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April 05, 2020, 12:47:15 PM *
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 1 
 on: Today at 12:37:23 PM 
Started by K1JJ - Last post by WD5JKO
I was a fresh Novice, wn8pep back in 1972. My first setup was a borrowed S40B Rcvr, and I built a Tx on an old chassis with a single 6AW8. Was patterned on a ARRL Handbook rig using a Compactron triode - pentode. I was also given a 3740 xtal. That rig, maybe 7 watts DC input gave me many CW contacts.

A few months later, was my first Field Day. I worked so hard to make my rig perform on FD. I go one of those hydrogen generators, and a WW2 balloon. On FD I had a 1/4 wave vertical on 80m. Man I was making contacts right and left. later the antenna wire (phosphor bronze braid) busted, and my antenna floated away. I quickly made another, but this time an end fed Hertz to a tree. The guys in the General tent were really hammering my S40B Rcvr, between my crappy antenna, and Rcvr overload made things really tough.

As fatigue set in (remember on CW, the S40B had no AGC, and was about 15 Khz wide), I went into offensive mode against those mean "Generals". I knew that that pierce oscillator would oscillate with or without a crystal....So out comes the crystal, and a begin to all CQ FD over and over. I am not sure what kind of signal I was putting out, but apparently it pretty much blanketed the whole band with hash...Enough so that the overall score for this ham club was impacted. In a few hours, somebody is going tent to tent wanting to know what the hell was going on. Quickly I insert that crystal, and with headphones on, key in hand, I never look up.

 2 
 on: Today at 12:29:23 PM 
Started by w4bfs - Last post by WBear2GCR
Just found out about WD-40 silicon spray ... tried it on a pot .... works very well and you get a lot ( 11 0z )  for $13 or so ... reminds me of the old silicon tuner sprays ( Not Blue Stuff ! )

Hey, I think you'd not want to use silicon spray. Silicone spray is the stuff!

But there are less expensive "silicone" sprays out there than the WD-40 product.
They come with a variety of carrier chemistry. Some are volatile solvents, others
are "food grade", non-solvent (afaik).

Not sure if silicone spray is ideal for carbon pots... although I admit to having used it
myself.

                     _-_-bear

 3 
 on: Today at 07:57:18 AM 
Started by w4bfs - Last post by w3khg
Just found out about WD-40 silicon spray ... tried it on a pot .... works very well and you get a lot ( 11 0z )  for $13 or so ... reminds me of the old silicon tuner sprays ( Not Blue Stuff ! )

 4 
 on: Today at 01:38:45 AM 
Started by pe1mph - Last post by pe1mph
Hello AM Lovers,
After a long time...
When I heard no AM from the Usa...

I heard this morning AM on 3885 and 3873 khz!😉

On 3885 Tim? and Don
On 3873 some AM stations, but I heard no names

Now it is 07:30 Summertime in the morning by me.
I listen with my Kenwood R 5000 connect with +/- 30 mtrs wire,
and homemade ant tuner in our living room.
Just before 07:30 I heard them on 3873...
But now nothing anymore...
On 3885 I heard now weak Don speaking.

But earlier this morning I saw good signals!!


Thats all and hopefull I hear you again,

Henk / pe1mph
Dokkum / The Netherlands😉

 5 
 on: Yesterday at 08:41:47 PM 
Started by N1BCG - Last post by WBear2GCR
Plan B.

When the cathode resistor = plate resistor the circuit (minus the cap doing the
feedback to make it oscillate) becomes a paraphase inverter circuit, aka unity gain.

So you could modify it by A) making the cathode resistor set up with a switch to
make a series ~900 ohm resistor bypass (for normal operation with a xtal)
or
B) add in a 5 watt or so pot of ~1kohm in series with the 100 ohm resistor...

one still needs to switch in and out the upper feedback cap off the grid.


That was Plan B.

 6 
 on: Yesterday at 08:36:01 PM 
Started by W2PFY - Last post by WBear2GCR
Terry -

Dollar Tree sells incandescent light bulbs.

You can also scrounge thrown out stoves/ovens for the elements.
The oven elements will have not much inductance.
Stove elements might have too much at 28mhz, but probably not.
Haven't measured the DCR, but since they're free, you can series up
all you need! Cheesy

If you have an electric stove, pretty easy to pull an element and check it.

                    _-_-bear

 7 
 on: Yesterday at 07:15:21 PM 
Started by Steve - K4HX - Last post by Steve - K4HX
No chumming. I did "cheat" in using a modern lure, the Dark Sleeper.

https://megabassusa.com/product/dark-sleeper/


 8 
 on: Yesterday at 05:09:30 PM 
Started by Steve - K4HX - Last post by W1RKW
Excellent, Steve!  Nice catch. Nice to know that the old stuff works just as good if not better than the new stuff.   Did you pre-breadcrumb that baby?

 9 
 on: Yesterday at 03:21:11 PM 
Started by ka1tdq - Last post by ka1tdq
I have the power transformer converted to a mod transformer with a properly phased negative feedback winding. The transmitter is sufficiently disassembled to rebuild as plate modulated. The power control knob hole position works out well to put another tube socket for the 12AU7.

To determine the phasing of the negative feedback winding I put a 2k ohm resistor between the B+ and final lead to simulate the resistance of the RF stage. I then put 6.3 vac into the leads for the two modulator tubes along with oscope leads for channel 2. I put the channel 1 leads on the 6.3 volt winding of the transformer. I then just had to compare the two waveforms to see when they were out of phase.

I think that's all right... correct me if I'm wrong.

The new power transformer and interstage audio transformer will arrive today with all the other components coming in tomorrow.

Jon

 10 
 on: Yesterday at 01:01:11 PM 
Started by Steve - K4HX - Last post by AG5UM
Adding in a Vintage slingshot......
we've got the makings for fancy..antenna launchers, if the fish are'nt biting..
73's

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