On Tue, 27 Aug 2013, gareth wrote:

"Percy Picacity" wrote in message
...
In article ,
"gareth" wrote:
"Percy Picacity" wrote in message
...
In article ,
"gareth" wrote:
But the fact remains that for those who understand the use of a
crystal
phasing control in pre-1950
receivers that the questions as posed above are as completely
informative
as
is necessary.
And you have had your answer - the tuning of the BFO has no effect on
the phasing control and vice versa. Do you not believe the answer?
Stating the bleeding obvious which we all knew any way is about as useful
and as relevant as quoting Newton's laws of motion; for neither are an
appropriate
response to the query as originally put.
I refer you page 79 of the previously mentioned book.

Sorry, perhaps you could tell us what the question was again. I thought
you were asking if there was an advantage to tuning the BFO half way
between the wanted and unwanted signals. There isn't.


There is. You get single signal reception for CW despite the wide bandwidth
of
a trnasformer-only IF strip.

No. single signal reception comes when you actually have decent bandwidth.
You can get that from IF transformers, if the IF frequency is low enough,
all those receivers that had a final IF at 50 or 85KHz.

As I said, you don't even need to have the notch, if you adjust the filter
"right" the notch is never there. You still get single signal
selectivity, because the other image is knocked out by being out of the
passband of the filter. The notch feature just adds to the thing.

You could just string a bunch of RC amplifiers together, be they triodes
or bipolar transistors or FETs, and then put matched crystals from the
"cathode" or whatever to ground. The crystal acts as a very selective
bypass capacitor, very low impedance at the signal frequency, so gain
happens then, and high impedance elsewhere, so gain tapers off. It's not
perfect and the selectivity requires a lower IF, but it's a simple scheme.
I've thought of making a WWV receiver that way, just some stages of
amplification with 10MHz crystals, and a diode detector.

Or pick some crystals all on the same frequency, and make a ladder filter.
Some have even worked on those so you can actually use the same crystals
for narrow (CW) and wide (SSB) reception, though sometimes it seems easier
to just use parallel filters, pick a frequency where the crystals are
cheap.

Michael VE2BVW

"Michael Black" wrote in message
ample.org...
On Tue, 27 Aug 2013, gareth wrote:

I refer you page 79 of the previously mentioned book.

I don't remember a book being mentioned.


11th edition of "Radio Handbook", 1947 edition (with endpaper adverts
for 1948) pub, Editos and Engineers Ltd, of Santa Barbara, Cal.

Those who claim that single-signal reception is due solely to the series
resonant peak
of the Xtal are quite wrong, because otherwies there'd be no need whatsoever
for
a notch facility.

This is what you should end up with ...

Wanted signal in the peak of series resonance.

Bfo adjusted on the HF side to give a pleasant tone.

Notch moved using the phasing control to be at the IF frequency that would
produce
the audio image from the current BFO setting.

What I was after was the procedure to set the notch frequency, because
unless you have a narrow
CW filter in the AF strip, how would you judge that you'd created the same
AF heterodyne whistle?

TKS FER heads-up on Lamb, I'll follow that.

"gareth" wrote in message
...
"Percy Picacity" wrote in message
...
Sorry, perhaps you could tell us what the question was again. I thought
you were asking if there was an advantage to tuning the BFO half way
between the wanted and unwanted signals. There isn't.

There is. You get single signal reception for CW despite the wide
bandwidth of a trnasformer-only IF strip.

Eh? Have I missed something? If you tune the BFO halfway between the two
signals the output from either will be at the same frequency; that sounds
like exactly what you DON'T want!
--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.co.uk

In article ,
"gareth" wrote:

snip

Wanted signal in the peak of series resonance.

Bfo adjusted on the HF side to give a pleasant tone.

Notch moved using the phasing control to be at the IF frequency that would
produce
the audio image from the current BFO setting.

What I was after was the procedure to set the notch frequency, because
unless you have a narrow
CW filter in the AF strip, how would you judge that you'd created the same
AF heterodyne whistle?

TKS FER heads-up on Lamb, I'll follow that.


You judge it by listening. If there isn't an interfering signal at that
frequency you don't have to do anything and you don't care where the
notch is (unless you use it to suppress a signal at a different
frequency which is probably less of a nuisance as the beat note is
different). You only have to adjust the notch if there is an
interfering signal, and you adjust it to make the desired signal easier
to read. If the phasing control makes no audible difference, or there
isn't any QRM, don't bother with it.

--

Percy Picacity

In article e.org,
Michael Black wrote:

On Tue, 27 Aug 2013, Stephen Thomas Cole wrote:

I know, I had one, complete with manual, back in the 1980s. I don't
recall any difficulties tuning up, just don't key up* for more than a few
seconds at a time. Common sense, really.
* or should that be "key down"?

Hell, if he's really having trouble without the manual, there's plenty of
videos on YouTube of people demonstrating the necessary actions. Or he
could just pop down his local club and ask a friendly soul there to show
him how to operate it.

That keeps happening to me. I follow a link, and instead of some
interesting text, I'm supposed to watch a video like it's some cooking
show. Sure it lets the masses in, but at what cost?

Michael VE2BVW

I agree. When I was a kid (in UK) I saw little or no TV and I have never
really got into having 10 minutes of video to explain something that
takes 2 minutes to read about. Perhaps I wouldn't feel so strongly if
my Internet connection actually permitted me to download youtube videos
in real time, I could quickly glance at them, *then* find a proper text
explanation!

--

Percy Picacity

In article ,
"gareth" wrote:

"Percy Picacity" wrote in message
...
In article ,
"gareth" wrote:
"Percy Picacity" wrote in message
...
In article ,
"gareth" wrote:
But the fact remains that for those who understand the use of a
crystal
phasing control in pre-1950
receivers that the questions as posed above are as completely
informative
as
is necessary.
And you have had your answer - the tuning of the BFO has no effect on
the phasing control and vice versa. Do you not believe the answer?
Stating the bleeding obvious which we all knew any way is about as useful
and as relevant as quoting Newton's laws of motion; for neither are an
appropriate
response to the query as originally put.
I refer you page 79 of the previously mentioned book.

Sorry, perhaps you could tell us what the question was again. I thought
you were asking if there was an advantage to tuning the BFO half way
between the wanted and unwanted signals. There isn't.


There is. You get single signal reception for CW despite the wide bandwidth
of
a trnasformer-only IF strip.

You get the selectivity regardless of the BFO setting. Putting the BFO
half way just makes it *harder* to distinguish the two signals. The
advantage of the notch is if you *want* the BFO at that setting to give
a comfortable pitch and there *happens* to be an interfering signal just
in the wrong place (presumably one of many interfering signals in the IF
bandwidth) then the notch gives you a way of suppressing it. But you
don't *deliberately* tune the BFO to give you an interfering audio
image, you would do better tuning the BFO to where the interfering
signals were all a few kHz different. If there isn't a gap big enough
between interfering signals, *then* the notch helps get rid of the most
annoying one.

--

Percy Picacity

Percy Picacity wrote:
In article e.org,
Michael Black wrote:

On Tue, 27 Aug 2013, Stephen Thomas Cole wrote:

I know, I had one, complete with manual, back in the 1980s. I don't
recall any difficulties tuning up, just don't key up* for more than a few
seconds at a time. Common sense, really.
* or should that be "key down"?

Hell, if he's really having trouble without the manual, there's plenty of
videos on YouTube of people demonstrating the necessary actions. Or he
could just pop down his local club and ask a friendly soul there to show
him how to operate it.

That keeps happening to me. I follow a link, and instead of some
interesting text, I'm supposed to watch a video like it's some cooking
show. Sure it lets the masses in, but at what cost?

Michael VE2BVW

I agree. When I was a kid (in UK) I saw little or no TV and I have never
really got into having 10 minutes of video to explain something that
takes 2 minutes to read about. Perhaps I wouldn't feel so strongly if
my Internet connection actually permitted me to download youtube videos
in real time, I could quickly glance at them, *then* find a proper text
explanation!

Yup, there's no substitute for information in a book or magazine (or a
print-out from the web. I don't enjoy poring over stuff on a screen, much
nicer to transfer to analogue and ruminate over on the sofa). And I say
that as a young whippersnapper raised on computers and the telly.

--
If the above message is full of spelling mistakes or the snipping is duff,
it's probably because it was sent from my iPhone, likely whilst walking.
Apologies!

On 27/08/13 22:00, Stephen Thomas Cole wrote:
"FranK Turner-Smith G3VKI" wrote:
"Stephen Thomas Cole" wrote in message
...
"FranK Turner-Smith G3VKI" wrote:
"gareth" wrote in message
...

I refer you page 79 of the previously mentioned book.

What book? The FT101 manual or your £350 law book?

The FT101's a pretty simple rig, Frank. I doubt the manual would be that
long. When Gareth finally sources a copy, perhaps he'd be kind enough to
confirm.

I know, I had one, complete with manual, back in the 1980s. I don't
recall any difficulties tuning up, just don't key up* for more than a few
seconds at a time. Common sense, really.
* or should that be "key down"?

Hell, if he's really having trouble without the manual, there's plenty of
videos on YouTube of people demonstrating the necessary actions. Or he
could just pop down his local club and ask a friendly soul there to show
him how to operate it.

He doesn't appear to be flavour of the month at his local club, so that
might be a problem.

--
;-)
..
73 de Frank Turner-Smith G3VKI - mine's a pint.
..
http://turner-smith.co.uk
..
Ubuntu 12.04
Thunderbirds are go.

Frank Turner-Smith G3VKI wrote:
On 27/08/13 22:00, Stephen Thomas Cole wrote:
"FranK Turner-Smith G3VKI" wrote:
"Stephen Thomas Cole" wrote in message
...
"FranK Turner-Smith G3VKI" wrote:
"gareth" wrote in message
...

I refer you page 79 of the previously mentioned book.

What book? The FT101 manual or your £350 law book?

The FT101's a pretty simple rig, Frank. I doubt the manual would be that
long. When Gareth finally sources a copy, perhaps he'd be kind enough to
confirm.

I know, I had one, complete with manual, back in the 1980s. I don't
recall any difficulties tuning up, just don't key up* for more than a few
seconds at a time. Common sense, really.
* or should that be "key down"?

Hell, if he's really having trouble without the manual, there's plenty of
videos on YouTube of people demonstrating the necessary actions. Or he
could just pop down his local club and ask a friendly soul there to show
him how to operate it.

He doesn't appear to be flavour of the month at his local club, so that might be a problem.

Ah, that's unfortunate. Maybe he could join RSGBTech and post a message
there asking for help?

--
If the above message is full of spelling mistakes or the snipping is duff,
it's probably because it was sent from my iPhone, likely whilst walking.
Apologies!

Ah, that's unfortunate. Maybe he could join RSGBTech and post a message
there asking for help?

yes....should be hundreds of pirate hammy mens who used an FT101 on there
.......