EMRFD Message Archive 689

Message Date From Subject
689 2007-05-01 18:13:23 Steve White Good Receiver or Transceiver to Build

All

 

I am wondering if any of you have some opinions regarding a good receiver or transceiver to build.  I already have built up a very stable VFO  (2.2 to 2.3 MHZ) and have built a large  enclosure (Gives me lots of room to experiment and make changes)  and am now ready to get after the rest of it.

 

I am more than happy to build the receiver first and then add transmit capability and really am only interested in CW at this time.  I have a 455 and 8.33  500 hz crystal filters also stashed away for this project and would use either or both of them as needed.  I have already built up a 2n240 and just love the low noise that the receiver has, and that is one of the reasons I am interested in building up my own.  My objective is to build up a multiband unit with AGC and not just a monobander but if I need to start that way then that is ok as well.

 

I have looked at the following designs:

 

W1FB “His Eminence the Receiver”  Uses CA3028 IF

W7ZOI/K5IRK Progressive Receiver  Uses MOSFET IF

W7ZOI 14Mhz QRP Transceiver from and old QST Uses MC1350 IF

David White’s Super Receiver and Electroluminescent Receiver  Uses MOSFET IF

A Receiving Package for 1.8 to 144 MHZ  Old Handbook Design  Uses CA3028 IF

 

I am trying to find if there are other designs which are well documented and might offer better performance than those listed above. Also if you have had any experience with any of these receivers and can comment on their performance I would be grateful.  Since I am primarily a QRP CW operator I really don’t need all the bells and whistles that are available today and really mostly interested in a good solid design which is low noise and has good AGC and covers the CW portions of the bands. In particular I am looking for one that has good low noise IF stage, and am not sure how the CA3028 IF would compare with a MOSFET or MC1350 IF in terms of noise.  I have heard that the MOSFET is much quieter or at least it was in it’s day and is it still the preferred choice for low noise IF’s?  I have a goodly amount of test equipment Scopes, HP 8640 Signal Generator, TEK Spectrum Analyzer etc. (not that I know how to use them all that well) but I have them.

 

So I am looking for something which can be built Manhattan style using leaded components, but I can and have built many PC boards myself.  I prefer to have a whole design not just the IF or Front end or VFO designs since I am not sure that I can build them independently and plug them together and expect them to work satisfactorily.

 

Any help or advice or guidance would be appreciated,  I’ll go warm up the soldering iron.

 

Steve NU0P

 

 

 

 

691 2007-05-01 18:53:00 Arvid Evans Re: Good Receiver or Transceiver to Build
Steve - NU0P
Check this out: http://www.phonestack.com/farhan/
Arv - K7HKL


696 2007-05-03 05:45:35 patt896 Re: Good Receiver or Transceiver to Build
Steve, check out RADCOM's CDG2000 and Pic-a-Star Transceivers:
http://groups.yahoo.com/group/CDG2000
http://uk.groups.yahoo.com/group/picastar

Both are well documented designs.

Dick

710 2007-05-04 12:57:55 Steve White Re: Good Receiver or Transceiver to Build

Dick

 

I have seen both of those designs and have the complete docs on the Pic-a-Star and both of them are bit more than I want to bite off right now.   I am looking for something of the older generation along the lines of  analog VFO, Analog Display, no IF shift, but with good noise figure and good dynamic range.  Both of the receivers you mention are of interest to me but think I want to eat that elephant one bite at a time and having the experience of something a bit simpler will serve me well..

 

Steve  NU0P

 


711 2007-05-04 13:26:40 Bob Miller Re: Good Receiver or Transceiver to Build
Another thing about the Pic-a-Star, some of the parts are hard to come by now.
Building the encoder disk can be another problem.
 
Bob
wb6kwt
-----Original Message-----
713 2007-05-04 15:18:20 Kevin Purcell Re: Good Receiver or Transceiver to Build
Do you have a copy of EMRFD? :-)

Not being sarcastic but there are quite a few idea starting designs
in EMRFD that are a bit more recent than the ones you cited in your
first emil but match up nicely with the list below. And it encourages
a modular approach for experimentation so you can build modules and
try them out. It would match up nicely with the bits you already have.

Any narrowing of the spec or constraints?

Mode? CW, SSB? Digital?

Usage? Contesting? Portable?

73 Kevin N7WIM

715 2007-05-04 16:42:30 Steve White Re: Good Receiver or Transceiver to Build

Kevin

 

Yes, I have a well worn copy of EMRFD and read it everyday.  It provides me with lots and lots to think about.  In my early post I mentioned many constraints but did not speak to usage which is very important.  I would be using this at home and have no need to take it out to the field at all and would use it primarily as a DX and Contesting type of Radio for CW only.  I am looking for a design which is complete since I am not too confident that I could take functional stages from EMRFD and just string them together and be successful.  I am sure the more competent builders can do that I am just not sure that I can.  As I indicated before I have built several receivers along the line of the 2N240 with great success and just love my 2N240 since it is so quite.  Now I am just looking to build a multiband unit of some kind that would give me at least 80 40 and 20 meters as a minimum.

 

I may have to just bite the bullet and do exactly as you recommend.  I have built the chassis already and made it a bit oversize just so I cold easily build up different modules and install and test them as I went along.

 

Steve NU0P

 


718 2007-05-06 07:13:59 patt896 Re: Good Receiver or Transceiver to Build
The gating factor for me, Steve, was price and availability of band
Xtals and Xtal filters. I found both on e-Bay from a Yaesu FT-101ZD
along with its VFO. The rest should be straight forward. H-Mode
mixer and RF board from CDG2000. IF/AF and maybe DSP from Star.

Dick


720 2007-05-06 13:06:32 Steve White Re: Good Receiver or Transceiver to Build

Dick

 

Are you suggesting that I just pick up these building blocks from the Pic a Star and use them with the FT-101  VFO and crystal and Filter set?  I wonder if you have already done this and if so how did it work out???  So it looks like you used all the elements from the Pic a Star except for the DSP and Synthesier.. Is that right?  How did you handle all the switching for the bands etc?  Isnt that micro Pro controlled in the PIC A Star?

 

Steve

 

 

 


722 2007-05-06 13:39:07 patt896 Re: Good Receiver or Transceiver to Build
Steve, I've been collecting parts, schematics and test equipment for
my incomplete receiver project for over three years now.
I chose the FT-101ZD since it has a 9MHz IF and 5.5-5.0 VFO which is
pretty standard for many designs.
Older models of the FT-101 used a 3.395MHz IF like the Heath SB-104
and SB-303. It's just an inexpensive
way to acquire band Xtals and Xtal filters. I also picked up a band
switch for the Yaesu on eBay.

I like the H Mode mixer in the CDG2000 but built the enhanced version
by IK4AUY.
http://xoomer.alice.it/sergiocartoceti/pdf%20files/IK4AUY_%20qex_07-
2004.pdf
Wouldn't you know there is even a newer version under development.
http://www.xs4all.nl/~martein/pa3ake/hmode/index.html

I've collected the parts and RF board for CDG2000.

The IF/AGC in Star is a duplicate of the famous design by Bill
Carver/K6OLG.

I've built several DDS VFOs but like the spectral purity of the
analog versions.

Dick


723 2007-05-07 06:12:31 Giancarlo Re: Good Receiver or Transceiver to Build
725 2007-05-08 05:52:32 neomag_magneo Re: Good Receiver or Transceiver to Build
Dear OM,

Although You already have received several replies/comments for your
inquire, I would like to add my own, since I have some experience on
the designs listed below, in particular those of W1FB and W7ZOI.

What I started from some 10 years ago, was the Progressive receiver.
It is a nice modular design which can include as many bands as You
wish, just by adding the filter and oscillator modules. The basic
receiver is for 80 mb (single-conversion), which allows the use of a
low-frequency (= stable) VFO. Despite of this fact, I did add the
huff-and-puff stabilizer almost immediately. The W7ZOI uses mosfets
for if-amp, but 2 x MC1350 works just as well, in both cases a simple
filter to reduce if-noise is useful, but as you already have your main
if-filter, this might be somewhat difficult to implement. Another
approach which I took is double-conversion for the basic receiver,
i.e. 455 kHz second if for which You obviously have the filter as
well. The main advantage for double conversion, in my opinion and
experience, can be found in the AGC system, which is quite tolerant
for BFO feedthrough while at higher if frequencies, considerable
amount of shielding is required. This also implies, that I strongly
recommend an if-derived AGC system. Although some have been succesful
with a af AGC, I cannot share their experience. The EMRFD book nicely
summarizes diffrentr detector types and also gives circuitry to match
the AGC system with the if amp chain selected.

The progressive receiver uses diode mixers (DBMs) in all mixer stages,
and a well-tested post-mixer amp based on 2N5109 or equivalent (I have
2N4427). For product detector I have used MC1496 discussed in this
group recently, because it was in hand, hihi.

This was the route I took and the receiver has been in operation for
abt 7 years. I has been under some modification all the time, e.g. I
have replaced the original 3 kHz ssb-filter with narrower 2.4 and 800
Hz homemade ladder filters, and more recently, DDS-frequency
generation with computer control. The latter is, however, for
operating convenience more than for rf performance, it might even have
an adverse effect, hihi.

The transmitting part I have handled with a completely separate tx
which I currently run in transceiver-type mode with the DDS, but in
the past I did the tuning of the both which is a little bit clumsy,
particularly in contests, but otherwise perfectly OK. If You are
interested in CW only, the tx should not pose You any major problems.
If SSB is required, I would recommend the W7ZOI QRP transceiver, which
for obvious reasons bears a great resemblance to the progressive
receiver. But for CW the tx can be kept very simple, one addition I
made to my first tx was the rtty (or FSK mode, which is just the 170
Hz frequency shift in any of the oscillators in the amplification
chain. This is something I have not seen published too often, maybe
all the rtty guys are satisfied with AFSK in their ssb gear...

The construction techniques I have followed is semi-manhattan style,
i.e. I design a double.sided PCB but leave the copper layer in the
component side intact, for a ground plane. This approach makes the
boards better looking and facilitates the component mounting, but
enables major changes afterwards. In some cases my boards have
transformed from vy pro-looking ones into a terrible mess, but the
performance never been compromized by the techniques.

The bottom line is that the designs I have mentioned consist of basic
rf circuitry, which can be combined with more modern modules (better
mixers like the H-mode, DDS, DSP etc.), but which as such already give
good performance. The components You have to deal with are also
macroscopic and can be handled without tweezers...

I wish You good luck with the constructi
726 2007-05-08 06:43:26 Steve White Re: Good Receiver or Transceiver to Build

Heikki

 

Thanks so much for your post.  Your insight has been most helpful and reassuring.  I have both a 8.33 and 455 filters from which to base a design on and like you I am well aware of the value of a IF derived AGC.  For that reason I am leaning towards a single conversion 455Khz based design. Sort of a tunable IF type of design. To cover multiple bands I would use converters ahead of the receiver.  Now the big question for me is should I build the receiver to cover 160M or 80 meters.  I have seen one design by W1FB  “His Eminence-The Receiver”  which covers 160 and uses a 455khz IF which uses IF derived AGC and I think that low freq AGC works well. What I am considering is to build this receiver to cover 80M instead of 160 and retain the single conversion architecture with a 455Khz IF.   The VFO would still be relatively low freq but I wonder if I would have other problems with spurs and birdies because of this.  I do not recall seeing an 80 Meter receiver with a single conversion to 455 Khz before.  Your thoughts would be greatly appreciated.

 

One thing I have is lots of time since I retired last year and have been looking forward to this project for some time now.  I have spent the money to get some good test equipment  and now just need to spend the time to get something useful built.

 

 


732 2007-05-08 16:50:45 patt896 Re: Good Receiver or Transceiver to Build
Wonderful reply, Heikki (OH2LZI). Your remarkable efforts remind me
of Markus Hansen/VE7CA's article in March, 2006, QST "A Homebrew High
Performance HF Transceiver - the HBR-2000."

733 2007-05-09 11:43:05 miltonhome Re: Good Receiver or Transceiver to Build
Steve,

the critical parts for a receiver to have in hand are the crystals
for the IF filter and BFO.

aside from these crystals, the rest of the receiver can be made from
common npn transistors and ordinary diodes.

i suggest examining the receiver in the 2n2-40 or one of the related
rigs. while its pretty well optimized, no reason that you got to
build it exactly that way (i didn't). but the essentials are there -
a diode ring mixer, optimal distributi
734 2007-05-09 12:03:02 neomag_magneo Re: Good Receiver or Transceiver to Build
Dear Steve,

Maybe I should have started from the very beginning... The first rx I
built was almost completely based on the two articles of the late
W1FB, the one you are referring to and an earlier one, actually in two
parts in QST June/July 1974. It seems that W1FB was very much in favor
of the 160 mb (maybe Wes Hayward would comment on this ?), but I
decided to built the basic unit for 80 mb. At that time (1979) I was
quite band-limited due to the ancient novice regulations in OH-country
and did not foresee any use for other bands than 80, 40 and 15, hihi.
The receiver was in active use for several years, and I cannot
remember having any problems with birdies. The VFO was from 3955 up to
4355 in two 200 kHz bands, since the 80 mb coverage in only 300 kHz in
Europe. The major deviation from W1FB design was a three stage mosfet
if-amplifier and an if-derived AGC based on the OH2GF receiver
(published in the Finnish Radioamatoori-periodical). This Finnish
design, btw, dates back to the 1969 and has already at that time a DBM
mixer with no rf amplification ! This might be one design to study
although the basic ideas are very well covered in other sources
available today, like EMRFD.

One reas
735 2007-05-09 15:59:57 Kevin Purcell Re: Good Receiver or Transceiver to Build
736 2007-05-09 17:41:37 Steve White Re: Good Receiver or Transceiver to Build

Hekki

 

Thanks for the words of encouragement.  Glad to know that I can use my 455 Khz filter in a 80 Meter single conversion receiver…I do like the mosfet IF and wonder if you still happen to have a copy of OH2GF receiver that you mention.  I certainly would like to see a copy of that.  

 

I am currently following the W1FB design very closely and will build initially for 160M and see how that works out and then I will make the mods to the receiver front end filters and the VFO to put it onto 80….It uses the CA3028 for the IF strip and I have two of them but think that the MOSFET IF would be much quieter.  Wonder if I can take the IF from David Whites “Super Receiver” and use it in place of the CA3028’s and have it work correctly??

 

Steve

 

 

 


737 2007-05-09 17:54:03 Alessandro Santuc... Re: Good Receiver or Transceiver to Build
Hi,
about your request in a recent SDR day in Modena (north of Italy) I had
pleasure of listen the finished CDG2000 by I4FAF and his son IK4AUY,
Cartoceti family.. hi. The receiver has an impressive clean reception, and
a very good IP3, but the job is quite long and expensive. But at the end you
have the best receiver you can at now, without any software inside, so an
analog RX. I'm doing it, but the time is not enough so I'm going quite
slowly.. hi

The link of I4FAF is http://xoomer.alice.it/sergiocartoceti/article_8.htm
hope to be useful!
73's



Alex - I0SKK

Alessandro Santucci

I QRP C #305

INORC # 536

ARI Telegraphy Club
Honorary Member #62

email: i0skk@eco-lavoro.com

Web: www.eco-lavoro.com/i0skk


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738 2007-05-09 18:25:35 Steve White Re: Good Receiver or Transceiver to Build

Curt

 

I have built a 2N240 and it was one of the very first transceivers that I built that I actually really liked.  It seems so quiet.. to me it has me working on building a multiband transceiver that will perform as well as it does.  I have considered building a 2N280 if you will and then adding on converters for the other bands.  The drawback is that the 2N240 has no AGC of any kind at all and not having that feature is what is causing me to build something else….

 

I would imagine someone smarter and more adept than me can come with an IF strip for the 2N series that does have AGC but not sure with my current design abilities that I could…But someday soon I will get there.

 

Steve

 

 

 


739 2007-05-09 23:07:15 Kevin Purcell Re: Good Receiver or Transceiver to Build
It struck me earlier that this might be the other reason why people
think the 2n2/40 as being a quieter receiver because the AGC doesn't
pump it up noise when there are no signals. So the response of the RX
seems more natural and quieter especially as you'll leave it turned
down so as not to get deafened.

Given the options described in EMRFD it should be easy to add AGC (at
least "ear saver" AGC) to the RX as is (perhaps by dropping the RF
amp and adding another IF amp stage with an improved mixer).

740 2007-05-09 23:10:12 Kevin Purcell Re: Good Receiver or Transceiver to Build
Interesting article.

For those of us who don't speak Italian you can get the idea from the
Google translation

2Fsergiocartoceti%2Farticle_8.htm&langpair=it%
7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools>

It's quite readable once you get used to Googles "literal"
translations. And the untranslated words then become pretty obvious.
I think I prefer phantoms to spurious responses.

Thanks for posting this.

741 2007-05-10 04:40:24 Giovanni Moretti Re: Good Receiver or Transceiver to Build
The translated page that Kevin posted below is available at:
http://tinyurl.com/355d9p
Cheers - Giovanni - ZL2BOI

Kevin Purcell wrote:
>
> Interesting article.
>
> For those of us who don't speak Italian you can get the idea from the
> Google translation
>
> >
> 2Fsergiocartoceti%2Farticle_8.htm&langpair=it%
> 7Cen&hl=en&ie=UTF-8&oe=UTF-8&prev=%2Flanguage_tools>
>
> It's quite readable once you get used to Googles "literal"
> translations. And the untranslated words then become pretty obvious.
> I think I prefer phantoms to spurious responses.
>
> Thanks for posting this.
>
>
742 2007-05-10 05:16:39 w4zcb77 Re: Good Receiver or Transceiver to Build (W1FB)
Maybe I should have started from the very beginning... The first rx
I
> built was almost completely based on the two articles of the late
> W1FB, the one you are referring to and an earlier one, actually in
two
> parts in QST June/July 1974. It seems that W1FB was very much in
favor
> of the 160 mb (maybe Wes Hayward would comment on this ?),

If I might put my oar in the water here. Doug (W1FB) was always very
much of a 160 meter enthusiast. In his last years from Luther
Michigan, he was a leading force in the group that assembled on 1919
KHz every day at 0700 and 1900 (EST). His loss is sorely missed. I
stumbled across the group one morning after the DX had disappeared
and heard his distinctive voice and recognized him even before he
identified. Always a technical discussion of something being aired.
Sometimes in error but always of interest. I have personally claimed
that my definition of Hell is having the perfect radio and no QSO's
of interest to talk to. They seem to be getting very difficult to
find.

It may be only me, but would it be permissible to ask that the group
edit their postings of reply to include perhaps just enough of the
earlier post to identify the subject of the response? I grow very
tired of polling thru the 6 previous posts attached to a response,
particularly when there are multiple responses and see the same half
dozen previous posts in their entirety.

Regards to all
W4ZCB
743 2007-05-10 05:58:21 Kenneth Stringham Re: Good Receiver or Transceiver to Build
I don't know what the problem is with using 1N914
switching diodes in the ring mixer. Ten-Tec has been
doing it for years. One could even purchase a
Mini-Circuits inexpensive mixer, should have a mind to
do it.

It sounds to me like someone needs to build and do a
thorough analysis of that design. There is a problem
some where in it.

It sounds to me like someone wants to take a
particular design and define it as the standard. In
this case where we are experimenting and reporting our
results and asking guidance from the elmers on this
forum, it seems to me that there is no gold standard
to shoot for. One has to define one's goals, do the
design work, build the resulting design, and then
evaluate what you have. Once that is done, then one
should determine what is needed to improve on their
design and finally share their results.

Ken


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744 2007-05-10 11:15:55 Giancarlo Re: Good Receiver or Transceiver to Build
Hi Ken,

746 2007-05-10 16:36:49 Kevin Purcell Re: Good Receiver or Transceiver to Build