From ianmwilson73 at gmail.com  Fri Jul  4 11:06:54 2014
From: ianmwilson73 at gmail.com (Ian Wilson)
Date: Fri, 4 Jul 2014 08:06:54 -0700
Subject: [HBR] Fixed a nasty problem (non-HBR)
Message-ID: <CAEz8jcQy6eQAfnQ5z0Kvr61N1Y7Gy07MVCxjQBSLzMVDbJFhsA@mail.gmail.com>

[OT but relevant I hope to receiver homebrewers].

One or twice a year I dig out my over-ambitious homebrew
dual conversion receiver, based on the 75S3-C. This uses
crystal-controlled downconverters followed by a ~3MHz tunable
IF tuned by a PTO.

Last time I lost patience with the rig I ripped out the HR-10
frontend and for the moment have a 6BZ6 (biased for low gain)
and toroids / dual-gang variable cap for preselector tuning.

This "sort of" worked but the audio was really horrible. This had
to be intermodulation or something in an early stage.

A few days ago I blew the dust off the rig and tried again. This
time I had an inspiration: listen to the output of the 3MHz bandpass
filter with a general coverage receiver. So we just have the RF amp
and first mixer in circuit. Aha! really horrible signals! Nothing to do
with the second mixer, xtal filter, IF strip....

This time around, I have a Tek 7704A scope that can show VHF
signals. It showed a vicious 200MHz squegging oscillation when
looking at the plate of the RF amplifier (through a tiny capacitor).
This disappeared when I removed the connection to the mixer
(at present a 6DJ8 second-generation Pullen). I had forgotten
to add a stubber resistor on the mixer grid. Added that, and
things improved enormously.

I guess I'll keep this project on the workbench for a while longer :)

73, ian K3IMW

From whitebear1122 at comcast.net  Fri Jul  4 13:48:58 2014
From: whitebear1122 at comcast.net (Whitebear1122)
Date: Fri, 4 Jul 2014 12:48:58 -0500
Subject: [HBR] Fixed a nasty problem (non-HBR)
In-Reply-To: <CAEz8jcQy6eQAfnQ5z0Kvr61N1Y7Gy07MVCxjQBSLzMVDbJFhsA@mail.gmail.com>
References: <CAEz8jcQy6eQAfnQ5z0Kvr61N1Y7Gy07MVCxjQBSLzMVDbJFhsA@mail.gmail.com>
Message-ID: <225E22AB-5B79-4A1C-8C17-92D12B1DBB5C@comcast.net>

Congrats on the discovery!  You had a good inspiration to check out the 3 Mc IF.  Hope that cleans everything up down the chain.   I know some folks build their radios from the audio amplifier and go backwards.  Me, I'm starting at the RF front end.   I'm a few weeks away from wiring my HBR13.  The mechanicals have been slow going.  I have just 5 holes left to drill in theRF front end now that I've lined up the 3 section variable capacitor with the Eddystone.  I have the RF front end shielding aluminum cut and just need to tap and screw together, then the mechanical is done.   My plan is to wire the RF front end first and check that out before moving onto the 1610 Khz IF amplifier stage on the main chassis, and then move on to the three stage (and 4 transformers) 100 Kc IF, checking each stage out before moving on to the next.  This is my first radio construction project so I need to take small steps lest I end up with multiple mistakes in many sections that are difficult to resolve. 

Good luck with your project.  I'm curious to hear just how well it works out!   If you get it going and are pleased to talk about it, I'd like to hear offline about your design and implementation.  73, Scott WA9WFA

On Jul 4, 2014, at 10:06 AM, Ian Wilson <ianmwilson73 at gmail.com> wrote:

> [OT but relevant I hope to receiver homebrewers].
> 
> One or twice a year I dig out my over-ambitious homebrew
> dual conversion receiver, based on the 75S3-C. This uses
> crystal-controlled downconverters followed by a ~3MHz tunable
> IF tuned by a PTO.
> 
> Last time I lost patience with the rig I ripped out the HR-10
> frontend and for the moment have a 6BZ6 (biased for low gain)
> and toroids / dual-gang variable cap for preselector tuning.
> 
> This "sort of" worked but the audio was really horrible. This had
> to be intermodulation or something in an early stage.
> 
> A few days ago I blew the dust off the rig and tried again. This
> time I had an inspiration: listen to the output of the 3MHz bandpass
> filter with a general coverage receiver. So we just have the RF amp
> and first mixer in circuit. Aha! really horrible signals! Nothing to do
> with the second mixer, xtal filter, IF strip....
> 
> This time around, I have a Tek 7704A scope that can show VHF
> signals. It showed a vicious 200MHz squegging oscillation when
> looking at the plate of the RF amplifier (through a tiny capacitor).
> This disappeared when I removed the connection to the mixer
> (at present a 6DJ8 second-generation Pullen). I had forgotten
> to add a stubber resistor on the mixer grid. Added that, and
> things improved enormously.
> 
> I guess I'll keep this project on the workbench for a while longer :)
> 
> 73, ian K3IMW
> ______________________________________________________________


From smithab11 at comcast.net  Fri Jul  4 13:55:27 2014
From: smithab11 at comcast.net (B. Smith)
Date: Fri, 04 Jul 2014 13:55:27 -0400
Subject: [HBR] Fixed a nasty problem (non-HBR)
In-Reply-To: <225E22AB-5B79-4A1C-8C17-92D12B1DBB5C@comcast.net>
References: <CAEz8jcQy6eQAfnQ5z0Kvr61N1Y7Gy07MVCxjQBSLzMVDbJFhsA@mail.gmail.com>
	<225E22AB-5B79-4A1C-8C17-92D12B1DBB5C@comcast.net>
Message-ID: <53B6EA8F.6000900@comcast.net>

Building  an HBR project backwards allows you to use the audio section 
and the "S" meter for troubleshooting.
http://k4che.com/HBR/Testing/Progress%20Testing%20pg%201.htm
breck k4che



On 7/4/2014 1:48 PM, Whitebear1122 wrote:
> Congrats on the discovery!  You had a good inspiration to check out the 3 Mc IF.  Hope that cleans everything up down the chain.   I know some folks build their radios from the audio amplifier and go backwards.  Me, I'm starting at the RF front end.   I'm a few weeks away from wiring my HBR13.  The mechanicals have been slow going.  I have just 5 holes left to drill in theRF front end now that I've lined up the 3 section variable capacitor with the Eddystone.  I have the RF front end shielding aluminum cut and just need to tap and screw together, then the mechanical is done.   My plan is to wire the RF front end first and check that out before moving onto the 1610 Khz IF amplifier stage on the main chassis, and then move on to the three stage (and 4 transformers) 100 Kc IF, checking each stage out before moving on to the next.  This is my first radio construction project so I need to take small steps lest I end up with multiple mistakes in many sections that are difficult to
>   resolve.
>
> Good luck with your project.  I'm curious to hear just how well it works out!   If you get it going and are pleased to talk about it, I'd like to hear offline about your design and implementation.  73, Scott WA9WFA
>
> On Jul 4, 2014, at 10:06 AM, Ian Wilson <ianmwilson73 at gmail.com> wrote:
>
>> [OT but relevant I hope to receiver homebrewers].
>>
>> One or twice a year I dig out my over-ambitious homebrew
>> dual conversion receiver, based on the 75S3-C. This uses
>> crystal-controlled downconverters followed by a ~3MHz tunable
>> IF tuned by a PTO.
>>
>> Last time I lost patience with the rig I ripped out the HR-10
>> frontend and for the moment have a 6BZ6 (biased for low gain)
>> and toroids / dual-gang variable cap for preselector tuning.
>>
>> This "sort of" worked but the audio was really horrible. This had
>> to be intermodulation or something in an early stage.
>>
>> A few days ago I blew the dust off the rig and tried again. This
>> time I had an inspiration: listen to the output of the 3MHz bandpass
>> filter with a general coverage receiver. So we just have the RF amp
>> and first mixer in circuit. Aha! really horrible signals! Nothing to do
>> with the second mixer, xtal filter, IF strip....
>>
>> This time around, I have a Tek 7704A scope that can show VHF
>> signals. It showed a vicious 200MHz squegging oscillation when
>> looking at the plate of the RF amplifier (through a tiny capacitor).
>> This disappeared when I removed the connection to the mixer
>> (at present a 6DJ8 second-generation Pullen). I had forgotten
>> to add a stubber resistor on the mixer grid. Added that, and
>> things improved enormously.
>>
>> I guess I'll keep this project on the workbench for a while longer :)
>>
>> 73, ian K3IMW
>> ______________________________________________________________
> ______________________________________________________________
> HBR mailing list
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>



From radio at daileyservices.com  Fri Jul  4 13:59:06 2014
From: radio at daileyservices.com (radio at daileyservices.com)
Date: Fri, 4 Jul 2014 11:59:06 -0600
Subject: [HBR] Nasty Problem & building in "reverse"
References: <CAEz8jcQy6eQAfnQ5z0Kvr61N1Y7Gy07MVCxjQBSLzMVDbJFhsA@mail.gmail.com>
	<225E22AB-5B79-4A1C-8C17-92D12B1DBB5C@comcast.net>
Message-ID: <15164B83927E4080A2D6EFC287430282@w0eaj>

Makes sense to me Scott - interestingly, the old Heathkit EK-2 "receiver", 
which was part of their electronics course, was built in pieces in the 
"reverse" order you mentioned..  I cleaned up, fixed, and aligned one from 
an SK buddy, before we sold it, and reading the manual, it was obvious that 
they'd designed it to be done EXACTLY that way.. p/s first, audio amp, 
oscillator, then the rest.

Tom - W0EAJ 


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From bcarling at cfl.rr.com  Thu Jul 10 17:05:07 2014
From: bcarling at cfl.rr.com (bcarling at cfl.rr.com)
Date: Thu, 10 Jul 2014 17:05:07 -0400
Subject: [HBR] FS: High Impedance Headhones
Message-ID: <53BF0003.25624.40ECDE@bcarling.cfl.rr.com>

For Sale: High Impedance Headhones

H-43 B/U headset in new condition. Comfortable set with nice padding. They look new and 
unused, but since is no package are being sold as "used" but in good working condition.

Found on the web:
"The H-43 B/U was a 3000 ohm set that was made for a Radiac Geiger Counter and also 
works well with crystal radios. "

Seems to be ideal for a regen or other homebrew receiver requiring hi-z.

Available for $15.00 plus shipping

73 de AF4K, Bry
Brian Carling, Radio AF4K

From bcarling at cfl.rr.com  Wed Jul 23 14:10:47 2014
From: bcarling at cfl.rr.com (bcarling at cfl.rr.com)
Date: Wed, 23 Jul 2014 14:10:47 -0400
Subject: [HBR] PARTS etc. FOR SALE
Message-ID: <53CFFAA7.3924.53E0ED@bcarling.cfl.rr.com>

PARTS etc. FOR SALE

1) Barker and Williamson Coaxial Antenna Switch model 592 (two way) - excellent condition 
QTY 1 available for $32.00 plus shipping

2) Sprague 8 uF at 1000V DC oil-filled capacitor. Tested and works fine, no leakage or
other issues. Dimensions 3.75"  X  1.25"  X  5.25" tall
QTY 1 available for $6.00 plus shipping

3) Pair of ceramic octal sockets wired for 6146 tubes, an a small copper plated subchassis, 
with a nice 2.5 mH choke, ceramic feedthru etc. $5.00 plus shipping

4) - Box of 16 power resistors and bleeder resistors, Ohmite etc. mostly 25, 50 and 100 watt.
Examples:  100 ohms at 100 watts,  12K at 100 watts, 14K at 50 watts, 15K at 72 watts,  16K 
at 50 watts,  20K at 100 watts, 24K at 72 watts,  25K at 100 watts, etc. This is about 10% of 
list price:
Available - all 15 for $25.00 plus shipping

5) DX100 plate tank coil including extra 160m coil - $5.00

6) RFC - Plate choke from a Viking II transmitter - $5.00

7) Pair of 10K at 10 watts resistors, plus one 15K at 10 watts from DX100 - $4.00 for all 3.

8) Panel Meter from DX100 Transmitter - $10.00

9) Chassis for DX100 Transmitter - $20.00

10)  VFO assembly for DX100 - $20.00

11) Transformer with secondary: 50V AC at 20 Amps. Like new, scientific grade, and in 
excellent condition.
Primary is 120V AC and this is a beautiful workhorse transformer. 4 hole mounting. 
Dimensions:  7" X 6.5" X 4.5" tall.
QTY 1 available for $25.00 plus $15 for USA shipping

12) Pair of ceramic 807 sockets with mounting hardware - $5.00

13)  Pair of ceramic plate caps for 807 tubes Millen - $4.00

14) Microphone socket for DX100 - 2-pin with hardware - $4.00

15) Group of capacitors - One Astron 0.1 uF at 600V DC, Two 0.05 at 1600V DC, One 
0.0002 uF at 1200V and two electrolytics 40 uF at 450V DC. These are good tested used 
parts. The 0.1 and 0.05 ones have usable short leads - others normal. Also,  one DX100 
Fixed loading capacitor HV, switches in parallel to the loading variable capacitor. 
Total of 7 capacitors for $6.00

16) New Silver mica 0.001 uF capacitors at 2500V DC. Available for $6.00 each while they 
last.

17) G.E. MASTR external speaker $5.00

18) G.E. mobile Power supply for two way radio - $5.00

19) Three black IERC tube shields, heat dissipating types, for 7 pin miniature tubes.
$6.00 for all three.

20) HAL-TRONIX model HAL FC-600A frequency counter. Good working condition. BNC 
inputs and runs on 120V AC. I have no manual for this. Available for $15.00 plus shipping.

21)  6Y6G tube made by G.E. - QTY 1 available for $3.00

22) 811 Transmitting tube Penta Labs - looks new - $12.00

23) 5R4WGY tube new in box JAN type from Chatham Electronics - $5.00

24) 5T4 tube, new - $2.00

25) 6146 (S2001A) from Matsushita - looks new, like 6146 - $6.00
 
26) Mullard TDD2A gold tube new in box - $10.00

27) 3B28 rectifier tube - JAN - QTY 1 only for $4.00

Shipping additional on all the above.  For additional details, pictures or questions, 
please e-mail me off the list.

73 & thanks for looking

Brian Carling, AF4K
Brian Carling, Radio AF4K

