VHF booster

[CDRIVE]

Give me some time to see what I can work up. Typically, I like to Spice a circuit before I post it but I may not be able to do that with this transistor.

 

[davenn]

this application should really be using an MMIC like a MAR1. extremely low component count, VERY wide band .... plenty of gain and are available world wide dirt cheap!!

here's a link to one using a MAV11 ( there's several sets of MMIC devices)
http://www.qsl.net/vk3jeg/wideband.html

cheers from dave in his hospital bed

 

[Miguel Lopez]

Sorry to hear you're in a hospital. Hope you get better soon.

There's no such components available to me here. I have only got those Soviet transistors at hand.

Thank you both for your support.

 

[CDRIVE]

Dave, I don't want to hijack his topic so go here...https://www.electronicspoint.com/lets-hope-its-just-bad-tuck-t251707.html#post1489049

Chris

 

[CDRIVE]

Miguel, I'm heading out to my watering hole. In the interim here's some good reading for you. Google is your friend. Do some leg work while I'm kick'n back.

http://www.google.com/search?q=germ...v&sa=X&ei=-149ULmwDI389gTRloHwAw&ved=0CCwQsAQ

This one is a very good read and and reminds me why I initially rejected transistors in those days. I played and had fun with them but I never took them seriously until Silicon came along. Trouble shooting Germanium circuits was a nightmare too!

http://www.wylie.org.uk/technology/semics/GEC/radio/article.htm

http://semiconductormuseum.com/MuseumStore/MuseumStore_Index.htm

 

[CDRIVE]

Miguel, have you dug up any designs?

 

[(*steve*)]

Did you get those jfets I sent to you?

They may be better suited to this application.

 

[CDRIVE]

Did you get those jfets I sent to you?

They may be better suited to this application.

Steve, did you do that? I wonder if they'll get past security? What FETs did you send him? Especially, since I'd want to just stick them in an envelope. I have about 500 MPF102's with Motorola factory markings (purchased mil surplus in1979) but I didn't think they'd get to Miguel. Uh... that's two or three, not 500.

Chris

 

[(*steve*)]

Steve, did you do that?

We have no restrictions on what we can send to Cuba (outside such things which are not permitted in the mail -- firearms, ammunition, dangerous goods, certain biological materials, etc.)

I also verified (as far as I could) that the components were not originally sourced from locations with a form of embargo.

*snap* I think some were MPF102's (or similar). However much of what I have is surface mount. and Miguel doesn't have much experience working with it.

 

[CDRIVE]

Ha, I was referring to Cuban security.

Chris

 

[Miguel Lopez]

Miguel, have you dug up any designs?

Sorry, "dug up any design". I don't understand this expression. Please, be more conventional. Thanks

Did you get those jfets I sent to you?

No, I haven't received the parcel. But there is no motive to worry yet, as our mail system is not known by it fast response precisely. . It is still on time. Thank you very much for your kindness.

 

[CDRIVE]

Sorry, "dug up any design". I don't understand this expression. Please, be more conventional. Thanks

Dig up: (1) To find, locate, discover, (2) To find or locate by searching, sifting and separating the inapplicable.

Dug up: Past tense of "dig up".

Example: Steve, near starvation, was wandering around in the Outback until he dug up some edible tuck.

Chris

 

[Miguel Lopez]

Then

Miguel, have you dug up any designs?

Eh??.... nop.

I have just been reviewing the link you gave me in post #25. Very interesting, but as there is almost no design available with Soviet germaniums, I try to understand how the circuit works, with some help from all of you.

I have to confess that radio frequencies have always been beyond my complete understanding. I work good enough in the audio range, but with high frequencies...... I guess I missed that part in the school

 

[CDRIVE]

Since Dave sent you some MPF102's here's some links of tuned RF amplifier designs. You would have to recalculate the resonant circuits for the frequency your using.

http://radiofrequencyamplifier.blogspot.com/2012/02/6m-rf-preamp-using-mpf102.html
http://radiofrequencyamplifier.blogspot.com/2012_02_01_archive.html

Attached is the Motorola PDF. It includes a broad band amplifier design.... Oops! I can't attach it because it's too large. Google the PDF but not all of them contain the broad band amp. My Motorola PFD does.

Chris

 

[CDRIVE]

Here's a direct link..

http://www.datasheetcatalog.org/datasheet/motorola/MPF102.pdf

Chris

 

[CDRIVE]

Then



Eh??.... nop.

I have just been reviewing the link you gave me in post #25. Very interesting, but as there is almost no design available with Soviet germaniums, I try to understand how the circuit works, with some help from all of you.

I have to confess that radio frequencies have always been beyond my complete understanding. I work good enough in the audio range, but with high frequencies...... I guess I missed that part in the school

They didn't coin it the "Iron Curtain" for no reason.

RF design is a field unto itself. If you want a fascinating topic, read up on "Transmission Line Theory & Design" in the ITT "Reference Manual For Radio Engineers". It's the RF Bible!

By the way, the broadband amp in the PDF uses a 50Ω input Z. TV transmission line (Coax) is 75Ω. This is not a severe mismatch though. To provide 75Ω input/output you'll have to calculate that too.

Chris

 

[Miguel Lopez]

Did you get those jfets I sent to you?

Yes, I did. Yesterday, when I got home, there was there the notification from the Post Office. I picked it up inmediately. Thank you very much