Date   
Re: re 2SC2570

JuanCarlos
 

Hi Fellow
You can find this transistor here
http://www.futurlec.com/cgi-bin/search/search.cgi
73's

Jc

2011/11/4 L <bear57@...>

**


Any one know of a supplier for this transistor or a suitable sub?
73 Lorne VE7BOX




--

Lic.Juan Carlos Berberena Gonzalez
WJ6C exCO6BG
www.berberena.com
http://espanol.groups.yahoo.com/group/cacharreando/


[Non-text portions of this message have been removed]

Re: re 2SC2570

Lorne Barber
 

JC, thanks for that site. Boy there are a lot of things there I like!

73 Lorne

-----Original Message-----
From: BITX20@... [mailto:BITX20@...] On Behalf Of
Juan Carlos Berberena Glez
Sent: November-04-11 7:58 PM
To: BITX20@...
Subject: Re: [BITX20] re 2SC2570

Hi Fellow
You can find this transistor here
http://www.futurlec.com/cgi-bin/search/search.cgi
73's

Jc

2011/11/4 L <bear57@...>

**


Any one know of a supplier for this transistor or a suitable sub?
73 Lorne VE7BOX




--

Lic.Juan Carlos Berberena Gonzalez
WJ6C exCO6BG
www.berberena.com
http://espanol.groups.yahoo.com/group/cacharreando/






------------------------------------

Yahoo! Groups Links

Re: re 2SC2570

JuanCarlos
 

It's is other where I bought a lot of componets
http://www.taydaelectronics.com/servlet/StoreFront

For the IRF510 and IRFZ24n and MC9416, among other
http://avnetexpress.avnet.com/store/em/EMController?langId=-1&storeId=500201&catalogId=500201&action=home

For the best transitor paying only tha S&H
https://www.onsemi.com/PowerSolutions/myon/checkout.do

Pic's for free(sample)
http://www.microchip.com/samples/default.aspx

DDS for free(samples)
AD9833,AD9834, AD9835 etc
http://www.analog.com/en/index.html

Have a Good Week end
73's
Jc/WJ6C exCO6BG


2011/11/4 Lorne Barber <bear57@...>

**


JC, thanks for that site. Boy there are a lot of things there I like!

73 Lorne

-----Original Message-----
From: BITX20@... [mailto:BITX20@...] On Behalf Of
Juan Carlos Berberena Glez
Sent: November-04-11 7:58 PM
To: BITX20@...
Subject: Re: [BITX20] re 2SC2570


Hi Fellow
You can find this transistor here
http://www.futurlec.com/cgi-bin/search/search.cgi
73's

Jc

2011/11/4 L <bear57@...>

**


Any one know of a supplier for this transistor or a suitable sub?
73 Lorne VE7BOX


--

Lic.Juan Carlos Berberena Gonzalez
WJ6C exCO6BG
www.berberena.com
http://espanol.groups.yahoo.com/group/cacharreando/

[Non-text portions of this message have been removed]

------------------------------------

Yahoo! Groups Links




--

Lic.Juan Carlos Berberena Gonzalez
WJ6C exCO6BG
www.berberena.com
http://espanol.groups.yahoo.com/group/cacharreando/


[Non-text portions of this message have been removed]

Re: External VFO

wheverly1@verizon.net
 

Thank you for the follow up.I have the vfo partially built now - the
oscillator, used a 2N5486 with some fancy lead bending to fit, and the
MPF102 buffer. The signal is nice out of the buffer stage. I waiting a
transistor for the next stage and I think I will stop there with the output
of the secondary of the transformer to match RG174. I'll keep all posted on
my progress. I like your idea of a connector between Q6 & Q7. I hope to use
the holes on the board where the offset components are supposed to be to
mount fine tuning components. Minor mods needed here.

Bill W3AOQ

-------Original Message-------

From: iam74@...
Date: 11/04/11 20:56:13
To: BITX20@...
Subject: [BITX20] Re: External VFO




--- In BITX20@..., "wheverly1@..." <wheverly1@...> wrote:

Thanks for all of the info. I can't get my VFO to come anywhere near the
required frequency. Currently the output is in the 10 mhz range. I have
tried many different LC combos with not much luck. It seems as thought the
vfo operates at whatever frequency it wants and is not too affected by L4
and many diffenent variable caps. I have wound L4 on T34-6, T54-6 and even
T68-6 and a lot of different turn counts. All have the same results. I can
get as low as near 8 mhz but not below. I have checked every component on
the board to make sure they were the proper values. I have replaced all of
the caps, double checked my soldering and all that I can think of. I'm not
a
beginner at this, starting in the 1950's, but am getting old (71) and do
have a few problems.

I believe that I am committed to W1FB's VFO. I have started accumulating
parts for it today. Checking my junk boxes and drawers. I was very happy
to
receive the info you provided.

Thanks again,
Bill W3AOQ


Bill:

The 10 MHz signal that you are measuring may be a harmonic, and not the
fundamental. Make sure there is no signal by tuning a general coverage
receiver from about 2 MHz to 6 MHz to try and pick it up. It may also be
your BFO...

In my first version of the BITX V.3 I used a morphed version of the BITX20A
VFO. The principal changes were using a T-68-6 with about 45 turns, IN
PARALLEL with a 100pf. npo cap across the coil, and a 100pf. npo cap to a
MVAM0108 varicap with a 10T pot in place of the zener. The variable cap is
an air variable, ca. 365pf, with a 180pf, cap in series. It covers about 3
10 to 3.46 MHz, with a 20 KHz bandspread by the varicap. I actually need
about 33pf. to 150pf. variable to cover the whole 20m band. My IF is 11.054
MHz. I can't use 10 MHz because of strong RFI from WWV.

It wouldn't work at first, until I looked closely at the poly caps and
discovered that they had been burnt by the soldering iron. After replacing
them, it came up with as a good oscillator, quite stable with a 10 Hz or so
short-term drift, and a 200 Hz. long-term drift. If yours doesn't work, you
might also check very closely the L-4 connection to the board. It is easy to
get a poor on non-solder joint if all the enamel has not been cleaned off
the wires.

Replace the .1uf cap between Q6 and Q7 with a two-pin connector. Or better
yet, a three-pin modified two row connector to provide a ground by drilling
an extra hole in the board. That way you can decide to power it with the
internal VFO and a .1uf cap on a jumper, or with an external VFO feeding Q7
with 2-3v Pk to Pk.

Far circuits has the Demaw "Universal VFO" boards, and also a copy of the
original pages from the book "W1FB's QRP Notebook" from whence it came. I
have built four or five of the boards and all worked very well, with
long-term drifts of about 100 Hz. or so over 24 hours. Use GOOD QUALITY
parts (known transistors, npo and silver-mica caps, known good ferrites,
etc). Build each section and test it before going to the next. Don't worry
about LPF's or output matching until the whole oscillator is finished and
does what you want it to do.

I put in a 9v VR at the lower left of the board, where the choke was,
between VCC+ and the supply to the transistors. That eliminated the need for
the zener (and the choke). However, you have to add a jumper wire to supply
12v to the buffer and power amp, and isolate them from the oscillator
circuit...

I have used many different kinds of FET's in the oscillator. I like the J309
the best. Watch the pinouts! they vary between FET's and it is easy to
install the one you have in the wrong way. Get your oscillator working with
the basic tank circuit using a good variable air cap. If you don't have any
in your junkbox, the Crystal Radio Society has some excellent ones at
reasonable prices. Avoid the polyvaricons. They are all not good enough for
a stable VFO above 1 MHz. or so (and even that is iffy). Don't install the
VFO offset circuit unless you are planning on using RIT.

I have used 2N3866's, 2N3035's, and 2N2219A's for the power amplifier. They
are all fine. Install the power amp if you need a 50 ohm output or have a
use for about 20 dBm of power. The buffer has a separate output of about 7
dBm into 600 ohms, which is fine for a diode ring mixer...

Demaw's board and circuit is a very fine VFO if it is done right, and
without too much effort, that can be done. I would recommend it. It can be
adapted to just about any frequency range from 455 Khz. to 9 or 10 MHz. The
signal is pure and is about 2.5v Pk to Pk out of the buffer circuit, about
5v. Pk to Pk with the power amp. The original book is still available fgrom
the ARRL, and I would highly recomment that too...

Hope this helps.

john
AD5YE

Re: External VFO

John Backo
 

--- In BITX20@..., "iam74@..." <iam74@...> wrote:



--- In BITX20@..., "wheverly1@" <wheverly1@> wrote:

Thanks for all of the info. I can't get my VFO to come anywhere near the
required frequency. Currently the output is in the 10 mhz range. I have
tried many different LC combos with not much luck. It seems as thought the
vfo operates at whatever frequency it wants and is not too affected by L4
and many diffenent variable caps. I have wound L4 on T34-6, T54-6 and even
T68-6 and a lot of different turn counts. All have the same results. I can
get as low as near 8 mhz but not below. I have checked every component on
the board to make sure they were the proper values. I have replaced all of
the caps, double checked my soldering and all that I can think of. I'm not a
beginner at this, starting in the 1950's, but am getting old (71) and do
have a few problems.

I believe that I am committed to W1FB's VFO. I have started accumulating
parts for it today. Checking my junk boxes and drawers. I was very happy to
receive the info you provided.

Thanks again,
Bill W3AOQ



Bill:

The 10 MHz signal that you are measuring may be a harmonic, and not the fundamental. Make sure there is no signal by tuning a general coverage receiver from about 2 MHz to 6 MHz to try and pick it up. It may also be your BFO...

In my first version of the BITX V.3 I used a morphed version of the BITX20A VFO. The principal changes were using a T-68-6 with about 45 turns, IN PARALLEL with a 100pf. npo cap across the coil, and a 100pf. npo cap to a MVAM0108 varicap with a 10T pot in place of the zener. The variable cap is an air variable, ca. 365pf, with a 180pf, cap in series. It covers about 3.10 to 3.46 MHz, with a 20 KHz bandspread by the varicap. I actually need about 33pf. to 150pf. variable to cover the whole 20m band. My IF is 11.054 MHz. I can't use 10 MHz because of strong RFI from WWV.

It wouldn't work at first, until I looked closely at the poly caps and discovered that they had been burnt by the soldering iron. After replacing them, it came up with as a good oscillator, quite stable with a 10 Hz or so short-term drift, and a 200 Hz. long-term drift. If yours doesn't work, you might also check very closely the L-4 connection to the board. It is easy to get a poor on non-solder joint if all the enamel has not been cleaned off the wires.

Replace the .1uf cap between Q6 and Q7 with a two-pin connector. Or better yet, a three-pin modified two row connector to provide a ground by drilling an extra hole in the board. That way you can decide to power it with the internal VFO and a .1uf cap on a jumper, or with an external VFO feeding Q7 with 2-3v Pk to Pk.

Far circuits has the Demaw "Universal VFO" boards, and also a copy of the original pages from the book "W1FB's QRP Notebook" from whence it came. I have built four or five of the boards and all worked very well, with long-term drifts of about 100 Hz. or so over 24 hours. Use GOOD QUALITY parts (known transistors, npo and silver-mica caps, known good ferrites, etc). Build each section and test it before going to the next. Don't worry about LPF's or output matching until the whole oscillator is finished and does what you want it to do.

I put in a 9v VR at the lower left of the board, where the choke was, between VCC+ and the supply to the transistors. That eliminated the need for the zener (and the choke). However, you have to add a jumper wire to supply 12v to the buffer and power amp, and isolate them from the oscillator circuit...

I have used many different kinds of FET's in the oscillator. I like the J309 the best. Watch the pinouts! they vary between FET's and it is easy to install the one you have in the wrong way. Get your oscillator working with the basic tank circuit using a good variable air cap. If you don't have any in your junkbox, the Crystal Radio Society has some excellent ones at reasonable prices. Avoid the polyvaricons. They are all not good enough for a stable VFO above 1 MHz. or so (and even that is iffy). Don't install the VFO offset circuit unless you are planning on using RIT.

I have used 2N3866's, 2N3035's, and 2N2219A's for the power amplifier. They are all fine. Install the power amp if you need a 50 ohm output or have a use for about 20 dBm of power. The buffer has a separate output of about 7 dBm into 600 ohms, which is fine for a diode ring mixer...

Demaw's board and circuit is a very fine VFO if it is done right, and without too much effort, that can be done. I would recommend it. It can be adapted to just about any frequency range from 455 Khz. to 9 or 10 MHz. The signal is pure and is about 2.5v Pk to Pk out of the buffer circuit, about 5v. Pk to Pk with the power amp. The original book is still available from the ARRL, and I would highly recommend that too...


Hope this helps.


john
AD5YE


P.S.


One thing I forgot to mention:

If you are using an old air variable, check its condition very carefully. It should be a ball bearing type. If the grease in the bearings is old or cracked, wash it out completely with contact cleaner and replace it with axle grease; a very small dab of either moly or lithium grease will do. Work it well into the bearings. Make sure that none of the balls are missing!

Make sure the plates are aligned and not rubbing anywhere in their travel. If one is bent and touching, it is often better to remove it than try to straighten it; you'll probably never get the alignment exactly right. If it can't be removed, remove as many plates as necessary to get to it and live with a smaller cap, or discard it.

If there are mica trimmers, make sure that they are sound and not intermittently shorting. If in doubt, overhaul them or remove the trimmers and, optionally, replace them with a fixed npo cap of about the same value.

A great many of the VFO troubles can be traced to a bad or ill-serviced variable cap, especially things like sudden jumps in frequency, scratchy or unstable tuning, etc. Having a smooth and freely turning rotor is vital to good performance. Also, check the condition of the tie points for connecting wires. Often these are rivited on and do not provide a good connection after 50 years or so. They may have to be cleaned and tightened. Soldering the ties to an aluminum frame is difficult at best. Use a pin punch to tighten them.

When installing a variable cap, make sure that the stator (the non-rotational part) is connected to the "hot" side of the circuit, and the rotor (the part that turns) is connected to ground. If you don't, the cap will be very sensitive to things like hand capacitance and will never be stable.

If you are using a polyvaricon, throw it away.


john

Bitx20 Ver3

HENRYK
 

Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

Re: Bitx20 Ver3

Ashhar Farhan
 

Check your mic bias. It might be missing. Also check if there is
sufficient bfo drivem

On 11/5/11, HENRYK <henryspcs@...> wrote:
Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

--
Sent from my mobile device

ferrite beads

javed4004
 

dear friends,

From where can i cheaply purchase the ferrite torroids and beads? kindly mention the sources (in India and outside)

Javed

Re: Bitx20 Ver3

HENRYK
 

Hi there Ashhar thanks for the return
Tests carried out are as followed: Q8 C11.99V B6.24V E6.56V  Q9 C11.99V B6.56V E6.03V
RF voltage at junction of T2 and the 0.1uf cap is 0.088v
Frequency 9.995.2
Bias voltage for mic input 4.87 volts
Regards Henry


________________________________
From: Ashhar Farhan <farhanbox@...>
To: BITX20@...
Sent: Saturday, 5 November 2011, 8:55
Subject: Re: [BITX20] Bitx20 Ver3


 
Check your mic bias. It might be missing. Also check if there is
sufficient bfo drivem

On 11/5/11, HENRYK <henryspcs@...> wrote:
Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

--
Sent from my mobile device



[Non-text portions of this message have been removed]

diplexer

terry lynch
 

Has anyone tried using a diplexer at the output of the first (rf) mixer?.I was wondering if it would make much difference.73S, terry.

Re: re 2SC2570

ludo schoofs <ludoschoofs@...>
 

All,

I used a BF199 transistor, this is also an RF NPN transistor. Works very
well.

Regards and 73's
Ludo
ON7JW

-----Oorspronkelijk bericht-----
Van: BITX20@... [mailto:BITX20@...] Namens Juan
Carlos Berberena Glez
Verzonden: zaterdag 5 november 2011 3:58
Aan: BITX20@...
Onderwerp: Re: [BITX20] re 2SC2570

Hi Fellow
You can find this transistor here
http://www.futurlec.com/cgi-bin/search/search.cgi
73's

Jc

2011/11/4 L <bear57@...>

**


Any one know of a supplier for this transistor or a suitable sub?
73 Lorne VE7BOX


--

Lic.Juan Carlos Berberena Gonzalez
WJ6C exCO6BG
www.berberena.com
http://espanol.groups.yahoo.com/group/cacharreando/






------------------------------------

Yahoo! Groups Links



-----
Geen virus gevonden in dit bericht.
Gecontroleerd door AVG - www.avg.com
Versie: 10.0.1411 / Virusdatabase: 2092/3998 - datum van uitgifte: 11/05/11

Re: Bitx20 Ver3

Mark <huitmarmottes@...>
 

Hi Henry,

How is your reception sounding?  Do the operators you hear sound like chipmunks too?  If so, then your BFO frequency is the culprit.  I adjusted mine by a spectrogram program and ended up at 9997.0 kHz but every filter will be a little bit different so 9995.2 may be fine for your set.

If not the BFO, then yeah maybe there is a problem in your mike amp.  The misplaced resistor in that circuit has been noted before -- I had it both ways and it didn't seem to make too much difference, but as you said it should provide power to the electret unit by feeding power from the 12V T line.  On mine, I did go ahead and also add a DC blocking cap between the electret and the first transistor base like they have it in the 20a version.  Your mic bias sounds fine, they have quite a large operating range from the specs I have seen.

73s and have a great weekend everyone,



 
Mark - N7EKU


________________________________
From: HENRYK KLETTKE <henryspcs@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, November 5, 2011 6:12 AM
Subject: Re: [BITX20] Bitx20 Ver3


 
Hi there Ashhar thanks for the return
Tests carried out are as followed: Q8 C11.99V B6.24V E6.56V  Q9 C11.99V B6.56V E6.03V
RF voltage at junction of T2 and the 0.1uf cap is 0.088v
Frequency 9.995.2
Bias voltage for mic input 4.87 volts
Regards Henry

________________________________
From: Ashhar Farhan <farhanbox@...>
To: BITX20@...
Sent: Saturday, 5 November 2011, 8:55
Subject: Re: [BITX20] Bitx20 Ver3

 
Check your mic bias. It might be missing. Also check if there is
sufficient bfo drivem

On 11/5/11, HENRYK <henryspcs@...> wrote:
Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

--
Sent from my mobile device

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

Re: Testing at C11 for received signals?

Kevin Bentley <kevin.bentley@...>
 

I have a similar problem. I have fully assembled my kit, and I get absolute silence across the band, except for birdies. I was able to test the AF circuit, but this is my only HF rig. I have a long wire attached for now.

When I watch the basic alignment video I notice there is noise on the band. I don't get any noise.

I don't have a signal generator, but I'm going to try to get one soon.

Any suggestions on how I could troubleshoot this? I do have a scope and meter, etc. I verified the VFO and BFO frequencies using the freq counter in my scope, and it's very close.

Thanks!

--- In BITX20@..., "LeonardL" <dredger@...> wrote:

If you have it completely assembled, you might try the alignment here. http://golddredgervideo.com/kc0wox/basicalignment.wmv
Leonard

--- In BITX20@..., "kc9lif" <kbergphd@> wrote:

Good Morning,

I am attempting to do the test on page 25 of manual (2/6/08). Connecting antenna to C-11 and tune VFO for received signals. I checked the band on another radio to make sure there were signals and there are several signals across the band, but when I hooked up to the BitX20 at C-11, it is quiet. Not a peep, except for some birdies as I tune. All the tests up to this point have been successful. I am running 13.6v and current of about 57ma. Any suggestions?

Thx, Kent KC9LIF

Re: External VFO

Mark <huitmarmottes@...>
 

Great input on old air variable caps John :-)

I have seen all those issues in old caps.  I might add that you also need to check the rotor to frame connection (usually in the back and/or between sections).  These can get pretty oxidized over time and its usually just a bronze or brass pressure spring connection.  I like to put some deoxit or at least some naptha (Coleman fuel) to rinse it clean of oxidation and old tobacco/grease/oil/etcetera.

That reminds me.  I read on an antique radio site a recipe for "deoxit" that is naptha with a few percent of oleic acid(a very mild acidified vegetable oil).  I tried it and found that actually just the pure naptha work even better than the mix with oleid acid.  It cleans up pots and switch contacts very well.  It also dries very quickly and I haven't had any damage at all to plastics or paint finishes.  It's good for washing out old grease too.


Cheers!


 Mark - N7EKU

[Non-text portions of this message have been removed]

Re: Bitx20 Ver3

HENRYK
 

Hi Mark found the problem cheap copy 2N3904's in the BFO changed for two 2N2222A's which i have a lot of now it works Ok.
Reception is great no problems there just was not getting the drive from the BFO on TX.
Have had alot trouble with this kit but its fun finding out why things do not work.
The linear gave me a lot of trouble IRF510 copy's.
Now we are boxing it all up and will be on air soon.
Regards Henry


________________________________
From: Mark <huitmarmottes@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, 5 November 2011, 20:34
Subject: Re: [BITX20] Bitx20 Ver3


 
Hi Henry,

How is your reception sounding?  Do the operators you hear sound like chipmunks too?  If so, then your BFO frequency is the culprit.  I adjusted mine by a spectrogram program and ended up at 9997.0 kHz but every filter will be a little bit different so 9995.2 may be fine for your set.

If not the BFO, then yeah maybe there is a problem in your mike amp.  The misplaced resistor in that circuit has been noted before -- I had it both ways and it didn't seem to make too much difference, but as you said it should provide power to the electret unit by feeding power from the 12V T line.  On mine, I did go ahead and also add a DC blocking cap between the electret and the first transistor base like they have it in the 20a version.  Your mic bias sounds fine, they have quite a large operating range from the specs I have seen.

73s and have a great weekend everyone,

 
Mark - N7EKU

________________________________
From: HENRYK KLETTKE <henryspcs@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, November 5, 2011 6:12 AM
Subject: Re: [BITX20] Bitx20 Ver3

 
Hi there Ashhar thanks for the return
Tests carried out are as followed: Q8 C11.99V B6.24V E6.56V  Q9 C11.99V B6.56V E6.03V
RF voltage at junction of T2 and the 0.1uf cap is 0.088v
Frequency 9.995.2
Bias voltage for mic input 4.87 volts
Regards Henry

________________________________
From: Ashhar Farhan <farhanbox@...>
To: BITX20@...
Sent: Saturday, 5 November 2011, 8:55
Subject: Re: [BITX20] Bitx20 Ver3

 
Check your mic bias. It might be missing. Also check if there is
sufficient bfo drivem

On 11/5/11, HENRYK <henryspcs@...> wrote:
Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

--
Sent from my mobile device



[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]

Re: Bitx20 Ver3

Mark <huitmarmottes@...>
 

Great news Henry!

Way to go!  I am also very happy to me learning and building at the same time; I find it a lot better than just reading from books.

I am finding too the importance of quality parts.  Finding new-old-stock components helps a lot (or buying new from a good dealer like Digikey or Mouser).  There are so many cheap quality/fakes around.  I ordered a big variety pack of transistors from a place in Hong Kong that sold Arduino stuff and when I tested the supposed 2N3904 or higher Ft ones in a standalone BITX amp, they were almost all the same (very poor amplification).  The transistors all looked so much alike (with no manufacturer name on them) that I think they were all just the same cheapo transistor with different numbers stamped on them!

It seems to be a good time though to find good old excess parts on eBay from closed factories/businesses.  Only a lot of times you have to buy large quantities...

Cheers and give us some pictures when your new BITX is all boxed up!

73s,

Mark.



 
Mark - N7EKU


________________________________
From: HENRYK KLETTKE <henryspcs@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, November 5, 2011 1:56 PM
Subject: Re: [BITX20] Bitx20 Ver3


 
Hi Mark found the problem cheap copy 2N3904's in the BFO changed for two 2N2222A's which i have a lot of now it works Ok.
Reception is great no problems there just was not getting the drive from the BFO on TX.
Have had alot trouble with this kit but its fun finding out why things do not work.
The linear gave me a lot of trouble IRF510 copy's.
Now we are boxing it all up and will be on air soon.
Regards Henry

________________________________
From: Mark <huitmarmottes@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, 5 November 2011, 20:34
Subject: Re: [BITX20] Bitx20 Ver3

 
Hi Henry,

How is your reception sounding?  Do the operators you hear sound like chipmunks too?  If so, then your BFO frequency is the culprit.  I adjusted mine by a spectrogram program and ended up at 9997.0 kHz but every filter will be a little bit different so 9995.2 may be fine for your set.

If not the BFO, then yeah maybe there is a problem in your mike amp.  The misplaced resistor in that circuit has been noted before -- I had it both ways and it didn't seem to make too much difference, but as you said it should provide power to the electret unit by feeding power from the 12V T line.  On mine, I did go ahead and also add a DC blocking cap between the electret and the first transistor base like they have it in the 20a version.  Your mic bias sounds fine, they have quite a large operating range from the specs I have seen.

73s and have a great weekend everyone,

 
Mark - N7EKU

________________________________
From: HENRYK KLETTKE <henryspcs@...>
To: "BITX20@..." <BITX20@...>
Sent: Saturday, November 5, 2011 6:12 AM
Subject: Re: [BITX20] Bitx20 Ver3

 
Hi there Ashhar thanks for the return
Tests carried out are as followed: Q8 C11.99V B6.24V E6.56V  Q9 C11.99V B6.56V E6.03V
RF voltage at junction of T2 and the 0.1uf cap is 0.088v
Frequency 9.995.2
Bias voltage for mic input 4.87 volts
Regards Henry

________________________________
From: Ashhar Farhan <farhanbox@...>
To: BITX20@...
Sent: Saturday, 5 November 2011, 8:55
Subject: Re: [BITX20] Bitx20 Ver3

 
Check your mic bias. It might be missing. Also check if there is
sufficient bfo drivem

On 11/5/11, HENRYK <henryspcs@...> wrote:
Hi all can any one help with Mic problem?
Using with mic supplied with kit and it sounds like a chip monk.
Tried balance pot and c51 cap no change as well as Bfo capC43.
Also fault on R50 placement on PCB in mic amp.
Regards Henry

--
Sent from my mobile device

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Re: diplexer

gabadola
 

yes friend,
i have tried the diplexer from the mixer and the result was very good. no loss of sensitivity and gain on quality .

Re: ferrite beads

Lawrence Galea
 

http://www.kitsandparts.com/

On Sat, Nov 5, 2011 at 12:02 PM, javed4004 <javed4004@...> wrote:

**


dear friends,

From where can i cheaply purchase the ferrite torroids and beads? kindly
mention the sources (in India and outside)

Javed



[Non-text portions of this message have been removed]

diplexer

terry lynch
 

Thanks,gaetano!,I am glad that the results you got were good,I will try it myself.Best 73s, terry EI3IZ.

No Reception troubleshooting

Kevin Bentley <kevin.bentley@...>
 

I have narrowed it down a bit, but I'm still a bit stuck. If anyone can
help I'd appreciate it.
When I connect the antenna directly to C11, I get nothing. When I
connect to the junction of C24/C29, I get a signal (and voice I can
almost understand, but lots of noise).
If I connect the antenna to the other side of C24 (the junction with L6)
I also get nothing. Shouldn't the signal make it through only C24? I
removed C18/C19/C20 and L6 from the circuit and connect the antenna to
the 'other side' of C24 and I still get no signal. Am I wrong in
assuming the signal should pass through C24 in that case?
Any tips are appreciated!

--- In BITX20@..., "Kevin Bentley" <kevin.bentley@...>
wrote:

I have a similar problem. I have fully assembled my kit, and I get
absolute silence across the band, except for birdies. I was able to test
the AF circuit, but this is my only HF rig. I have a long wire attached
for now.

When I watch the basic alignment video I notice there is noise on the
band. I don't get any noise.

I don't have a signal generator, but I'm going to try to get one soon.

Any suggestions on how I could troubleshoot this? I do have a scope
and meter, etc. I verified the VFO and BFO frequencies using the freq
counter in my scope, and it's very close.

Thanks!