Arv's post says to use a T37-6, but both of mine came with T30-6 cores as seen in the picture. The core on the left is a T37-6 and the core on the right is the one shipped with my BitX40 board. 
Joel? KB6QVI
toggle quoted message
Show quoted text
On Feb 20, 2017, at 11:13 AM, Jerry Gaffke via Groups.Io < jgaffke@...> wrote: Check out Arv's post: ? /g/BITX20/message/19167 On Mon, Feb 20, 2017 at 10:57 am, Tom, SQ9DJE wrote:
Hello, I renew my question in another thread about what the core is the transformer T4.
?
|
Hi Tom,
It's a T30-6 yellow powdered core. Joel? KB6QVI
toggle quoted message
Show quoted text
On Feb 20, 2017, at 10:57 AM, Tom, SQ9DJE < tomasz@...> wrote: Hello, I renew my question in another thread about what the core is the transformer T4. Unfortunately, my BITX40 came damaged T4 was lying horizontally and detached 2 wires, I suspect damage to the core .... I thought it was the core is FT37-43 but this, however, is different .... I can not find anywhere what is the type of core.. best regards Tom
|
Check out Arv's post: ? /g/BITX20/message/19167
On Mon, Feb 20, 2017 at 10:57 am, Tom, SQ9DJE wrote:
Hello, I renew my question in another thread about what the core is the transformer T4.
?
|
If the purpose is to create a carrier for tuning purposes, a much easier to implement solution may be the generation of an audio tone with the Nano, injecting it into the mike input.
For really picky people about a square wave, an LC filter may transform it into a nice sinewave one. That is what Steve KD1JV made for his MBDC design, a very wise solution.
jon, ea2sn
|
Hello, I renew my question in another thread about what the core is the transformer T4. Unfortunately, my BITX40 came damaged T4 was lying horizontally and detached 2 wires, I suspect damage to the core .... I thought it was the core is FT37-43 but this, however, is different .... I can not find anywhere what is the type of core.. best regards Tom
|
Thanks for posting Allison's info over here Jack. Based on this info and the other thread on this message board I tried the 19MHz VFO approach yesterday. I can report that it was very effective.?For reference, my?Bitx is scratch built with termination insensitive amps but overall it follows the latest Bitx40 architecture. I am using the Adafruit SI5351 board to generate VFO and BFO signals. The rig has been a blast to operate?and the only non-ideal behavior?occured in the evening as?I was hearing CW and SW broadcasts in the phone band. It wasn't terrible, just enough to be a little annoying. The biggest offender was a?station in SC on 7.385 and a quick check of the numbers pointed to the 4th harmonic problem. When I changed the VFO to 19MHz and moved the BFO to the other side of my IF filter I initially had poor carrier supression and a hollow sounding receiver. Adjusting the BFO down a little more took care of both problems?as expected. Last night I did not hear any SW stations in band that weren't also heard on my reference Kenwood. The big station from SC was booming in on 7.385 but not heard at all in our 40M band. I'm hopeful that the problem is solved. A few more nights of listening?should prove or disprove that. I did not have the 7200 birdie with my VFO at 4.8MHz but I do have it now. That doesn't bother me though as I kind of avoid that frequency anyway.
|
So, what does this mean to the rest of us? "The mixers using 1N914/4148 diodes are not level 7 mixers (nominal 7dbm drive) like commercial DBMs.
the reason for this is Schottky diodes have a lower turn on threshold than silicon junction diodes with the difference being .2V compared to .65V. This means you need more LO drive for the terminal impedance
of all ports to be 50 ohms. It also means they are higher level mixers by about 3db. So enough drive is important to intermod and overload." - Allison Is this the part where Tom W5KUB "solved" the low TX power problem with taking the SMD dual diode off and replaced it with two regular diodes? It did seem to make a small difference. But not with the 1N60. Only after changing it again with 1N4148. Is this what she is talking about here? I am not an engineer. So, is it saying lower turn on threshold helps driving the PA? Or is it higher?
|
Yup. ?When operating the VFO down around 5mhz we get images of SW Broadcasters from the 4'th harmonic of the vfo, as first explained by PA4Q in post 21996. ?As you suggest, 7.2mhz gets received twice, once as LSB and once as USB. As a separate issue explained in post 21941, we get a birdie at 7.2mhz from the 5'th harmonic of the 4.8mhz vfo beating with the 2'd harmonic of the 12mhz BFO. The above two have both been complained about mightily over the last month or so. We can avoid both if we move the VFO up to the high side as per your recommendation. ?However, as noted in post 22005, the 8'th harmonic of the bfo can beat with the 5'th harmonic of the vfo, giving us a birdie at 7.2mhz. ? ?(Likely faint if there at all, and shielding the bfo/demodulator should kill it.) Conclusion: ?7200000 is an extremely inauspicious number for this radio.? Jerry, KE7ER
On Mon, Feb 20, 2017 at 07:09 am, <ajp166@...> wrote: The likely problem is interaction between the BFO and the LO causing a result at 7.2 when tuned to 7.2. ?
|
Using the digital chip for the bfo sounds like the answer but I know nothing about programming the Arduino and the digital chip so I'll have to wait until someone smarter decides to tackle it! ?:-))
Roy WA0YMH
On Feb 20, 2017 9:39 AM, "Jerry Gaffke via Groups.Io" <jgaffke= [email protected]> wrote: Will work fine if you move the BFO a khz over into the crystal filter passband.? Trivial if the BFO is driven from a second channel of the Si5351, and gives us a better option for USB/LSB switching as well.? If you insist on analog, perhaps a varactor diode in the BFO as used on the analog vfo. See post?/g/BITX20/message/20933 Still no Bitx40 here though.
On Mon, Feb 20, 2017 at 06:59 am, Roy Appleton wrote:
So that means that unbalancing the mixer will never be a legitimate way to introduce a carrier for tuning purposes?
? On Feb 19, 2017 10:37 PM, "Ashhar Farhan" < farhanbox@...> wrote: The center tap that takes the audio from the mic. A caveat though, the carrier is on the skirt rather than in the center of the filter.
?
|
Will work fine if you move the BFO a khz over into the crystal filter passband. ?Trivial if the BFO is driven from a second channel of the Si5351, and gives us a better option for USB/LSB switching as well. ?If you insist on analog, perhaps a varactor diode in the BFO as used on the analog vfo. See post?/g/BITX20/message/20933 Still no Bitx40 here though.
On Mon, Feb 20, 2017 at 06:59 am, Roy Appleton wrote: So that means that unbalancing the mixer will never be a legitimate way to introduce a carrier for tuning purposes?
? On Feb 19, 2017 10:37 PM, "Ashhar Farhan" < farhanbox@...> wrote: The center tap that takes the audio from the mic. A caveat though, the carrier is on the skirt rather than in the center of the filter.
?
|
The likely problem is interaction between the BFO and the LO causing a result at 7.2 when tuned to 7.2. I used a SI70 and a crystal osc based on a spare crystal from builidng the filter for the BFO so I could isolate them and it was not an issue. ? Note I tried an actual 19mhz VFO and it worked fairly well but required really good construction to be stable. ?FYI there were/are commercial radio that use high VFOs namely Tentec Argonaut 505 and Atlas 180/210/215 and with good construction and temperature compensation I can say they work as I have both. ?It does take some effort and I've built a VFO at 14mhz that was very stable but mechanically involved.
That brings up a possible issue. ?Long wires connecting things and shielding of stray signals. ?Care is required there as the NCO can and will radiate is the wires are somewhat random.
--
Allison/KB1GMX
|
Re: Need help with constant tone in audio output
try large capasitor ie ?50uf ?25 volt working ? ? across power supply.............
On Monday, 20 February 2017, 13:51, Raj vu2zap <vu2zap@...> wrote:
FIrst I am suspecting the power supply.
Second disconnect the volume plug and see, I would suspect the tone will
be there if the PS is at fault.
Third If the tone stops then suspect the preamp transistor or
earlier.
As you said you have disconnected the rest.
Raj
At 20/02/2017, you wrote:
Good morning Jerry and the
group,
Had to stop last night, having probed for nearly 10 hours. Jerry, my
trouble shooting is hampered by not having an up-to-date schematic. My
board is a Bitx40 V3. It's interesting to note that when I power the '40
up the tone is immediate and the rcvr comes on about a second later. I
have all the components taken out of the '40 except the volume control...
still the tone. I wonder if India could replace the board given the
amount of time spent trying to get it working? I'll continue to trouble
shoot today and will keep you and the group updated. BTW, the tone
encountered is not a clicking noise.
73,
Chuck K3VPZ
From: "Jerry Gaffke via Groups.Io"
<jgaffke@...>
To: [email protected]
Sent: Sunday, February 19, 2017 4:59:53 PM
Subject: Re: [BITX20] Need help with constant tone in audio
output
Did you enable the analog vfo by adding L4?
If the tone is still there with no vfo, that's a hint
On Sun, Feb 19, 2017 at 01:07 pm, <chucke2@...> wrote:
- Have disconnected the Raduino, tone still there.
?
|
So that means that unbalancing the mixer will never be a legitimate way to introduce a carrier for tuning purposes?
Roy WA0YMH
On Feb 19, 2017 10:37 PM, "Ashhar Farhan" < farhanbox@...> wrote: The center tap that takes the audio from the mic. A caveat though, the carrier is on the skirt rather than in the center of the filter. - f
|
I also have that case, too, but I'm adding a Muppet board and there wasn't enough room for both in the Banggood case. It is, however, a very nice case.
Jack, W8TEE
From: Buck <RadioK4ia@...>
To: [email protected]
Sent: Monday, February 20, 2017 9:26 AM
Subject: Re: [BITX20] Calibration
A similar case is on Banggood but check the dimensions. Buck, k4ia Honor Roll 8BDXCC On 2/20/2017 9:13 AM, Jack Purdum via Groups.Io wrote: > I was looking for the order, but can't find it. The supplier was Allied > Electronics and the case was: > > > > They have a bazillion cases. If I can confirm the order, I'll post it to > the group. > > Jack, W8TEE > > > ------------------------------------------------------------------------ > *From:* Leo de Blaauw < L.deblaauw@...> > *To:* [email protected]> *Sent:* Monday, February 20, 2017 1:45 AM > *Subject:* Re: [BITX20] Calibration > > Hi Jack, > > Slightly off-topic, but may I ask what enclosure you are using ? > > regards and 73 > Leo de Blaauw - PD1LDB > >
|
A similar case is on Banggood but check the dimensions.
Buck, k4ia
Honor Roll
8BDXCC
toggle quoted message
Show quoted text
On 2/20/2017 9:13 AM, Jack Purdum via Groups.Io wrote: I was looking for the order, but can't find it. The supplier was Allied
Electronics and the case was:
They have a bazillion cases. If I can confirm the order, I'll post it to
the group.
Jack, W8TEE
------------------------------------------------------------------------
*From:* Leo de Blaauw <L.deblaauw@...>
*To:* [email protected]
*Sent:* Monday, February 20, 2017 1:45 AM
*Subject:* Re: [BITX20] Calibration
Hi Jack,
Slightly off-topic, but may I ask what enclosure you are using ?
regards and 73
Leo de Blaauw - PD1LDB
|
Re: Need help with constant tone in audio output
Good morning Larry,
Success! Using a battery cleared up the tone. Now on to packing it up in its enclosure. Many thanks to all for helping including Jerry!
73, Chuck K3VPZ
From: "Larry Acklin" <acklin@...> To: [email protected]Sent: Monday, February 20, 2017 8:30:31 AM Subject: Re: [BITX20] Need help with constant tone in audio output
Try a battery supply.? My shack supply does not play nice with the BitX.? A small wall wart 2A, 12V is silent.? I get tone with the shack PS.
Larry KB3CUF
|
I was looking for the order, but can't find it. The supplier was Allied Electronics and the case was:?
They have a bazillion cases. If I can confirm the order, I'll post it to the group.
Jack, W8TEE
From: Leo de Blaauw <L.deblaauw@...>
To: [email protected]
Sent: Monday, February 20, 2017 1:45 AM
Subject: Re: [BITX20] Calibration
Hi Jack,
Slightly off-topic, but may I ask what enclosure you are using ?
regards and 73 Leo de Blaauw - PD1LDB
|
Re: Need help with constant tone in audio output
FIrst I am suspecting the power supply.
Second disconnect the volume plug and see, I would suspect the tone will
be there if the PS is at fault.
Third If the tone stops then suspect the preamp transistor or
earlier.
As you said you have disconnected the rest.
Raj
At 20/02/2017, you wrote:
toggle quoted message
Show quoted text
Good morning Jerry and the
group,
Had to stop last night, having probed for nearly 10 hours. Jerry, my
trouble shooting is hampered by not having an up-to-date schematic. My
board is a Bitx40 V3. It's interesting to note that when I power the '40
up the tone is immediate and the rcvr comes on about a second later. I
have all the components taken out of the '40 except the volume control...
still the tone. I wonder if India could replace the board given the
amount of time spent trying to get it working? I'll continue to trouble
shoot today and will keep you and the group updated. BTW, the tone
encountered is not a clicking noise.
73,
Chuck K3VPZ
From: "Jerry Gaffke via Groups.Io"
<jgaffke@...>
To: [email protected]
Sent: Sunday, February 19, 2017 4:59:53 PM
Subject: Re: [BITX20] Need help with constant tone in audio
output
Did you enable the analog vfo by adding L4?
If the tone is still there with no vfo, that's a hint
On Sun, Feb 19, 2017 at 01:07 pm, <chucke2@...> wrote:
- Have disconnected the Raduino, tone still there.
?
|
Re: Need help with constant tone in audio output
Try a battery supply.? My shack supply does not play nice with the BitX.? A small wall wart 2A, 12V is silent.? I get tone with the shack PS.
Larry KB3CUF
On Mon, Feb 20, 2017 at 8:01 AM, Chuck <chucke2@...> wrote: Good morning Jerry and the group,
Had to stop last night, having probed for nearly 10 hours. Jerry, my trouble shooting is hampered by not having an up-to-date schematic. My board is a Bitx40 V3. It's interesting to note that when I power the '40 up the tone is immediate and the rcvr comes on about a second later. I have all the components taken out of the '40 except the volume control... still the tone. I wonder if India could replace the board given the amount of time spent trying to get it working? I'll continue to trouble shoot today and will keep you and the group updated. BTW, the tone encountered is not a clicking noise.
73, Chuck K3VPZ
From: "Jerry Gaffke via Groups.Io" <jgaffke= [email protected]> To: [email protected]Sent: Sunday, February 19, 2017 4:59:53 PM Subject: Re: [BITX20] Need help with constant tone in audio output
Did you enable the analog vfo by adding L4? If the tone is still there with no vfo, that's a hint
On Sun, Feb 19, 2017 at 01:07 pm, <chucke2@...> wrote:
Have disconnected the Raduino, tone still there. ?
|
Re: Need help with constant tone in audio output
Good morning Jerry and the group,
Had to stop last night, having probed for nearly 10 hours. Jerry, my trouble shooting is hampered by not having an up-to-date schematic. My board is a Bitx40 V3. It's interesting to note that when I power the '40 up the tone is immediate and the rcvr comes on about a second later. I have all the components taken out of the '40 except the volume control... still the tone. I wonder if India could replace the board given the amount of time spent trying to get it working? I'll continue to trouble shoot today and will keep you and the group updated. BTW, the tone encountered is not a clicking noise.
73, Chuck K3VPZ
From: "Jerry Gaffke via Groups.Io" <jgaffke@...> To: [email protected]Sent: Sunday, February 19, 2017 4:59:53 PM Subject: Re: [BITX20] Need help with constant tone in audio output
Did you enable the analog vfo by adding L4? If the tone is still there with no vfo, that's a hint
On Sun, Feb 19, 2017 at 01:07 pm, <chucke2@...> wrote:
Have disconnected the Raduino, tone still there. ?
|
Joel Caulkins/N6ALT
Raj vu2zap