Date   
Re: TV baluns

larry allen <larya@...>
 

Hi...
Would you give the a better web address?
www.kitandparts.com
doesn't work...
Larry ve3fxq

----- Original Message -----
From: "Jim Kortge" <jokortge@...>
To: <BITX20@...>
Sent: Sunday, February 25, 2007 10:40 AM
Subject: Re: [BITX20] TV baluns




Bruce Conner wrote:
I wanted to order some TV baluns, but I see there are a number of
different ones out there. What's the best type to get?

Bruce
WB8OGK
I'm assuming that the cores would be used for the mixer transformers in the rig.
For those, type 43 material is preferred, and type 61 as an alternate, but less
desirable. The BN2402 style cores made with 43 material are available from Diz,
W8DIZ at kitandparts.com and also from Brad, AA1IP. The last time I bought
BN2402 cores from Brad they were 20 pieces for $1.00 plus shipping which was
nominal. Both sources are highly recommended.

72,

Jim, K8IQY

Re: TV baluns

Jim Kortge <jokortge@...>
 

Bruce Conner wrote:
I wanted to order some TV baluns, but I see there are a number of
different ones out there. What's the best type to get?
Bruce WB8OGK
I'm assuming that the cores would be used for the mixer transformers in the rig. For those, type 43 material is preferred, and type 61 as an alternate, but less desirable. The BN2402 style cores made with 43 material are available from Diz, W8DIZ at kitandparts.com and also from Brad, AA1IP. The last time I bought BN2402 cores from Brad they were 20 pieces for $1.00 plus shipping which was nominal. Both sources are highly recommended.

72,

Jim, K8IQY

TV baluns

Bruce Conner
 

I wanted to order some TV baluns, but I see there are a number of
different ones out there. What's the best type to get?

Bruce
WB8OGK

Re: losses in xtal filter

wimmie262000 <wvh@...>
 

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

Hi all,

I am building a bitx IF strip using 9 Mhz xtals. My problem is that
the filter is lossy. The losses are 18 db.
Does anyone know what could be the problem?

I have use 27 Mhz overtone xtals. They match within 100Hz.
The bandwidth is Ok: 2Khz @ 3 db.The signal sounds ok , it is just
weak. I bought 15 of them. they are from 1 batch.

Some 9.8 Mhz ground tone xtals were tried as well. That filter was
much better. The losses were 6 db.

I hope anyone can help

73
PA3EMY
As the others said, it is probably due to the high Rs of your
crystals. The optimal input and output impedance of your filter will
also increase with higer Rs. As I see it the BITX has about 200 ohm at
both sides of the filter. What you could do is use an
(auto)transformer on both sides to match the impedance better. Tap the
autotransformer at 2/3 or even 1/2 when Rs is really high.
This way you avoid the complexity of adding bi-directional gain
stages. The usual BITX stages alternate 50 and 200 ohm each stage...

Good luck,

Joop (pe1cqp)

Re: Rx not work

David Snell <dgsnell@...>
 

Hi Vakarcs,

You have been silent on BITX lately.

Are you OK and have you built it yet?

73 de Dave M1DGS

----- Original Message -----
From: Vakarcs Szilárd
To: BITX20@...
Sent: Friday, January 06, 2006 2:24 PM
Subject: Re: [BITX20] Rx not work


Hi to all!
I need 10 pieces of tv baluns who can help me in this
case. My location is in Romania.Sorry but here is no
tv baluns in the stores because there is no commercial
interest in this product.
Thanks a lot.

--- Sanil73 <sanil73@...> wrote:

> Did u receive the transistors ??
> VU2TRI
>




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Tip for winding Balun Cores...

Dan Reynolds
 

Hi everyone. I got the main board (V.3) PC board populated and I have
the receiver section debugged and working. The band is pretty dead here
but I am hearing stuff in the BITX.

I came across a good way to help wind the baluns. I got a board and some
cores from Sunil in India (TNX again Sunil) and I was having a problem
winding them and not breaking wire or nicking the wire due to the sharp
edges. I took a tiny strip of teflon thread sealing tape and ran it
through the inside of the core about four or five times (where you would
wind the wire). Worked like a charm. Kept me from nicking the wire and
gave a little 'cushion' to keep me from breaking the wires when I tugged
on them.

Might help someone else...

Dan KB9JLO
<><

Now I'm ready to finish the transmitter section!!!!

Re: losses in xtal filter

Jim Kortge <jokortge@...>
 

luuk_h wrote:
Hi all,
I am building a bitx IF strip using 9 Mhz xtals. My problem is that the filter is lossy. The losses are 18 db.
Does anyone know what could be the problem?
Yes, poor equivalent resistance (Rs) in the units that you have, leading to horrible losses in the filter. You need less lossy units; higher Q
I have use 27 Mhz overtone xtals. They match within 100Hz.
The bandwidth is Ok: 2Khz @ 3 db.The signal sounds ok , it is just weak. I bought 15 of them. they are from 1 batch.
Well you could add another gain stage, but I'd be looking for better crystals.
Some 9.8 Mhz ground tone xtals were tried as well. That filter was much better. The losses were 6 db.
That's a lot better. The Rs values for the 11 MHz crystals that I use in the 2N2/20 design are typically 8-10 Ohms resulting in Q values over 100K. The insertion loss for a 4-pole filter using these crystals is about 5 dB.

72 and I hope you can find some good crystals to use.

Jim, K8IQY

Re: Bitx for 28Mhz 10m band Please Help!

Jim Kortge <jokortge@...>
 

ewcheeguan wrote:
Hi all,
I had just got my ham license
Way to go.....

and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:
1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?
No, not without some external circuitry to keep it on frequency. If it were me, I'd be inclined to use a VXO with two crystal elements to improve the tuning range. Also, if you have access to various crystals, you could use either 16 or 18 MHz crystals in the VXO, double that to get an even larger tuning range, and pick an IF crystal that will allow you to operate in the part of the 10 meter band where you are legal.
2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?
I wouldn't go above 12 or 13 MHz for the IF. The coupling capacitors will probably be too small to be practical.
3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?
Yes, if by VXO you really mean BFO, which is oscillating at nominally the IF frequency. That shouldn't be a problem.

For those experienced senior, please Help!!!
I trying to do my part! :-)
Thank you
Regards,
EW
9W2ECG
72/72 EW; keep us posted on your progress.

Jim, K8IQY

Re: A good site

kc0wox <bitx@...>
 

http://www.giangrandi.ch/electronics/crystalfilters/xtalfilters.shtml
Hello all
A good site to build a cristal filter
best 73
michel
I really like that!
It answered a lot of my questions. I can feel a video coming on in the
future running through a design. His equipment was a lot newer than
mine though.
Leonard
KC0WOX

A good site

Michel Van Der Biest <f6feo@...>
 

http://www.giangrandi.ch/electronics/crystalfilters/xtalfilters.shtml


Hello all



A good site to build a cristal filter

best 73

michel

Re: losses in xtal filter

sg2112 <SG2112@...>
 

The crystals you got are probably low Q and hence have more loss ...
I've never tried to characterize an overtone crystal but I suspect
they might inherently have a lower Q at their fundamental than a
regular crystal

JR

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

Hi all,

I am building a bitx IF strip using 9 Mhz xtals. My problem is that
the filter is lossy. The losses are 18 db.
Does anyone know what could be the problem?

I have use 27 Mhz overtone xtals. They match within 100Hz.
The bandwidth is Ok: 2Khz @ 3 db.The signal sounds ok , it is just
weak. I bought 15 of them. they are from 1 batch.

Some 9.8 Mhz ground tone xtals were tried as well. That filter was
much better. The losses were 6 db.

I hope anyone can help

73
PA3EMY

Re: Bitx for 28Mhz 10m band Please Help!

ewcheeguan
 

Hi all,
Thanks for all the superb suggestions, I will try Huff-Puff
stablizer and see how it goes, Thanks!

Regards,
EW
9W2ECG

Re: Bitx for 28Mhz 10m band Please Help!

Martien Rijssemus <martien.rijssemus@...>
 

Hi,

For some reason the picture of the H&P stabiliser was lost so I posted
it in the FILE section.
This is a circuit I used and found on the website of PA2RF.

Martien PE1BWI

________________________________

Van: BITX20@... [mailto:BITX20@...] Namens
ewcheeguan
Verzonden: woensdag 21 februari 2007 3:06
Aan: BITX20@...
Onderwerp: [BITX20] Bitx for 28Mhz 10m band Please Help!




Hi all,

I had just got my ham license and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?

For those experienced senior, please Help!!!

Thank you

Regards,
EW
9W2ECG





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Re: Bitx for 28Mhz 10m band Please Help!

Martien Rijssemus <martien.rijssemus@...>
 

HI ,

You could also use a normal 18Mhz VFO and stabilise it with a "huff and
puff " circuit.
Try google "huff and puff" or "H&P stabilizer" and you will find a lot
of info.

Of course the first step is to make the VFO as stable as possible using
only the best components,
especially the coil and the capacitors. Also stabilise the supply
voltage. Use a separate housing for the VFO
to shield it from temperature fluctuations.

I used this cicuit below which works very well. Connect RF in to your
VFO, if there is not enough level present
use a simple one transistor amplifier to boost the signal.

"To varicap" is connected to a separate varicap in your VFO. Make sure
this varicap has limited tuning range
lets say around 20 KHz. This circuit will stabilise your VFO in very
small steps of about 20 Hz.


Best regards and have fun experimenting,

Martien PE1BWI



________________________________

Van: BITX20@... [mailto:BITX20@...] Namens
ewcheeguan
Verzonden: woensdag 21 februari 2007 3:06
Aan: BITX20@...
Onderwerp: [BITX20] Bitx for 28Mhz 10m band Please Help!




Hi all,

I had just got my ham license and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?

For those experienced senior, please Help!!!

Thank you

Regards,
EW
9W2ECG





______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________

Re: Bitx for 28Mhz 10m band Please Help!

luuk_h <luuk_h@...>
 

Hi,

l will try to answer the questions
1) Stable 5 MHz VFO's can be build. Higher Frequencies are much more
difficult. Better use 5 MHz as maximum for homebrew.

2) 24 MHz is a good IF. Although The filter will be hard to build.
The 24 MHz Xtals are probably overtone Xtals.

3)A 10 MHz VFO will be hard build


-A super VXO is a good solution.
-You could build a 5mW version of the bitx. Then you can build a
transverter. This is not as difficult as it seems. A Crystal
oscillator( metal can) and a SBL1 mixer will do the trick. This is
what I will do for a 50 MHz version.
-You can build a VCO for 10 MHz but then you need a stabilizer. For
example the 'huff and puff' stabilizer.
-The IRF510 PA will be hard (if not impossible) to build for 10
meter, better use another PA.

Good luck



-- In BITX20@..., "ewcheeguan" <tru168@...> wrote:


Hi all,

I had just got my ham license and I'm only allowed to operate at
10m
band or above, I'm going to take class A exam (for HF band) but
need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't
know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz
right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at
10Mhz?

For those experienced senior, please Help!!!


Thank you

Regards,
EW
9W2ECG

Re: New video's

Bill Meara
 

Leonard: Wonderful videos. Thanks for putting them together. I
have linked to them on the video page of http://www.gadgeteer.us

Have you thought about uploading them to YouTube or some similar
site? I find that that makes it easier for people to access the
videos -- no need to put anything on their hard drives -- they can
watch them as streaming video. It is free and easy. Also, the
worldof online video is in desperate need of the addition of
intelligent, educational work like yours.

73 Bill M0HBR N2CQR



--- In BITX20@..., "kc0wox" <bitx@...> wrote:

I added two new Bitx videos to my website at
http://golddredgervideo.com/bitx20/

One is a 12 1/2 minute tutorial on amplitude and double sideband
modulation. It's 40.5 mb in size.

http://golddredgervideo.com/bitx20/amplitudeanddoublesideband.wmv

The second one is a troubleshooting tutorial on the mike amp
section.
It's 7 1/2 minutes and 24.4 mb in size.

http://golddredgervideo.com/bitx20/mikeamptest.wmv

It illustrates how easy it is to plug a part in the wrong place.

Leonard
KC0WOX

Re: Bitx for 28Mhz 10m band Please Help!

Rahul Srivastava
 

Hi!
Congratulations for your ticket. With rest of BITX remaining same use 18.432Mhz xtal in super VXO configration for VFO. Try Google on Super VXO.
Hope this helps.
73
Rahul VU3WJM

ewcheeguan <tru168@...> wrote:

Hi all,

I had just got my ham license and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?

For those experienced senior, please Help!!!

Thank you

Regards,
EW
9W2ECG






---------------------------------
New Yahoo! Mail is the ultimate force in competitive emailing. Find out more at the Yahoo! Mail Championships. Plus: play games and win prizes.

Re: Bitx for 28Mhz 10m band Please Help!

MM Ali <ali@...>
 

UHF/Microwave Antenna Design Engineer
Immediate opening with a large US Based company, a part of a large conglomorate - offering packaged services [Radio Based]

Position in Bangalore, No constraint for the right candidate.

Engineer will be responsible for designing & integration of Antennas with the final product. The antennas incude strip-antennas, for portable devices.
Package is no constraint for the right candidate. Send your Resumes

----- Original Message -----
From: ewcheeguan
To: BITX20@...
Sent: Wednesday, February 21, 2007 5:05 AM
Subject: [BITX20] Bitx for 28Mhz 10m band Please Help!



Hi all,

I had just got my ham license and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?

For those experienced senior, please Help!!!

Thank you

Regards,
EW
9W2ECG





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This message was checked by NOD32 antivirus system.
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Bitx for 28Mhz 10m band Please Help!

ewcheeguan
 

Hi all,

I had just got my ham license and I'm only allowed to operate at 10m
band or above, I'm going to take class A exam (for HF band) but need
to wait for another year to seat for that exam.
Now I already etched and build the PCB and also get all parts
ready, and I'm going to build 10m band version. since I have signal
generator and 60Mhz scope ,I finished the rx band pass filter and
adjusted to perfect working condition at 28Mhz, but now, I don't know
what to do next!! my problem is:

1) What is the max. frequency for the VCO to operate at stable
condition? sure it will not be stable if I operate it at 18Mhz right?

2) By increasing the Mhz of crystal filter, I can use lower VCO
frequency, but what is the best value? 18Mhz or 24Mhz? is 24 Mhz
acceptable?

3) If I use 18Mhz crystal, the VCO will be stable operating at 10Mhz?

For those experienced senior, please Help!!!


Thank you

Regards,
EW
9W2ECG

losses in xtal filter

luuk_h <luuk_h@...>
 

Hi all,

I am building a bitx IF strip using 9 Mhz xtals. My problem is that
the filter is lossy. The losses are 18 db.
Does anyone know what could be the problem?

I have use 27 Mhz overtone xtals. They match within 100Hz.
The bandwidth is Ok: 2Khz @ 3 db.The signal sounds ok , it is just
weak. I bought 15 of them. they are from 1 batch.

Some 9.8 Mhz ground tone xtals were tried as well. That filter was
much better. The losses were 6 db.

I hope anyone can help

73
PA3EMY