New Amature seeks to make his own small radio..
 

hello all im new to the amautre world and i was thinking of makeing my own
first radio..i have some old books about how they did it way back in the
day..but am flabergasted about todays techniques.i have taken some electronics
classes in college..if anyone is able to help or would have any advise i would
be gratly apprecitive. i live in northwest georgia..if anyone is from this area
that could show me how,that would also be great..

Thanks

Scott.

Try Build Your Own Intelligent Amateur Radio Transceiver by Randy Lee
Henderson Buy the Book Today!


URL:
http://www.amazon.com/exec/obidos/AS...andd/104-52237
91-3894306




"ScottnDess" wrote in message
...
hello all im new to the amautre world and i was thinking of makeing my own
first radio..i have some old books about how they did it way back in the
day..but am flabergasted about todays techniques.i have taken some
electronics
classes in college..if anyone is able to help or would have any advise i
would
be gratly apprecitive. i live in northwest georgia..if anyone is from this
area
that could show me how,that would also be great..

Thanks

Scott.

Try Build Your Own Intelligent Amateur Radio Transceiver by Randy Lee
Henderson Buy the Book Today!


URL:
http://www.amazon.com/exec/obidos/AS...andd/104-52237
91-3894306




"ScottnDess" wrote in message
...
hello all im new to the amautre world and i was thinking of makeing my own
first radio..i have some old books about how they did it way back in the
day..but am flabergasted about todays techniques.i have taken some
electronics
classes in college..if anyone is able to help or would have any advise i
would
be gratly apprecitive. i live in northwest georgia..if anyone is from this
area
that could show me how,that would also be great..

Thanks

Scott.

"ScottnDess" wrote in message
...
hello all im new to the amautre world and i was thinking of makeing my own
first radio..i have some old books about how they did it way back in the
day..but am flabergasted about todays techniques.i have taken some
electronics
classes in college..if anyone is able to help or would have any advise i
would
be gratly apprecitive. i live in northwest georgia..if anyone is from this
area
that could show me how,that would also be great..

Thanks

Scott.


What college teaches the spelling of the word "amature"? On second
thought, don't bother.

"ScottnDess" wrote in message
...
hello all im new to the amautre world and i was thinking of makeing my own
first radio..i have some old books about how they did it way back in the
day..but am flabergasted about todays techniques.i have taken some
electronics
classes in college..if anyone is able to help or would have any advise i
would
be gratly apprecitive. i live in northwest georgia..if anyone is from this
area
that could show me how,that would also be great..

Thanks

Scott.


What college teaches the spelling of the word "amature"? On second
thought, don't bother.

NE602s are indeed simple, but a poor choice for a direct conversion
receiver. It's really important for a DC receiver mixer to retain good
linearity and balance with large signals. Otherwise, strong AM signals
will be demodulated and their audio will appear in the background (or
foreground!). Doubly balanced mixers like the SBL-1 or one you can
easily make from a couple of ferrite cores and 4 silicon or hot carrier
diodes are much less sensitive to this problem than an NE602. In some
circles, DC receivers have a bad reputation, and one reason is that
people aren't aware of this problem so use inappropriate components.

The problem is particularly acute on 40 meter, which it's difficult or
impossible to filter out strong AM broadcast stations before they get to
the mixer.

Roy Lewallen, W7EL

John R. Strohm wrote:
"Joshua P Luben" wrote in message
...

Get a CD-ROM from ARRL of the past few years QST articles. There are some
pretty simple to build receivers and transmitters.

Then get yourself an ARRL handbook, it will be your best reference for a
long time to come.

Since you're just begginning, start simple. Work on direct conversion
receivers using SBL-1 mixers and LM386 audio op-amps. Keep them simple;

once

you get one working, tinker with it, add on to it. Most importantly, if it
doesn't work--ask very specific questions.


NE602 front-ends are even simpler than SBL-1 front ends. Contrary to
popular belief in some circles, you can still get the NE602 in 8-pin DIP,
new, from Philips: the new name, for an improved part, is SA612AN. (The N
suffix means 8-pin DIP.)

You can find most of the "Amidon" toroids on eBay: the key is to search for
MicroMetals (the actual manufacturer). www.kitsandparts.com also sells the
popular toroids in 25-count quantities, for CHEAP.

Ocean State Electronics has a lot of useful stuff. www.oselectronics.com (I
think).

I'd add a copy of "W1FB's Design Notebook" to that CD-ROM and the ARRL
Handbook. If you can find DeMaw & Hayward's "Solid State Design for the
Radio Amateur", grab it. Check www.qrpbooks.com; they may still have a few
copies.

NE602s are indeed simple, but a poor choice for a direct conversion
receiver. It's really important for a DC receiver mixer to retain good
linearity and balance with large signals. Otherwise, strong AM signals
will be demodulated and their audio will appear in the background (or
foreground!). Doubly balanced mixers like the SBL-1 or one you can
easily make from a couple of ferrite cores and 4 silicon or hot carrier
diodes are much less sensitive to this problem than an NE602. In some
circles, DC receivers have a bad reputation, and one reason is that
people aren't aware of this problem so use inappropriate components.

The problem is particularly acute on 40 meter, which it's difficult or
impossible to filter out strong AM broadcast stations before they get to
the mixer.

Roy Lewallen, W7EL

John R. Strohm wrote:
"Joshua P Luben" wrote in message
...

Get a CD-ROM from ARRL of the past few years QST articles. There are some
pretty simple to build receivers and transmitters.

Then get yourself an ARRL handbook, it will be your best reference for a
long time to come.

Since you're just begginning, start simple. Work on direct conversion
receivers using SBL-1 mixers and LM386 audio op-amps. Keep them simple;

once

you get one working, tinker with it, add on to it. Most importantly, if it
doesn't work--ask very specific questions.


NE602 front-ends are even simpler than SBL-1 front ends. Contrary to
popular belief in some circles, you can still get the NE602 in 8-pin DIP,
new, from Philips: the new name, for an improved part, is SA612AN. (The N
suffix means 8-pin DIP.)

You can find most of the "Amidon" toroids on eBay: the key is to search for
MicroMetals (the actual manufacturer). www.kitsandparts.com also sells the
popular toroids in 25-count quantities, for CHEAP.

Ocean State Electronics has a lot of useful stuff. www.oselectronics.com (I
think).

I'd add a copy of "W1FB's Design Notebook" to that CD-ROM and the ARRL
Handbook. If you can find DeMaw & Hayward's "Solid State Design for the
Radio Amateur", grab it. Check www.qrpbooks.com; they may still have a few
copies.

One of the worst mistakes most beginner amateurs make is to aim for "small".

That takes skills you don't have. Trying to cram everything into a small
package will get you couplings you don't want and will result in all sorts
of problems.

You should aim for "simple", but you already knew that.

One of the worst mistakes most beginner amateurs make is to aim for "small".

That takes skills you don't have. Trying to cram everything into a small
package will get you couplings you don't want and will result in all sorts
of problems.

You should aim for "simple", but you already knew that.

NE602 front-ends are even simpler than SBL-1 front ends. Contrary to
popular belief in some circles, you can still get the NE602 in 8-pin DIP,
new, from Philips: the new name, for an improved part, is SA612AN. (The N
suffix means 8-pin DIP.)


I don't think it's exactly like that.

The NE602 was manufactured by Signetics. Philips bought Signetics in 1975
from its previous parent company Corning Glass WOrks. In 1991 Philips
Semiconductors became a separate company within the Philips group, and
Signetics was integrated into Philips Semiconductors in 1993 to give greater
product recognition in the US. From what I understand Signetics was aquired
from Philips in 1995 by the Keo Pyung (KP) Group, and subsequently
transferred to private ownership.

Anyway, a few years ago legend has it that there was a fire at a Signetics
semiconductor manufacture plant in Korea, destroying (amongst other things)
the master die and several year's worth of NE602 stocks. This is what gave
rise to the rumour amongst radio amateurs already hit by dicontinuation of
other mixers, that the NE602 had been discontinued.

In fact it hadn't, Philips continued production of the NE602 as part SA602.
Philips also offered a less expensive but slightly inferior equivalent, the
SA612. Later, a new manufacturing process was developed producing better
performance and reliability, and at the same time minor changes were made to
the SA602/612 circuit to improve performance. The new devices are part
numbers SA602A and SA612A. The N suffix is for 8-pin DIP, D suffix for 8-Pin
SO Surface Mount.

So, both the SA602A and the SA612A are still in production by Philips, the
602 being slightly superior to the 612.

Incidentally, despite the datasheet sating the internal oscillator can be
used up to 200MHz, I am having a lot of success using it in a VCO covering
range 140-300MHz. See some preliminary pictures of my spectrum analyser
project http://www.hanssummers.com/electroni...ctrumanalyser/.

Hans G0UPL