[ARC5] 70+ year old errors
Paddy Ryan
pei7cn at eircom.net
Tue Jun 11 07:18:23 EDT 2013
Thanks Ken..very interesting and well done..persistent patience pays
off..nothing is as it seems..I had the same experience here..an osc coil
cover was marked in pencil ''bad coil''..no continuity from the pins and
then one assumes (never assume anything ass u me) that there is a break in
the winding inside the fine litz wave weave..I disconnected the wire leads
from the terminal pins and out of curiosity threw the meter across the wire
leads..the coil was ok and when I resoldered it to the pins everything was
ok..it had never been tampered with and was covered in solder but had never
actually been in circuit..you just can't be too-careful..nice to hear of
another one going,hi!..73 de Pat/EI7CN
-----Original Message-----
From: arc5-request at mailman.qth.net
Sent: Tuesday, June 11, 2013 1:44 AM
To: arc5 at mailman.qth.net
Subject: ARC5 Digest, Vol 113, Issue 46
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Today's Topics:
1. Re: Band noise (Was dynos and receivers)
(brianclarke01 at optusnet.com.au)
2. Re: B-36J Radio Operator Position (Robert Eleazer)
3. 70+ year old errors found and corrected. (Kenneth G. Gordon)
----------------------------------------------------------------------
Message: 1
Date: Tue, 11 Jun 2013 10:05:53 +1000
From: brianclarke01 at optusnet.com.au
To: "Ken Gordon" <kgordon2006 at frontier.com>, "Dennis Monticelli"
<dennis.monticelli at gmail.com>, "ARC-5 List" <arc5 at mailman.qth.net>
Subject: Re: [ARC5] Band noise (Was dynos and receivers)
Message-ID:
<5b762553b440c43e388ef2adc3035ffa3be8d3aa at webmail.optuszoo.com.au>
Content-Type: text/plain; charset=UTF-8
Hello Ken,
Outback Australia is good. Unfortunately, compared with the?city,
the?cost of living goes up when you want to go shopping. And motor
fuel shops get further apart - running out of fuel is a certain recipe
for death by heart failure / dehydration.
There are places much closer and less hazardous than the outback?-
even just down the road a wee way. Most mains-borne noise falls off as
the square or the cube of the distance from the noise source. Even
burying the power lines, so beloved of the weenie-greenies, does not
attenuate the noise that much (except from the weenies); the
permeability of earth-like material and concrete is not sufficient to
shield from mains frequencies.?So, set up your preferred
remotely-controllable receiver on a distant mountain top and
communicate with it via your own private line or use a LOS link at say
5.6 GHz. A software-defined radio as a plug-in board for a junker
computer is a good basis for your remotely-controllable receiver.
Just a thought ... This idea is not new - I saw it first in Wayne
Green's _73 Amateur Radio Today_ at least 15 years ago. What is new is
the proliferation of cheap boards and software.
73 de Brian, VK2GCE.
----- Original Message -----
From:"Ken Gordon"
To:"Dennis Monticelli" , "ARC-5 List"
Cc:
Sent:Mon, 10 Jun 2013 15:11:03 -0000
Subject:Re: [ARC5] Band noise (Was dynos and receivers)
On 9 Jun 2013 at 22:55, Dennis Monticelli wrote:
>
> I have the Timewave. I tried it before the loop. It only works well
if your noise source is local and
> the "noise antenna" close to that source. Under those circumstances
one antenna has a good
> S/N (your regular aerial) while the noise antenna has a good N/S.
The high differentiation allows
> the magnitude/phase cancellation to be effective. The other issue is
that the phase cancellation
> depends upon a stable noise source. If it drifts in frequency as
most switching supplies, do, then
> the phase changes as well and you will find yourself trying to track
it manually. Further if you have
> more than one major noise source it will be unlikely that the noise
antenna could be placed in
> proximity to both simultaneously.
>
> Been there,...done that. It helps if your noise situation is
straightforward.
Rats! I was thinking of getting an ANC-4, but from the sound of things
it would be only
marginally helpful in my case.
I guess the only real solution is to move to some place at least 100
miles from the nearest
power line and run the entire house off batteries.
The outback of Australia might be a good place...or possibly the
middle of the Pacific Ocean
somewhere.
Poop! :-(
Ken W7EKB
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Message: 2
Date: Mon, 10 Jun 2013 20:41:58 -0400
From: "Robert Eleazer" <releazer at earthlink.net>
To: <arc5 at mailman.qth.net>
Subject: Re: [ARC5] B-36J Radio Operator Position
Message-ID: <2868B00144A843D38D605DC2C23F4296 at DH26DQ31>
Content-Type: text/plain; charset="iso-8859-1"
First, the B-36J did not have an Ipod charger. That was not added until the
B-52H.
As for the Jimmy Stewart movie, I have a copy, and always look in that scene
where they have crashed in the Arctic to see what kinds of radios are
visible. But I can never ID anything. Looking at a reference work I have,
I can tell that the radio operator position was indeed in the location as
depicted in the movie. In the movie, recall that one guy kept at the radio
transmitting until impact, but I don't think you can see anything of the
radio itself.
Anyone out there who would not have loved to have a play house - or a
hamshack - made out of the nose of a B-36?
I am impressed that the ART-13 and BC-348 was fitted to an airplane that did
not start to come off the production lines until late 1953. Musta been
pretty darn good equipment.
Wayne
------------------------------
Message: 3
Date: Tue, 11 Jun 2013 00:44:32 -0000
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: ARC-5 List <arc5 at mailman.qth.net>
Subject: [ARC5] 70+ year old errors found and corrected.
Message-ID: <51B672F0.32671.67E6D7A6 at kgordon2006.frontier.com>
Content-Type: text/plain; charset=US-ASCII
You know that 1.5 - 3.0 MHz coil box I was having troubles with? The one out
of the receiver
that had been hacked for crystal control back in the 1970s?
Well, today, not having anything much else to do (yeah, right), I decided to
take a closer look
at it to see if I could figure out exactly what was wrong with it.
First, since the HFO coil had been the one that had been messed with (I
figured this out
when I looked at the screws holding the coil in the box: there were 2
different kinds, and the
paint had been "broken").
Although I had restored the two resistors, R-3 and R-6 to their original
values, the HFO still
didn't work. I looked more closely at the connections to the coils and after
taking my glasses
off and looking VERY closely, I discovered that one lead of the plate coil
was no longer
soldered to its connection. What looked at first like solder was flux, and
all 6 of the Litz wires
were not soldered. When I had tested the coils for continuity, I had
clip-leaded one lead of the
ohm-meter to one end of the coil, and had used the probe on the other end.
The clip-leaded
end turned out to be the open one....of course.
Have any of you 70+ year old folks ever attempted to 1) clean the enamel off
of 6 pieces of
#60 Litz wire, and then 2) solder them in place with shaky hands? Well, I
managed...finally.
Putting it all back together and installing in my working receiver, I found
that the HFO was
now working, but the signal through the mixer was way down. However, the RF
amp did peak
by the Align Input control, so that meant that the RF amp coil was OK.
Back to the coil box. After swapping the good coils, one at a time from my
working coil box
into the non-working coil box, I zeroed in on the mixer coil as the culprit.
Obviously, however,
the coil had never been tampered with as the screws still had their red
paint on them and
they were very tight.
Even so, I removed them with some effort, and removed the coil. Using my
clip-lead and
ohm-meter I again determined that both coils had continuity. Furthermore,
there were drops
of the original ruby-red enamel on all the connections.
Then, remembering my experience with the HFO coil, I used both of the
ohm-meter probes,
without any clip-lead, to check continuity through the connections at the
bottom of the coil
from outside it.
Sure enough: one coil no longer had continuity.
Again removing my glasses, I looked VERY closely at the two connections of
the now open
coil, both of which looked "factory" and both of which had that ruby-red
enamel on them.
One of those connections had never been soldered: the Litz wire had been
wrapped around
the connection, never soldered, and then had been covered with ruby-red
quality-control
enamel.
A 70+ year old construction error, followed by a quality-control error
uncovered.
A few seconds with the soldering iron and solder fixed the problem.
Re-installing the now repaired coil box proved that the receiver was now
working properly.
Alignment followed, and I am now listening to it.
Sheesh!
Ken W7EKB
------------------------------
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