¿ªÔÆÌåÓý

  1. BITX20
  2. Messages
Expanded Topics Messages Polls
Date
Receiver comparison

 

After my initial troubles with a broken L2, the BITX40 is hearing well and making some surprising contacts. Here's a little comparison video of the received audio from the BITX, the FT-817, and the FT-450D.



Kent
W9WB?
Ideally, with the stock kit

 

Ideally with the stock lm386 & with an 8 ohm loudspeaker, for good intelegebility, how many watts would be best? Also, though a mic element is already supplied, what would be the ideal impedance for a microphone element??

Tnx

Jerry AA1OF/6
Re: 100k 10 turn Pot

 

Got it, thank you. I couldn't find the pot wiring on the schematic showing the wiper.

73

Tom
Re: It stopped transmitting

 

Sometimes, I use IC base for those relays...

'Repair & Reuse or Recycle E-Waste'
Re: It stopped transmitting

Bill Kittilson
 

¿ªÔÆÌåÓý

Ok relay is working then.?

On Jan 1, 2017, at 1:09 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

?

that's not how it is wired. refer to the circuit on? to see the pins, they are numbered like a 16 pin dip IC.

- f

On Sun, Jan 1, 2017 at 11:22 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I have no conductivity between the outside pins and middle ones. when the button is pushed. When release I do have conductivity between the center pins and inner pins. I hear the relay clicking. ?
Looks like the relay contacts went bad??

I order a replacement relay.?

On Jan 1, 2017, at 12:33 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

?

disconnect the PA power line. Push the PTT and check if the transmit relay is switching. measure the connectivity with a VOM. copy?

- f

On Sun, Jan 1, 2017 at 8:04 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I can hear the bitx on a near by receiver.? The coils look fine. The 510 gets hot on transmit.? I hear the relay but it don't sound quite right. I order the replacement relays. I hope it's the simple.? Thanks. I'll update you when i get the replacement. ?

Thanks.?

On Jan 1, 2017, at 1:56 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:

?

Bill,

Check L6 and L7 and see if it is making contact with the solder on the board.

Check the relay K2, I seriously suspect that it could be faulty. Take the output from K2 pin 16 and ground to a (bnc) connector and check the TX out there with a power meter. If there is normal output then relay is suspect.. or not operating. When you
press PTT the relay should click, you should feel that with your finger. I have seen a lot of similar relays fail in my service
experience.

Cood luck and Happy new year!
Raj vu2zap

At 31/12/2016, Bill Kittilson bill@... [BITX20] wrote:
>
>
>I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.
>
>Any idea what to look at next?
Re: It stopped transmitting

 

that's not how it is wired. refer to the circuit on? to see the pins, they are numbered like a 16 pin dip IC.

- f

On Sun, Jan 1, 2017 at 11:22 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I have no conductivity between the outside pins and middle ones. when the button is pushed. When release I do have conductivity between the center pins and inner pins. I hear the relay clicking. ?
Looks like the relay contacts went bad??

I order a replacement relay.?

On Jan 1, 2017, at 12:33 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

?

disconnect the PA power line. Push the PTT and check if the transmit relay is switching. measure the connectivity with a VOM. copy?

- f

On Sun, Jan 1, 2017 at 8:04 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I can hear the bitx on a near by receiver.? The coils look fine. The 510 gets hot on transmit.? I hear the relay but it don't sound quite right. I order the replacement relays. I hope it's the simple.? Thanks. I'll update you when i get the replacement. ?

Thanks.?

On Jan 1, 2017, at 1:56 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:

?

Bill,

Check L6 and L7 and see if it is making contact with the solder on the board.

Check the relay K2, I seriously suspect that it could be faulty. Take the output from K2 pin 16 and ground to a (bnc) connector and check the TX out there with a power meter. If there is normal output then relay is suspect.. or not operating. When you
press PTT the relay should click, you should feel that with your finger. I have seen a lot of similar relays fail in my service
experience.

Cood luck and Happy new year!
Raj vu2zap

At 31/12/2016, Bill Kittilson bill@... [BITX20] wrote:
>
>
>I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.
>
>Any idea what to look at next?
Re: It stopped transmitting

Bill Kittilson
 

¿ªÔÆÌåÓý

I have no conductivity between the outside pins and middle ones. when the button is pushed. When release I do have conductivity between the center pins and inner pins. I hear the relay clicking. ?
Looks like the relay contacts went bad??

I order a replacement relay.?

On Jan 1, 2017, at 12:33 PM, Ashhar Farhan farhanbox@... [BITX20] <BITX20@...> wrote:

?

disconnect the PA power line. Push the PTT and check if the transmit relay is switching. measure the connectivity with a VOM. copy?

- f

On Sun, Jan 1, 2017 at 8:04 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I can hear the bitx on a near by receiver.? The coils look fine. The 510 gets hot on transmit.? I hear the relay but it don't sound quite right. I order the replacement relays. I hope it's the simple.? Thanks. I'll update you when i get the replacement. ?

Thanks.?

On Jan 1, 2017, at 1:56 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:

?

Bill,

Check L6 and L7 and see if it is making contact with the solder on the board.

Check the relay K2, I seriously suspect that it could be faulty. Take the output from K2 pin 16 and ground to a (bnc) connector and check the TX out there with a power meter. If there is normal output then relay is suspect.. or not operating. When you
press PTT the relay should click, you should feel that with your finger. I have seen a lot of similar relays fail in my service
experience.

Cood luck and Happy new year!
Raj vu2zap

At 31/12/2016, Bill Kittilson bill@... [BITX20] wrote:
>
>
>I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.
>
>Any idea what to look at next?
Re: Sad reality of stock vfo

 

In the rush to digital signal sources, it seems that we are forgetting that there are other possible
ways to correct VFO drift.
  • A few have changed the on-board chip capacitors to leaded polystyrene types and report
    good stability.

  • It is possible to build a very stable external VFO and connect this as one would do with
    a digital source.

  • Huff-and-Puff technology might be useful as a way to minimize VFO drift, whether the VFO
    is internal or external.

  • FLL (Frequency Locked Loop) technique is interesting, especially if you have built a frequency
    counter as the digital dial.? The same counter might be employed to hold to stable frequency
    settings.

Arv? K7HKL

_._



On Sat, Dec 31, 2016 at 8:12 PM, Thomas Noel tnoel@... [BITX20] <BITX20@...> wrote:
?

I knowingly and with full understanding of the expected consequences built out my Bitx40 fully stock. Analog VFO, original resistors etc.


All alignment went just as described in manual, and everything works just as advertised. The receiver is quite sensitive, and even without AGC it is easy to operate weak and strong stations. I have about 220kc of tuning range from 7.070 to 7.290.

The challenge is the VFO drift - even though I leave the set on all the time with volume turned down to silent, the drift is so severe that I must re-tune at least every 10-15 seconds during an attempted QSO or I drift so far off frequency that when I un-key - the other station is often gone, moved out of my passband. Never dreamed the drift would be this bad.

I have the replacement resistors for the VFO, and that will be next. I may try some of the other suggested changes just to further my own learning experience with this simple and elegant design.

But I have also ordered the DDS VFO parts!


Thomas W Noel
KF7RSF


Re: It stopped transmitting

 

disconnect the PA power line. Push the PTT and check if the transmit relay is switching. measure the connectivity with a VOM. copy?

- f

On Sun, Jan 1, 2017 at 8:04 PM, Bill Kittilson bill@... [BITX20] <BITX20@...> wrote:
?

I can hear the bitx on a near by receiver.? The coils look fine. The 510 gets hot on transmit.? I hear the relay but it don't sound quite right. I order the replacement relays. I hope it's the simple.? Thanks. I'll update you when i get the replacement. ?

Thanks.?

On Jan 1, 2017, at 1:56 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:

?

Bill,

Check L6 and L7 and see if it is making contact with the solder on the board.

Check the relay K2, I seriously suspect that it could be faulty. Take the output from K2 pin 16 and ground to a (bnc) connector and check the TX out there with a power meter. If there is normal output then relay is suspect.. or not operating. When you
press PTT the relay should click, you should feel that with your finger. I have seen a lot of similar relays fail in my service
experience.

Cood luck and Happy new year!
Raj vu2zap

At 31/12/2016, Bill Kittilson bill@... [BITX20] wrote:
>
>
>I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.
>
>Any idea what to look at next?
Re: Sad reality of stock vfo

 

I'm sorry Thomas,

In my New Years festive mood I misread your first post and thought you were talking about an earlier design- not the new Bitx40 smd version. Farhan is, of course, the expert and he knows the ins and out completely. Heat seems to be the usual suspect and perhaps NPO caps might be some benefit but ultimately a digital VFO may be the answer you're looking for.
Unless! you want to take a detour and take a huff and puff circuit for a spin. :)

John
KC9OJV


From: "Thomas Noel tnoel@... [BITX20]"
To: BITX20@...
Sent: Saturday, December 31, 2016 10:14 PM
Subject: Re: [BITX20] Sad reality of stock vfo

?
John,

As I said - I knew from others¡¯ experience that the stock design has some significant limitations. I just had no previous personal experience with such builds. I have read of quite a few design mods that offer improvement. The design is simple and easy to mod as Farhan intended. I built the stock design as a starting place for learning.?

I was surprised to see the drift so severe that it is hard to hold frequency during an ¡°over¡±. I have made more than a dozen QSOs in less than two hours of operation. The operator on the other end even commented that I was drifting off frequency.

I would like to continue to experiment with the all-analog radio before moving to the DDS VFO.

Where exactly would you start? Replace the resistors as suggested by Farhan? They were included with my purchase. Which capacitors would you replace to stabilize the VFO, and change just the type, or change any of the values? My tuning range is just where I would want it now.

If anyone can give me a step-by-step attack plan in order of best anticipated return on effort, I would appreciate it a lot.

Thomas W Noel
KF7RSF

On Dec 31, 2016, at 7:28 PM, John Greusel greusel@... [BITX20] <BITX20@...> wrote:


Thomas,
That's not optimal behavior for that sort of design. It can do much better than that. I think you should revisit the traditional solutions for such problems and them implement them before moving on- NPO and styrene capacitors might be a start.

John
KC9OJV
Re: Complaints About Shipping

 

Jeez dude, take a chill pill! Don't like them don't read them!

Roy
WA0YMH

On Jan 1, 2017 8:56 AM, "kg4rul@... [BITX20]" <BITX20@...> wrote:
?

Can we PLEASE NOT POST about shipping schedules, etc.!!!!!? HF Signals is the one shipping your products NOT THIS GROUP!!!? We can't do anything to help you!!!? All you are doing is wasting our time and a lot of bandwidth.


TNX


Dennis KG4RUL
Complaints About Shipping

 

Can we PLEASE NOT POST about shipping schedules, etc.!!!!! ?HF Signals is the one shipping your products NOT THIS GROUP!!! ?We can't do anything to help you!!! ?All you are doing is wasting our time and a lot of bandwidth.


TNX


Dennis KG4RUL
Re: It stopped transmitting

Bill Kittilson
 

¿ªÔÆÌåÓý

I can hear the bitx on a near by receiver. ?The coils look fine. The 510 gets hot on transmit. ?I hear the relay but it don't sound quite right. I order the replacement relays. I hope it's the simple. ?Thanks. I'll update you when i get the replacement. ?

Thanks.?

On Jan 1, 2017, at 1:56 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:

?

Bill,

Check L6 and L7 and see if it is making contact with the solder on the board.

Check the relay K2, I seriously suspect that it could be faulty. Take the output from K2 pin 16 and ground to a (bnc) connector and check the TX out there with a power meter. If there is normal output then relay is suspect.. or not operating. When you
press PTT the relay should click, you should feel that with your finger. I have seen a lot of similar relays fail in my service
experience.

Cood luck and Happy new year!
Raj vu2zap

At 31/12/2016, Bill Kittilson bill@... [BITX20] wrote:
>
>
>I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.
>
>Any idea what to look at next?
Re: Sad reality of stock vfo

 

quote =======

The challenge is the VFO drift - even though I leave the set on all the time with volume turned down to silent, the drift is so severe that I must re-tune at least every 10-15 seconds during an attempted QSO or I drift so far off frequency that when I un-key - the other station is often gone, moved out of my passband. Never dreamed the drift would be this bad.

unquote =====

It might be prudent to add a so called? "Huff and Puff" vfo stabiliser,
originally made and published by PA0KSB , SK?? and later simplified by Hans Summers ,G0UPL , probably on his web site.

Frank , GM0CSZ / KN6WH?????? in IO87AT
??

On Sun, Jan 1, 2017 at 3:12 AM, Thomas Noel tnoel@... [BITX20] <BITX20@...> wrote:
?

I knowingly and with full understanding of the expected consequences built out my Bitx40 fully stock. Analog VFO, original resistors etc.


All alignment went just as described in manual, and everything works just as advertised. The receiver is quite sensitive, and even without AGC it is easy to operate weak and strong stations. I have about 220kc of tuning range from 7.070 to 7.290.

The challenge is the VFO drift - even though I leave the set on all the time with volume turned down to silent, the drift is so severe that I must re-tune at least every 10-15 seconds during an attempted QSO or I drift so far off frequency that when I un-key - the other station is often gone, moved out of my passband. Never dreamed the drift would be this bad.

I have the replacement resistors for the VFO, and that will be next. I may try some of the other suggested changes just to further my own learning experience with this simple and elegant design.

But I have also ordered the DDS VFO parts!


Thomas W Noel
KF7RSF


Re: No tracking info

 

¿ªÔÆÌåÓý

I just got a shipping notice from PayPal. I ordered my BITX40 on 24/12/16. Also got initial tracking info from IndiaPost. Look forward to receiving it in about 2-3 weeks!

73's from Sydney

Carl VK2XSM


Sent from my iPad

On 1 Jan 2017, at 12:41, Thomas Noel tnoel@... [BITX20] <BITX20@...> wrote:

?

My experience was the same as most - I got initial tracking info from IndiaPost, but never heard again until it was on my doorstep.


Have Faith!

Tom
kf7rsf

On Dec 31, 2016, at 4:19 PM, donfrasher@... [BITX20] <BITX20@...> wrote:


I placed my order on 12-23, and I did get a tracking # via paypal. ?However, even if I enter it directly at Indiapost, google , or elswhere, I get no info received.

? ?Has anyone else had better luck?? ?or have they not actually shipped them yet?


73

Don Frasher AD7LL
Re: Sad reality of stock vfo

Rahul Srivastava
 

Hi ,

Can try putting a couple of 4148 on either side of tuning pot depending upon the direction to provide some compensation for thermal drift.

Rahul VU3WJM


On Sun, Jan 1, 2017 at 1:17 PM, Ashhar Farhan farhanbox@... [BITX20]
wrote:
?


raj,

the varactors have a bad temperature coefficient. they contribute too.

- f

On Sun, Jan 1, 2017 at 11:52 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:
?
NP0 capacitors for C94 95 96 WILL tackle the heat problem Farhan!

Happy new year!
Raj

>2. The culprit is heat. The RF amplifiers have significant current, there are three of them. The heat dissipates through the ground plane and heats up the VFO components. This heat would be missing if we used through hole components as those components are off the board.
Repairing a Bitx40 transmitter fault (video)

 

A friend had a mishap with a Bitx40 that left it receiving fine but not transmitting.?

It turned out to be Q13.?


Here's how we fixed it ?




73, Peter VK3YE
Re: Bitx40 BFO

 

Doesn't need to move that far. ?Typically it only needs to be shifted approx 6 kHz to the other side of the crystal filter's bandpass.?

Eg LSB (as it is now) requires the filter's bandpass to be below the carrier crystal frequency. ?

USB requires the filter's bandpass to be above the carrier crystal frequency.?

Since it's easier to change the frequency of a single carrier crystal rather than the centre frequency of a ladder crystal filter that's what we do.?

So to get USB we need to move the carrier crystal DOWN by approx 6kHz. ?Fortunately shifting a 12 MHz crystal down this amount is fairly easy and you won't necessarily need a crystal of another frequency. ?You just put inductance in series with it to provide a VXO. ?Adding a second crystal in parallel makes shifting down easier but is probably not required. ?

73, Peter VK3YE
Re: Sad reality of stock vfo

 

raj,

the varactors have a bad temperature coefficient. they contribute too.

- f

On Sun, Jan 1, 2017 at 11:52 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:
?

NP0 capacitors for C94 95 96 WILL tackle the heat problem Farhan!

Happy new year!
Raj

>2. The culprit is heat. The RF amplifiers have significant current, there are three of them. The heat dissipates through the ground plane and heats up the VFO components. This heat would be missing if we used through hole components as those components are off the board.
Re: It stopped transmitting

 

John,

Check if you have correct voltage at the TX and RX points. They come from relay K1 - it could be faulty or not operating.

Good luck and Happy new year!
Raj vu2zap

At 31/12/2016, you wrote:

?

Bill - I believe I did the same thing to my BITX40 as, now when I flip the switch to transmit, it stays in the receive mode, but the frequency shifts slightly. No sure if the relay switches or if I blew the PA final. Receiver is fine, like your receive. I thought I may have left the radio in transmit mode when I switched off the volume control pot overnight? (as I had planned to keep the radio powered on) but now believe that the issue may have resulted from using my TS-480 in transmit to locate my BITX40 frequency. Have been hoping to see Farahan's "troubleshooting the BITX40 transmitter" YouTube video, but I guess it still is "in production." If you receive any feedback on correcting your transmit side issues of the BITX40 could you please share this information with me? I ordered the IFR510 and 2n2219a from W8DIZ, but I hope to identify the issue before replacing the parts, if their replacement is even required. 73? and tks. W4USF - John - Lutz, FL.

Sent from my iPhone

On Dec 31, 2016, at 07:07, Bill Kittilson bill@... [BITX20] <BITX20@... > wrote:

?

I managed to kill my bitx40. It was working great until I decided to tune up the big rig. I can still receive. No power at all on transmit. I replace the 510 transistor. Sill no output. The current does jump up to over 1 amp when I switch to transmit.

Any idea what to look at next?
96521 - 96540 of 116131