From hbr@mailman.qth.net  Thu Mar  6 15:55:28 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Thu, 6 Mar 2003 10:55:28 -0500
Subject: [HBR] HBR2K -- Chapter 15 -- Large Signal Performance, Part 2
In-Reply-To: <3E593391.30921.22CABBD@localhost>
References: <185.176c8dfa.2b8a91e1@aol.com>
Message-ID: <3E672920.20881.56A451@localhost>

Subtitle: The education continues.

As I increased the overall gain and cleaned up assorted problems the 
HBR2K's third order IMD dynamic range wound up 55 db.    
Reference points:  FT-101 (early transistor set, 1970) -- 55 db, KWM-
2A -- 62 db,  R-390 -- 80 db,  current state of the art -- 100+ db.   

The receiver sounds outstanding -- way better than the second best 
receiver here, a KWM-2A.   But you'd sooner tell your mother you 
make adult toys for a living than that your receiver has a 55 db IMD 
dynamic range.   

Several days of thrashing about followed.   The usual problem is in 
the first mixer but that didn't seem to be the case here.   

Shoot.   Finally I figured out how to do the measurement on 
successive stages and began to pin things down.   It was equally 
bad (55 db) at the grid of the second mixer but went up to the over-60 
db range when measured at various other points from the second 
mixer plate to the filter input.   Clearly the second mixer is a 
problem.  

But why only 63 db at the filter input?   This is the place to start work 
because there's no obvious reason it should be so low and the 
receiver's overall performance can never be better than the worst 
stage.

At the filter there's sort of nothing left that ought to be non-linear 
before the filter throws away the two unwanted signals.   To clarify:  
Feeding signals at 3200 and 3220 kcs into a 3180/2.4 kcs filter can 
only produce a spurious 3180 signal if mixing happens *in or before* 
the filter -- after the filter the 3200 and 3220 kcs signals are so much 
attenuated that they're not going to cause a problem.

I disconnected all the filter selection diode switching stuff and wired 
the SSB filter directly.   The dynamic range went up to 68 db.   The 
filter switching is done with diodes, chokes and resistors; at first I 
suspected the diodes and the chokes.   The signal required to 
produce an S-1 spurious signal is 12,500 uV and the filter impedence 
is 500 ohms; maybe the diode switching current is not high enough 
to avoid distortion?  

But no such luck -- doubling the switching current made *no* 
difference in the dynamic range.   There followed several more days 
of poking at the problem with a sharp stick that eliminated non-
linearity in the filter switching parts as the limiting factor.

Dynamic range is the ratio of two numbers:  The largest signal the 
circuit can handle without distortion, seemingly set in this case by 
the filter itself, divided by the smallest, set by internal noise or gain.   
With circuits ahead of the filter disconnected (and no input) the noise 
from the 1st 3180kcs IF amp is not sufficient to cause S-meter 
deflection so the limit is probably gain, however the noise is easily 
audible so a noise limit isn't far off.  

The upper limit could be hurt if the filter is mismatched, however I'm 
satisfied that that isn't the case.   The passband looks perfect and it 
sounds just fine -- you don't get that with a mismatched filter.

Most likely the filter switching circuitry hurts the performance (68 db 
with one filter hardwired, down to 63 with switching for three filters) by 
increasing losses.   Probably this can be improved by changing the 
switching circuit.   It certainly seems that relays would be better than 
diodes and resistors but I'll try some other things first -- I'm not sure 
there's space for relays.   

(In a complete redesign one could consider using the MODE switch 
directly although the mechanical challenges might be considerable 
and the FT-101 parts set would not have the necessary switch.)

The FT-101 was the first mass-production modern HF transceiver, ca 
1970.   With a 55 db overall dynamic range set by the available 
transistor technology there's no reason it should have filter circuitry 
that will do better than 60-some db.

Next steps:

1.  Measure the noise floor at the 1st 3180kcs IF stage -- a 6EH7.    
Improve this number if possible.   (Maybe a cascode amp instead of 
a pentode?)   Look at increasing the detector sensitivity.   Increase 
the IF gain.  I may try 6KT6's -- half again the Gm but still good AGC 
characteristics.

2.  Try to reduce switching losses in the filter circuits.   

3.  When performance at the filter is as good as possible, tackle the 
second mixer.

Those who want to know a lot more about IMD testing of high 
performance receivers will find a very interesting article on the AOR 
(UK) web site at:

www.aoruk.com/comments.htm

The comments are by John Thorpe, the designer of the AR 7030.  
Way, way the best writing I've seen on the subject.  

Walt Hutchens
KJ4KV

From hbr@mailman.qth.net  Sun Mar 16 03:44:45 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sat, 15 Mar 2003 22:44:45 -0500
Subject: [HBR] HBR2K -- Chapter 14 -- Large Signal Performance, Part 3
In-Reply-To: <3E593391.30921.22CABBD@localhost>
References: <185.176c8dfa.2b8a91e1@aol.com>
Message-ID: <3E73ACDD.6801.137A014@localhost>

(In previous parts I focused on trying to understand and improve the 
IMD dynamic range at the input to the crystal filters leading to a need 
to increase the IF gain.)

Measurements on 1st 3180 kcs IF stage showed a noise floor (10 db 
s+n/n) of 0.3 uV and an AGC threshold of 4 uV.   Certainly a 
respectable noise performance however, we need to do better than 
'respectable.'   Since the stage was driven directly from the 500 ohm 
filter, the first thing to try was impedence matching.   

After a week's work and several dead ends I had a 1:8 toroidal 
transformer with a tuned secondary.  Now *that* improved sensitivity -
- or was it just pickup of things I didn't want to hear in the new high 
impedence grid circuit?   It took a day to shield the carrier oscillators 
(on the other side of the chassis but still close enough to radiate into 
that tuned grid circuit), re-route all non-essential wiring away from the 
stage, and put a tin sheld across the 1st IF socket.   That fixed the 
spurious pickup except for one very strong signal that comes in in 
the evening; a tin shield over the grid components takes care of that.

The noise floor improved to 0.05 uV  (not very accurate!) with an AGC 
threshold of 1 uV.   That's more like it -- should be plenty of gain.  
But the IMD dynamic range at the filter input was now 61 db -- 
certainly no better than the 62 db or so before the sensitivity 
improvement.   Lowering the amplitude of the signals going through 
the filter should allow a *higher* ratio because the 3rd order IMD 
spurious signal rises or falls as the third power of the input.   How 
could there be no improvement?

I had been using two URM-25D's to do the tests.   I *thought* they 
were okay, but ... Thinking some about the problem of 
crossmodulation between the generators (which would mimic IMD 
occuring in the receiver) I came up with an easy test.  I set the 
carrier level to the maximum available without visible distortion; this 
turned out to be about 0.6 volts p-p.   Then I turned the two output 
attenuators down one step, thereby adding 40 db more generator-to-
generator isolation to the 30-40 db provided by the hybrid combiner.   
The result was still enough signal to do a dynamic range test and -- 
voila!  Doing the same test that had produced the 61 db result, I got 
74 db.   

So (a) the filter and driver section is good enough for now, and (b) the 
signal generators are a problem.   They do not limit measurements 
significantly below 74 db so I can use them to try to improve the 55 
db ratio set by the second mixer but to actually *measure* dynamic 
ranges 74 db and above (when the second mixer problems are 
solved) I'll have to come up with better instruments.  

Basically I need two oscillators capable of a sizeable fraction of a volt 
output, pure sine wave, and immune to comparable signals being 
injected at the output.   Fancier signal generators aren't necessarily 
better for this job; the HP8640 is considered poor.  John Thorpe (in 
the reference cited last time) discusses the problems.   

There's no obvious reason the URM-25's shouldn't work.   There's 
some waveform distortion at extremely high (above spec) signal 
levels due to the cathode follower output but since they lack ALC 
(you set the level by hand at each frequency) the problem found in 
fancier units simply can't happen.   But since they don't work well 
more analysis is needed ... maybe the diode circuit used to drive the 
output meter?  Maybe the output stage itself?    I am trying to 
download and print a BAMA manual but the software needed for the 
new space-saving format seems not to support printing if you run 
WIN 95.

The 3180kcs IF gain increase was still a good idea.   The road ahead 
includes reducing distortion in the second mixer as much as 
possible; some gain may be lost there.   Then substantially reducing 
the max gain of the RF stage -- maybe to the 6 db range or so, from 
the current 20 db.   Definitely couldn't do the latter without the higher 
IF gain.

Then another light went on again ... I remembered I had a specialized 
military test set from some long-forgotten hamfest.   I had never done 
anything with it but I remembered the manual saying something 
about testing of SSB receivers and transmitters.   Retrieved the unit 
from the archives and, wow, it is a URM-144, designed specifically to 
do distortion testing with two RF signals.   Crystal controlled on 2, 
3.6, 4, 7.2, 8 ... 28.8 Mcs.    It consists of two solid state Butler 
variable-freq. crystal oscillators with buffer amps and/or three 
doublers switched in as necessary to reach the output freq.   The 
combiner is built in, as is a 120 db step attenuator.   Unfortunately 
the frequency separation is only a couple of kcs at the lowest 
frequency so only the highest bands would allow tests at 20 kcs 
spacing.   There is some frequency adjustment available but not 
enough to make it work.

However, substituting a 3.579 Mcs clock crystal for one of the 3.6 
Mcs crystals gave a spacing of about 25 kcs and I was able to 
measure an IMD dynamic range at the antenna jack of the HBR2K of 
60 db at that frequency.   That's consistant with the 50's numbers 
from before, considering the greater spacing (which allows pre-crystal 
filter selectivity to do more) and testing on 80 rather than 40 meters.

This set is intended for pass-fail testing of in-service military gear; 
closer frequency spacing tests a radio all the way to the detector.   
However, for receiver development work, 20 kcs is more useful 
because it lets us focus on designed-in distortion ahead of the 
narrow filter.  The set could be modified so the bandswitch selects 
offset crystals to give a frequency difference of 20 kcs.    All 
frequencies start with 2 Mcs or 3.6 Mcs so if you used 2.020, 3.620, 
(two fundamental frequencies), 2.010, 3.610 (for 4 Mcs and 7.2 Mcs), 
and so on, you'd have it.  Expen$ive, but just doing the 3.6 Mcs 
crystals would take care of all the ham bands.

Distortion is spec'ed at 60 db below output rather than in terms of 
IMD range.   If I knew what gear it was intended to be used with I 
probably could find out what it's intended to measure -- hafta look 
into that. 

Anyway I have what I think is a reliable way to measure IMD for the 
whole receiver and a technique that will allow using the URM-25's to 
test later stages on other frequencies.   

This ought to be a lot more than one would want to learn about 
receiver design, but I'm actually finding it pretty interesting.

Walt Hutchens
KJ4KV


From hbr@mailman.qth.net  Sun Mar 16 13:56:15 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 16 Mar 2003 07:56:15 -0600
Subject: [HBR] HBR2K -- Chapter 14 -- Large Signal Performance, Part 3
Message-ID: <20030316.080424.-243441.0.windy10605@juno.com>

Very impressive, Walt. Glad you are telling us all about it.
That's true homebrew.

73  Kees K5BCQ

From hbr@mailman.qth.net  Tue Mar 18 01:53:07 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Mon, 17 Mar 2003 19:53:07 -0600
Subject: [HBR] Fw: Miller 1709 IF Transformers
Message-ID: <20030317.195810.-266081.4.windy10605@juno.com>

Received this note which may be of interest.

73  Kees K5BCQ

--------- Forwarded message ----------
    If you or any body at the HBR site is trying to locate some of the 
original JW Miller

    1709,s  plus the 1800 kc and an osc coil, I found an auction on E-Bay

that has 

     four of them listed.   I thought you be might be interested or some
one 
else

     trying to obtain some.  You might post this auction number on the 
reflector if your

     not interested.    Auction number   3013399032   $5.00  and no bids
yet, 
a real

     steal, but the seller is in Canada.   Take care my friend,  73,s 
John

From hbr@mailman.qth.net  Tue Mar 18 02:14:33 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Mon, 17 Mar 2003 20:14:33 -0600
Subject: [HBR] Pictures ....more
Message-ID: <20030317.201437.-266081.6.windy10605@juno.com>

I have a few more pictures to go onto the web site:

One set from Bob Mattson (W2AMI) of a late HBR with the 
back-to-back IFs. Pictures are ready to go.

One set of a barn rescued HBR-16 complete with mouse
nest from Morry Weinschenker (K3DPJ). I'm having a little
trouble scanning the excellent large photos down to an
acceptable .jpg size (50-70KB). He said he MIGHT be 
interested in trading it.

Any more pictures while I'm at it again......

Been busy bringing an old R-390A back to life. Details on
my web site http://www.qsl.net/k5bcq/

73  Kees K5BCQ

From hbr@mailman.qth.net  Tue Mar 18 03:23:03 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Mon, 17 Mar 2003 21:23:03 -0600
Subject: [HBR] Fw: Pictures ....are online
Message-ID: <20030317.212307.-266081.7.windy10605@juno.com>

The subject 6 pictures have been added to the HBR web site.

Kees

--------- Forwarded message ----------
From: windy10605@juno.com
To: hbr@mailman.qth.net
Date: Mon, 17 Mar 2003 20:14:33 -0600
Subject: Pictures ....more

I have a few more pictures to go onto the web site:

One set from Bob Mattson (W2AMI) of a late HBR with the 
back-to-back IFs. Pictures are ready to go.

One set of a barn rescued HBR-16 complete with mouse
nest from Morry Weinschenker (K3DPJ). I'm having a little
trouble scanning the excellent large photos down to an
acceptable .jpg size (50-70KB). He said he MIGHT be 
interested in trading it.

Any more pictures while I'm at it again......

Been busy bringing an old R-390A back to life. Details on
my web site http://www.qsl.net/k5bcq/

73  Kees K5BCQ

From hbr@mailman.qth.net  Sun Mar 23 17:20:32 2003
From: hbr@mailman.qth.net (Kevin Berlen K9HX)
Date: Sun, 23 Mar 2003 12:20:32 -0500
Subject: [HBR] Help with old home-brew receiver
Message-ID: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>

Hi, I am brand new to the list and need some assistance. I recently picked up
a old tube type home brew receiver, and hope someone on the list can help me
identify it. The receiver uses plug in coils for band switching, and has 
several
parts that have been salvaged from an old command set including three 85KC
IF transformers, the 85KC BFO coil and several three section .05MFD caps.

The rig uses an external power supply and the tube line up is:

6AQ5
12AX7A
6AL5
6BY6
12AU7A
6BE6
6C4
6BJ6 x2
1 other 7 pin minature that I can't get the number off of.

I was told that it was built from a QST article for the 1950's, and most of 
the
tubes have late 50's date codes on them. If anyone can help me locate the
original construction article and schematic I would be very grateful. TIA, 
and 73,

Kevin, K9HX


From hbr@mailman.qth.net  Sun Mar 23 19:22:15 2003
From: hbr@mailman.qth.net (LORNE BARBER)
Date: Sun, 23 Mar 2003 11:22:15 -0800
Subject: [HBR] Help with old home-brew receiver
Message-ID: <001f01c2f171$881e97e0$44897240@default.sunwave.net>

Kevin, a picture would be nice.

The unmarked tube may be a voltage regulator.

73
Lorne  Ve7box



From hbr@mailman.qth.net  Sun Mar 23 20:07:51 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 23 Mar 2003 15:07:51 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>
Message-ID: <3E7DCDC7.25784.1B843C1@localhost>

I can heartily recommend a visit to the HBR website; if there's a 
resource related to these receivers that isn't available there, I can't 
imagine what it would be.   I believe the link appears at the bottom of 
all posts to this list.

Good luck with it!

Why don't I stumble on to one of these sets?    Okay, so I guess it 
helps to go to hamfests and such, instead of working on a homebrew 
receiver project ...

Walt Hutchens 
KJ4KV

From hbr@mailman.qth.net  Sun Mar 23 21:34:43 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 23 Mar 2003 15:34:43 -0600
Subject: Fw: Re: [HBR] Help with old home-brew receiver
Message-ID: <20030323.153446.-317563.2.windy10605@juno.com>

I personally think it's good that you don't stumble across one of these,
Walt. How else could we continue to get details as you develop your 
HBR2K.

73  Kees K5BCQ


--------- Forwarded message ----------
From: waltah@earthlink.net
To: hbr@mailman.qth.net
Date: Sun, 23 Mar 2003 15:07:51 -0500
Subject: Re: [HBR] Help with old home-brew receiver
Message-ID: <3E7DCDC7.25784.1B843C1@localhost>

I can heartily recommend a visit to the HBR website; if there's a 
resource related to these receivers that isn't available there, I can't 
imagine what it would be.   I believe the link appears at the bottom of 
all posts to this list.

Good luck with it!

Why don't I stumble on to one of these sets?    Okay, so I guess it 
helps to go to hamfests and such, instead of working on a homebrew 
receiver project ...

Walt Hutchens 
KJ4KV
************************************
Visit the HBR Receiver Web Site with over 100 pictures of receivers and 
construction notes...... via http://www.qsl.net/k5bcq/ 

Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr

From hbr@mailman.qth.net  Sun Mar 23 21:56:03 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 23 Mar 2003 16:56:03 EST
Subject: [HBR] Help with old home-brew receiver
Message-ID: <130.1d1ef57c.2baf8773@aol.com>

In a message dated 3/23/03 12:22:31 PM Eastern Standard Time, K9HX@joink.com 
writes:

> Hi, I am brand new to the list and need some assistance. I recently picked 
up
>  a old tube type home brew receiver, and hope someone on the list can help 
me
>  identify it. The receiver uses plug in coils for band switching, and has 
>  several
>  parts that have been salvaged from an old command set including three 85KC
>  IF transformers, the 85KC BFO coil and several three section .05MFD caps.
>  
>  The rig uses an external power supply and the tube line up is:
>  
>  6AQ5
>  12AX7A
>  6AL5
>  6BY6
>  12AU7A
>  6BE6
>  6C4
>  6BJ6 x2
>  1 other 7 pin minature that I can't get the number off of.
>  
>  I was told that it was built from a QST article for the 1950's, and most 
of 
>  the
>  tubes have late 50's date codes on them. If anyone can help me locate the
>  original construction article and schematic I would be very grateful. TIA, 
>  and 73,

To my knowledge this does not match any design in QST. 

>From the tube lineup, it appears to be an adaptation of the HBR concept, 
using miniature tubes and an external supply. Here's my best guess on the 
tube lineup functions:

6AQ5 - Audio Output

12AX7A - 1st Audio

6AL5  Noise limiter & AM detector

6BY6 Product detector

12AU7A BFO

6BE6 2nd converter 

6C4 HF oscillator

6BJ6 x2  IF amplifiers

The unknown tube is probably the 1st mixer. What do its innards look like?

Some questions:

How many sections on the tuning capacitor?

What controls are on the front panel, and how are they labeled?

Any crystals in the receiver?

How many coil sets?

Does it have any meters?

What does the dial look like?

--

It IS possible to reverse-engineer a homebrew rx like this. First job is to 
trace out all the wiring - quite a task but very illuminating. 

Pix are a big help.

73 de Jim, N2EY 

From hbr@mailman.qth.net  Mon Mar 24 01:45:07 2003
From: hbr@mailman.qth.net (Kevin Berlen K9HX)
Date: Sun, 23 Mar 2003 20:45:07 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <130.1d1ef57c.2baf8773@aol.com>
Message-ID: <5.1.1.6.1.20030323202602.00b3abc0@joink.com>

At 04:56 PM 3/23/2003 -0500, you wrote:
>In a message dated 3/23/03 12:22:31 PM Eastern Standard Time, K9HX@joink.com
>writes:
>
> > Hi, I am brand new to the list and need some assistance. I recently picked
>up
> >  a old tube type home brew receiver, and hope someone on the list can help
>me
> >  identify it. The receiver uses plug in coils for band switching, and has
> >  several
> >  parts that have been salvaged from an old command set including three 85KC
> >  IF transformers, the 85KC BFO coil and several three section .05MFD caps.
> >
> >  The rig uses an external power supply and the tube line up is:
> >
> >  6AQ5
> >  12AX7A
> >  6AL5
> >  6BY6
> >  12AU7A
> >  6BE6
> >  6C4
> >  6BJ6 x2
> >  1 other 7 pin minature that I can't get the number off of.
> >
> >  I was told that it was built from a QST article for the 1950's, and most
>of
> >  the
> >  tubes have late 50's date codes on them. If anyone can help me locate the
> >  original construction article and schematic I would be very grateful. 
> TIA,
> >  and 73,
>
>To my knowledge this does not match any design in QST.
>
> >From the tube lineup, it appears to be an adaptation of the HBR concept,
>using miniature tubes and an external supply. Here's my best guess on the
>tube lineup functions:
>
>6AQ5 - Audio Output
>
>12AX7A - 1st Audio
>
>6AL5  Noise limiter & AM detector
>
>6BY6 Product detector
>
>12AU7A BFO
>
>6BE6 2nd converter
>
>6C4 HF oscillator
>
>6BJ6 x2  IF amplifiers
>
>The unknown tube is probably the 1st mixer. What do its innards look like?
>
>Some questions:
>
>How many sections on the tuning capacitor?
>
>What controls are on the front panel, and how are they labeled?
>
>Any crystals in the receiver?
>
>How many coil sets?
>
>Does it have any meters?
>
>What does the dial look like?
>
>--
>
>It IS possible to reverse-engineer a homebrew rx like this. First job is to
>trace out all the wiring - quite a task but very illuminating.
>
>Pix are a big help.
>
>73 de Jim, N2EY
>************************************
>Visit the HBR Receiver Web Site with over 100 pictures of receivers and
>construction notes...... via http://www.qsl.net/k5bcq/
>
>Retrieve reflector archived data via 
>http://mailman.qth.net/mailman/listinfo/hbr

Hi Jim and others that have responded to my request for help. My digital camera
failed about a month ago and I don't have it replaced yet. The tube I can't 
identify
looks like a 6BE6 or something similar to it. The tuning cap has three 
sections and
there are three plug-in coils. I have an s-meter , and the dial is a 
National Velvet type.
Controls number five and are labeled as follows:

RF Gain
Trimmer
AVC-MVC-BFO
BFO pitch
AF Gain
Also I have a switch to turn the ANL on.

There are two additional pots, one on the rear apron and one on top of the 
chassis
near the back. The antenna input is on a three terminal strip and appears 
to be set
up to take both balanced and un-balanced line. The dial is calibrated for 
80, 40, 20,
and 15 meters. The power supply apparently supplied 200 VDC and regulated (?)
105 VDC.

Thanks again, and if I can borrow a camera, Kees has offerd to post them. 
Thanks
again for all of the responses and your help so far. 73,

Kevin, K9HX



From hbr@mailman.qth.net  Mon Mar 24 01:47:53 2003
From: hbr@mailman.qth.net (Kevin Berlen K9HX)
Date: Sun, 23 Mar 2003 20:47:53 -0500
Subject: [HBR] Help with old home-brew receiver
Message-ID: <5.1.1.6.1.20030323204555.00b42e88@joink.com>

I neglected to mention that there is one crystal in the unit marked
1685KC. 73 again,

Kevin, K9HX

  


From hbr@mailman.qth.net  Mon Mar 24 01:51:06 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 23 Mar 2003 20:51:06 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <130.1d1ef57c.2baf8773@aol.com>
Message-ID: <3E7E1E3A.31315.2F29351@localhost>

Jim said:
> It IS possible to reverse-engineer a homebrew rx like this.

And very interesting to us homebrew receiver vultures!   Kevin, I hope 
you're not feeling you've gotten just a bit too enthusiastic a 'welcome' 
to the list!

Even if you just trace out the control grid and plate connections on 
each stage -- what other stages does each stage connect to -- you'll 
have the big picture.   And that's enough to get started making it 
work.   The use of those recycled command set caps is ... searching 
for suitably delicate word ... unfortunate.   You will very likely have to 
replace all of them, right at the start;  I'm not sure I've ever gotten a 
command set working without changing at least one and they get 
worse as the years go by.   If you want to keep it authentic, contact 
me off-list and I'll see about liberating some ARC type 12 caps;  
they're structurally identical but infinitely better quality.   Not quite 
identical, I guess -- the insulating top is plastic or ceramic, rather 
than mica -- but same 'tub' structure, mounting method, same type 
terminals.   

Don't just throw the juice to it, as a shorted cap will probably take out 
at least one other part.   Also, they do not all fail right away ... some 
will go from 'works but slightly leaky' to 'dead short' over a period 
ranging up to weeks of operation.   Been there, done that ...

The design is interesting.   Either the ?? tube is another mixer and 
it's a double conversion receiver without an RF stage, or it's an RF 
stage and it's single conversion.   Is there another IF transformer?  
How many coils per band?

I can't recall a published design going either way, but it could be a 
modification of one.   Okay, so I'm just a sucker for this stuff -- I'll 
take a look at my QST microfishes and see what I can find.

Welcome to the list!

Walt Hutchens
KJ4KV

From hbr@mailman.qth.net  Mon Mar 24 02:41:25 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sun, 23 Mar 2003 21:41:25 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>
Message-ID: <3E7E2A05.25375.320A6AE@localhost>

Well ... We may have a winner.   QST, March, 1956, p. 39, "A Nine 
Tube Amateur Band Receiver With 3-Kc. Selectivity", by Emory E. 
Toops, Jr., W9HLH.   This is a double conversion receiver with the 
tubes as listed by Kevin except that there's a 6BA6, there's no 
6BY6, and there's no 12AU7.

The tube lineup in the W9HLH receiver is:

6AQ5 Audio Output
12AX7 1st Audio/BFO
6AL5 Detector/AVC/ANL
6BJ6 x2  85 Kcs IF's
6BE6 x2 1st & 2nd mixer
6BA6 RF
6C4 Local Osc.

The 1st IF freq. is 1600 kcs and consists of just one transformer 
located between the two mixer stages.   The 6BE6 2nd mixer is self-
excited, with a crystal at 1685 kcs.   

That looks like it, though there are obvious questions about the 
12AU7 and 6BY6.   The 6BY6 is probably a substitute for a 6BE6 -- 
the basing is the same.   I'd guess the unidentified tube is the 6BA6 
RF stage -- if so it will be nested in with the coils.   The 12AU7 ... Q-
multiplier?    Selecto-ject?   The TNS (twin noise squelch) used a 
12AX7 I think?   

The author describes his goal as coverage of 80 through 10 meters, 
simple to construct, and use as many parts as possible from a BC-
453.   He describes use of the IFTs, BFO coil, nine bypass caps 
(ugh ...) and resistor terminal boards from the command set.

"No S-meter was included because it was considered an 
unnecessary expense."   The receiver is tuned with a National UM-15 
three gang 15 mmf/section variable cap.

Congratulations, Kevin -- you snagged a *rare* one!   And that's a 
good sound design;  it should be quite usable on the lower bands in 
any case and on 20 and up according to the builder's degree of 
fanaticism.   

Unfortunately I have no blowback facilities for microfiche but maybe 
someone can go to a CDROM version and print the article for you.   
It's a pretty good article, too.

Walt Hutchens
KJ4KV

From hbr@mailman.qth.net  Mon Mar 24 03:01:50 2003
From: hbr@mailman.qth.net (Kevin Berlen K9HX)
Date: Sun, 23 Mar 2003 22:01:50 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <3E7E2A05.25375.320A6AE@localhost>
References: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>
Message-ID: <5.1.1.6.1.20030323215014.00b5b908@joink.com>

Hi Walt,

Thanks for your help. As it turns out I beleive the author of that article
was a local ham. He was a silent key prior to my entry into ham radio
in 1974. I don't believe this rig was constructed by him, but he no doubt
inspired it's construction. Now, does anyone have a copy of the QST
article they can get to me?? Thanks again and very 73,

Kevin, K9HX


From hbr@mailman.qth.net  Mon Mar 24 10:18:17 2003
From: hbr@mailman.qth.net (Mike Feher)
Date: Mon, 24 Mar 2003 05:18:17 -0500
Subject: [HBR] Help with old home-brew receiver
References: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>
 <5.1.1.6.1.20030323215014.00b5b908@joink.com>
Message-ID: <001401c2f1ee$b06673d0$0500a8c0@eoz>

Kevin -

I have every issue of QST from Dec. 1915 till now. So, I can either scan it
for you or copy and mail it. 73 - Mike



Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-901-9193



----- Original Message -----
From: "Kevin Berlen K9HX" <K9HX@joink.com>
To: <hbr@mailman.qth.net>
Sent: Sunday, March 23, 2003 10:01 PM
Subject: Re: [HBR] Help with old home-brew receiver


> Hi Walt,
>
> Thanks for your help. As it turns out I beleive the author of that article
> was a local ham. He was a silent key prior to my entry into ham radio
> in 1974. I don't believe this rig was constructed by him, but he no doubt
> inspired it's construction. Now, does anyone have a copy of the QST
> article they can get to me?? Thanks again and very 73,
>
> Kevin, K9HX
>
> ************************************
> Visit the HBR Receiver Web Site with over 100 pictures of receivers and
> construction notes...... via http://www.qsl.net/k5bcq/
>
> Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr
>
>


From hbr@mailman.qth.net  Mon Mar 24 11:19:23 2003
From: hbr@mailman.qth.net (Kevin Berlen K9HX)
Date: Mon, 24 Mar 2003 06:19:23 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <001401c2f1ee$b06673d0$0500a8c0@eoz>
References: <5.1.1.6.1.20030323114959.00b2a4a8@joink.com>
 <5.1.1.6.1.20030323215014.00b5b908@joink.com>
Message-ID: <5.1.1.6.1.20030324061716.00b5da30@joink.com>

Hi Mike,

Thanks for your offer. A scan would be just fine. Thanks, and 73,

Kevin, K9HX


From hbr@mailman.qth.net  Mon Mar 24 11:26:57 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Mon, 24 Mar 2003 06:26:57 EST
Subject: [HBR] Help with old home-brew receiver
Message-ID: <190.17b63a37.2bb04581@aol.com>

In a message dated 3/23/03 9:40:24 PM Eastern Standard Time, 
waltah@earthlink.net writes:

> Well ... We may have a winner.   QST, March, 1956, p. 39, "A Nine 
>  Tube Amateur Band Receiver With 3-Kc. Selectivity", by Emory E. 
>  Toops, Jr., W9HLH.   

(Homer Simpson mode ON)

DOH!!!!!!!

(Homer Simpson mode OFF)

Dunno how I missed that one, but I agree 100% with Walt. The rx may be based 
on the 1956 article, or it may be the original with modifications. Got the 
mag right here, too close a match to be anything else.

>  This is a double conversion receiver with the 
>  tubes as listed by Kevin except that there's a 6BA6, there's no 
>  6BY6, and there's no 12AU7.

It's possible the unidentified tube is a 6BA6.
>  
>  The tube lineup in the W9HLH receiver is:
>  
>  6AQ5 Audio Output
>  12AX7 1st Audio/BFO
>  6AL5 Detector/AVC/ANL
>  6BJ6 x2  85 Kcs IF's
>  6BE6 x2 1st & 2nd mixer
>  6BA6 RF
>  6C4 Local Osc.
>  
>  The 1st IF freq. is 1600 kcs and consists of just one transformer 
>  located between the two mixer stages.   The 6BE6 2nd mixer is self-
>  excited, with a crystal at 1685 kcs.   
>  
>  That looks like it, though there are obvious questions about the 
>  12AU7 and 6BY6.   The 6BY6 is probably a substitute for a 6BE6 -- 
>  the basing is the same.   I'd guess the unidentified tube is the 6BA6 
>  RF stage -- if so it will be nested in with the coils.   The 12AU7 ... Q-
>  multiplier?    Selecto-ject?   The TNS (twin noise squelch) used a 
>  12AX7 I think?   

All good possibilities. Another is that the noisy 6BE6 first mixer was 
replaced by a 12AU7 a la Pullen, and the 6BY6 added as a product detector. Or 
the 12AU7 may be the product detector. 12AU7 could also be a tube to drive an 
S meter (external?).
>  
>  The author describes his goal as coverage of 80 through 10 meters, 
>  simple to construct, and use as many parts as possible from a BC-
>  453.   He describes use of the IFTs, BFO coil, nine bypass caps 
>  (ugh ...) and resistor terminal boards from the command set.

I know others have had bad luck with Command set caps, but mine just keep on 
working. But I agree they need to be checked before applying power. Changing 
them all as a preventive is certainly a good idea. Only three ARC-5 cans are 
used, not a big job. 
>  
>  "No S-meter was included because it was considered an 
>  unnecessary expense."   The receiver is tuned with a National UM-15 
>  three gang 15 mmf/section variable cap.
>  
>  Congratulations, Kevin -- you snagged a *rare* one!   And that's a 
>  good sound design;  it should be quite usable on the lower bands in 
>  any case and on 20 and up according to the builder's degree of 
>  fanaticism.   
>  
Agreed!  Now all you need is a power supply and speaker. Article says a 90 ma 
transformer is more than adequate. 

73 de es sri for the earlier confusion

Jim, N2EY


From hbr@mailman.qth.net  Mon Mar 24 18:48:50 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Mon, 24 Mar 2003 13:48:50 -0500
Subject: [HBR] Help with old home-brew receiver
In-Reply-To: <190.17b63a37.2bb04581@aol.com>
Message-ID: <3E7F0CC2.6038.11403F8@localhost>

Wow, a feeding frenzy among the HBR vultures!   This sure is more 
exciting than making the next yard-and-a-half on the HBR2K project!

Jim:
> All good possibilities. Another is that the noisy 6BE6 first mixer was
> replaced by a 12AU7 a la Pullen, and the 6BY6 added as a product detector.
> Or the 12AU7 may be the product detector. 12AU7 could also be a tube to
> drive an S meter (external?)

This seems a better bet than my ideas.   If I were doing it with those 
tubes I'd make the 12AU7 the first mixer, a la Pullen (dual triode 
mixer with particular operating conditions) and use the 6BY6 as a 
product detector.   Among other problems this solves, the 6C4 local 
osc really needs more isolation than feeding a 6BE6 directly -- I don't 
think it's possible to get good SSB reception above 10 Mcs with 6C4-
6BE6 lineup.

I once converted a 3-6 Mcs command receiver to dual conversion 
using one of the original 1415kcs IFTs and two 85 Kcs ones.   It 
worked fine, tho just a little more gain would have been desirable.   
Actually, something along that line might also make a good HB 
project.   With the frame grid tubes you'd have plenty of gain.

That could even be a way to go for a simple general coverage home 
brew receiver -- just have to add a converter in front of it for the 
successive bands.

Back to the 9-tube receiver.   Power supply -- a pair of Radio Shack 
12 volt 3 amp filament transformers back to back with filaments fed 
from the center and the second primary bridge rectified would give 
you around 160-70 volts; the radio should work okay and the slightly 
lower voltage would be kinder to the command set caps.   Ground 
the center tap of the 'input' transformer and divide the receiver 
filaments into two strings.   I am running the HBR2K project receiver 
(vacuum tube dual conversion receiver designed around an FT-101 
chassis and parts) at 145 volts with no problems.

But maybe you already have a power supply.   Anyhow, let us know 
how it goes!

Walt Hutchens
KJ4KV







From hbr@mailman.qth.net  Tue Mar 25 18:59:55 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Tue, 25 Mar 2003 13:59:55 EST
Subject: [HBR] Help with old home-brew receiver
Message-ID: <142.dc89fba.2bb2012b@aol.com>

In a message dated 3/24/03 1:48:13 PM Eastern Standard Time, 
waltah@earthlink.net writes:

> I once converted a 3-6 Mcs command receiver to dual conversion 
>  using one of the original 1415kcs IFTs and two 85 Kcs ones.   It 
>  worked fine, tho just a little more gain would have been desirable.   
>  Actually, something along that line might also make a good HB 
>  project.   With the frame grid tubes you'd have plenty of gain.
>  
>  That could even be a way to go for a simple general coverage home 
>  brew receiver -- just have to add a converter in front of it for the 
>  successive bands.

OK, how about this......

Find some really hacked-up ARC-5 sets - BC-453, 454, 455. Pick the best 
chassis of the three and assemble an rx as follows:

Tuning gang - from BC-455
Tuning coils - from BC-454 (add low-Z link to RF coil)
New tuning gang will cover about 1 Mc. Suggest 3 to 4 Mc. range. Better dial 
readout and tuning rate.
IF cans - one from BC-454, two from BC-453
BFO - BC-453, remotely tuned with mini antenna trimmer from BC-454 or BC-455
Replace all canned bypasses with better types.

Tube Lineup:

12SG7 RF amp
12K8Y 1st mixer/osc
12K8Y or 12SA7 2nd mixer/xtal osc (need a 1500 kc. xtal, or reuse the BC-454 
BFO coil)
12SK7 IF amp
12SR7 detector/AVC/1st audio
12A6 Audio output (use dpdt switch to select cathode resistor and output 
transformer so that stage can drive 'phones or speaker).
12SQ7 BFO (mount in dynamotor socket)
1629 magic eye instead of S meter

With a little care, the original chassis will hold everything except the 
1629. 

An external converter can be built to cover the bands 40 thru 10:

~10.5 Mc. xtal permits coverage of 40 and 20 
~21.5 Mc. xtal permits coverage of 17 and 12
~25.0 Mc. xtal permits coverage of 15 and lowest mc. of 10
- 6.5 Mc. xtal permits coverage of 30

Lots of leeway in the xtal freqs and other combos possible because the tuning 
range is a full Mc.

73 de Jim, N2EY

From hbr@mailman.qth.net  Sat Mar 29 17:00:49 2003
From: hbr@mailman.qth.net (john)
Date: Sat, 29 Mar 2003 12:00:49 -0500
Subject: [HBR] HBR Ebay alert
Message-ID: <3.0.3.32.20030329120049.02862590@pop-server.nc.rr.com>

Looks like a nice HBR14 (which will need a new power transformer?)

John
K5MO


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4673&item=3014943104

From hbr@mailman.qth.net  Sat Mar 29 22:05:26 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sat, 29 Mar 2003 16:05:26 -0600
Subject: Fw: [HBR] HBR Ebay alert
Message-ID: <20030329.160839.-303757.9.windy10605@juno.com>

Definitely an HBR receiver, but what is that circuitry to the right of 
the power transformer ? These receivers are everywhere !!

73  Kees K5BCQ

--------- Forwarded message ----------
From: john <johnmb@nc.rr.com>
To: hbr@mailman.qth.net
Date: Sat, 29 Mar 2003 12:00:49 -0500
Subject: [HBR] HBR Ebay alert
Message-ID: <3.0.3.32.20030329120049.02862590@pop-server.nc.rr.com>

Looks like a nice HBR14 (which will need a new power transformer?)

John
K5MO


http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4673&item=30149431
04
************************************
Visit the HBR Receiver Web Site with over 100 pictures of receivers and 
construction notes...... via http://www.qsl.net/k5bcq/ 

Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr

From hbr@mailman.qth.net  Sat Mar 29 23:06:57 2003
From: hbr@mailman.qth.net (john)
Date: Sat, 29 Mar 2003 18:06:57 -0500
Subject: Fw: [HBR] HBR Ebay alert
In-Reply-To: <20030329.160839.-303757.9.windy10605@juno.com>
Message-ID: <3.0.3.32.20030329180657.02839520@pop-server.nc.rr.com>

Good question! It almost looks like an IF strip!
John



At 04:05 PM 3/29/03 -0600, you wrote:
>
>Definitely an HBR receiver, but what is that circuitry to the right of 
>the power transformer ? These receivers are everywhere !!
>
>73  Kees K5BCQ
>
>--------- Forwarded message ----------
>From: john <johnmb@nc.rr.com>
>To: hbr@mailman.qth.net
>Date: Sat, 29 Mar 2003 12:00:49 -0500
>Subject: [HBR] HBR Ebay alert
>Message-ID: <3.0.3.32.20030329120049.02862590@pop-server.nc.rr.com>
>
>Looks like a nice HBR14 (which will need a new power transformer?)
>
>John
>K5MO
>
>
>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4673&item=30149431
>04
>************************************
>Visit the HBR Receiver Web Site with over 100 pictures of receivers and 
>construction notes...... via http://www.qsl.net/k5bcq/ 
>
>Retrieve reflector archived data via
>http://mailman.qth.net/mailman/listinfo/hbr
>************************************
>Visit the HBR Receiver Web Site with over 100 pictures of receivers and 
>construction notes...... via http://www.qsl.net/k5bcq/ 
>
>Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr
>
>
>
>---
>
>Checked by AVG anti-virus system (http://www.grisoft.com).
>Version: 6.0.463 / Virus Database: 262 - Release Date: 3/17/03
>

From hbr@mailman.qth.net  Sat Mar 29 23:28:48 2003
From: hbr@mailman.qth.net (Mike Feher)
Date: Sat, 29 Mar 2003 18:28:48 -0500
Subject: [HBR] HBR Ebay alert
References: <20030329.160839.-303757.9.windy10605@juno.com>
Message-ID: <017001c2f64a$f3be8f40$0500a8c0@eoz>

It almost looks like mechanical parts only for possible future expansion of
capabilities, like a Q multiplier. Does not appear that any of the tube
holders have tubes in them, also, it appears as the IFs have been gutted.
Anyway, I count 16 tubes without these extra 4, so that would make it an
HBR-16 and not 14. Looks fairly similar to one of them that I built as a
young teenager. I do not think mine had as nice of a case however. BTW, the
receiver discussed previously and found to be in the March 1956 copy of QST
has been forwarded to Kevin and he is convinced that indeed it is the one.
In case anyone else would like to see it, I have uploaded the scanned pages
and, they can be found at:

http://www.monmouth.com/~n4fs/qst035639.jpg
http://www.monmouth.com/~n4fs/qst035640.jpg
http://www.monmouth.com/~n4fs/qst035641.jpg
http://www.monmouth.com/~n4fs/qst0356118.jpg
http://www.monmouth.com/~n4fs/qst0356120.jpg

73 - Mike





Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-901-9193



----- Original Message -----
From: <windy10605@juno.com>
To: <hbr@mailman.qth.net>
Sent: Saturday, March 29, 2003 5:05 PM
Subject: Fw: [HBR] HBR Ebay alert


> Definitely an HBR receiver, but what is that circuitry to the right of
> the power transformer ? These receivers are everywhere !!
>
> 73  Kees K5BCQ
>
> --------- Forwarded message ----------
> From: john <johnmb@nc.rr.com>
> To: hbr@mailman.qth.net
> Date: Sat, 29 Mar 2003 12:00:49 -0500
> Subject: [HBR] HBR Ebay alert
> Message-ID: <3.0.3.32.20030329120049.02862590@pop-server.nc.rr.com>
>
> Looks like a nice HBR14 (which will need a new power transformer?)
>
> John
> K5MO
>
>
> http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=4673&item=30149431
> 04
> ************************************
> Visit the HBR Receiver Web Site with over 100 pictures of receivers and
> construction notes...... via http://www.qsl.net/k5bcq/
>
> Retrieve reflector archived data via
> http://mailman.qth.net/mailman/listinfo/hbr
> ************************************
> Visit the HBR Receiver Web Site with over 100 pictures of receivers and
> construction notes...... via http://www.qsl.net/k5bcq/
>
> Retrieve reflector archived data via
http://mailman.qth.net/mailman/listinfo/hbr
>
>


From hbr@mailman.qth.net  Sun Mar 30 01:53:27 2003
From: hbr@mailman.qth.net (hbr@mailman.qth.net)
Date: Sat, 29 Mar 2003 19:53:27 -0600
Subject: Fw: Re: [HBR] HBR Ebay alert
Message-ID: <20030329.195330.-303757.12.windy10605@juno.com>

The same seller also has other homebrew items for sale which appear to
be built in the same type of cabinets. The RTTY unit has VE6AGQ on it
and the 2m transceiver has VE6PB, Hank Heslinga on it. The seller said 
he didn't know the builder(s) but just bought a bunch of misc stuff.

73  Kees K5BCQ


--------- Forwarded message ----------
From: Mike Feher <n4fs@monmouth.com>
To: hbr@mailman.qth.net
Date: Sat, 29 Mar 2003 18:28:48 -0500
Subject: Re: [HBR] HBR Ebay alert
Message-ID: <017001c2f64a$f3be8f40$0500a8c0@eoz>
References: <20030329.160839.-303757.9.windy10605@juno.com>


It almost looks like mechanical parts only for possible future expansion
of
capabilities, like a Q multiplier. Does not appear that any of the tube
holders have tubes in them, also, it appears as the IFs have been gutted.
Anyway, I count 16 tubes without these extra 4, so that would make it an
HBR-16 and not 14. Looks fairly similar to one of them that I built as a
young teenager. I do not think mine had as nice of a case however. BTW,
the
receiver discussed previously and found to be in the March 1956 copy of
QST
has been forwarded to Kevin and he is convinced that indeed it is the
one.
In case anyone else would like to see it, I have uploaded the scanned
pages
and, they can be found at:
73 - Mike

