The AM Forum

There was a lot of PisWeaker activity on 75M AM tonight.
Probably as a result of Bruce's post here today.  Seems
like many guys are interested in bringing out the old rigs
from 9 years ago or building up new ones.

These PW rigs are less than 10 watts output and  2-5 watts
being a perfect level - and homebrew.  Many are xtal controlled,
plate, screen or series modulated. We haven't seem a small Class
E or PDM version yet... hint- hint.

Let's post our PisWeakers here to give everyone some good ideas
as well as get us all excited.  Try to show a shot of top and bottom
as well as post a URL for a schematic if available for building.

This internet stuff is so much easier than using the mail like we did
nine years ago for sharing PW info.  We hope to be on 75M regularly
after 3:30PM and start up the PW Net when interest and rigs are
rocking in the future.

Bruce and Paul - You might repost your PW pictures here too so that
we can have everything in one place for EZ reference...

Thanks!
73,
Tom, K1JJ
------

Schematic:
http://www.amwindow.org/tech/htm/series.htm

Here's my 6AQ5 series modulated  2W or 5W PisWeaker. It uses a
single VXO xtal controlled power oscillator for all RF duties. A
second 6AQ5 in the cathode provides clean series modulation from
10hz-15khz. A 6KE8 dual pentode/triode amplifies low level
audio. Complete rig = 3 tubes. The VXO [variable xtal oscillator]
circuit lets a crystal be pulled down up to 3kc so that a few xtals
cover the complete 3870-3890 area.
(http://home.comcast.net/~k1jj/wsb/media/254120/site1095.jpg)

Here's the underside. Notice the Variac to adjust the output power.
The RF components are good for at least 100 watts...  works
160-20M, baby!
(http://home.comcast.net/~k1jj/wsb/media/254120/site1094.jpg)


Here's a shot of the K1JJ HF station in the center and VHF 6M station
to the right. The big amps and Class E rig are in racks to the left, out
of view. Notice the place of honor the PW rig has - front and center -  
eye level and within molesting distance... :lol: :
(http://home.comcast.net/~k1jj/wsb/media/254120/site1093.jpg)

My Home Brew station including PW Xmitter, pics at the bottom of the page.

 http://community.webshots.com/album/164844654sgUTfy

Good to hear all the PisWeakers on last night!

Let's see if we can get the PW Net going again, ala Tom Vu as the host.

My pisweaker, Cakepan TX, below.

(http://brucehowes.com/images/Cakepan%20TX_small.JPG)

I’m ready….

(http://home.comcast.net/~chnord/homebrew2.jpg)

This is a 6AG7 osc to a 6F6 plate modulated by a 12AX7 / 6V6. Puts out 7 watts, but I have a switch that adds in some extra screen resistance to drop it to 1/2 watt. Have had good contacts with it on 160.

The idea was to use only parts in the junk box I had kicking around so I grabbed an old parts receiver for the PS and tube sockets and went from there.. Plate meter is from an old boonton sig generator. Very nicely damped.

Rcvr is a homebrew 2 mtr super regen circa early 50’s I got at the last Hossetraders (from someone who was with Gary WA1EWQ). I kept the audio stage and PS and put in a 6J7 regen. Wound coils for BS, 160 80 and 40 on pill bottles.

Have used the pair on the GHN several times. with good reports even on low power.

Look forward to joining in!

Hey Carl, I like that very buzzardly!

Carl - I second Bruce's statement. Thre rx is very FBOM. How well does it perform?

I have a National 1-10 VHF job just sitting on a shelf and would like to actually use it someday (on HF). Where did you get your coil data from?

Nice photos George. Do you have an antenna hooked up to any of that equipment? I never heard you on the air. Is there a problem that we may help you with? I live far away but someone may be in your area to help you with an antenna if that is the problem. :idea:

733

Terry

Terry, you be strapping over here to the Maine coast, heard you on just a few moments ago.

We are getting socked with a major snowstorm, car is stuck in the driveway.

-Bruce




...-.-

I'll listen for you guys on my radio:

(http://i16.ebayimg.com/01/i/03/93/d2/6b_12_sb.JPG)

Joe,
I would be happy to send you the complete circuit with coil data. The BC coil I figured out using an old ARRl "Lightening" calculator. I have built a number of regens and this one works the best of all. I am very happy with it.

Bruce,
Glad to see you are in the new QTH and was happy to see Larry playing with the old rig. I assume he had had a check ride before you let him solo like that'

The following is a little better view of the PW Xmtr
 

(http://home.comcast.net/~chnord/IMG_2431.JPG)

Hi Carl,

I have a couple of National 1-10s that I would love to use on HF as well, so if you could forward the coil data.

Larry was posing for the pix, with the move I have not yet had a chance to build up a power supply for that rig, or my other breadboards. I keep saying I will do it this winter, but with the move and new business, things keep getting pushed back....

Nice to hear from you Carl!

-Bruce



.

Tom,
 Here are a couple of "pics" of my homebrew 6AG7-6L6 pw cw xmtr
 that I have plate modulated with a solid state PA amp es used on
 both 40  and 75 AM , and had good reports.
 The modulator(not shown)--I will try to post later.
 Am now working on a homebrew 6146 xmtr, with a pair of 807`s
 as a modulator, so this rig is on the "shelf" for now.
                                      73`s , K1MVP

  P.S.,  Hope to "pics" come out ok.                                  



(http://C:\Documents and Settings\Rene\Desktop\My Pictures\Ham Radio Pics\IM000270)

(http://C:\Documents and Settings\Rene\Desktop\My Pictures\Ham Radio Pics\IM000271)

 Thanks Terry, But I have plenty of antennas, just not much interest in getting on the air  any more. Other than  a sked with some friends Sun mornings on 75, I'm not very active.

Wow, now THAT is what I call a RADIO!!!

This piss weaker net interests me.
Did someone say it would be in March? Will it still be going in April as that is when I might have this thing done? Do you have to be running tubes?
I have actually been experimenting with a piss weak transmitter that had its routes as a QRP Vectronics CW transmitter. I put a radio shack 8 ohm to 1k ohm transformer in the series with the collector supply on the final. Then I got a 4 watt audio amp board. Puts out 1 watt of carrier so it certainly is piss weak.
I have two xtals in it one on 3885 and the other on 3880.
I have not packaged it up yet and I am just experimenting on the bench but with me whistling  the negative peaks seem funny. Someone once told me that with solid state devices you have to modulate both the input signal and collector voltage to make it right. Is that true or will it sound ok for this piss weak test. When I listen on my HF rig it sounds ok fine but my ears are old. Actually I can way overmodulate if I want and the audio response is wide.  
The pictures of the transmitter and the envelope while whistling are below.
You can see the 4 watt modulator board to the left of the vectronics board.


(http://home.comcast.net/~w1qwt/images/vectAM2.jpg)

(http://home.comcast.net/~w1qwt/images/1wam2.jpg)

Hi Q,

You can run virtually anything you like. There are no rules like nine years ago.  

But in the PW spirit you'll find it is more fun to build up a 1-5 watt output rig that is self contained with everything on one chassis.  Tubes, fets, transistors - do whatever you like.

It's a blast when everyone's on running flea power on freq with good conditions - you can tell who's runnimng 100 watts cuz they stick out like a sore thumb... :-)

Most guys find running a ricebox throttled down to 10 W gets old real fast -It's on the outside looking in when everyone else is talking about their own PW creations. Spend a weekend building up one of the many simple designs out there [or the FB solid state rig you now have] and it can be used a lifetime.  This PW stuff seems to get real popular in the late Winter/Spring and Fall.  I've kept mine on line for about 11 years now.  

PW operating makes one a better operator and reminds us what it's like to walk in a PisWeaker's shoes once in awhile.

In fact. I'm gonna fire up my 1W PisWeaker now and see if the guys copy me on 3890.. :-)

Catch ya on, OM!  

T

I was able to turn my bc610 down to five watts output. It didn't sound good but it could be done. Is there a weight limit on a pissssssss weaker?


[/img]

No good Terry... you actually have to build something!!!!  :lol:  :lol:

Hey Tom I heard all the birds are going to crap on your roof because the primary wire coming up your street is too cold to warm their little feet.

5V6GT series modulated by 6V6GT.
Outboard audio.  Had it on the air again
this past Sunday on 3.825.  

(http://www.amwindow.org/pix/jpg/k2orc/k2orc2.jpg)

(http://www.amwindow.org/pix/jpg/k2orc/k2orc1.jpg)

Hi Paul,

I think you get the award for the "plettiest" looking PisWeaker. I really like the look of plexiglass and the ability to see the insides like that.

Some of my stuff here uses it too - it's so EZ to put a piece on a table edge and heat it slightly with a torch - then bend it into a 90 degree turn for many uses.

There's been many, many PW rigs on lately and guys talking about building more. Oughta be a fun season.

T

My Pletty Pissweakah and I thank you velly much, Mista Vu.  Yep, seeing tubes was the reason for that clear faceplate.  I like the idea of being able to see the stuff that makes a thing work.  Sort of like the Visible Man kit we got as kids that showed the skeleton and guts -- except for some of you preverts who ran out and bought the Visible Woman.  The same company sold a visible motor on a motor mount.  Someday I'd like to try building a little radio on a clear chassis.  

7th grade shop class at Everett Junior High School in Lincoln, Nebraska, was where I was first shown how to work with clear plastic.  We started with key fobs cut into shapes, then we made letter holders with scrolled tops and a few other things.  Whenever I smell warm plastic, I'm reminded of that shop class.   Electric Radio a few years ago had a short article about working with plexiglass.   The public library would probably have a book about working with plastic, too.   As you say, Tom, it's neat stuff and if you work patiently and carefully, there's lots that can be done with it.

I built the Visible V-8 as well as the Visible Auto Chassis when I was young.  Those two kits taught me more about how a car works than ANYTHING.  Everything worked in it - the clutch, the transmission shifted, it had a real differential, even the hydraulic brakes worked if you filled the master cylinder with water.  What a cool education kit... too bad they don't make 'em anymore.

Wow v8 I only got the 6. I remember my Dad telling me it would be easier to see the guts. Man was I ticked that it wouldn't power a go cart.
The little electric motor in the transmission was PW.

The company went under because of  5 mph bumpers, roll over protection and emissions controlls.

Yea,
there was a big law suit when an air bag went off while  driving down the sidewalk.
Unleaded gas was hard on the valves so a total redesign would have been required.

(http://international.ehobbies.com/images/product/1000-1254.gif)Which would you rather put together?(http://international.ehobbies.com/images/product/1000-8898.gif)

But I see a crank on that Visible V-8, and where's the visible auto chassis?

My Visible V-8 was installed in the auto chassis, and would crank over (weakly) and illuminate little light bulbs in each cylinder to simulate the spark plug lighting....

I'll hafta grap one of those V-8s for my boys.  TNX, Paul!

Ah I remember the little grain of wheat bulbs acting like spark plugs.