4NEC2?
 

On 15/10/2018 20:42, Roger Hayter wrote:
wrote:

Roger Hayter wrote:

You say "none of us" - there are only three of you! Most group users
don't particularly love Reay and his acolytes much more than Spike, I
would think.

I'd **** on Burt if he weren't on fire. Does that make you feel better,
Rog? I'd also put a dog dirt through his letterbox.

Quite so. But there are still only three of you.

What did we do to deserve such tedious windbags?

--
Spike

"Nearly all men can stand adversity,
but if you want to test a man's character,
give him an internet group to manage"

4NEC2?
 

On Tue, 16 Oct 2018 14:18:56 +0000
Spike wrote:

On 15/10/2018 20:42, Roger Hayter wrote:
wrote:

Roger Hayter wrote:

You say "none of us" - there are only three of you! Most group
users don't particularly love Reay and his acolytes much more
than Spike, I would think.

I'd **** on Burt if he weren't on fire. Does that make you feel
better, Rog? I'd also put a dog dirt through his letterbox.

Quite so. But there are still only three of you.

What did we do to deserve such tedious windbags?


Burt, you spent years of your life on Usenet being a horrible ****,
Burt.


Burt, Thanks, Burt.

4NEC2?
 

In article , lid
says...

Very interesting, but I'd have to say that none of what you say refutes
my original contention that the distant station, which after all is the
one we are trying to communicate with, will notice any difference to the
received signal whether the sending station's antenna was tuned with a
20c torch bulb or a $300 VNA. You touched on the main vagaries of the
system when you said "What I've found is that such side by side
comparisons do not account for variations in propagation, path,
interference, local noise, time of day, position of the moon, and other
factors beyond the operators control".




Sometimes it is who is doing the adjusting and not how good the
equipment is.

Almost 40 years ago I started keeping a repeater on the air that was
started by someone else. My test equipment at that time was a VTVM, a
$ 25 Heathkit signal generator, old Oscilloscope, swr meter, and
frequency counter.

To tune the receiver my best 'signal generator' was a ham near the edge
of the repeater coverage. I would have him just to key down for a
minuit or two at a time while I adjusted the receiver. Over the years a
better receiver and transmitter was installed. Now I have some very
good test equipment, but can not say the coverage of the repeater is
very much better. What little improvement is made is probably because
the radio equipment is better.

At that time one thing I did not try to adjust or check was the duplexer
as I did not think I could with what I had to work with. Many years ago
the tuning instructions for duplexers was to tune for maximum signal on
the pass and best rejection. As test equipment became better and priced
in range, the pass tuning changet to using a return loss bridge and
SA/TG. This seems to work much better. I found the pass was broad and
you could usually give the tuning rod a turn or two without much effect,
but he RLB shows up in less than 1/2 of a turn. Does it make a
difference ? Probably not in effective coverage (it may extend the
range a foot or two,hi), but atleast I know it tuned the best it can be
with what I have to work with.

One thing that does come with better test equipment is knowing that the
equipment is tuned so it meets or exceeds the specificatioins. Before
it was just a guess as if the equipment did or did not meet
specifications.

4NEC2?
 

On Tue, 16 Oct 2018 07:44:53 +0000, Spike
wrote:

Very interesting, but I'd have to say that none of what you say refutes
my original contention that the distant station, which after all is the
one we are trying to communicate with, will notice any difference to the
received signal whether the sending station's antenna was tuned with a
20c torch bulb or a $300 VNA. You touched on the main vagaries of the
system when you said "What I've found is that such side by side
comparisons do not account for variations in propagation, path,
interference, local noise, time of day, position of the moon, and other
factors beyond the operators control".

Perhaps an analogy might be useful. Instead of an HF radio, you're
dealing with your automobile. Under normal circumstances, it will get
you to work and back fairly efficiently. However, you notice that
your gasoline (petrol) mileage is not quite what you might expect. So,
you have a choice of mechanics. The first mechanic tunes the engine
with a light bulb, divining rod, magic incantations, and offers a
rather bizarre description of what work was done on the vehicle. The
second mechanic uses proper computerized test equipment to analyze the
situation, uses factory parts, and delivers the car with a detailed
printout of what was done, what changes were made, what parts were
used, and a before-after gas mileage comparison performed on a
dynamometer.

Now, which mechanic would you prefer? Your car will still go to work
and back in some manner. The second mechanic will cost more, because
he has to pay for all the expensive equipment and genuine parts. If
you're impoverished, obviously the first mechanic will be the only
available choice, but assuming you plan to keep the vehicle, one might
suspect it is a bad long term solution.

From my perspective, both professional and as a ham, I deal in
numbers. I can tell by looking at the numbers what is happening and
what needs to be done. I have a small collection of aging test
equipment to help me generate the numbers. Light bulbs do not
generate numbers and are therefore (in my never humble opinion)
useless and worthless.

However, I will concede that if your intent is "to be able to transmit
signals intended to be received by another station", a light bulb is
sufficient to determine that your transmitter is spewing RF, spurs,
harmonics, and noise into an antenna-like device that is either
radiating the RF, absorbing it into heat, or reflecting it back to the
transmitter (because the light bulb indicates the same in both
directions).



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

4NEC2?
 

In article ,
says...

Perhaps an analogy might be useful. Instead of an HF radio, you're
dealing with your automobile. Under normal circumstances, it will get
you to work and back fairly efficiently. However, you notice that
your gasoline (petrol) mileage is not quite what you might expect. So,
you have a choice of mechanics. The first mechanic tunes the engine
with a light bulb, divining rod, magic incantations, and offers a
rather bizarre description of what work was done on the vehicle. The
second mechanic uses proper computerized test equipment to analyze the
situation, uses factory parts, and delivers the car with a detailed
printout of what was done, what changes were made, what parts were
used, and a before-after gas mileage comparison performed on a
dynamometer.

Now, which mechanic would you prefer? Your car will still go to work
and back in some manner. The second mechanic will cost more, because
he has to pay for all the expensive equipment and genuine parts. If
you're impoverished, obviously the first mechanic will be the only
available choice, but assuming you plan to keep the vehicle, one might
suspect it is a bad long term solution.



Again, it all depends on the mechanic. The computer tune may only get
you a small improvement and it will take 5 years to make up the cost
difference. I had a car that started running real bad. After the
simple things I replaced like spark plugs, wires and coil, I looked on
an Autozone page and one thing was a $ 500 sensor that may cause the
problem. I took it to a dealer that should have all the proper
equipment. After about 3 weeks he finally replaced that sensor and it
fixed the problem. The part would have taken less than half an hour to
replace. They may still have been working on it if I had not sent off a
nice email to Toyota after a week and a half of no repair.

I know of a case where a Freeze plug was leaking and the motor company
wanted to pull the engine to get to it. Shade tree mechanic pulled back
the carpet inside the car, took a hole saw and cut a hole in the
firewall to get to the plug. Repaired the hole with a beer can and pop
rivits for less than $ 100.

4NEC2?
 

On Tue, 16 Oct 2018, Spike wrote:

On 16/10/2018 09:14, Jeff wrote:

A common way of generating both usb and lsb was to have 2 switched
crystals with frequencies just above and below 9MHz in the oscillator,
feeding a balanced mixer, before the xtal filter, and switch depending
on which sideband you required.

Is there a mathematician on here that can explain the maths of sideband
inversion/retention?

No inversion is required with this method.

If you feed a ~9MHz signal and audio into a balanced mixer the output
will be both sidebands plus a suppressed carrier.

Your xtal filter is ~2.4kHz wide centred on 9MHz, so if you move the
frequency of the ~9Mhz signal (switch a crystal) going into the balanced
mixer either above or below 9MHz you can select which side band goes
through your filter.

Simples.

Wasn't a similar system used in the Yaesu FT-200 (9MHz IF, 5 MHz VFO)?

IIRC the set had a NORM/INV sideband switch.

That wasn't uncommon, the conversion scheme allowing for the "default"
sideband to be one switch position, so the only time you needed to switch
sidebands was if you needed the "wrong" sideband".

Michael

4NEC2?
 

On Tue, 16 Oct 2018 13:22:28 -0400, Ralph Mowery
wrote:

Again, it all depends on the mechanic. The computer tune may only get
you a small improvement and it will take 5 years to make up the cost
difference. I had a car that started running real bad. After the
simple things I replaced like spark plugs, wires and coil, I looked on
an Autozone page and one thing was a $ 500 sensor that may cause the
problem. I took it to a dealer that should have all the proper
equipment. After about 3 weeks he finally replaced that sensor and it
fixed the problem. The part would have taken less than half an hour to
replace. They may still have been working on it if I had not sent off a
nice email to Toyota after a week and a half of no repair.

I know of a case where a Freeze plug was leaking and the motor company
wanted to pull the engine to get to it. Shade tree mechanic pulled back
the carpet inside the car, took a hole saw and cut a hole in the
firewall to get to the plug. Repaired the hole with a beer can and pop
rivits for less than $ 100.

All that you've shown is that an idiot with all the technology of
modern electronics can screw things up, and that simple repairs can be
done simply and cheaply by someone who has some experience. I'm
talking about a given situation, which could be done with either a
light bulb or a pile of test equipment. Not two different repair
situations.

So, let's take your blown $500 black box, presumably out of warranty.
Would you take the problem to the shade tree mechanic with his beer
can and pop rivet tool? What would you expect him to do? Drill open
the black box and start replacing parts until it works? Would he
offer a warranty? At best, he would find a similar black box at a
scrap yard, box rebuider, or midnight auto, and sell it to you at a
discount. Would you consider that acceptable?

Let me bring it closer to home. You purchased an expensive HF radio
with all the bells and whistles. It's out of warranty and you need
something fixed. Would you send it to 1) the factory, 2) an
authorized repair station, 3) a rebuilder in China, 4) the ham
equivalent of the shade tree mechanic, or 5) the teenager next door?
The distinction between these choices is a experience and training,
but also access to the necessary test equipment and parts. Better
yet, if you knew any of these used a light bulb to determine if your
transmitter was working, and a "talk test" as QA, would you do
business with them?

No need to answer the questions. Just think about the implications.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

4NEC2?
 

On 16/10/2018 14:38, Ralph Mowery wrote:
In article , lid
says...

Very interesting, but I'd have to say that none of what you say refutes
my original contention that the distant station, which after all is the
one we are trying to communicate with, will notice any difference to the
received signal whether the sending station's antenna was tuned with a
20c torch bulb or a $300 VNA. You touched on the main vagaries of the
system when you said "What I've found is that such side by side
comparisons do not account for variations in propagation, path,
interference, local noise, time of day, position of the moon, and other
factors beyond the operators control".

Sometimes it is who is doing the adjusting and not how good the
equipment is.

That's very true, of course. Some good equipment is in the 'wrong hands'.

Almost 40 years ago I started keeping a repeater on the air that was
started by someone else. My test equipment at that time was a VTVM, a
$ 25 Heathkit signal generator, old Oscilloscope, swr meter, and
frequency counter.

To tune the receiver my best 'signal generator' was a ham near the edge
of the repeater coverage. I would have him just to key down for a
minute or two at a time while I adjusted the receiver. Over the years a
better receiver and transmitter was installed. Now I have some very
good test equipment, but can not say the coverage of the repeater is
very much better. What little improvement is made is probably because
the radio equipment is better.

Thanks! That's just the sort of thing I was on about - in this case you
actually used a distant station to help with the set-up, and it worked well.

At that time one thing I did not try to adjust or check was the duplexer
as I did not think I could with what I had to work with. Many years ago
the tuning instructions for duplexers was to tune for maximum signal on
the pass and best rejection. As test equipment became better and priced
in range, the pass tuning change to using a return loss bridge and
SA/TG. This seems to work much better. I found the pass was broad and
you could usually give the tuning rod a turn or two without much effect,
but he RLB shows up in less than 1/2 of a turn. Does it make a
difference ? Probably not in effective coverage (it may extend the
range a foot or two,hi), but at least I know it tuned the best it can be
with what I have to work with.

One thing that does come with better test equipment is knowing that the
equipment is tuned so it meets or exceeds the specifications. Before
it was just a guess as if the equipment did or did not meet
specifications.

Quite so. But 'specifications' are often written with other things in
mind - compatibility, spurii, stability, etc, and not necessarily
anything at all to do with how the distant station receives/perceives
one's signal.


--
Spike

"Nearly all men can stand adversity,
but if you want to test a man's character,
give him an internet group to manage"

4NEC2?
 

On 16/10/2018 20:47, Jeff Liebermann wrote:

Let me bring it closer to home. You purchased an expensive HF radio
with all the bells and whistles. It's out of warranty and you need
something fixed. Would you send it to 1) the factory, 2) an
authorized repair station, 3) a rebuilder in China, 4) the ham
equivalent of the shade tree mechanic, or 5) the teenager next door?

If you send to anyone other than yourself then you are not
a real radio ham or radio amateur.

A CBer, probably.

4NEC2?
 

On 16/10/2018 16:17, Jeff Liebermann wrote:
On Tue, 16 Oct 2018 07:44:53 +0000, Spike
wrote:

Very interesting, but I'd have to say that none of what you say refutes
my original contention that the distant station, which after all is the
one we are trying to communicate with, will notice any difference to the
received signal whether the sending station's antenna was tuned with a
20c torch bulb or a $300 VNA. You touched on the main vagaries of the
system when you said "What I've found is that such side by side
comparisons do not account for variations in propagation, path,
interference, local noise, time of day, position of the moon, and other
factors beyond the operators control".

Perhaps an analogy might be useful. Instead of an HF radio, you're
dealing with your automobile. Under normal circumstances, it will get
you to work and back fairly efficiently. However, you notice that
your gasoline (petrol) mileage is not quite what you might expect. So,
you have a choice of mechanics. The first mechanic tunes the engine
with a light bulb, divining rod, magic incantations, and offers a
rather bizarre description of what work was done on the vehicle. The
second mechanic uses proper computerized test equipment to analyze the
situation, uses factory parts, and delivers the car with a detailed
printout of what was done, what changes were made, what parts were
used, and a before-after gas mileage comparison performed on a
dynamometer.

Now, which mechanic would you prefer? Your car will still go to work
and back in some manner. The second mechanic will cost more, because
he has to pay for all the expensive equipment and genuine parts. If
you're impoverished, obviously the first mechanic will be the only
available choice, but assuming you plan to keep the vehicle, one might
suspect it is a bad long term solution.

From my perspective, both professional and as a ham, I deal in
numbers. I can tell by looking at the numbers what is happening and
what needs to be done. I have a small collection of aging test
equipment to help me generate the numbers. Light bulbs do not
generate numbers and are therefore (in my never humble opinion)
useless and worthless.

They don't need to generate numbers!

I can think of at least one method, using light bulbs, that will get a
pretty accurate measurement of power, and if you want, balance, in a
system. The distant station, of course, knows nothing of this, and
couldn't tell whether I'd used the 'numbers' of your method or the
analogue approach of mine.

However, I will concede that if your intent is "to be able to transmit
signals intended to be received by another station", a light bulb is
sufficient to determine that your transmitter is spewing RF, spurs,
harmonics, and noise into an antenna-like device that is either
radiating the RF, absorbing it into heat, or reflecting it back to the
transmitter (because the light bulb indicates the same in both
directions).

But the people your imaginary friend works for care for none of this, as
his car gets him to work on time.

To bring this back to the issue at hand, I claimed that "I'd have to say
that none of what you say refutes my original contention that the
distant station, which after all is the one we are trying to communicate
with, will notice any difference to the received signal whether the
sending station's antenna was tuned with a 20c torch bulb or a $300 VNA"
and so far that still stands.

--
Spike

"Nearly all men can stand adversity,
but if you want to test a man's character,
give him an internet group to manage"