variable capacitor;little help needed

[rkgwapo]

what is the difference betweend the terminals FO, G, FA and the terminals O, G, A..?

 

[karesz]

Hi,
I remember, that have had some smaller trimmers built in too, you can see the 4x screws_they are their.
I dont know more exact, but I think the "Fo" version means "Foil C-section o", also the rotatable capacitor self & the simple "o" is than the trimmer C from it...
This pin("o") can you solder (if Im right) to the other("Fo"), and you have some adjustmenttrimm possibility the frequencys place on scala.
K.

 

[rkgwapo]

oh thanks.. im having a little trouble because the varicap i have only have the O, G, A legs. im not sure of what to do to substitute because it requires the FO and G legs..

 

[karesz]

Hali rkgwapo,
Their are usual with two different capacitances(for oscillator you need some smaller value), but not all!
I think you must take G (maybe means "GND" "& 1, i.e. FO and see it is right with frequency range, you have good guessed, otherwise change Fo to Fa...
I dont know a varicap signalisation with "O/G/ &&A", but if you has a schema/kit description-must be right...
Do you have documentation?
K.

 

[betwixt]

I think the pins are O=oscillator, A=antenna and G=ground. They refer to the larger values variable capacitors inside the module. The letter 'F' before them signifies 'FM', a reference to the FM broadcast band. They are lower value variable capacitors on the same shaft.

If you need ones labeled FO and FA, but all you have is O and A, you probably have a capacitor intended for use in single band (AM) radios and the value will probably be too large for your circuit. You could try adding a series capacitor of about 37pF in each connection to drop the effective value.

Brian.

 

[karesz]

Hi Brian,
as you told it; fully clear, but I didnt have so a component over 30 years in my hands...
Best regards!
K.

 

[betwixt]

I have several here in my junk box.

For junk box understand:
"A box of ancient out of date parts pulled out of old Japanese radios many years ago. Now turning yellow with age (like me) and buried in cobwebs and dust. Kept just in case they might be useful in the future but all the time I really know the only place that might want them is a science museum"

Brian.

 

[karesz]

Hey OM, can I ask the Nr of your yung years pls?
Such junk box have we all-I think (I too, my oldest components are from the 30th, but isnt at hand at these time...), and we are in the junk box of life?...
Good night,+ luck Brian!
Karesz

 

[betwixt]

53 years young - but now I've run out of fingers and toes to count on, I've decided not to get any older!

I've been 'playing' electronics since about age 10 and started working in the electronics industry at age 14.

Brian.

 

[keith1200rs]

53 years young - but now I've run out of fingers and toes to count on, I've decided not to get any older!

I've been 'playing' electronics since about age 10 and started working in the electronics industry at age 14.

Brian,

So I guess you remember the Jackson variable capacitors, dual speed verniers, Eddystone radios & valves? I am 51 and started blowing things up in mains sockets before I was 10.

Keith.

 

[karesz]

Hi funs_
greatings in the "Club of 50ths"

Im in 6 weeks 58 (young?)...
I did learned in the "technikum"_middle school_ detailed over tubes, some over transistors & nothing over ICs, (yet I have a _10 years old_ diplom over ASICs too) after 3 years in PTT region; I begann with developments CD4000 circuits for a good established firm. And so on.... In practicum I did worked minimal, max 1-2%, with tubes(MCP/Vidicon/TV), but their are mosten over 30 years ago. I begann to play w. electronics 45 years ago_w. 13...

In an other topic wrote Audioguru; he is 64, & Erikl is (I thik) another in the Club...
Have nice time!
Karesz

 

[betwixt]

I remember them well keith1200rs and probably still have samples here somewhere.
I recall Denco coils, GET873 transistors and my first 'real' radio which was a Marconi 52 set, complete with vibrator power supply, something that has a rather different meaning these days! I seem to remember having to wallop the vibrator can every so often when it's contacts got stuck! Later I went hi-tech and got a rotary converter for it - far more civilised if you ignored the whining noise.

Later I built what must have been one of the first home computers as soon as the Z80 came out and then worked with IBM on the "Acorn" which later became known as the IBM PC!

I progressed through the ranks of TV engineer to working on the design of GSM base stations then to custom test equipment.

These days I still design things, mostly with high end PIC controllers and I have kept my interest in radio although I no longer have the 52 set, I have an Icom IC-756Pro2 instead. Ten times the performance, one tenth of the size and it doesn't need two people to lift it !!

Times have changed!

Brian.

 

[keith1200rs]

Brian,

I remember the vibrator supplies. There was one in the ex-PYE radio I converted for 2m use, but I bypassed it.

I wish I still had all the valves from back then. I have recently taken up the guitar and valves are all the rage!

Keith.

 

[karesz]

Hallo OMs,
I had, ca. at `70-72, so an vibrator "converter" in some millitary tarnsceiver too, than at my beginning (>`70s)
with Ham things we had a rotary converter too, relative big one for maybe 150-200W_bulky - heavy...
My first RX was a self build 1V2 _clear with tubes...
Next one some transistorized, but from rig the first "profi RX" was a Hallicrafters SX12, it was optically nice with bfo_lot of tubes_ and no mechanical stability, the next one BC347, "THEIR" has had stability in all kind of possibility & waight too, but it was a big progress...
Than RTTY, Siemens T34, was similar loud too as the Russian T34 tanks... Enorme problems mastered for organize an SSTV tube, I have had become, but was not so modern more(I think D= 10-12cm, & ca. 40 cm long..)_would not finished as project...
Nowadays; Icom; FRGxxx & companions as brian too, & some old equipments as "Privat Musem"...
Im not every time sure over real progresses, but in case technique; I think it is absolutly clear!

Have best time!
Karesz