Valve Radio Vs Solid State Radio

[Patrick Turner]

Steve Batt wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
newsevfe.14620$J12.5496@newssvr14.news.prodigy.com...
Hello Patrick,

Most comm radios I have repaired have lousy AM, but
quite reasonable FM.

The ones I dealt with never had FM. The pro-receivers are usually 10kHz to
30MHz. I did see some that went all the way to a GHz but I wasn't too
impressed.

Most folks wouldn't know about this, and not want to get a comm radio
for the lounge.

It's usually their wives who'd object to that ;-)

6 kHz isn't a great deal of bw.

For one sideband it's plenty. In the US stations must not emit anything
past their slot which is 9kHz wide. In other countries it is 10kHz but
that also won't allow more than 5kHz audio BW. Else the radio authorities
would come out and shut the place down.

The original poster wanted good local reception i thought,
and for that an AM radio doesn't have to have the complexity
of a comm set, especially if tubes are to be used.
There is the synchrodyne type of circuit,
which can be done with a chip, but I have
not seen an easy to make tomorrow kit.

Kits aren't around much anymore these days, at least not in the US. For
good local AM I'd still vote for the tube set. Plus, a glass of Merlot
just looks nicer in front of that versus some plastic transistor thingie.

Regards, Joerg

http://www.analogconsultants.com

As I said before, check out the Tivoli Audio range of am/fm radios

Steve

The manuals on line for the Tivoli Audio AM/FM radios don't include the AF
response data.

So I will assume the products are junk.

Ain't it grand the way idiots advertise their products,
but they don't tell you what you could expect.

Patrick Turner.

 

[Joerg]

Hallo Patrick,

My set with a long wire antenna and dual
input LC circuit hums real badly right on 846 kHz which is the Radio National station,
and its because of some really bad source of local interference, presumably
coming in on the mains wiring.

Often this hum is caused when the local AM signal is strong enough to
get into the mains wiring, being partially demodulated across a
rectifier diode in some power supply. Then the AM signal plus the newly
added audio components of 50Hz, 150Hz and so on reaches your receiver.
In the olden days engineers knew that there should be a few nF across
each diode section to "spoil" its RF performance. But now most forego
that, either out of ignorance or to save a few pennies.

Sometimes I hear when they switch on.

That way you could figure out what it is. But it's likely going to be
water under the bridge because they probably won't let you solder a few
caps across the diodes.

Regards, Joerg

http://www.analogconsultants.com

 

[Patrick Turner]

Joerg wrote:

Hallo Patrick,

My set with a long wire antenna and dual
input LC circuit hums real badly right on 846 kHz which is the Radio National station,
and its because of some really bad source of local interference, presumably
coming in on the mains wiring.

Often this hum is caused when the local AM signal is strong enough to
get into the mains wiring, being partially demodulated across a
rectifier diode in some power supply.

Some power supply in someone's house in my street.
The noise continues after I turn off my set and the audio fades slowly down
due to a large cap in my radio supply.
So I know its something external.
A battery portable shows pick up of the hum on 846 kHz as well.

Then the AM signal plus the newly
added audio components of 50Hz, 150Hz and so on reaches your receiver.
In the olden days engineers knew that there should be a few nF across
each diode section to "spoil" its RF performance. But now most forego
that, either out of ignorance or to save a few pennies.

Maybe its some SMPS somewhere.

Sometimes I hear when they switch on.

That way you could figure out what it is.

Not a chance, without being intrusive and un-neighbourly.

But it's likely going to be
water under the bridge because they probably won't let you solder a few
caps across the diodes.

I placed a few ferrites around the mains input active and neutral,
and it made no difference.
I don't like placing a cap across my mains.

I also earthed the ground at the power point in the kitchen to a water pipe immediately
under where the radio sits, which is also just inside a wall where the metal meter box is.
But elsewhere in the house I get hum with valve sets with
a wire antenna and old style RF input coil with a small ferrite slug adjust.

Patrick Turner.

Regards, Joerg

http://www.analogconsultants.com

 

[Steve Batt]

"Patrick Turner" <info@turneraudio.com.au> wrote in message
news:427F4B1F.C6501C0E@turneraudio.com.au...

Steve Batt wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
newsevfe.14620$J12.5496@newssvr14.news.prodigy.com...
Hello Patrick,

Most comm radios I have repaired have lousy AM, but
quite reasonable FM.

The ones I dealt with never had FM. The pro-receivers are usually 10kHz
to
30MHz. I did see some that went all the way to a GHz but I wasn't too
impressed.

Most folks wouldn't know about this, and not want to get a comm radio
for the lounge.

It's usually their wives who'd object to that ;-)

6 kHz isn't a great deal of bw.

For one sideband it's plenty. In the US stations must not emit anything
past their slot which is 9kHz wide. In other countries it is 10kHz but
that also won't allow more than 5kHz audio BW. Else the radio
authorities
would come out and shut the place down.

The original poster wanted good local reception i thought,
and for that an AM radio doesn't have to have the complexity
of a comm set, especially if tubes are to be used.
There is the synchrodyne type of circuit,
which can be done with a chip, but I have
not seen an easy to make tomorrow kit.

Kits aren't around much anymore these days, at least not in the US. For
good local AM I'd still vote for the tube set. Plus, a glass of Merlot
just looks nicer in front of that versus some plastic transistor
thingie.

Regards, Joerg

http://www.analogconsultants.com

As I said before, check out the Tivoli Audio range of am/fm radios

Steve

The manuals on line for the Tivoli Audio AM/FM radios don't include the AF
response data.

So I will assume the products are junk.

Ain't it grand the way idiots advertise their products,
but they don't tell you what you could expect.

Patrick Turner.

Remember Patrick that assume made an ass out of u and me.

I have one of these table radios and they certainly do not sound 'junk',
have a listen before you pass comment.

Steve

 

[Patrick Turner]

So I will assume the products are junk.

Ain't it grand the way idiots advertise their products,
but they don't tell you what you could expect.

Patrick Turner.


Remember Patrick that assume made an ass out of u and me.

I have one of these table radios and they certainly do not sound 'junk',
have a listen before you pass comment.

To escape from what I am left to assume, what is the
measured AF bw for the AM radio?

Patrick Turner.

Steve

 

[Steve Batt]

"Patrick Turner" <info@turneraudio.com.au> wrote in message
news:42803D3C.6C390019@turneraudio.com.au...

So I will assume the products are junk.

Ain't it grand the way idiots advertise their products,
but they don't tell you what you could expect.

Patrick Turner.


Remember Patrick that assume made an ass out of u and me.

I have one of these table radios and they certainly do not sound 'junk',
have a listen before you pass comment.


To escape from what I am left to assume, what is the
measured AF bw for the AM radio?

Patrick Turner.

You know, I cannot answer that question

I am at least going on what my ears tell me not what is not told to me by
the manufacturers. As I said above 'have a listen'

Steve

 

[Patrick Turner]

Steve Batt wrote:

"Patrick Turner" <info@turneraudio.com.au> wrote in message
news:42803D3C.6C390019@turneraudio.com.au...

So I will assume the products are junk.

Ain't it grand the way idiots advertise their products,
but they don't tell you what you could expect.

Patrick Turner.


Remember Patrick that assume made an ass out of u and me.

I have one of these table radios and they certainly do not sound 'junk',
have a listen before you pass comment.


To escape from what I am left to assume, what is the
measured AF bw for the AM radio?

Patrick Turner.

You know, I cannot answer that question
I am at least going on what my ears tell me not what is not told to me by
the manufacturers. As I said above 'have a listen'

One day I might.

Too busy right now to farnarkle around with AM radios.

Patrick Turner.

Steve

 

[Joerg]

Hello Patrick,

Sometimes I hear when they switch on.

That way you could figure out what it is.

Not a chance, without being intrusive and un-neighbourly.

In our neighborhood we'd walk over there with a six pack of Fosters. Or
a bottle of Merlot. Then you are always welcome ;-)

I placed a few ferrites around the mains input active and neutral,
and it made no difference.
I don't like placing a cap across my mains.

Did you place ferrites separately on each wire? Common mode filtering
doesn't always work. I had to do that on a (new!) printer. Ten turns or
so each on large #43 toroids, one per line. That did the trick.

However, if the stuff gets re-radiated from your neighbor's house wiring
there is nothing you can do (except for the method above...).

Regards, Joerg

http://www.analogconsultants.com

 

[Patrick Turner]

Joerg wrote:

Hello Patrick,

Sometimes I hear when they switch on.

That way you could figure out what it is.

Not a chance, without being intrusive and un-neighbourly.

In our neighborhood we'd walk over there with a six pack of Fosters. Or
a bottle of Merlot. Then you are always welcome ;-)

I placed a few ferrites around the mains input active and neutral,
and it made no difference.
I don't like placing a cap across my mains.

Did you place ferrites separately on each wire? Common mode filtering
doesn't always work. I had to do that on a (new!) printer. Ten turns or
so each on large #43 toroids, one per line. That did the trick.

I am talking about the mains wires from the power pole.
There is no way I could wind both active and neutral
around ferrite torroids ten times.

I just clamped ferrites onto the wires.
It made zero difference.

However, if the stuff gets re-radiated from your neighbor's house wiring
there is nothing you can do (except for the method above...).

And I don't have a shooter's licence.
I forgot the poison recipe I had.....

But the hum is far worse with a long wire antenna compared to a ferrite rod,

so methinks the hum is due to electrostatic pick up rather than magnetic
pick up.

Patrick Turner.

Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

Hello Patrick,

But the hum is far worse with a long wire antenna compared to a ferrite rod,

so methinks the hum is due to electrostatic pick up rather than magnetic
pick up.

Methinks the same. Then it will probably also be difficult to notch it
out by rotating the ferrite rod.

Regards, Joerg

http://www.analogconsultants.com

 

[Patrick Turner]

Joerg wrote:

Hello Patrick,

But the hum is far worse with a long wire antenna compared to a ferrite rod,

so methinks the hum is due to electrostatic pick up rather than magnetic
pick up.

Methinks the same. Then it will probably also be difficult to notch it
out by rotating the ferrite rod.

Regards, Joerg

Along with my own kitchen set which I built, I had
3 customers radios going today.
The '56 Grundig hums a bit, an Oz '48 Kriesler hardly hums at all,
a '60 Astor ditto, and mine hums a lot.
Only the Astor has a ferrite rod.
Placing any king of caps across the mains inputs, or from A&N to chassis
makes no difference.
placing 0.01 caps across diodes made zero difference; the noise when tuned to
846 kHz stayed put.

The Grundig improved a lot when its chassis was earthed, like my own design did.

A long wire antenna taken up over the roof was worse.

I can only conclude that where I am, which is only 5Km away from a
5,000 ABC watt AM transmitter, I still have appalling interference on many
sets.

My next step is to try a shielded loop antenna, with the coil inside an aluminium
case
which is carefully prevented from being a shorted turn.

Patrick Turner.

http://www.analogconsultants.com

 

[Joerg]

Hello Patrick,

My next step is to try a shielded loop antenna, with the coil inside an aluminium
case
which is carefully prevented from being a shorted turn.

That would make a nice antenna and I'll do the same some day. Most
people use copper pipe for it because it is solderable and very
available in hardware stores. When you polish and then lacquer coat it
the antenna would also have a cool look.

If grounding did make a difference maybe you could try a huge common
mode choke. One that loops all three (hot, neutral, PE) through a large
ferrite. Maybe a big #77 core or the pot core from a surplus PC power
supply. If you fuse it at a few amps before the choke you may be able to
use thinner lines and avhieve more turns.

Regards, Joerg

http://www.analogconsultants.com

 

[Patrick Turner]

Joerg wrote:

Hello Patrick,

My next step is to try a shielded loop antenna, with the coil inside an aluminium
case
which is carefully prevented from being a shorted turn.

That would make a nice antenna and I'll do the same some day. Most
people use copper pipe for it because it is solderable and very
available in hardware stores. When you polish and then lacquer coat it
the antenna would also have a cool look.

AL channels are easier, and can be fitted over a wooden coil
former.

If grounding did make a difference maybe you could try a huge common
mode choke. One that loops all three (hot, neutral, PE) through a large
ferrite. Maybe a big #77 core or the pot core from a surplus PC power
supply. If you fuse it at a few amps before the choke you may be able to
use thinner lines and avhieve more turns.

I think the problem is with a long wire antenna picking up the signal with hum
modulation.
I have not tried a toroid with well insulated turns wound trifilar.

Presumably that make a high Z series impedance to all 3 wires from the power point.
Then Ideally I should have to earth the set to an earth stake away from the
water pipes, probably also riddled with
hum modulated signals.

Its a lot of bother to have to go to.

Patrick Turner.

Regards, Joerg

http://www.analogconsultants.com