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PostPosted: 24 Jun 2012, 11:23 
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Joined: 24 Jun 2012, 01:55
Posts: 8
hi, i am asking for suggestions as to a good circuit to use one of these tv output valves as a transmitter on the ham bands.
i am thinking of a power oscillator using just the tube and a small transmitting loop as the tank circuit. that should cover 4 bands for cw and i have an old carbon mike in a telephone handset that i would like to use to am modulate it.
about stability: is there a way i can get away with not using crystals in the design?
if i do need crystals then that will severely limit it. i dont have crystals except a 14.318 from a monitor and some unmarked ones in a pager. cant buy any.
how would it be done in the old days?
how can i check the frequency of the unknown crystals using my grid dip meter?

before i build this, i want to make a regenerative receiver. can i double up somehow the circuits to make a rtx using the same loop tank circuit so i always rx and tx on the same fx?

i also read about first downconverting before using a regenerative circuit so i tune the if stage rather than keep tweaking the regen control. can anyone explain this better?

thanks, 73
ed
lz2ilr


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PostPosted: 03 Sep 2012, 18:46 
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Joined: 29 Jan 2010, 12:50
Posts: 10
I made many AM transmitters for 1.7 MHz band years ago. If you make proper VFO you will not have any problems with stability on 1.8 - 14MHz. But if you use just one tube, maybe it'll be some frequency drift on 14 MHZ. If you want AM modulation you need small amplifier to modulate G2 screen grid, it's my recommendation.

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PostPosted: 14 Dec 2012, 19:16 
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Joined: 27 Jun 2011, 10:13
Posts: 146
Location: PA
the 1944 aarl hand book has single tube transmitter reciver combo units. Very simple build


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PostPosted: 23 Dec 2012, 00:04 
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Joined: 21 Dec 2012, 23:08
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lz2ilr:
Using Pl type TV tubes is a economic way to build a transmitter, you have to get two more stage to drive it, osc. stage, buffer stage, otherwise it wont be stable. Using crystal is the best element to perform, lc tank cct is not a stable ones, receiver, best to use superhet. type, regen. not as good as TRF type. you have to consider these facts before starting your project. Once you have decided your plan, step by step to get start, PSU, and transmitter, then your receiver, receiver can get from market and modify it, an AM receiver by alter the osc coil / 360pf cap. and ant. coil to fit the tx frequiency. cro, and sig. gen is a must to build RF stuff.

mitwrong
All suggestion is for your reference only, no responsibilities or liabilities


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PostPosted: 27 Dec 2012, 14:05 
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Joined: 08 Aug 2009, 03:11
Posts: 2229
Location: Chilliwack, BC
Google around for some european pirate transmitters.

One site (now defunct) had a couple dozen scematics with one or two tubes cranking out the power and PL-heater tubes were in the lot.

Cheers!

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PostPosted: 24 Mar 2013, 18:42 
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Joined: 29 Jan 2010, 12:50
Posts: 10
1.7 MHZ AM Pirate transmitter with PL519

It's just slight modulation with PL500 / EL500 ... if you need details please pm me ...

Here is AM Pirate transceiver with 3 x EL519 in output stage

Nowdays EL519 6KG6A are very scarce, try to find PL519 types ...

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