[AMRadio] 813 tx


CHRIS PAPAIOANNOU amateur at ipnet.gr
Tue Oct 26 11:50:13 EDT 2004


73 Jim,
During WWII  and before it too many one tube crystal  controled  Txs has
been used  as you know....common tubes of  that era were 6V6 or 6L6...i'm
and i guess many others who are reading now this txt  curious about testing
everything..so why don't use instead of the 6L6 or 6V6  the EL34/6CA7
also?It's a tube which gives some more output pwr compared to 6V6 or 6L6 but
with the same characteristics...now a 6J5 has been added to that rig you saw
in my site and became a crystal controled 2 tubes AM/CW tx.
The 6J5 is the oscillator tube.
It's a neat audio tube but the 807 is a transmitting tube...i saw many 807s
in tube amps so allthough made for particular uses i believe we're aren't
limited on using them only there where have been designed for but everywhere
we can proove they work...
Regarding non-licenced AM/MW activity it's a passed...Was illegal  at that
time and many "amateurs" went in jail.You were taking the risk to loose your
stuff  and go to jail and pay big amounts of money if  arrested...seems that
the radio's wish is stronger than the law cause too many took this
risk....at that time...
The topic of  conversation as you mentioned was about rigs,technical on the
air suggestions,tests,endless tests on improvement and even music..yes
music..a lot of rock ,soul,and local music...
A lot of "babes" had been used then...813s,829s,6146s,EL504s,EL509s,and even
high power tubes like the 100TH.The guy who had the station with the 100TH
has
 an FM broadcast radio now.
...811s also...PL504s,and others....i remember during the early evening
hours,when propagation was better down in 1600Khz ,-was not only surface
ground airwave,-communications were long distant compared to the daylight
ones...was not organized Jim (associations etc.)we were just trying to have
fun experiment and of course were nutz on communications,electronics you
know...
Seems that the AM germ is too much strong...even now i like this mod.but
with tube radios..like then...
When Bry AF4K invited me in a group chatting on tube stuff  couldn't
resist...Tnx Brian..
73,Chris,SV1DAF.
----- Original Message -----
From: "Jim candela" <jcandela at prodigy.net>
To: "Discussion of AM Radio" <amradio at mailman.qth.net>
Sent: Tuesday, October 26, 2004 2:48 PM
Subject: RE: [AMRadio] 813 tx


>
> Welcome Chris,
>
>        I grew up in Detroit, Michigan where one day I discovered Ham radio
> when tuning an old barn radio ( a Crosley) up past 1700 Khz until I
reached
> 1806 Khz. Back around 1970 the Detroit area had several dozen hams on AM
> using mostly home-brew gear on 160 where 1806 was the mobile frequency,
and
> 1835 was the base frequency. The rigs back then were often low power, and
> simple such as the two rigs on your web page. By the mid 70's 2 meter FM
> took over, and the low power 160m rigs faded from the scene.
>       I am curious about the non-licensed activity in Greece you refer
too.
> I wonder how organized it was, and since many had homemade tube rigs, I
> suppose the topic of conversation was often about the equipment,
> modifications, etc. I wonder if you can describe to the group how that
went.
>      Looking at your web page I see a rig using the EL-34 tube in a self
> excited crystal oscillator. As you know this is a neat audio tube, and
other
> than myself you are the only person I've heard of using the EL-34 for RF
> use. The EL-34 is inexpensive, readily available, has small diameter (like
a
> tall 6V6), and has beefy ratings. On the downside it has high
interelectrode
> capacitance (Cgp), and a fair amount of cathode lead inductance. These
> characteristics may make it an excellent oscillator like what you have
done.
> In my case, being a masochist, I decided to use the EL-34 in a linear
class
> AB2 RF amplifier from 160-20 meters for amplification of AM / SSB signals.
> This turned out to be a huge challenge for me. Along the way I noticed
that
> the 6550 was a better tube (more linear and stable) except that the 6550
was
> too large, and had less gain. I also tried the 7591 with excellent
results,
> but the 7591 (NOS) is too rare and expensive. I continued on however with
> the EL-34 determined and being bull headed until I achieved my objectives,
> linearizing the EL-34 while maintaining stability. At the following link I
> show an application of the EL-34 in use along with partial schematics.  I
> did some more modifications to that rig, and the waveforms are a little
> cleaner now. I was actually using a Svetlana EL-34 that cost US $12.00.
>
> http://pages.prodigy.net/jcandela/CE20AQRO/20AQRO3.DOC
>
> Regards, Jim Candela
> WD5JKO
> Austin, Texas
>
>
>
> -----Original Message-----
> From: amradio-bounces at mailman.qth.net
> [mailto:amradio-bounces at mailman.qth.net]On Behalf Of CHRIS PAPAIOANNOU
> Sent: Monday, October 25, 2004 10:45 PM
> To: AMRadio at mailman.qth.net
> Subject: [AMRadio] 813 tx
>
>
> 73 to all group's members around,
> i'm new in this list.My name is Chris,my call is SV1DAF and i'm located in
> Athens,Greece.
> I'm not new in AM..20-25 years ago there was too much AM activity
here,with
> homemade tube rigs,in the MW band.Was illegal but there was.Then most of
the
> "amateurs"became hams with legal activity in the ham bands.The rest of
them
> left the radiowaves.
> Not long ago i started homebrewing again after long time.My homebrew rigs
> now are:
> 1)6V6/807 crystal controlled where the 1st tube is the oscillator tube and
> the 2nd one the pa one.
> 2)6J5/EL34
> I prefer plate modulation and the reasons are known and clear,and i'm
using
> an amp with 2 EL504s like output tubes.These are sweep tubes.
> I'm now searching for a tx drawing with an 813 tube like pa tube.Any
replies
> will be too much appreciated.
> Tnx for the attention paid to my introduction,
> 73,Chris,SV1DAF.
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