Don, et al,
Comments in-line:

On 1 Apr 2006 12:29:49 -0800, wrote:

Ted, Dale, Ken,

Ken that is true about the hen's teeth. I think that price is worth it
though. Dales receiver looks like a 2B. The blue backlighting is really
cool.

Dale's receiver looks like it belongs in a hospital, inside the case,
anyway...I'm sure an artificial liver or whatever doesn't have any
more "tubing" connections! That's taking the art of modular
construction to a whole 'nother level! The receiver also looks very
"sanitary", as we used to say back in the '70s, or I guess the word
would be "sick" in today's vernacular. More hospital tie-ins,
yuk-yuk!

I just like making homebrew verniers and dials but am getting lazy and
have been using Jackson Bros.stuff for the last two projects. I tried
what I believe is an Oren Elliot drive but it is so stiff I didn't use
it. One of the last projects used a small CD for the dial. Looks clever
and homebrewish but kinda tacky too. I am dangerous with certain tools
in my hands so I try to use ready made stuff. But the dial on my SSB
transceiver needed a little more work due to the way the dial had to
mounted. I am pleased with my mechanically challenged self. I'll follow
Dales and your advice and create it on my PC. Sharpy usually used here.

I won a door prize at the last NoGa meeting of a National Velvet
vernier. I don't have it handy for the number, but it's a fairly
small one...the dial area is about 3" wide. The cardboard scale has
been humidified somewhere along the way, so I'll need to scan that and
redo it in photoshop. The gears are ok, but a bit stiff. It looks
like it will be perfect for a VFO, maybe my long-wanted heterodyne VFO
for the HT-40.

Ted, on the VFO I roughly calculate the L and C from a few old DeMaw
and Hayward publications. But I generally go for less L more C. I think
those calculations are rough approximations anyways. I think the 2nd
edition of DeMaws QRP Notebook has the rough equations for Colpitts and
Clapp. I haven't seen one for Hartley. I have several old toroids wound
that I use for various things like VFO's. I used a number in the
Huffpuff circuit Hans Summers designed and substituted for
experimentation and optimum performance. I also have a bunch of cut and
try capacitors I use when I am building something like a VFO. I am
afraid to admit I do a lot of empirical construction on VFO's. Just the
opposite on filters and amplifiers. I use my SA when I build LC filters
and I measure all my critical L and C with my homebrew LC meter.
One thing I learned was to use ugly construction on my VFO's. I don't
know the fellow but W7EL mentioned something somewhere that made me try
that method. It simpler at the very least.

From what I understand, all other things being equal, the inductor is
more likely to suffer the effects of temperature-induced drift than
the capacitors, as long as C0G/NP0 and polystyrene caps are used.
Therefore, it makes sense to have a higher C to L ratio, although the
configuration of the VFO circuit will probably impose limits, as in
failure to oscillate at some point. I generally look at somebody
else's design as a prototype, and try to work around the same ratiios.

I went over and over the calculations again, and I'm pretty sure I'm
right, and there's a typo in the "Progressive Receiver" appendix. Then
it suddenly occurred to me, " Why don't you just lash up the
capacitors and the inductor and measure the darn thing?" Duh! I have
a grid dip meter, and I'm still making use of my cheap-but-fairly
accurate Rainbow capacitance meter, the one from the Handbook, until I
get the PIC programmed for the "Everyday Practical Electronics" one
that the Columbus QRP club built. This mystery will soon be solved!

Ted maybe I'll catch you on the other site but did you get the VFO
working? I knew you were working on a Hartley Huff Puff VFO. I tried
link coupling on the output from my Pierce version from the coil and
was suprised at how much cleaner the output was. I was going to try the
control circuit from a link too but had my grandson over the last two
weekends. He is just discovering his feet and rolling over. It is an
important time for grandpas.

One of the Hartley designs I'm looking at for the LO of my EMRFD
transceiver project is the Fig. 6.148 4 MHz one, which I would conver
to 5 MHz. Now that one is tapped, but what you did Don was to not tap
the coil, but to add a coupling winding, as I understand it. In the
Figure I just mentioned, Wes has an MV209 on the tap for fine tuning,
so I guess that's where the Huff and Puff would attach.

The other circuit I've been studying to the point of actually cadding
it, is Figure 12.25 in EMRFD. That one also has the familiar C1 C2 C3
Cvariable issue I've been trying to figure out, as does the Hartley
above. This VFO is a Colpitts, though (I guess; the output is off the
gate alone, and not the source). I suppose I'd either tap onto the
coil or use a coupling winding on that one, similar to what you did.
Conveniently, this one is a 5 MHz VFO already.

I just put in the order to Digi-Key a couple of days ago for the chips
for the fast stabilizer, so no, I haven't built it yet. I decided not
to go ahead with the other 2-chip minimalist one after your suggestion
on the fast one. The crystal oscillator I ordered is 66.66 MHz, so it
should work.

Its spring yardwork weekend here so not much radio going on. BTW, what
is a Nugatory Numptie (see other post)? I could be one. Do we have a
website?

K5UOS

I've got to go back and look at the other post. Don't know how I
missed that!

Ted KX4OM

Using those old verniers is risky to me only because finding
replacements if they start to slip or have backlash. I at least try to
find or build something I can replace. But the Eddiestone are just so
nice looking.

What I did on the HP VFO was like in fig 7.27 EMRFD. The output of the
IC is a square wave. I was concerned after I looked at the output on my
analyzer. I see why the cmos marker generators are so popular. Strong
harmonics way above 100MHz. The output was significantly cleaner from
the tap. Right around then I decided to go back and finish my SSB
receiver and mount it in the chassis so I didn't have to use so many
clip leads while I was playing with it.

I was going to do something similar to the fig 12.25 mixing type LO and
I still may. My original receiver had a 9MHz filter but a relatively
strong birdy from the LO at 7.2MHz. I decided to just change the filter
to 9.216MHz and no birdies. Was hell trying to find closely matched
9.216MHz crystals though. I got 65 ea from Mouser and only got ten
within 5%. Mostly a wide discrepancy in ESR. I guess you can make up
for a lossy filter but after spending as much time as I did on both
filters in measuring crystals I wanted something to show for it.

I was going to try the control circuit on the tap in my HP VFO. I know
it will work thiough even though I haven't tried it. Its just getting
the correct link and varactor. The fast HP VFO's still amazes me.
I get started on too many things so I went back to my SSB rig.

On the inductor drift I agree. I seem to have luck with slightly lower
L and using the slight neg temp coefficient of the COG caps. I did that
in my tube receiver built with toroids. I ended up using a small silver
mica for temp compensation of all things. Like you I look at other
circuits and copy. I didn't on this VFO because I was copying my own
circuit that worked before from something I am sure I copied. The more
I try other things though the less I copy. Right now I am working on a
25 VDC 6AMP power supply for the transceiver. I am going to try power
mosfets again as I had good luck in the last low power linear I built.
I am only looking for 40W or so. Plenty big for the type of SSB I will
work. I have a 28 VDC 3 A supply I made years ago. Just not sure it is
big enough for the PA I am going to use. Its not that efficient.

Gosh, typo errors in ham publications! Hard to believe! Not!. Good for
you for checking. I have a mess of spreadsheets with most of the common
formulas. I also made some for double and triple tuned BP filters,
feedback amps, my LC meter calculations, a logarithmic power meter and
crystal parameter testing. I check a lot of circuits in books by
plugging in the data to my sheets.

EMRFD is a great book. One thing I have been using in my transceiver LO
now is the hybrid splitter shown in fig 6.75. The vfo in 12.25 shows a
resistive version. I used the hybrid on both my VFO and BFO. That is a
nice technique even if it is a few more parts. I guess Wes must be a
better Numptie than all of us?

I bet you will really enjoy experimenting with the fast HP VFO. I
haven't had that much fun with a simple project in a long time. Once
you build a few you start getting alot of ideas on how to use it. Then
it starts adding to your list of projects. You start losing sleep, the
wife keeps asking you to take the trash out, you stop shaving, grow
your hair long and start smoking and drinking too much coffee. Then you
are in Nugatory. Thats ham purgatory. My wife calls it the doghouse.

Maybe I will put a picture of my progress on the SSB transceiver on the
tech site soon. I never know what Chuck is willing to accept though. So
I get a little cautious.

Keep me up on your progress.

On 1 Apr 2006 15:55:06 -0800, wrote:

Using those old verniers is risky to me only because finding
replacements if they start to slip or have backlash. I at least try to
find or build something I can replace. But the Eddiestone are just so
nice looking.
Well, maybe this one WILL be nice looking

What I did on the HP VFO was like in fig 7.27 EMRFD. The output of the
IC is a square wave. I was concerned after I looked at the output on my
analyzer. I see why the cmos marker generators are so popular. Strong
harmonics way above 100MHz. The output was significantly cleaner from
the tap. Right around then I decided to go back and finish my SSB
receiver and mount it in the chassis so I didn't have to use so many
clip leads while I was playing with it.
Figure 7.27? I don't quite follow that, unless you're talking about
how you've band-switched it.

I was going to do something similar to the fig 12.25 mixing type LO and
I still may. My original receiver had a 9MHz filter but a relatively
strong birdy from the LO at 7.2MHz. I decided to just change the filter
to 9.216MHz and no birdies. Was hell trying to find closely matched
9.216MHz crystals though. I got 65 ea from Mouser and only got ten
within 5%. Mostly a wide discrepancy in ESR. I guess you can make up
for a lossy filter but after spending as much time as I did on both
filters in measuring crystals I wanted something to show for it.
I'm using that design because I'll need 2 HFO's in two separate rigs
I'm working on. That one is interesting because of the 5 MHz output,
but I won't be using that for the rig itself. I'm using a 74HC4053
switch to mix either of two LOs with the 5 MHz VFO. The transceiver
I'm using EMRFD circuits for is a 15 and 20 meter SSB/CW traansceiver.
I'm using a 9MHz If, with HFO frequencies of 25 and 18 MHz. I'll use
the sums to produce the correct LO frequencies.

The other rig is one I've been working on, off and on, for over a
year. That one is based on G4GXOs Belthorn SSB/IF module. I picked
an IF of 11 MHz for it, because 32 and 25 MHz HFO crystals will allow
me to use a VFO of the toal span of 3.890 4.148 MHz. All of the
crystals are Mouser 39-cent variety.

I didn't realize it, but when I put in my order from Digi-Key last
wee, I stumbled across the ECS 18 MHz crystal, a value I didn't have
in my data base of available frequencies...that allows me to make the
EMRFD rig a 2-bander, adding 20 meters!

I was going to try the control circuit on the tap in my HP VFO. I know
it will work thiough even though I haven't tried it. Its just getting
the correct link and varactor. The fast HP VFO's still amazes me.
I get started on too many things so I went back to my SSB rig.

On the inductor drift I agree. I seem to have luck with slightly lower
L and using the slight neg temp coefficient of the COG caps. I did that
in my tube receiver built with toroids. I ended up using a small silver
mica for temp compensation of all things. Like you I look at other
circuits and copy. I didn't on this VFO because I was copying my own
circuit that worked before from something I am sure I copied. The more
I try other things though the less I copy. Right now I am working on a
25 VDC 6AMP power supply for the transceiver. I am going to try power
mosfets again as I had good luck in the last low power linear I built.
I am only looking for 40W or so. Plenty big for the type of SSB I will
work. I have a 28 VDC 3 A supply I made years ago. Just not sure it is
big enough for the PA I am going to use. Its not that efficient.

Gosh, typo errors in ham publications! Hard to believe! Not!. Good for
you for checking. I have a mess of spreadsheets with most of the common
formulas. I also made some for double and triple tuned BP filters,
feedback amps, my LC meter calculations, a logarithmic power meter and
crystal parameter testing. I check a lot of circuits in books by
plugging in the data to my sheets.

EMRFD is a great book. One thing I have been using in my transceiver LO
now is the hybrid splitter shown in fig 6.75. The vfo in 12.25 shows a
resistive version. I used the hybrid on both my VFO and BFO. That is a
nice technique even if it is a few more parts. I guess Wes must be a
better Numptie than all of us?
I'm not sure I really knew much of anything until I got EMRFD. The
first few weeks, I had a running stream of Q&A emails with Wes, and he
was kind enough to be patient and explain some things. One in
particular was a problem I had in adapting a published L-network to
the actual impedances of my crystal filter in the 30 meter rig I built
for Straight Key Night .

In Fig. 12.25, he's actually using the take-off point from the VFO to
the mixer from the attenuator pad for the 5 MHz output, to get the -10
dBm for 5 MHz for the 20 meter part of the rig.

I bet you will really enjoy experimenting with the fast HP VFO. I
haven't had that much fun with a simple project in a long time. Once
you build a few you start getting alot of ideas on how to use it. Then
it starts adding to your list of projects. You start losing sleep, the
wife keeps asking you to take the trash out, you stop shaving, grow
your hair long and start smoking and drinking too much coffee. Then you
are in Nugatory. Thats ham purgatory. My wife calls it the doghouse.
Sleep? What's that? Fortunately, my wife is busy getting her business
up and running, and I have plenty of time on my hands (I've inherited
the dog and cat-tending responsibilities).

Maybe I will put a picture of my progress on the SSB transceiver on the
tech site soon. I never know what Chuck is willing to accept though. So
I get a little cautious.
I understand completely. However, why not start a folder anyway?
There's only a couple of them there, and it's not like it's stuff that
belongs in the Smithsonian. Now if Dale had his receiver on the site,
that's certainly Smithsonian-quality!

When I was building the SKN Special, I did running updates to the NoGa
list with the latest photos on my web site. Now that it's finished, I
recently went back and reorganized that page to reflect past tense.
One of the highlights was definitely getting the VFO going. On the
scope, the signal has a weird distortion in the sine wave, like the
trailing edge is partially scooped out; I should post that on the
yahoo group site and see if anyone can figure out what it means. But,
since it's feeding an NE602, and they can take square waves, I guess a
little distortion doesn't matter.

Keep me up on your progress.
Tomorrow, I lash up a test capacitance circuit. Then, once I can
finally do the math and figure out which variable I can use, I'll
start building. the Digi-Key prts for the Huff and Puff whould be
here mid-week.

72/73,
Ted KX4OM