EMRFD Message Archive 605
Message Date From Subject 605 2007-04-05 11:34:18 chuck allen How to approach EMRFD?
This is my first post and I'm trying to put my questions into words.
After being away from electronic components and soldering for 20 years
I am eager to pick it up again. I've never homebrewed radios but used
to work in the electronics industry. So, I've setup a work bench and
have some modest test equipment that I've picked up over the years
(signal generator, scope, freq counter, VOM, power supply).
I am currently reviewing my basic electronic component theory
(transistors, FET's, etc) but am eager to try my hand at actually
homebrewing something. But what?
I recently purchased EMRFD and after reading the first chapter and
skimming thru much of the remainder of the book I come away a bit
overwhelmed but excited.
Where do I start? Is there some suggested approach to EMRFD that
others have taken?
Do you work thru the chapters one at a time (in order) and build the
individual ckts and models- shown (such as an audio amp ckt) and
eventually come away with a working radio?
OR do you choose a transmitter or a receiver system to build at the
beginning and begin building and testing the actual ckt blocks in that
particular radio? (It would seem this latter approach would involve
skipping around in the book to find what's applicable to the block you
are working on at the time).
One other point, I'm not really interested in building a `kit' per
say. I'd rather try the ugly construction method.
Anyway, I hope you understand the essence of my question. I'm guess
I'm trying to figure out a plan for working thru this impressive book.
Thanks in advance.
chuck
AF4XK606 2007-04-05 11:49:43 Archie Lamb Re: How to approach EMRFD?
People tend to gravitate for one reason or another to what is
interesting to them and while lots of us have overlapping interests,
they are unique to each of us. You'll likely need some basic stuff
to get started (maybe a "simple" audio amp or similar) but go ahead
and look at things that interest you - some or all may be over
your head but you'll learn by figuring it out and asking questions.
Even though you say 'ugly' or mahatten or whatever - I suggest a small
radioshack socket board to start with. its very quick and you can go
608 2007-04-05 12:48:29 chuck allen Re: How to approach EMRFD?
i have a decent background in electronics. i worked as an electronic
technician (testing and troubleshooting ckts) for about 5 years and
then another 5 years as a lab technician building prototype ckts (lots
of wiring, soldering, machining). that was with an AAS degree in
electronics technology. then i went back to school for another 2 years
and got a bachelors degree in electrical engineering technology. that
was over twenty years ago.
i left the 'electronics' field upon graduating and got into the
telephony end of things where i still am today. since my working with
components was so long ago i definitely needed to review the basics.
i've only been a ham about 8 years (since becoming interested as a
teen) and have determined my interest are in this directi609 2007-04-05 13:47:34 arv evans Re: How to approach EMRFD?
While there are many good homebrew designs out there on the Internet, you might want to take a look at this URL:
http://groups.yahoo.com/group/BITX20/
The BITX20 SSB QRP Transceiver was designed right out of the EMRFD book by Farhan VU3ICQ and has been built and modified by many homebrewers. There are kits available, but many builders prefer to do it in Manhattan or ugly style construction, which makes it easier to test and make changes to the circuit.
Arv - K7HKL
_._
chuck allen wrote:Hello,
This is my first post and I'm trying to put my questions into words.
After being away from electronic components and soldering for 20 years
I am eager to pick it up again. I've never homebrewed radios but used
to work in the electronics industry. So, I've setup a work bench and
have some modest test equipment that I've picked up over the years
(signal generator, scope, freq counter, VOM, power supply).
I am currently reviewing my basic electronic component theory
(transistors, FET's, etc) but am eager to try my hand at actually
homebrewing something. But what?
I recently purchased EMRFD and after reading the first chapter and
skimming thru much of the remainder of the book I come away a bit
overwhelmed but excited.
Where do I start? Is there some suggested approach to EMRFD that
others have taken?
Do you work thru the chapters one at a time (in order) and build the
individual ckts –and models- shown (such as an audio amp ckt) and
eventually come away with a working radio?
OR do you choose a transmitter or a receiver system to build at the
beginning and begin building and testing the actual ckt blocks in that
particular radio? (It would seem this latter approach would involve
skipping around in the book to find what's applicable to the block you
are working on at the time).
One other point, I'm not really interested in building a `kit' per
say. I'd rather try the ugly construction method.
Anyway, I hope you understand the essence of my question. I'm guess
I'm trying to figure out a plan for working thru this impressive book.
Thanks in advance.
chuck
AF4XK
610 2007-04-05 14:09:53 Graham Haddock Re: How to approach EMRFD?
Well, it depends where you want to go.
I personally suggest you go over to the Yahoo Softrock40
group and spend $20 or $40 on one of their Software Defined
Radio kits, which for a very small amount will get you
hands on experience with surface mount parts and SDR,
and down the rabbit hole you will go.
It will force feed you with some of the most modern stuff
for an extremely small amount of money, then perhaps you can decide
where you want to go from there.
611 2007-04-05 15:43:38 Archie Lamb Re: How to approach EMRFD?
I've been in the field for a long time too - I know I had
several things I always wanted to do and never quite got to do them.
I finally just picked one (several) and started them. Things ALWAYS
come up - you know, different from what you expect. You just work
through them. There are lots of really cool stuff out there (the
software defined radios are really cool!) for me, I wanted to build
a radio from scratch (and make some contacts). I found the 2N22-40
by K8IQY. Neat little radio. EMRFD has lots of that kind of stuff.
Do you like RF or audio? Analog or Digital? Hardware or Software?
You get my point. ABOVE all - have fun (and don't sweat the small stuff)!
Good Luck
Archie (KX5X)
613 2007-04-06 00:21:07 Y.Gopikrishna Re: How to approach EMRFD?
If you are up for it - try and build this one. Its a
spetrum analyzer. The project will cover a lot of
circuit blocks commonly used in RF projects.
Besides you will have a spectrum analyzer at the end
of it.
Here is hte website
http://www.cpu-net.com/host/wsprowls/
Enjoy!!
Gopi
615 2007-04-06 05:38:49 Don Kelly Re: How to approach EMRFD?
Since this is your first homebrew project(s) a good place to start or
migrate to would be the Measurement Equipment chapter 7.
Most of circuits are simple, straightforward and useful.
My favorites are the Carver LC meter, the logarithmic power meter and
the signal generator.
I built the signal generator with +13dBm output and a built in step
attenuator.
Another area I personally have enjoyed is the direct conversion
receiver section. Experimentation here resulted in two DSB
tranceivers and an audio section for the RX portion of a 40M SSB
transceiver.
You can never have enough test gear and this will give you some hands
on bench time and a period to decide what you really want to build.
73, good luck, have fun,
Don K5UOS616 2007-04-06 06:51:07 Ramakrishnan Muth... Re: How to approach EMRFD?
>Don,
> I built the signal generator with +13dBm output and a built in step
> attenuator.
Would like to know more details about your signal gen. This is one of
the things that I really want to build. There was a nice project by
Steven Hageman published in QEX sometime in 2000, if I remember right
on building a bench top RF signal generator.
--
Ramakrishnan - VU3RDD617 2007-04-06 09:15:13 Don Kelly Re: How to approach EMRFD?
I have built several narrower signal generators for specific use.
This was my 1st general purpose. It covers 2.9 to 12 MHz. I did not
include the higher range. I used the same band set, spread and fine
tune method as the article. This was familiar as it is the same
method I used in my first receiver. The Hartley oscillator is suited
for this method. This generator been used mostly for crystal filter
and various LC filter construction.
Mechanically I used a 12 x 7 x 3 chassis. The oscillator board is
further shielded within a 4 x 6 x 3 utility box. This box in box
provides good mechanical stability and the screw outline can be seen
from the top of the generator. The power amp is outside the inner
box. I used a different buffer and power amp but likely designed it
using the calculators included with the EMRFD CD.
The step attenuator is constructed in a box made from very thin
double side board. I used 4 ea DPDT switches I bought at a fleamarket
100/$1.00. I used 1, 3, 6, and 10 dB. The oscillator is not entirely
flat over the total range but the attenuator lets me keep it flat
over the full range. Usually I use outboard attenuation too.
I can open it up and provide some more specific photos. It is just a
pain getting it back together. All boards were constructed ugly style.
Ramakrishnan, I can send you the variable capacitors described in the
article if you would like? I guess they are the most difficult
components to find. Some switches too if you want the step atten.
I am sure DDS kits will more than compete with this classic method of
frequency generation. Yet L/C oscillators are my comfort zone. They
are fun.
I hope it was ok to post the pictures.
K5UOS618 2007-04-06 09:23:39 Don Kelly Re: How to approach EMRFD?
Forgot to say I posted pictures in the Photos area.
73
Don K5UOS619 2007-04-06 11:05:18 Thomas S Knutsen Signal Generator, was: How to approach EMRFD?
Nice signal generator.
Is this the design presented in EMRFD pg. 7.15?
seems to me that this migth be an good design for an analog signal
generator.
I'm thinking about building an DDS controlled signal generator. I have
an DDS 60 from AMQRP and with an keypad, rotable encoder and an LCD
display controlled by an PIC prosessor this migth be an easy way to go
to generate some RF from 0-60MHz.
The reason for building a DDS signal generator is mainly that variable
capacitors is hard to get here, as is most RF components.
73 de Thomas LA3PNA
Btw, nice chassis in the background of photos.
Don Kelly wrote:
>
> Hi Ramakrishnan,
>
> I have built several narrower signal generators for specific use.
> This was my 1st general purpose. It covers 2.9 to 12 MHz. I did not
> include the higher range. I used the same band set, spread and fine
> tune method as the article. This was familiar as it is the same
> method I used in my first receiver. The Hartley oscillator is suited
> for this method. This generator been used mostly for crystal filter
> and various LC filter construction.
>
> Mechanically I used a 12 x 7 x 3 chassis. The oscillator board is
> further shielded within a 4 x 6 x 3 utility box. This box in box
> provides good mechanical stability and the screw outline can be seen
> from the top of the generator. The power amp is outside the inner
> box. I used a different buffer and power amp but likely designed it
> using the calculators included with the EMRFD CD.
>
> The step attenuator is constructed in a box made from very thin
> double side board. I used 4 ea DPDT switches I bought at a fleamarket
> 100/$1.00. I used 1, 3, 6, and 10 dB. The oscillator is not entirely
> flat over the total range but the attenuator lets me keep it flat
> over the full range. Usually I use outboard attenuation too.
>
> I can open it up and provide some more specific photos. It is just a
> pain getting it back together. All boards were constructed ugly style.
>
> Ramakrishnan, I can send you the variable capacitors described in the
> article if you would like? I guess they are the most difficult
> components to find. Some switches too if you want the step atten.
>
> I am sure DDS kits will more than compete with this classic method of
> frequency generation. Yet L/C oscillators are my comfort zone. They
> are fun.
>
> I hope it was ok to post the pictures.
>
> K5UOS
>
>620 2007-04-06 11:17:29 Ramakrishnan Muth... Re: Signal Generator, was: How to approach EMRFD?
> Hey Don.Yes, I would like to second Thomas' opinion and congratulate Don on
> Nice signal generator.
>
> ..
> ..
> Btw, nice chassis in the background of photos.
the fine piece of homebrew gear on his desk. Very nice pictures.
Ramakrishnan, VU3RDD622 2007-04-06 12:53:07 chuck allen Re: How to approach EMRFD?
suggestions and impressive web sites. I think I'll start out with the
L/C tester (I do need one of those) and then possibly the 2N2-40 and
eventually the BITX. At least now I have a directi623 2007-04-06 21:34:57 Hari G Re: How to approach EMRFD?
On 4/7/07, chuck allen <callen1155@yahoo.com> wrote:I appreciate each one responding to my question. There were some great
suggestions and impressive web sites. I think I'll start out with the
L/C tester (I do need one of those) and then possibly the 2N2-40 and
eventually the BITX. At least now I have a directi