?

What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?

Tom

KF7RSF

Sent from my iPhone

On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:

?

I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
Any ideas on the drift?
Other than that , I'm very happy with the board and look forward to building onto it in the near future.
Thanks
Mark. K3MRK

?

I only received the 220 ohm resistors on my second order.? Does someone have six that they would sell me so I could complete the first rig??

Thanks

Bill

---

From: BITX20@... <BITX20@...> on behalf of Ashhar Farhan farhanbox@... [BITX20] <BITX20@...>
Sent: Thursday, November 24, 2016 8:47 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.

?

?

mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f

On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote:

>

> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote:

>>

>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>>

>>> ?

>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>

?

No I did not receive any resistors. What size are they? I’ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct?

I have received my enclosure and am almost done installing.

Mark

K3MRK

?

?

From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, November 24, 2016 8:48 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.

?

?

mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f

On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote:

>?

> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote:

>>?

>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>>

>>> ?

>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>

?

Mark. K3MRK

Either 10K or 100K, or anything in between, will work fine for the

tuning pot.? A 10-turn type pot makes tuning much easier if you

have one available.?

Resistors for decreasing heat generation are 220 ohms.

Arv? K7HKL
_._

On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote:

?

No I did not receive any resistors. What size are they? I’ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct?

I have received my enclosure and am almost done installing.

Mark

K3MRK

?

?

From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, November 24, 2016 8:48 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.

?

?

mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f

On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote:

>?

> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote:

>>?

>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>>

>>> ?

>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>

?

--- wrote :

We starting including the resistors after the reports of the drift. the pads are big enough for you to solder regular 1/4 watt in place of wthe smd resistors (in manhattan style). if you do really want them, drop a mail to and they will post a 'pinch' of them to you for free, though the cost of postage is prohibitive but they have agreed to bear it.? - f

That is indeed very generous, but I hope no North American or European takes advantage of the offer. 1/4 watt resistors are ***far too easy*** to come by on both continents for any sense to be made of sending a "pinch" of them all the way from India! Moreover, it's my understanding that this effort by RF Signals is part of a community fund-raising and money *earning* (as opposed to money *making*) project. That was one of my reasons for buying one of the boards. I'd like to see as much of that money stay in India as possible.

I think there's another issue involved here that bears some thought and discussion. So the BitX40 VFO has some drift? BFD (Big Fat Deal)! I hope I never get to the point either physically or psychologically when having to touch a VFO knob to sharpen the tuning up a bit now and then becomes burdensome or somehow unacceptable. And God forbid I would ever become such a jerk as to mar an otherwise pleasant QSO by pointing out to the other guy--more often than not a total stranger--that he's drifting (or exhibiting some other meaningless "flaw" in his signal) unless I'm **asked** for a detailed signal report.

This ongoing inflation of features and expectations needs some serious reconsideration, reflection, and soul searching. It's made possible by **store-bought** DDS and SDR technology, along with all the feature bloat that goes along with much of it: waterfalls and spectral displays and other means of finding fault with the other-guys transmission.

Sure, lower the bias current by putting in 220 ohm resistors to minimize heating. Take any other reasonable route to maximize the VFO's stablility. Figuring all that out is part of the fun. But if you can't get around to any of that, stick an antenna on the thing and get on the air anyway! If you end up offending the spectrum police, too bad for them!

73,

Todd K7TFC ?

?

Thanks Arv,

Are they SMD resistors? If so, what size are they? Physical size. I don’t work with SMD enough to tell by looking.

I have a multiturn pot on the way. My tuning is super touchy. It takes quite a while to tune a signal in correctly. I literally have to tap the shaft to fine tune.

Thanks for the info

Mark

K3MRK

?

?

From: BITX20@... [mailto:BITX20@...]
Sent: Saturday, November 26, 2016 11:24 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.

?

?

Mark. K3MRK

Either 10K or 100K, or anything in between, will work fine for the

tuning pot.? A 10-turn type pot makes tuning much easier if you

have one available.?

?

Resistors for decreasing heat generation are 220 ohms.

Arv? K7HKL
_._

?

On Sat, Nov 26, 2016 at 8:56 PM, 'Mark W' k3mrk1@... [BITX20] <BITX20@...> wrote:

?

No I did not receive any resistors. What size are they? I’ll try to find some. I also noticed that my tuning pot is 10k. The board info on the website says it should be 100k. Which is correct?

I have received my enclosure and am almost done installing.

Mark

K3MRK

?

?

From: BITX20@... [mailto:BITX20@...]
Sent: Thursday, November 24, 2016 8:48 PM
To: BITX20@...
Subject: Re: [BITX20] Bitx 40 board.

?

?

mark,
you must have received a strip of 220 ohm resistors in the pack. if you replace the 100 ohm emitter resistors of the six amps with these, the drift will drastically reduce. the details are on the blog.
- f

On 25-Nov-2016 4:58 am, "Mark Walton k3mrk1@... [BITX20]" <BITX20@...> wrote:

>?

> ?
>
> It might be worse since there is no enclosure at all. Maybe not really warming up at all. I'm hoping the enclosure itself will have some heat retention. There are some transistors that can be used as heaters. I'll wait till I get the enclosure and see how it is. I realize that this circuit is prone to some drift on warm-up, but I think mine may be excessive. Bad cap? I haven't really started digging in yet. I have all the parts for a DDS and may just go that way from the start. I'm no engineer and will have to figure out how that is done as well.
> Mark
> K3MRK
>
>
> On Nov 24, 2016 4:21 PM, "Thomas Noel tnoel@... [BITX20]" <BITX20@...> wrote:

>>?

>> ?
>>
>> What would happen if you added an intentional heater to the enclosure? I'm thinking of something like the flat stick-on pads used to warm reptile tanks, stuck on the underside of the radio enclosure? Thinking a giant version of an oven controlled crystal oscillator?
>>
>> Tom
>> KF7RSF
>>
>> Sent from my iPhone
>>
>> On Nov 24, 2016, at 12:53, Mark Walton k3mrk1@... [BITX20] <BITX20@...> wrote:
>>

>>> ?

>>>
>>> I recently received my BitX-40 board. Until I get the enclosure, I only hooked it up for receive. Worked right out of the box. The only issues I've found is the drift is pretty bad even after being powered up for an hour. What should I be looking at to try to improve the stability? I do plan to build a DDS VFO for it over the winter.
>>> The only other issue is the running is very touchy. I have coming a multiturn pot to fix that.
>>> Any ideas on the drift?
>>> Other than that , I'm very happy with the board and look forward to building onto it in the near future.
>>> Thanks
>>> Mark. K3MRK
>
>
>

?

?

After about 30 minutes warm-up, it becomes pretty stable.?

?

Hi Mark, I confirm the drift problem, if you change the six resistor from 100 to 220 ohm this help realy in RX mode. But in TX mode the problem return mybe becauae the PA warm up all the PCB...and make difficult voice qso and impossibile the use with Digital modes. I decide to move to DDS, already Done some tests and it work well. You Can use also an external analog VFO if you want. More info on blog site of hack page.?

73 de ik8yfw

Giuseppe.