Don (and Dale, if you're still listening),
I apologize in advance for not snipping this reply, but I want to
preserve the whole thread and file it to my Hints and Kinks folder on
the hard drive, for that dial mechanism.

Speaking of the Progressive Receiver, I was thinking about building
one myself a couple of months ago. At the end of the article in the
November '81 QST, Wes shows the math to figure out capacitor values
for the VFO. Well, I spreadsheeted that, and I may have found an
error. I check for errata on the ARRL site, and didn't find any
further references.

Everything checks out perfectly until the last step, where he solves
for C3. Wes's example yields C3 = 127.02 X 10E-12 F.

My values show C3= 355 -(1/50 + 1/126.8) quantity to the -1 power,
which is 355 - 35.85 or 319.1 pF, not 127.02 pF. Did I mess up with
the math?

This is fairly significant to me, because I can see use for this
calculation beyond this particular project, never seeming to have the
right variable cap on hand. I floated this problem to the local NoGa
QRP math gurus, but it turns out I guess we don't have any . I
didn't really want to put it on qrp_tech.

Dale, I've commented to you previously on your magnificent receiver,
and Don, that's a nice idea on the dial plate. One thing you could do
is design the markings in a drawing program to fit your brass disk,
and then iron on a Press-n-Peel image to the brass, and etch it. Then
you could apply a layer of black paint to the disk, and carefully wipe
it off until only the etched areas remained with paint. Alternatively,
If your image is clear enough (reversed this time), you could simply
use that after ironing it on, and spray it with a fixative to protect
the toner and the brass. A couple of the guys were doing that for
panel legends.

Some of the guys in the homebrew_pcb Yahoo group have built their own
CNC milling machines, and the do their PC boards that way. That would
be good for this, as well.

72/73 to you both,
Ted KX4OM

On 26 Mar 2006 07:00:39 -0800, wrote:

Well Dale it looks very nice and obviously works well too. I thought I
remembered you saying the Progressive Receiver. I am glad I had a
chance to compliment you.

Since the subject was the Eddiestone dial I expect that was probably a
chore to install. I usually build homebrew dial chord and drum
mechanisms and more recently use the flange type Jackson Brothers and
Oren Elliot drives. I just figured out a way to make custom dial
plates. Probably an old idea but new to me.

I just finished a 40M receiver for a SSB transceiver. I thought about
using a small blank CD for the dial plate. What I ended up doing was
getting a piece of brass sheet from ACE Hardware and using a 2 1/4"
hole saw (my chassis panel is 3") I cut a round disc. I had a small
amount of deburring to do but the brass is way tougher than aluminum
and a simple file removed the burrs. The 3/8" drill bit also provided a
true center for the dial plate. I polished it with super fine auto
rubbing compound. I ended up with a nice dial plate.

I need to mount it to a small shaft section of a vernier capacitor from
Ocean State Electronics. I took a shaft coupler, the type with
removable couplings on both sides, and using very tiny scews mounted
this removable portion of the coupling to the plate.

Its hard to describe. But I am pleased with myself as I a mechanically
weak.

This is a good method for making custom dial plates. I had to use a
good chord type drill as my cordless was getting warm. I also mounted
the plate for drilling using two wood screws and fastening the uncut
plate to a scrap 2 x 4 by drilling holes slightly above and below my
cut.

Now I gotta figure out how to mark the plate. Well maybe I will catch
you on the air sometime Dale.

K5UOS

Dale Parfitt wrote:
wrote in message
oups.com...
Dale W4OP,

Dale,

I believe you posted an e-mail and a link to QRP-L a while back to show
your receiver. Should have said this before but better late than never.
Nice job.

If I remember correctly you used a basic 160M receiver with multiple
front end convertors. Also I believe you used blue backlighting?

Don,

K5UOS

Hi Don,
Thanks for the kind words. The receiver is based on W7ZOI's Progressive RX
from the late 80's. To Wes's excellent design I added,
S meter
AM detection
LM386 for loudspeaker w/ tone control
audio notch filter
Homebrew 5/2.5/.5 xtal filters
fast/slow/off AGC

80M RX with xtal controlled converters for 160/49/40/20/15/10ABC
The VFO drifts a little over 150Hz in the 1st 5 minutes then settles down to
+/- 20Hz in a 5 minute period. Wonderful sound and gets more use than the
PRO II
73,

Dale W4OP

Hi Don and Ted,
While it has been over a year now since I did the VFO- I too had some
difficulties with the QST values. In talking w/ W7ZOI, Wes indicated that
some errors had worked their way into the design over the years. One was on
the audio amp- values I had caused severe rolloff below about 2KHz- making
SSB very tinny.
The other was on the VFO. Because of the Eddystone dial, I wished to make
the VFO as linear as possible- book values led to a highly non linear scale.
I do not recall exactly what I did- although I played with the math for a
long time- to lienarize it- but I would trust your calcs.
At some point I will open her up again as I want to buffer the VFO and tap
off for a TX VFO- the plan is to build a Drake style reciter for the RX- and
at that time will better document the changes I made.

Dale W4OP

Dale & Don,
I haven't had a chance to lash up the components yet, but I checked my
spreadsheet using Wes's example on page 4.4. The numbers check out;
unfortunately, Wes specifies a value for C3 in the EMRFD example, and
in the Progressive Receiver Article, C3 is the unknown; i.e., how much
additional capacitance you'd have to add in parallel with the coil to
use a specific variable cap in the given configuration.
Now that I can see the "C12v" equation in EMRFD, which is not in the
QST article, but I've modified my spreadsheet to include it I can
check the resonance using the given values for L.

Dale, when I looked at your jpg's again yesterday, I noticed that
you've modified the receiver internals a lot since I first saw the
rig. Since the links I had were to a directory on your commercial
site, I'm not sure if you have another site where you described what
you did.

Early last Spring, I got rid of all my new-fangled ham rigs, like the
FT-817 and the not-so-new, but pristine TS-530s and bought an HW-101
and some equipment to restore. Homebrewing and boatanchors is what
I'm about now. I did the VFO alignment on the HW-101 and was able to
get it within 1kHz, end to end, as indicated on the dial, anyway. That
surprised the heck out of me. I've since acquired an LMO from an
SB-401 that I'm going to put in a project somewhere along the line. I
have a complete set of Heath HFO crystals, and both CW and SSB filters
from another source. I might make myself a broadbanded QRP rig out of
those.

73,
Ted KX4OM


On Sun, 02 Apr 2006 02:20:25 GMT, "Dale Parfitt"
wrote:

Hi Don and Ted,
While it has been over a year now since I did the VFO- I too had some
difficulties with the QST values. In talking w/ W7ZOI, Wes indicated that
some errors had worked their way into the design over the years. One was on
the audio amp- values I had caused severe rolloff below about 2KHz- making
SSB very tinny.
The other was on the VFO. Because of the Eddystone dial, I wished to make
the VFO as linear as possible- book values led to a highly non linear scale.
I do not recall exactly what I did- although I played with the math for a
long time- to lienarize it- but I would trust your calcs.
At some point I will open her up again as I want to buffer the VFO and tap
off for a TX VFO- the plan is to build a Drake style reciter for the RX- and
at that time will better document the changes I made.

Dale W4OP

"Ted" wrote in message
...
Dale & Don,
I haven't had a chance to lash up the components yet, but I checked my
spreadsheet using Wes's example on page 4.4. The numbers check out;
unfortunately, Wes specifies a value for C3 in the EMRFD example, and
in the Progressive Receiver Article, C3 is the unknown; i.e., how much
additional capacitance you'd have to add in parallel with the coil to
use a specific variable cap in the given configuration.
Now that I can see the "C12v" equation in EMRFD, which is not in the
QST article, but I've modified my spreadsheet to include it I can
check the resonance using the given values for L.

Dale, when I looked at your jpg's again yesterday, I noticed that
you've modified the receiver internals a lot since I first saw the
rig. Since the links I had were to a directory on your commercial
site, I'm not sure if you have another site where you described what
you did.

Early last Spring, I got rid of all my new-fangled ham rigs, like the
FT-817 and the not-so-new, but pristine TS-530s and bought an HW-101
and some equipment to restore. Homebrewing and boatanchors is what
I'm about now. I did the VFO alignment on the HW-101 and was able to
get it within 1kHz, end to end, as indicated on the dial, anyway. That
surprised the heck out of me. I've since acquired an LMO from an
SB-401 that I'm going to put in a project somewhere along the line. I
have a complete set of Heath HFO crystals, and both CW and SSB filters
from another source. I might make myself a broadbanded QRP rig out of
those.

73,
Ted KX4OM

Hi Ted,
I quickly looked at the VFO schematic in my1994 Handbook that had the PR. I
seem to recall in the end I replaced C1 with a short- just eliminating it.
Not 100% positive, but think that was what it came down to in order to get
good linearity out of my VFO.

Dale

On Mon, 03 Apr 2006 01:37:23 GMT, "Dale Parfitt"
wrote:


Hi Ted,
I quickly looked at the VFO schematic in my1994 Handbook that had the PR. I
seem to recall in the end I replaced C1 with a short- just eliminating it.
Not 100% positive, but think that was what it came down to in order to get
good linearity out of my VFO.

Dale

Dale,
I'll check that out. My value for C3 from the spreadsheet came out to
be 319.1 vs the 127.02 in the magazine. I used the spreadsheet on the
example on page 4.4 of EMRFd and it worked out ok. In the QST
example, setting C1 to a very low value actually increases the
discrepancy with C3, though. More mystery!

Tnx,
Ted KX4OM

"Ted" wrote in message
...
On Mon, 03 Apr 2006 01:37:23 GMT, "Dale Parfitt"
wrote:


Hi Ted,
I quickly looked at the VFO schematic in my1994 Handbook that had the PR.
I
seem to recall in the end I replaced C1 with a short- just eliminating it.
Not 100% positive, but think that was what it came down to in order to
get
good linearity out of my VFO.

Dale

Dale,
I'll check that out. My value for C3 from the spreadsheet came out to
be 319.1 vs the 127.02 in the magazine. I used the spreadsheet on the
example on page 4.4 of EMRFd and it worked out ok. In the QST
example, setting C1 to a very low value actually increases the
discrepancy with C3, though. More mystery!

Tnx,
Ted KX4OM
Hi Ted,
No doubt, the VFO could be put on the correct freq range with C3 included-
it was just very nonlinear.

Dale