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Today's Topics:
1. SELL: Power/SWR Bridge Component Package (w2cqm@juno.com)
2. Alpha 87A Problem (TNeill1648@aol.com)
3. AL-811 AMP. (Ray)
4. Re: AL-811 AMP. (carl seyersdahl)
5. W7EME 144 mcs. 8877 problems (Jeremy Alexander)
6. Re: W7EME 144 mcs. 8877 problems (jeff millar)
7. Fusing the Plate winding (Jim Isbell, W5JAI)
8. Re: 10dB and propagation (K3BU@aol.com)
9. Re: 10dB and propagation (Ian White G3SEK)
10. Re: QRO (John Irwin)
----------------------------------------------------------------------
Message: 1
Date: Sun, 6 Feb 2005 12:19:48 -0500
From: w2cqm@juno.com
Subject: [Amps] SELL: Power/SWR Bridge Component Package
To: Amps@contesting.com
Message-ID: <20050206.122037.3880.0.W2CQM@juno.com>
Content-Type: text/plain; charset=us-ascii
Offering a legal limit+, small footprint, relative power/SWR bridge pick
up component assembly. Can be series installed permanently in an
amplifier's output circuit or mounted outboard in a project box as a
custom, relative power/SWR bridge. Complete with the pickup assembly,
matched diodes, forward/reverse meter adjustment rheostats, and all
wiring. Ready to drop in! Includes the RF shield (amp mounting) and
hardware. Tested and operating perfectly. Removed intact from a Yaesu
amplifier. $20+ shipping Ron W2CQM/3
http://swap.qth.com/453692.jpg
------------------------------
Message: 2
Date: Sun, 6 Feb 2005 14:29:50 EST
From: TNeill1648@aol.com
Subject: [Amps] Alpha 87A Problem
To: amps@contesting.com
Message-ID: <2b.6c32ea64.2f37ca2e@aol.com>
Content-Type: text/plain; charset="US-ASCII"
I am experiencing my first ever problem with my 87A. The problems appears
to
be the "ON" switch not functioning properly.
The amp was working fine when I turned it off but failed to turn ON the
next
day. Fuses are OK and the amp is getting AC power. The internal fuse by
the
AC strip next to the rear panel is OK also.
Wonder if anyone knows of a method of checking the "ON" switch without
removing the front panel or if you might know of something else to check.
Thanks for the assistance.
Tom K4XG
------------------------------
Message: 3
Date: Sun, 6 Feb 2005 14:46:55 -0500
From: "Ray" <w8cnl@mindspring.com>
Subject: [Amps] AL-811 AMP.
To: "AMPS" <amps@contesting.com>
Message-ID: <016a01c50c84$9d2940b0$d289bd3f@W8CNL>
Content-Type: text/plain; charset="iso-8859-1"
AL-811 AMP.
Three 572b's
AC on, Opr off.
Tubes light up
HV shows about 1800 volts
Ip shows no grid current
Opr to XMIT
Nothing, no red xmit light, no standby grid current,can not key amp.
I don't believe the antenna change over relays are operating.
Turn off at night, was working great. Next morning nothing.
Nice little amp when it works. Sucks when it doesn't.
Any ideas ?? What breaks by turning it off ( or on).
Any mods for this thing? Meter lights last about 4 or 5 months.
My 751A keys it perfect. First thing it did was burn relay contacts in my
761.
* * * * * * * * * * * * * * * * * * * * * * * *
Raymond H. McClure - W8CNL
5 McKenzie Circle
North Augusta, S.C.
29841-4319
Meddle not in the Affairs of Dragons, for Thou Art Crunchy and Taste Good
with Catsup or BBQ Sauce
* * * * * * * * * * * * * * * * * * * * * * * *
------------------------------
Message: 4
Date: Sun, 6 Feb 2005 16:07:32 -0500
From: "carl seyersdahl" <carlseye@tampabay.rr.com>
Subject: Re: [Amps] AL-811 AMP.
To: "Ray" <w8cnl@mindspring.com>
Cc: Amps@contesting.com
Message-ID: <00d901c50c8f$e3e4b380$f13bca44@tampabay.rr.com>
Content-Type: text/plain; charset="iso-8859-1"
Ray. It would seem that the op/stby switch has failed , because if that
switch doesn't work you wont get a transmit lite , and the antenna relay
can't operate either.It's also possible you've lost the gnd connection
that
keys the amp . Also, you shouldnt have any grid current in stby anyway.
There is peculiarity in the metering which I've seen before, but that's
another story and has no bearing on the current problem.
carl / kz5ca
----- Original Message -----
From: "Ray" <w8cnl@mindspring.com>
To: "AMPS" <amps@contesting.com>
Sent: Sunday, February 06, 2005 2:46 PM
Subject: [Amps] AL-811 AMP.
AL-811 AMP.
Three 572b's
AC on, Opr off.
Tubes light up
HV shows about 1800 volts
Ip shows no grid current
Opr to XMIT
Nothing, no red xmit light, no standby grid current,can not key amp.
I don't believe the antenna change over relays are operating.
Turn off at night, was working great. Next morning nothing.
Nice little amp when it works. Sucks when it doesn't.
Any ideas ?? What breaks by turning it off ( or on).
Any mods for this thing? Meter lights last about 4 or 5 months.
My 751A keys it perfect. First thing it did was burn relay contacts in my
761.
* * * * * * * * * * * * * * * * * * * * * * * *
Raymond H. McClure - W8CNL
5 McKenzie Circle
North Augusta, S.C.
29841-4319
Meddle not in the Affairs of Dragons, for Thou Art Crunchy and Taste Good
with Catsup or BBQ Sauce
* * * * * * * * * * * * * * * * * * * * * * * *
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------------------------------
Message: 5
Date: Sun, 6 Feb 2005 13:23:24 -0800
From: "Jeremy Alexander" <oaxaca@oregoncoast.com>
Subject: [Amps] W7EME 144 mcs. 8877 problems
To: <amps@contesting.com>
Message-ID: <LNEILDCCGNGGJDLMNLLGOEHACMAA.oaxaca@oregoncoast.com>
Content-Type: text/plain; charset="iso-8859-1"
Aloha to all:
My QRO is having fits. I have an 8877 on 144 Mcs, the classic w6po design.
It is showing some arcing at the control grid ring to chassis ground. This
should be a low-inductance coupling shouldn't it? Instead of a continuous
finger stock, it has four, three fingered pieces at each 90 degrees around
the grid ring. Arcing is occurring between the fingers and grid ring. Were
the fingers attach to the chassis, things look clean. I assume this "less
than great" (my opinion) configuration is to allow more airflow through
the
chimney aperture? I think I can hear faint arcing sounds inside the
cabinet
causing these small pitting in the grid ring.
Also about the same time my input tuning is not consistent. I use an
external input tuning network, two series inductances and a shunt
capacitor.
I sometimes need to retune the cap to get coupling with the QRO?
I see all of this as a changing input impedance due to the changing grid
to
ground resistance???
Have any of you encountered these symptoms before? I am getting a lot of
mail back saying this ground to grid arrangement is not suitable at 144
mcs., however people seem to still be building these the same way!? It
looks
too easy to simply finger all the way around the grid ring and pressurize
the cabinet in a more appropriate matter, with chimney on top of the
valve?
OR, Is my tube tired again already? Is it shorted between the control grid
and cathode, only under load somehow? Or, another problem?
Any help is welcome.
73 Jeremy
http://www.oregoncoast.com/oaxaca
------------------------------
Message: 6
Date: Sun, 06 Feb 2005 17:03:19 -0500
From: jeff millar <wa1hco@adelphia.net>
Subject: Re: [Amps] W7EME 144 mcs. 8877 problems
To: Jeremy Alexander <oaxaca@oregoncoast.com>
Cc: amps@contesting.com
Message-ID: <42069427.10406@adelphia.net>
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Jeremy...
I've seen this behavior with light output loading, which causes the Q of
the output network to soar and results in very high circulating
currents. All the plate network circulating current flow through the
grid ring. The high currents then burn the contact points between the
finger stock and the grid ring. Once the contact points begin to
overheat, it snowballs into serious problems.
The solution is to replace the fingers, polish the grid ring, ensure the
finger pressure is high, use as many fingers as possible and always tune
up from the more heavily loaded side of the operation...or use very
light drive while hunting for the correct operating point.
jeff, wa1hco
Jeremy Alexander wrote:
Aloha to all:
My QRO is having fits. I have an 8877 on 144 Mcs, the classic w6po design.
It is showing some arcing at the control grid ring to chassis ground. This
should be a low-inductance coupling shouldn't it? Instead of a continuous
finger stock, it has four, three fingered pieces at each 90 degrees around
the grid ring. Arcing is occurring between the fingers and grid ring. Were
the fingers attach to the chassis, things look clean. I assume this "less
than great" (my opinion) configuration is to allow more airflow through
the
chimney aperture? I think I can hear faint arcing sounds inside the
cabinet
causing these small pitting in the grid ring.
Also about the same time my input tuning is not consistent. I use an
external input tuning network, two series inductances and a shunt
capacitor.
I sometimes need to retune the cap to get coupling with the QRO?
I see all of this as a changing input impedance due to the changing grid
to
ground resistance???
Have any of you encountered these symptoms before? I am getting a lot of
mail back saying this ground to grid arrangement is not suitable at 144
mcs., however people seem to still be building these the same way!? It
looks
too easy to simply finger all the way around the grid ring and pressurize
the cabinet in a more appropriate matter, with chimney on top of the
valve?
OR, Is my tube tired again already? Is it shorted between the control grid
and cathode, only under load somehow? Or, another problem?
Any help is welcome.
73 Jeremy
http://www.oregoncoast.com/oaxaca
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------------------------------
Message: 7
Date: Sun, 6 Feb 2005 16:56:02 -0600
From: "Jim Isbell, W5JAI" <jim.isbell@gmail.com>
Subject: [Amps] Fusing the Plate winding
To: Mail List for Amplifiers <amps@contesting.com>
Message-ID: <b0295dbe0502061456278060a6@mail.gmail.com>
Content-Type: text/plain; charset=US-ASCII
I am in the final steps of designing and building a linear to
supplement my station om 160 thru 10 Meters. The chassis is being
built at this time and I will soon be mounting parts.
It is a single 4-1000A running GG with a plate supply that is
switchable in steps from 3KV to 6KV. The transformer is a 12KVA
transformer which will obviously be able to handle 2 amps on the
secondary winding. I will be using a pair of VT-42A Mercury vapor
rectifiers.
Yes, I know there are "better" ways of doing it, but none would be
prettier. This is to be an amp capable of full amateur legal limit
that will be a JOY TO WATCH. not just an appliance.
OK, the questions.
I have heard from very good authority that the mercury vapor
rectifiers might short on occasion and that the secondary of my plate
transformer would probably "fuse" just as fast (or even faster) as a
FB 1 amp fuse in the plate lead.
The first question. If I don't need a fuse any bigger than 1/2 amp
and the secondary is rated for 2 amps. Will I be safe from blowing
the transformer?
The second question. If the above answer is NO, is there any circuit
I can build that will protect the transformer?
I would sure hate to leave off the glow of a pair of VT-42As to light
the inside of the chassis around my 4-1000A which will be behind a
window. This is art now, not engineering, and I sure like that purple
glow.
--
Jim Isbell
W5JAI
UltraVan #257
CAL - 27 #221
------------------------------
Message: 8
Date: Sun, 6 Feb 2005 18:08:32 EST
From: K3BU@aol.com
Subject: Re: [Amps] 10dB and propagation
To: amps@contesting.com
Message-ID: <a9.6c9306e8.2f37fd70@aol.com>
Content-Type: text/plain; charset="US-ASCII"
In a message dated 2/6/2005 9:57:54 AM Eastern Standard Time,
k7fm@teleport.com writes:
I used to wonder how come I could use a tri-band beam, advertised at 8 db
gain, and an amplifier advertised at 1500 watts and yet be 15 db down from
other local stations who were using 3 element mono-banders. Since the
power
limit is 1500 watts, they would naturally have been running the same power
as me.
This non-linear ionospheric amplification must therefore have been the
explanation. I had been puzzled for years. They obviously lived in such
a
duct, while I did not.<<
You guys might try to poke fun at this. But there are many factors
contributing to signal levels received at the other end. Antenna pattern,
local ground
conditions, terrain and propagation conditions. VHFers know about ducting
on
VHF between W6 and KH6, you drive up the hill and you can find spot where
your
signal (few watts) will hit it and you QSO with KH6. You go few hundred
feet
up or down and you lose it.
Skewed and varying (high) angle propagation with spotlight effect is now
"normal" on 160m, where earlier when I mentioned it, I was "kockoo".
Yuri, K3BU.us
------------------------------
Message: 9
Date: Sun, 6 Feb 2005 23:30:46 +0000
From: Ian White G3SEK <G3SEK@ifwtech.co.uk>
Subject: Re: [Amps] 10dB and propagation
To: amps@contesting.com
Message-ID: <syDlV9lmiqBCFAsb@ifwtech.co.uk>
Content-Type: text/plain;charset=us-ascii;format=flowed
Yuri wrote:
You guys might try to poke fun at this. But there are many factors
contributing to signal levels received at the other end. Antenna
pattern, local ground conditions, terrain and propagation conditions.
VHFers know about ducting on VHF between W6 and KH6, you drive up the
hill and you can find spot where your signal (few watts) will hit it
and you QSO with KH6. You go few hundred feet up or down and you lose it.
Sure, all of that is true... but it all goes strictly dB for dB. There
is no support for tropo ducts behaving in a non-linear fashion.
Let's not confuse the variable *importance* of a dB under different
circumstances (which is obviously true) with any suggestion that the
propagation medium itself is non-linear.
A non-linear medium would have to mean that your signal was directly
affecting the ionization density or the refractive index of the
troposphere. As I already said, that's wishful thinking at amateur power
levels.
--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek
------------------------------
Message: 10
Date: Sun, 6 Feb 2005 15:48:21 -0800 (PST)
From: John Irwin <crazytvjohn@yahoo.com>
Subject: Re: [Amps] QRO
To: PA3DUV <pa3duv@planet.nl>
Cc: amps@contesting.com
Message-ID: <20050206234821.92851.qmail@web21006.mail.yahoo.com>
Content-Type: text/plain; charset=us-ascii
LACK OF MONEY CAN BE A STRONG MODIVATOR
JOHN KB9TC
PA3DUV <pa3duv@planet.nl> wrote:
Yes, thats right, Ray has been selling on e-bay but he has stopped about 6
months ago. I'm surprised to see him him back.
Cheers, Dick
PA3DUV
----- Original Message -----
From: "Will Matney"
To:
Sent: Sunday, February 06, 2005 5:23 AM
Subject: Re: [Amps] QRO
Heh, just shows how much I pay attention, not much! I seen he has a
feedback of only 9 and figured he's only been on there for a short time.
That's the first one I'd ever seen on there of his. That's not very many
over a 3 year period. I just looked and he's be there since 2002.
Evidently, he just dont sell much on there.
Will
On Sat, 5 Feb 2005 23:18:33 -0500, Pat Poirier wrote:
Will,
Ray has been selling his amplifiers on eBay for quite some time now. I
was surprised to see them there for the first time about a year ago.
73,
Pat W1KA
----- Original Message ----- From: "Will Matney"
To:
Sent: Saturday, February 05, 2005 10:41 PM
Subject: [Amps] QRO
Anybody ever notice that QRO Tech. was selling now on eBay?
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=48700&item=5749412310&rd=1
Will
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End of Amps Digest, Vol 26, Issue 26
************************************
