[ARC5] Transistorized ARC-5 Receiver

Phillip Carpenter carpenterpa at tds.net
Sun Jan 1 15:34:16 EST 2017 

Ok Group. The guy's name is Edward who makes the solid state tube replacements on eBay. He lives in Pennsylvania.

He said he can do it but his biggest concern is with have many tubes of the tube types in Command receivers (I.e. 12SK7s, 12K8, 12A6, & 12SR7/12SQ7) he could sell to recoup his development costs.

Looks like as someone pointed out earlier that he could recoup the 12SK7 development cost pretty quickly. The other tubes might not be used enough in other radio sets to allow him to recoup his cost to develop.

How many of you guys would commit to buying a set of solid state tubes from the guy for the Command receivers? This current cost per tube runs about $45 per tube.

Please all let me know what you think.

It would be interesting to see if solid state replacements for the noisy 12K8 Mixer might be a vast improvement to start with.

Respectfully,

Phillip W4RTX 

Sent from my iPhone

> On Jan 1, 2017, at 3:19 PM, Bill Cromwell <wrcromwell at gmail.com> wrote:
> 
> Hi Dennis,
> 
> I run my BC-453 stock from a pair of "slab"s in series for the heaters and 10 of the 9-volt batteries in series. The 9 volts batteries last me for months of casual operation and the heater supply might last a weekend - but is rechargeable. I have considered mounting FETs and/or bipolar transistors in tube bases. So far I am satisfied running the original tubes from batteries. I was pleasantly surprised how long those last.
> 
> Dual gate mosfets are available in a tiny package with fairly long leads laid out in a cross pattern. Those could be bent to fit through-hole patterns in a circuit board or in a tube base for plug-in.
> 
> Happy New Year and...
> 
> 73,
> 
> Bill  KU8H
> 
>> On 01/01/2017 12:44 PM, Dennis Monticelli wrote:
>> JFETs are readily available.  I have seen dual gate MOSFETs NOS from Dan's Small Parts.  I'm sure there are other sources.  You can make a dual gate JFET by stacking a higher Vp part in cascode over a lower Vp part.  Biasing would be different that the MOSFET version but similar function.
>> 
>> I will close with reporting that the BC-453 works fine as-is battery operated.  The filaments are not so hungry as to prevent a night of listening in the field via a gel cell (12V conversion).  B+ is a stack of seven 9V batteries in my case. I have taken such a config to the field and it works great. Alternatively you can stack two gels for filament and run the B+ off the 28V too.  Gain would be lower and the osc may or may not reliably start (try different tubes).  There is a simple reversible screen divider mod that helps with B+ that low.
>> 
>> Dennis AE6C
>> 
>> 
>> 
>> On Sun, Jan 1, 2017 at 9:26 AM, MICHAEL ST ANGELO <mstangelo at comcast.net <mailto:mstangelo at comcast.net>> wrote:
>> 
>>    Actually it is a good way to resurrect a gutted receive or a set
>>    missing tubes. Since you have to replace the capacitors you may
>>    explore the solid state option.
>> 
>>    I am a longtime LF listener. In the 1970's I was looking for a
>>    battery powered receiver to listen to the LF band. I rebuilt a
>>    BC-453 with solid state devices.
>> 
>>    I used JFETS's in the RF, oscillator and BFO stages and Dual Gate
>>    MOSFET's in the mixer and IF stages. I forgot what I used in the
>>    detector and audio stages. It was an excellent receiver with very
>>    low power consumption. I operated it form 12 volts.
>> 
>>    I was going to built solid state converters for the ham bands but
>>    college, employment got in the way.
>> 
>>    I referenced an article in QST or Ham Radio about a solid state
>>    conversion in a BC-348 for my design. If I find the article I will
>>    post the information.
>> 
>>    JFETS are still available but it may be difficult to find Dual
>>    Gate MOSFETS. I believe some Dual GAte devices are available in
>>    SMT packages.
>> 
>>    Happy New Year,
>> 
>>    Mike N2MS
>> 
>>    > On December 31, 2016 at 8:50 PM Phillip Carpenter
>>    <carpenterpa at tds.net <mailto:carpenterpa at tds.net>> wrote:
>>    >
>>    >
>>    > I just want to read the article...
>>    >
>>    > Phillip
>>    >
>>    > Sent from my iPhone
>>    >
>>    > > On Dec 31, 2016, at 8:22 PM, Bob Moody <bob at vanirmail.com
>>    <mailto:bob at vanirmail.com>> wrote:
>>    > >
>>    > > Isn't that like putting a smog pump on a Model A?
>>    > >
>>    > > K7IRK
>>    > >
>>    > >
>>    > >
>>    > > ----- Original Message ----- From: "Phillip Carpenter"
>>    <carpenterpa at tds.net <mailto:carpenterpa at tds.net>>
>>    > > To: <arc5 at mailman.qth.net <mailto:arc5 at mailman.qth.net>>
>>    > > Sent: Saturday, December 31, 2016 3:48 PM
>>    > > Subject: [ARC5] Transistorized ARC-5 Receiver
>>    > >
>>    > >
>>    > >> Does anyone on the Forum know the correct citation for an
>>    article that describes how to transistorize the Command BC-45x
>>    series receivers?
>>    > >>
>>    > >> It is thought that the article appeared in Short Wave or
>>    RadCom magazines or perhaps one of the other radio journals back
>>    in the late 1960s or 1970s.
>>    > >>
>>    > >> Thank you in advance to all who reply!
>>    > >>
>>    > >> Respectfully,
>>    > >>
>>    > >> Phillip W4RTX
>>    > >>
>>    > >> Sent from my iPhone
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>> 
>> 
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> -- 
> bark less - wag more
> 
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