[Boatanchors] Using a Q-5er with a Command Set Rx

Sat Nov 19 12:41:43 EST 2022

It’s easy to use a BC-453 Q-5er with a BC-454 or BC-455 Command Set receiver.  To convert from the high frequency IF of the 454 or 455 to the 190 to 550 tuning range of the 453, you pull the BFO of the hf receiver down to, say 500 kHz below the normal IF frequency and inject it into the control grid of the second IF stage, making it into a mixer.  Replace the output transformer of the second IF with a (broadband) resistor and couple the resulting 500 kHz signal into the antenna connector of the 453, tuned to 500 kHz.  I have an ER magazine article with the details that I can send to anyone interested.

Jim, W8KGI 

Sent from my iPhone

> On Nov 19, 2022, at 7:54 AM, boatanchors-request at mailman.qth.net wrote:
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> Today's Topics:
> 
>   1. Re: 85 kHz transformers (Jeff Quay)
>   2. BC-348 (ROSS HOCHSTRASSER)
>   3. Re: 85 kHz transformers (Dave and Sharon Maples)
>   4. Re: 85 kHz transformers (William Cromwell)
> 
> 
> ----------------------------------------------------------------------
> 
> Message: 1
> Date: Sat, 19 Nov 2022 03:29:54 +0000
> From: Jeff Quay <jeff_quay at hotmail.com>
> To: Dave and Sharon Maples <dsmaples at comcast.net>,
>    "boatanchors at mailman.qth.net" <boatanchors at mailman.qth.net>,
>    "wrcromwell at gmail.com" <wrcromwell at gmail.com>
> Subject: Re: [Boatanchors] 85 kHz transformers
> Message-ID:
>    <MWHPR12MB16634B7500E6403D7FF58C0183089 at MWHPR12MB1663.namprd12.prod.outlook.com>
>    
> Content-Type: text/plain; charset="utf-8"
> 
> Hi All,
> The link from Dave below takes you to page 33 of the electronic document. If you substitute page 0032, 0035, 0037, 0041, and 0043 for the link's -0033 you will be able to download the entire article. Hope that helps. Sounds like a fun project!
> Jeff - K7UUA
> ________________________________
> From: boatanchors-bounces at mailman.qth.net <boatanchors-bounces at mailman.qth.net> on behalf of Dave and Sharon Maples <dsmaples at comcast.net>
> Sent: Friday, November 18, 2022 1:55 PM
> To: boatanchors at mailman.qth.net <boatanchors at mailman.qth.net>; wrcromwell at gmail.com <wrcromwell at gmail.com>
> Subject: [Boatanchors] 85 kHz transformers
> 
> Bill: That's wonderful.  Please let me know the price of shipping.
> 
> Thank you VERY MUCH!
> 
> All: The Q6'er appeared in an Australian magazine back in the fall of 1960.  Basically the author took six of the 85 kHz transformers and operated them in pairs.  He had a product detector, BFO, and AM detector in the system.  Overall it seemed very nice.  I imagine it was highly selective, but the adjustment of inductor spacing and stagger tuning might have allowed him to create a very customized SSB filter with a very good shape factor.  There is one page of the article out there in Internet land: https://worldradiohistory.com/hd2/IDX-AUSTRALIA/IDX/Archive-Radio-and-Hobbies-IDX/60s/Radio-and-Hobbies-1960-12-OCR-Page-0033.pdf  I hope to be able to spring for the issue of Radio, Television, and Hobbies that had this in it so I can see the full spread.
> 
> What I plan to do is measure one of the 85 kHz transformers on the bench and document its selectivity at both coupling points, and from there try to estimate what a Q6er or similar design might deliver.
> 
> I got curious about these IF cans.  Apparently to resonate around 85 kHz with a 180 pf capacitor the coils have to be around 19.5 millihenries.  Murata Power Solutions makes an inductor (https://www.mouser.com/ProductDetail/Murata-Power-Solutions/17226C?qs=sGAEpiMZZMv126LJFLh8y6ElRBzbBTips6jRdwtJxGI%3D) that is 22 millihenries and has a Q of 100 at 50 kHz.  It seems like mounting one of these on a moving PCB so it is lined up axially with another one that is fixed might allow reproducing the variable-bandwidth tuning arrangement.  The coils are cheap (less than $1.25 from Mouser).  They are also quite small (just over 0.25" diameter) so it might be possible to build some low-frequency bandpass filters with fixed adjustments that would fit nicely inside a BC-348.  I may pick up a couple of the coils just to see what they would be like coupled that way.
> 
> The Hammarlund HC-10 is horrendously expensive and hard to find, but it occurs to me that it might be possible to come up with something that provides similar functionality for a lot less cash.  The result won't be the same as an Icom 7300, but it would still be fun to examine.  Setting up something like a Q6er with a mixer stage in front of it and a LO that could adjust with a vernier +/- 5 kHz around the desired IF frequency to be downconverted from could be handy with R390s, BC-348s, and even Command sets.  The same chassis could have multiple inputs and a switched mixer to allow any of the receivers to be brought in and passed through the system.  Each receiver would be responsible for its own AGC up to the point the IF signal left the receiver, and this thing would do AGC processing for the downconverted IF.  For very-high-quality AM reception an infinite-impedance detector or a precision full-wave rectifier might be part of the design.  It might be built with vacuum tub
> es or with solid-state devices.
> 
> Not sure which year I'd be able to finish this ?, but it might be interesting.
> 
> Thanks,
> Dave WB4FUR
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> ------------------------------
> 
> Message: 2
> Date: Sat, 19 Nov 2022 09:07:55 -0500 (EST)
> From: ROSS HOCHSTRASSER <bavarianradio at comcast.net>
> To: boatanchors <boatanchors at mailman.qth.net>
> Subject: [Boatanchors] BC-348
> Message-ID: <1377376365.76996.1668866875332 at connect.xfinity.com>
> Content-Type: text/plain; charset=UTF-8
> 
> Hi All, I am looking for a clean, working BC-348 for a friend that wants to give it for a Christmas present to his 26 year old son who just got his ham license a year ago. Please contact me off list at bavarianradio at comcast.net mailto:bavarianradio at comcast.net     THANKS!! 73 Ross W1EKG
> 
> 
> ------------------------------
> 
> Message: 3
> Date: Sat, 19 Nov 2022 09:13:01 -0500
> From: "Dave and Sharon Maples" <dsmaples at comcast.net>
> To: "'Jeff Quay'" <jeff_quay at hotmail.com>,
>    <boatanchors at mailman.qth.net>,    <wrcromwell at gmail.com>
> Subject: Re: [Boatanchors] 85 kHz transformers
> Message-ID: <[email protected]>
> Content-Type: text/plain; charset="utf-8"
> 
> All: I got the pages together and put them into a single PDF (attached).  Thanks very much to Jeff for his capturing these!
> 
> Thanks,
> Dave WB4FUR 
> 
> ------------------------------
> 
> Message: 4
> Date: Sat, 19 Nov 2022 09:53:59 -0500
> From: William Cromwell <wrcromwell at gmail.com>
> To: Dave and Sharon Maples <dsmaples at comcast.net>,    'Jeff Quay'
>    <jeff_quay at hotmail.com>, boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] 85 kHz transformers
> Message-ID: <a6d7286e-1a69-a977-2b2a-49af5bc2a08a at gmail.com>
> Content-Type: text/plain; charset=UTF-8; format=flowed
> 
> Hi,
> 
> Reading all of this fascinating stuff makes me rethink giving up up 
> those cans. April fools! I have long since decided to give those up to 
> the first person who asks. I can just about see the end of my road from 
> here and other projects have higher priority. I *AM* interested in these 
> projects and I hope the builders will keep us posted.
> 
> I have three of the "Q5er" receivers to play with and any of my projects 
> will use those pretty much as-is. With two IF stages (three cans) they 
> give a reasonable ssb passband. I will probably nest a (reversible) 
> product detector inside one (solid state will accommodate that nicely) 
> and put a converter for 160, 80, 60, and 40 (maybe 30)meters ahead of 
> it. I have played at that before. From time to time there are "classic 
> radio" operating events for legacy gear and I would like to have the 
> Q5er paired with my Johnson Ranger or a homebrewed transmitter in one of 
> those affairs.
> 
> By the way - the command receivers can successfully be operated from 
> batteries. The heavy load is the heater strings and I use a 7 A-H lead 
> acid battery for that. The B+ at 90 volts from a series string of 
> transistor batteries gives good performance and lasts me several weeks 
> of operation.
> 
> 73,
> 
> Bill KU8H
> 
> bark less - wag more
> 
>> On 11/19/22 09:13, Dave and Sharon Maples wrote:
>> All: I got the pages together and put them into a single PDF (attached).  Thanks very much to Jeff for his capturing these!
>> 
>> Thanks,
>> Dave WB4FUR
> 
> 
> ------------------------------
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> End of Boatanchors Digest, Vol 226, Issue 7
> *******************************************