Re: Using Vacuum Tube heathkit as Linear Amplifier for QRP

Gordon Gibby
 

There is this MFJ pin diode rig that I managed to pick up on ebay for $100.   You might look around for another of those.   They do take some tinkering I'm told.    

An even easier solution is to simply emulate the HW-16 and have TWO devices --- one used for transmit and one used for receive -- and control both of them with the same digitally created frequency (from a Raduino) and just use diode protection of the input of the "receiver" just as many qrp rigs do.    There are probably a lot of schematics out there for creating a diode switch also.   

Gordon


On Tue, Nov 12, 2019 at 4:08 PM Richard Spohn <wb2gxm@...> wrote:
Bill, do you have the schematic for the solid-state T/R switch, or
even better, do you still have that switch?  I am keenly interested in
an all-electronic (no relays) T/R switch for QSK.  Building one from
scratch may be slightly outside my skill set tho. -- Rich WB2GXM

On 11/10/19, Bill Cromwell <wrcromwell@...> wrote:
> Hi,
>
> In the 80s I built boots for an Ten Tec Argonaut 509 using the carcass
> of a Heathkit DX-35. There is no receive circuitry involved. I biased
> the single 6146 for class AB1 operation. I built a solid state T-R
> antenna switch to keep the QSK feature of the 509. It served me for a
> several years and then the 509 moved to a new home. The remains of the
> DX-35 also went to another ham.
>
> I have the CW portion of a Heathkit DX-100 down for overhaul. The AM
> phone parts were all gone when I got the DX-100. I am going to dpo the
> mods to include the linear operation in phone mode to amplify SSB
> signals and keep the class C operation for it's CW operation - ala the
> Apache (TX-1). Grid block keying has already been part of this
> particular DX-100.
>
> Sometimes QRP is just not enough.
>
> 73,
>
> Bill  KU8H
>
> On 11/10/19 7:35 AM, Don Richards wrote:
>> Hi Gordon
>> I ran across this a while back but never tried it.
>>
>> https://www.google.com/url?sa=t&source=web&rct=j&url=https://frrl.files.wordpress.com/2008/09/hotwaterforthek2.pdf&ved=2ahUKEwjwzsTQ09_lAhWsmuAKHQ1MCyYQFjACegQIARAB&usg=AOvVaw1PdjqVxSUEw-wayoqwuZyO
>>
>> 73 Donve3ids
>
> --
> bark less - wag more
>
>
>
>



Join BITX20@groups.io to automatically receive all group messages.