTED] wrote:
In fear of moving off topic... I'd like to
Hi Guys,
My question is have you ever put up a downtilt antenna to replace an antenna of
the same configuration, i.e. gain, etc. and have been able to say with 100%
certainly that the downtilt worked? My 911 center went to high band for fire.
Within a few days Industry Canada was on the phone
OK, thanks Jeff. That could well be.
I'm aware that higher gain figures on an omni antenna result in a narrower
vertical beam width, so maybe the stations that aren't getting in as well as
I'm expecting are under the optimal antenna beamwidth/pattern.
Or am I just trying to be too cerebral
So throwing in an RX pre-amp wouldn't help much either, then... hehehehe
Thanks, Bob!
Mark - N9WYS
-Original Message-
From: Repeater-Builder@yahoogroups.com On Behalf Of [EMAIL PROTECTED]
Sent: Saturday, June 07, 2008 11:35 AM
To: Repeater-Builder@yahoogroups.com
Subject: RE:
The Stationmaster is a collinear array (I believe that is how it is best
described?) and not a multiple folded dipole array; so the elements are not
fed in parallel but rather in series. If I was reading the thread
correctly, parallel fed dipole arrays are not susceptible to
frequency-dependent
I was looking for more of a generic answer along the lines
of, As you
move down in frequency, electrical downtilt . (Enter INCREASES or
DECREASES here as necessary -- if this is the case.)
I know you wanted a short answer, but this got kind of long-winded...
A series-fed antenna will
At 6/7/2008 10:24, you wrote:
Hi Guys,
My question is have you ever put up a downtilt antenna to replace an
antenna of the same configuration, i.e. gain, etc. and have been able to
say with 100% certainly that the downtilt worked? My 911 center went to
high band for fire. Within a few days
Hello Mark - I wondering at what height your antenna is mounted?
Or going to be mounted - Dave / NØATH
- Original Message -
From: n9wys
To: Repeater-Builder@yahoogroups.com
Sent: Saturday, June 07, 2008 11:17 AM
Subject: RE: [Repeater-Builder] Re: antenna suggestions for 440mhz
Thanks
I Have A Spectra D43KXA7JA5BK . How Can I Fix To Make It Scan My Freq.
Do I Need To Reprogrammed ? Or Change The MLM Module ? Or What ?
Someone . PLEASE HELP !! Thanks
You need to add the channels to a scan list to get them to be scanned.
Whether your radio will scan or not is controlled by the firmware. Some will,
some won't. It requires programming to enter the scan list and test it. If the
radio's feature-set and firmware won't support it, the programming
Jeff
Thank you - you did an excellent job of explaining / writing the answer.
Now save it, so you can cut and paste it next month when someone asks the
question again.
I am a Spirit Dealer, and at New-Tronics (the parent company for Hustler
Antennas too), we actually make the antennas
I guess I'm going to have to post the picture to the group... it's relevant
to good repeater building in rugged ice conditions...
W6CBS - CBS Bill
-Original Message-
From: Repeater-Builder@yahoogroups.com
[mailto:[EMAIL PROTECTED] On Behalf Of Bill Hudson
Sent: Saturday, June 07, 2008
OK - I put 3 pictures in the photos section at Yahoo Groups - repeater
builders.
its at the end of the pictures because the album is W6CBS - Spirit
Antennas in Snow...
Bill - W6CBS
--- In Repeater-Builder@yahoogroups.com, Bill Hudson [EMAIL PROTECTED]
wrote:
I guess I'm going to have
HI, Jeff.
I realize that yours was a rather lengthy reply, but I appreciate it!
Anyway, in answer to your inquiry the specs on the antenna are:
Vertical Beamwidth: 6°
Gain: 10dBd
If you want the spec sheet, I can send it.
-Original Message-
From: Repeater-Builder@yahoogroups.com On
Hi, Dave,
It is atop a building at 240 ft AGL
the tallest building in Joliet. wink
Mark N9WYS
From: Repeater-Builder@yahoogroups.com On Behalf Of N0ATH
Hello Mark - I wondering at what height your antenna is mounted?
Or going to be mounted - Dave / NØATH
No, parallel-fed antennas do NOT suffer uptilt/downtilt as frequency is varied
unless the harness was special-ordered for factory downtilt. If the antenna
wasn't ordered with downtilt, all of the elements are fed in phase, and they
will always be in phase regardless of frequency.
Jeff, the
At 6/7/2008 17:18, you wrote:
No, parallel-fed antennas do NOT suffer uptilt/downtilt as frequency is
varied unless the harness was special-ordered for factory downtilt. If the
antenna wasn't ordered with downtilt, all of the elements are fed in
phase, and they will always be in phase
Paul,
Perhaps you can now explain how the radiation pattern changes on a single
center fed, 1/2 wave length simple dipole when the frequency is changed both
above and below the dipole resonant frequency, and how that relates to the
statements you have made below.
73 Allan Crites WA9ZZU
Allan,
I question the relevance, but here goes. I just modeled an ordinary half-wave
dipole in free space in EZNEC. 20 MHz low at 450 MHz is about 4.5%.
At 4.5% above design frequency, the difference in the pattern of the single
dipole is negligible, and the gain rises 0.04 dB.
At 4.5% below
Paul,
No, it is not my position that combining a bunch of dipoles in a co-linear
array does not change their behavior compared to a single dipole.
I was interested in having the explanation made to show that radiation
pattern down tilt of a parallel feed multiple dipole antenna is
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