[Boatanchors] Comarison?

[Carl]

----- Original Message ----- 
From: "Michael Tauson" <wh7hg.hi at gmail.com>
To: <boatanchors at mailman.qth.net>
Sent: Sunday, December 20, 2009 6:02 PM
Subject: Re: [Boatanchors] Comarison?


> On Fri, Dec 18, 2009 at 1:11 PM, Carl <km1h at jeremy.mv.com> wrote:
>> All filaments on regulated DC. B+ 175V maximum and regulated. PS and 
>> audio
>> amp in seperate enclosure(s).
>
> Okay, I understand the PS but why the audio?  And would an enclosed
> section of the same chassis be adequate?

Heat. The rest of the radio is on 175V or less and regulated. The 6V6's can 
run off the unregulated output of the filters at 250V  for some nice 
performance. Im planning on using a Hallicrafters PM23 or R42 speaker and 
there is plenty of room in it for the audio output.stage which wont be used 
for any serious work and the first audio stage in the radio drives the 
headphones either directly at high impedance or thru a small triode/pentode 
for low impedance. It can even be the full audio section if a big sound isnt 
needed. I just happen to like lots of quality audio when Im on AM.

Speaking of heat, to aid thermal stability the LMO is mounted on a slab of 
heatsink.


>
>> This should all be pretty much modular allowing easy changes and repairs. 
>> Im
>> using SMA connectors and mini Teflon coax for RF.
>
> Which confirms what I was planning for my transceiver.  Thank you.  :-)


Your welcome. I used mini BNC in the past but that old MIL stuff is getting 
scarce. My stash of AN/WRR-2 parts is about gone.  SMA's are everywhere and 
cheap in this century.


>
>> And the best for last, absolutely no rotary switches in any signal path, 
>> its
>> all done with miniature dip relays.
>
> While I know you don't like fused sand aside from the 2-legged sort,
> there are a few places I'm looking at it for signal path switching in
> the SS transceiver.


All it causes is problems, the high end radios use relays.


Against that, using dip relays for the hollow
> state version(s) sounds like a better plan.  While it's not germane to
> the topic, what would you use for switching at higher levels like PA
> tank circuits - think: 20w PEP and 100w PEP output.

The same DIP relays from receiver input to 100W. They are used in many amps 
to switch the input bandpass filters. The ones in my LK-500ZC have held up 
to 100W for almost 25 years. Simple, cheap, reliable and they dont cause 
IMD. The input section of the amp is also a dip and a vacuum relay is on the 
output. Its properly sequenced and can easily handle 50 wpm CW. Thats close 
enough to QSK for me.

They are also used in the xcvr built in automatic antenna tuners as well as 
remote ones such as the SGS at the 200W level.


Ive nothing against SS, it allowed me a good life style during my working 
years. Its also used extensively here in the main SSB/CW station as well as 
VHF to microwave.

This project is more of a taking off from where the tube rig industry died 
and using components or adapting circuits that werent around then. I simply 
want to see what tubes are really capapble of.

Can I improve battle condition performance above my well modified 75A4 or 
the tweaked R-390A???

>
> Best regards and much thanks for your thoughts,
>
> Michael, WH7HG

Carl
KM1H


> -- 
> http://www.nationalmssociety.org/chapters/NTH/index.aspx
> http://wh7hg.blogspot.com/
> http://kludges-other-blog.blogspot.com
> Hiki Nô!
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html