Date   
Re: VXO

Stanley Grixti
 

Hi Greg

This is interesting....1mhz & 5.0688 maybe difficult to find for me though

I have never played with DDS, I understand the theory behind it but have never actually tried it so it's beyond me at this stage

I tried pulling 4mhz cermanic resonators (10 in parallel!!)

got them to 4.070 but wasn't reliable...power starts dropping at 4.065!

Tonight I will have a look at huff & puff based design and also see what combinations of crystals i have to try the mixing tecnique, also I might try a PLL approach but I'm a bit weiry about phase noice as experience i've had on 23cm and 3cm with pll derived oscillators were not very satisfactory for SSB...but on hf the story may be different

I would also like to hear Farhan's ideas about direct baseband PSK31

73

Stan 9H1LO


Greg Derda wrote:


Stan,

I am building a BitX for PSK as well and am temporarily using a DDS,
but another idea for the VXO-type LO is to mix two (crystal)
frequencies, similar to KD1JV's "Unique PSK Transceiver". If you
could find an affordable 1Mhz crystal, then 5.0688Mhz (easy to find)
minus 1Mhz gets you pretty close. I've played with all combinations
of crystals I have available but haven't come up with a close enough
combination yet. Here is Steve's rig, and there are few others out
there.....

http://kd1jv.qrpradio.com/PSKTX/SIMPLEPSKTX.HTM <http://kd1jv.qrpradio.com/PSKTX/SIMPLEPSKTX.HTM>

Greg
ki4mmm

On Fri, Apr 25, 2008 at 8:04 AM, Stanley Grixti <stanley@... <mailto:stanley%409h1lo.net>> wrote:






I think DDS is abit overkill as a vfo for my intended psk31 beacon
project

I'll be trying the huff&puff designs and if I find it stable and
reliable enough in the long term i'll stick to it.

otherwise i'll investigate using a PLL or ordering a custom
crystal....but getting the crystal ruins the experimental fun HIHI :)

73

Stan 9H1LO

Hans Summers wrote:

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>,
"ah6gi" <ah6gi@...> wrote:

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>, Arv

Evans <arvid.evans@> wrote:

You could always use a conventional VFO but with H&P
stabilization for
extreme stability to support digital modes.
Perhaps this is overkill and not quite in the spirit of Homebrew but
here is another option.

<http://www.sseng.com/My_Homepage_Files/Page2.html
<http://www.sseng.com/My_Homepage_Files/Page2.html>
<http://www.sseng.com/My_Homepage_Files/Page2.html
<http://www.sseng.com/My_Homepage_Files/Page2.html>>>

Hi hi, generated some amusement here during my lunchtime! Did you see
the price? $170! Hello? That's TWO of Doug's BITX20A kits, or even
more BITX20's if you went for the bareback "ugly" style
construction...

The best bit is "exacting performance that can't be beat"... one has
to wonder what aspect of performance they're referring to?

- Phase noise: improve it by not using the internal clock multiplier
on the AD9850, or by using a more modern DDS chip
- Spurious outputs: reduce them by using a more modern DDS chip e.g.
AD9951 or even the latest AD9910/12
- Frequency stability: improve it by ovenising the crystal reference
oscillator or thermal compensation
- Cost: reduce it by... well, just REDUCE it, PUR-LEASE!!!

Ok, pay $170 for extreme high performance, but that DDS kit won't
give it - I suggest if you want DDS fine, but there MUST be better
value kits around than this one!

73 Hans G0UPL
http://www.hanssummers.com <http://www.hanssummers.com>
<http://www.hanssummers.com <http://www.hanssummers.com>>

Re: VXO

Greg Derda
 

Stan,

I am building a BitX for PSK as well and am temporarily using a DDS,
but another idea for the VXO-type LO is to mix two (crystal)
frequencies, similar to KD1JV's "Unique PSK Transceiver". If you
could find an affordable 1Mhz crystal, then 5.0688Mhz (easy to find)
minus 1Mhz gets you pretty close. I've played with all combinations
of crystals I have available but haven't come up with a close enough
combination yet. Here is Steve's rig, and there are few others out
there.....

http://kd1jv.qrpradio.com/PSKTX/SIMPLEPSKTX.HTM

Greg
ki4mmm

On Fri, Apr 25, 2008 at 8:04 AM, Stanley Grixti <stanley@...> wrote:






I think DDS is abit overkill as a vfo for my intended psk31 beacon project

I'll be trying the huff&puff designs and if I find it stable and
reliable enough in the long term i'll stick to it.

otherwise i'll investigate using a PLL or ordering a custom
crystal....but getting the crystal ruins the experimental fun HIHI :)

73

Stan 9H1LO

Hans Summers wrote:
>
> --- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
> "ah6gi" <ah6gi@...> wrote:
> >
> > --- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Arv

> Evans <arvid.evans@> wrote:
> >
> > > You could always use a conventional VFO but with H&P
> stabilization for
> > > extreme stability to support digital modes.
> >
> > Perhaps this is overkill and not quite in the spirit of Homebrew but
> > here is another option.
> >
> > <http://www.sseng.com/My_Homepage_Files/Page2.html
> <http://www.sseng.com/My_Homepage_Files/Page2.html>>
>
> Hi hi, generated some amusement here during my lunchtime! Did you see
> the price? $170! Hello? That's TWO of Doug's BITX20A kits, or even
> more BITX20's if you went for the bareback "ugly" style
> construction...
>
> The best bit is "exacting performance that can't be beat"... one has
> to wonder what aspect of performance they're referring to?
>
> - Phase noise: improve it by not using the internal clock multiplier
> on the AD9850, or by using a more modern DDS chip
> - Spurious outputs: reduce them by using a more modern DDS chip e.g.
> AD9951 or even the latest AD9910/12
> - Frequency stability: improve it by ovenising the crystal reference
> oscillator or thermal compensation
> - Cost: reduce it by... well, just REDUCE it, PUR-LEASE!!!
>
> Ok, pay $170 for extreme high performance, but that DDS kit won't
> give it - I suggest if you want DDS fine, but there MUST be better
> value kits around than this one!
>
> 73 Hans G0UPL
> http://www.hanssummers.com <http://www.hanssummers.com>
>
>

Re: VXO

Stanley Grixti
 

I think DDS is abit overkill as a vfo for my intended psk31 beacon project

I'll be trying the huff&puff designs and if I find it stable and reliable enough in the long term i'll stick to it.

otherwise i'll investigate using a PLL or ordering a custom crystal....but getting the crystal ruins the experimental fun HIHI :)

73

Stan 9H1LO


Hans Summers wrote:


--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, "ah6gi" <ah6gi@...> wrote:

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>, Arv
Evans <arvid.evans@> wrote:

You could always use a conventional VFO but with H&P
stabilization for
extreme stability to support digital modes.
Perhaps this is overkill and not quite in the spirit of Homebrew but
here is another option.

<http://www.sseng.com/My_Homepage_Files/Page2.html
<http://www.sseng.com/My_Homepage_Files/Page2.html>>

Hi hi, generated some amusement here during my lunchtime! Did you see
the price? $170! Hello? That's TWO of Doug's BITX20A kits, or even
more BITX20's if you went for the bareback "ugly" style
construction...

The best bit is "exacting performance that can't be beat"... one has
to wonder what aspect of performance they're referring to?

- Phase noise: improve it by not using the internal clock multiplier
on the AD9850, or by using a more modern DDS chip
- Spurious outputs: reduce them by using a more modern DDS chip e.g.
AD9951 or even the latest AD9910/12
- Frequency stability: improve it by ovenising the crystal reference
oscillator or thermal compensation
- Cost: reduce it by... well, just REDUCE it, PUR-LEASE!!!

Ok, pay $170 for extreme high performance, but that DDS kit won't
give it - I suggest if you want DDS fine, but there MUST be better
value kits around than this one!

73 Hans G0UPL
http://www.hanssummers.com <http://www.hanssummers.com>

Re: VXO

Mike W <mike@...>
 

All comments absolutely right Hans, at that price its a steal, for the vendor.
I wonder if the AM-Qrp DDS daughter board will ever be re-issued ?. They were
magic for many apps, small and easily programmed by PC or with dedicated pics,
or even using your interface :-)
Hope alls well with you, later, Mike G8NXD

On 25 Apr 2008 at 11:35, Hans Summers wrote:

--- In BITX20@..., "ah6gi" <ah6gi@...> wrote:

--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

You could always use a conventional VFO but with H&P
stabilization for
extreme stability to support digital modes.
Perhaps this is overkill and not quite in the spirit of Homebrew but
here is another option.

<http://www.sseng.com/My_Homepage_Files/Page2.html>
Hi hi, generated some amusement here during my lunchtime! Did you see
the price? $170! Hello? That's TWO of Doug's BITX20A kits, or even
more BITX20's if you went for the bareback "ugly" style
construction...

The best bit is "exacting performance that can't be beat"... one has
to wonder what aspect of performance they're referring to?

- Phase noise: improve it by not using the internal clock multiplier
on the AD9850, or by using a more modern DDS chip
- Spurious outputs: reduce them by using a more modern DDS chip e.g.
AD9951 or even the latest AD9910/12
- Frequency stability: improve it by ovenising the crystal reference
oscillator or thermal compensation
- Cost: reduce it by... well, just REDUCE it, PUR-LEASE!!!

Ok, pay $170 for extreme high performance, but that DDS kit won't
give it - I suggest if you want DDS fine, but there MUST be better
value kits around than this one!

73 Hans G0UPL
http://www.hanssummers.com

Re: VXO

hans.g0upl@...
 

--- In BITX20@..., "ah6gi" <ah6gi@...> wrote:

--- In BITX20@..., Arv Evans <arvid.evans@> wrote:

You could always use a conventional VFO but with H&P
stabilization for
extreme stability to support digital modes.
Perhaps this is overkill and not quite in the spirit of Homebrew but
here is another option.

<http://www.sseng.com/My_Homepage_Files/Page2.html>
Hi hi, generated some amusement here during my lunchtime! Did you see
the price? $170! Hello? That's TWO of Doug's BITX20A kits, or even
more BITX20's if you went for the bareback "ugly" style
construction...

The best bit is "exacting performance that can't be beat"... one has
to wonder what aspect of performance they're referring to?

- Phase noise: improve it by not using the internal clock multiplier
on the AD9850, or by using a more modern DDS chip
- Spurious outputs: reduce them by using a more modern DDS chip e.g.
AD9951 or even the latest AD9910/12
- Frequency stability: improve it by ovenising the crystal reference
oscillator or thermal compensation
- Cost: reduce it by... well, just REDUCE it, PUR-LEASE!!!

Ok, pay $170 for extreme high performance, but that DDS kit won't
give it - I suggest if you want DDS fine, but there MUST be better
value kits around than this one!

73 Hans G0UPL
http://www.hanssummers.com

Re: VXO

Stanley Grixti
 

Ok Mike, Arv, ah6gi, and all who answered

I will get looking into this and start experimenting tonight when at the 'lab'

Will reports results later on...

best 73

Stan 9H1LO


Mike W wrote:

Thinking further, how about a "VXO VXO" mixer VXO.

Basically two oscillators, both VXO'ed and mixed together to get the required frequency at the output. possibly using an NE612 or whatever its called.
eg a 20Mhz and a 24Mhz mixed and filtered will give 4Mhz, shift the 20Mhz down about 35khz and the 24Mhz up 35khz and you get the difference frequency of 4.07 Mhz and the sum freq of 48-ish Mhz, 35Khz is not unreasonable with care in a VXO

On 24 Apr 2008 at 20:07, Stanley Grixti wrote:


OK I re-phrase my question

I want to get the bitx20 onto 14.070mhz (PSK31)

The BFO and XTAL Filter are at 10Mhz as per the design

The VXO must then be 4.07mhz....i don't have a crystal for this freq.

I have many normal 4mhz xtals and ceramic resonators

can someone help out with getting the oscillator running at 4.070mhz with 4.00mhz xtals??!!

73

9H1LO





Re: antenna and baluns

 

Ashish,

Let me add that it is common in India to use a plastic coated wire for
dipoles. Use plain enamel wire for your dipole.

Plastic coated wire will be shorter in length than bare wire due to the
dielectric effect of the plastic. This I have noticed varies with aging as
most of the coating is not UV stabilized.

One of my dipoles for 40M is only 28' on one side due to the plastic.
This suited me fine as there was no place to tie the end if it was longer.
You can use this to your advantage but I'd stick with bare copper.

73 Raj

Normally one would just place an insulator in the center of your dipole
and connect a coaxial feedline across the insulator. If the antenna is
resonant on 20 meters the feedline should present a 50 to 75 ohm load to
the transceiver. Try this first before you put a lot of effort into
optimizing your dipole antenna and feedline.

You can make a suitable decoupling type balun by winding the coax into a
10-turn 6 inch (15 cm) diameter coil at the antenna connection point.

Re: Crystal Filter

Arv Evans
 

Stanley

For pulling your 4 MHz resonators up to 4.070, you might want to take a
look at this web page:

<http://www.qsl.net/7n3wvm/expt-vxo.html>

Not sure it will answer your need, but it is a place to read about
another's work in this area.

Arv
_._


Stanley Grixti wrote:


Yes i already change them to 1.1K :-)

The issue is oscillator radiation as I hooked up the spectrum analyser
and the carrier is very very low
The Ft-817 is quite sensitive when close by :) HIHI

OK...it seems to be working FB now I have one hassle....I need to get
the LO to 4.070 if I want to tx on 14.070

I have a couple of 4Mhz ceramic resonators....I have tried with 10 in
parallel !!! and it just gets to 4.068 and with some more capacitor
pulling it arrives to 4.070 but sometimes unreliably and o/p seems to
fall too...it think i'm at the limit

Anyone have any suggestions about pulling the resonators so far?

Farhan, I am also interested in what you mentioned on Solder Smoke about
direct baseband PSK31 transmission. Maybe you could elaborate?

Thanks to all you answered, this sure is a fine group!

73's

Stan 9H1LO

Ashhar Farhan wrote:

hi,

change the feedback resistors from 2.2k to 1K. when the two amps are
used back to back, their feedback resistances show up in parallel to
each other through the 0.1 caps. hence, the effective resistance is
1.05K, 1K resistor will do well.

i think that you might have made a mistake in wiring the SBL-1
properly. usually, it has an excellent carrier suppression. almost
50db in the usual case. check that you have wired it properly and all
the pins that ought to be grounded have been grounded. if you hav
another SBL-1, you can try that too.

- farhan

On Wed, Apr 23, 2008 at 11:51 PM, Greg W:-)
<onegammyleg@... <mailto:onegammyleg%40yahoo.com.au>
<mailto:onegammyleg%40yahoo.com.au>> wrote:






We are certainly very fortunate to have such a good group of
knowledgeable hams in here that are willing to help others.

I would say this is the best group that I have ever been associated
with.

''THANK YOU'' - to all.


gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>
<http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>>

=====================================================================

--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>, Arv
Evans <arvid.evans@...> wrote:
SNIP

They include Farhan,
Raj, Sunil, Dan, Jim, Doug, Allison, Hans, Miguel, Greg, just to
name a
few
SNIP

Arv
--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: VXO

ah6gi
 

--- In BITX20@..., Arv Evans <arvid.evans@...> wrote:

You could always use a conventional VFO but with H&P stabilization for
extreme stability to support digital modes.
Perhaps this is overkill and not quite in the spirit of Homebrew but
here is another option.

<http://www.sseng.com/My_Homepage_Files/Page2.html>

de ah6gi/4

Re: VXO

Arv Evans
 

Stanley

You could always use a conventional VFO but with H&P stabilization for
extreme stability to support digital modes.

<http://downloads.hanssummers.com/sprat122b.pdf>

<http://www.hanssummers.com/radio/huffpuff/library/index.htm>


Using a Huff and Puff stabilized VFO could let you use the rig on other
frequencies and for other than just PSK-31.

Arv
_._


Stanley Grixti wrote:


OK I re-phrase my question

I want to get the bitx20 onto 14.070mhz (PSK31)

The BFO and XTAL Filter are at 10Mhz as per the design

The VXO must then be 4.07mhz....i don't have a crystal for this freq.

I have many normal 4mhz xtals and ceramic resonators

can someone help out with getting the oscillator running at 4.070mhz
with 4.00mhz xtals??!!

73

9H1LO

--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: antenna and baluns

Arv Evans
 

Ashish

Normally one would just place an insulator in the center of your dipole
and connect a coaxial feedline across the insulator. If the antenna is
resonant on 20 meters the feedline should present a 50 to 75 ohm load to
the transceiver. Try this first before you put a lot of effort into
optimizing your dipole antenna and feedline.

You can make a suitable decoupling type balun by winding the coax into a
10-turn 6 inch (15 cm) diameter coil at the antenna connection point.

It is also possible to put a ferrite balun at the antenna connection
point. This can be used as a transformer to match antenna impedance
with feedline impedance, or as lumped decoupling inductance around the
coax to minimize feedline radiation.

Your BITX20 is designed for feeding a 50 ohm load. If you build a
simple impedance bridge and find the antenna is resonant on 20 meters
and it's feed impedance at the transceiver matches 50 ohms, then it
should work.

There is a trick you can use if you know the velocity factor of your
feedline. Make your total feedline an exact multiple of half
wavelengths (calculated using velocity factor) in length, and at the
transmitter end it will mirror the impedance at the antenna connection
point. You can measure feedline velocity factor by using TDR (Time
Domain Reflectometry) methods. Insert a narrow pulse into a known
length of feedline (preferably several wavelengths in length) with the
far end shorted. Using an oscilloscope you can measure the time it
takes for that pulse to be reflected back from the far end. From that
time versus distance measurement you can mathematically determine the
velocity factor of your feedline. Remember that the measured time is
round-trip delay, so you must divide that by 2 to get one-way
transmission delay. Using half wavelength multiples is a trick because
it lets you effectively use feedline that does not match the antenna or
transmitter impedance.

Arv
_._


Ashish wrote:


I nearly completed building my Bitx.Its on a copper clad board.
Now i need an antenna for my bitx.Can any one suggest me an easy to
make dipole antenna?And also how to make it 50 ohm load?Is there any
thing like a balun needed for connecting the antenna to bitx?
Or will the antenna itself be matched to the tranceiver?

--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: A Signal Generator

wbdmxbaileybobbuttercup
 

well, instead of using straws for the inductors, I think I will try
it with toroids.
I am thinking any small fet should work ok, like a bs170. or simular.


- In BITX20@..., Mark Jones <Mark@...> wrote:

Hi All

Nothing fails to amaze me regarding this group; so I now need a
McDonalds and a Subway straw - of a specific size!

Any chance of a rough guess at the actual inductance?

This is indeed fun...

Regards,

Mark.

G0MGX

Arv Evans wrote:

Occasionally one of the surplus electronics dealers will have
very
attractive prices on small trim-pots, individually or as
assortments.
With these you can have almost any weird value resistor you
might need.
They do add a tiny bit more inductance to the circuit, but still
seem to
work quite well.

Arv
_._

Ashhar Farhan wrote:

i am plain lazy here. for years, i have been promising myself
a step
attenuator. the most taxing part is to gather those really
weird
values of resistors. let me check the values in my junk box
now that
you have challenged me .. :)

- farhan

On Thu, Apr 24, 2008 at 10:00 PM, Greg W:-)
<onegammyleg@... <mailto:onegammyleg%40yahoo.com.au>
<mailto:onegammyleg%40yahoo.com.au>> wrote:






Hi Farhan

I was just thinking of making just the same thing Farhan :-)

Only thing that I was going to add was a integrated stepped
attenuator
and also using narrower bands with plug in coils (as seen in
DIP
meters) + also a Xtal osc with external Xtal socket.

Good work..

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>
<http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>>

=====================================================================



--- In BITX20@... <mailto:BITX20%
40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>,
"Ashhar Farhan" <farhan@> wrote:

spurred by OM Wes's comments and experimentation, I
decided to move
from my primitive crystal oscillator as a signal generator
to
brew up
a better one in a PC's power supply box.

I have spent the last one week having fun with it,
measuring
things i
never cared for before (like the resonance frequency of my
14MHz
dipole) as well as what I have been working on at present -
RF
filters
for SSB transceivers.

I have posted the project on my website (I did a bit of
overhaul as
well) on www.phonestack.com/farhan.

- farhan
--
======================================
Web: http://K7HKL.homelinux.net <http://K7HKL.homelinux.net>
http://bitx20a.livejournal.com <http://bitx20a.livejournal.com>
http://home.earthlink.net/~arvevans/
<http://home.earthlink.net/%7Earvevans/>
http://www.geocities.com/k7hkl_arv/
<http://www.geocities.com/k7hkl_arv/>
======================================






VXO

Stanley Grixti
 

OK I re-phrase my question

I want to get the bitx20 onto 14.070mhz (PSK31)

The BFO and XTAL Filter are at 10Mhz as per the design

The VXO must then be 4.07mhz....i don't have a crystal for this freq.

I have many normal 4mhz xtals and ceramic resonators

can someone help out with getting the oscillator running at 4.070mhz with 4.00mhz xtals??!!

73

9H1LO

Re: A Signal Generator

Mark Jones <Mark@...>
 

Hi All

Nothing fails to amaze me regarding this group; so I now need a
McDonalds and a Subway straw - of a specific size!

Any chance of a rough guess at the actual inductance?

This is indeed fun...

Regards,

Mark.

G0MGX

Arv Evans wrote:


Occasionally one of the surplus electronics dealers will have very
attractive prices on small trim-pots, individually or as assortments.
With these you can have almost any weird value resistor you might need.
They do add a tiny bit more inductance to the circuit, but still seem to
work quite well.

Arv
_._

Ashhar Farhan wrote:

i am plain lazy here. for years, i have been promising myself a step
attenuator. the most taxing part is to gather those really weird
values of resistors. let me check the values in my junk box now that
you have challenged me .. :)

- farhan

On Thu, Apr 24, 2008 at 10:00 PM, Greg W:-)
<onegammyleg@... <mailto:onegammyleg%40yahoo.com.au>
<mailto:onegammyleg%40yahoo.com.au>> wrote:






Hi Farhan

I was just thinking of making just the same thing Farhan :-)

Only thing that I was going to add was a integrated stepped attenuator
and also using narrower bands with plug in coils (as seen in DIP
meters) + also a Xtal osc with external Xtal socket.

Good work..

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>
<http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>>

=====================================================================



--- In BITX20@... <mailto:BITX20%40yahoogroups.com>
<mailto:BITX20%40yahoogroups.com>,
"Ashhar Farhan" <farhan@...> wrote:

spurred by OM Wes's comments and experimentation, I decided to move
from my primitive crystal oscillator as a signal generator to
brew up
a better one in a PC's power supply box.

I have spent the last one week having fun with it, measuring
things i
never cared for before (like the resonance frequency of my 14MHz
dipole) as well as what I have been working on at present - RF
filters
for SSB transceivers.

I have posted the project on my website (I did a bit of overhaul as
well) on www.phonestack.com/farhan.

- farhan
--
======================================
Web: http://K7HKL.homelinux.net <http://K7HKL.homelinux.net>
http://bitx20a.livejournal.com <http://bitx20a.livejournal.com>
http://home.earthlink.net/~arvevans/
<http://home.earthlink.net/%7Earvevans/>
http://www.geocities.com/k7hkl_arv/ <http://www.geocities.com/k7hkl_arv/>
======================================



Re: A Signal Generator

Arv Evans
 

Occasionally one of the surplus electronics dealers will have very
attractive prices on small trim-pots, individually or as assortments.
With these you can have almost any weird value resistor you might need.
They do add a tiny bit more inductance to the circuit, but still seem to
work quite well.

Arv
_._


Ashhar Farhan wrote:


i am plain lazy here. for years, i have been promising myself a step
attenuator. the most taxing part is to gather those really weird
values of resistors. let me check the values in my junk box now that
you have challenged me .. :)

- farhan

On Thu, Apr 24, 2008 at 10:00 PM, Greg W:-) <onegammyleg@...
<mailto:onegammyleg%40yahoo.com.au>> wrote:






Hi Farhan

I was just thinking of making just the same thing Farhan :-)

Only thing that I was going to add was a integrated stepped attenuator
and also using narrower bands with plug in coils (as seen in DIP
meters) + also a Xtal osc with external Xtal socket.

Good work..

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM
<http://groups.yahoo.com/group/CB2HAM>

=====================================================================



--- In BITX20@... <mailto:BITX20%40yahoogroups.com>,
"Ashhar Farhan" <farhan@...> wrote:

spurred by OM Wes's comments and experimentation, I decided to move
from my primitive crystal oscillator as a signal generator to brew up
a better one in a PC's power supply box.

I have spent the last one week having fun with it, measuring things i
never cared for before (like the resonance frequency of my 14MHz
dipole) as well as what I have been working on at present - RF filters
for SSB transceivers.

I have posted the project on my website (I did a bit of overhaul as
well) on www.phonestack.com/farhan.

- farhan
--
======================================
Web: http://K7HKL.homelinux.net
http://bitx20a.livejournal.com
http://home.earthlink.net/~arvevans/
http://www.geocities.com/k7hkl_arv/
======================================

Re: A Signal Generator

Ashhar Farhan <farhan@...>
 

i am plain lazy here. for years, i have been promising myself a step
attenuator. the most taxing part is to gather those really weird
values of resistors. let me check the values in my junk box now that
you have challenged me .. :)

- farhan

On Thu, Apr 24, 2008 at 10:00 PM, Greg W:-) <onegammyleg@...> wrote:






Hi Farhan

I was just thinking of making just the same thing Farhan :-)

Only thing that I was going to add was a integrated stepped attenuator
and also using narrower bands with plug in coils (as seen in DIP
meters) + also a Xtal osc with external Xtal socket.

Good work..

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM

=====================================================================



--- In BITX20@..., "Ashhar Farhan" <farhan@...> wrote:
>
> spurred by OM Wes's comments and experimentation, I decided to move
> from my primitive crystal oscillator as a signal generator to brew up
> a better one in a PC's power supply box.
>
> I have spent the last one week having fun with it, measuring things i
> never cared for before (like the resonance frequency of my 14MHz
> dipole) as well as what I have been working on at present - RF filters
> for SSB transceivers.
>
> I have posted the project on my website (I did a bit of overhaul as
> well) on www.phonestack.com/farhan.
>
> - farhan
>

Re: A Signal Generator

Greg W:-) <onegammyleg@...>
 

Hi Farhan

I was just thinking of making just the same thing Farhan :-)

Only thing that I was going to add was a integrated stepped attenuator
and also using narrower bands with plug in coils (as seen in DIP
meters) + also a Xtal osc with external Xtal socket.

Good work..

gregW:-) OH2FFY
http://groups.yahoo.com/group/CB2HAM

=====================================================================

--- In BITX20@..., "Ashhar Farhan" <farhan@...> wrote:

spurred by OM Wes's comments and experimentation, I decided to move
from my primitive crystal oscillator as a signal generator to brew up
a better one in a PC's power supply box.

I have spent the last one week having fun with it, measuring things i
never cared for before (like the resonance frequency of my 14MHz
dipole) as well as what I have been working on at present - RF filters
for SSB transceivers.

I have posted the project on my website (I did a bit of overhaul as
well) on www.phonestack.com/farhan.

- farhan

A Signal Generator

Ashhar Farhan <farhan@...>
 

spurred by OM Wes's comments and experimentation, I decided to move
from my primitive crystal oscillator as a signal generator to brew up
a better one in a PC's power supply box.

I have spent the last one week having fun with it, measuring things i
never cared for before (like the resonance frequency of my 14MHz
dipole) as well as what I have been working on at present - RF filters
for SSB transceivers.

I have posted the project on my website (I did a bit of overhaul as
well) on www.phonestack.com/farhan.

- farhan

Re: Power amp

Allison Parent <kb1gmx@...>
 

--- In BITX20@..., "Ashish" <geniusashish85@...> wrote:

is that power amplifier needed for reception?or can I recieve signals
with out the PA itself?
Yes, you can receive without the power amp.

Allison

Power amp

Ashish
 

is that power amplifier needed for reception?or can I recieve signals
with out the PA itself?