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Re: Frequency from dds pcb

EA3IAV
 

What frequency should I get if I attach a freq counter to te dds connector? At 7.000mhz on the dds I read 5.005,687 on the fcounter
Re: Frequency from dds pcb

EA3IAV
 

I have a freq counter but I don't want to fry it. I mean, where do I tiuchbwith the wire in order to pick freq without overloading the fcounter

thanks
Re: BITX40 package size

 

Jerry KE7ER

I'm confused.? How does one get a negative output from a 3-terminal regulator
with input shorted.? Where does the negative voltage come from?

I see that we are almost neighbors.? I'm in Meridian Idaho.? May have to get
together sometime for coffee and discussion of ham radio ideas.

Arv K7HKL



On Sun, Jun 11, 2017 at 11:55 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The 1n4148w is good for 300ma, plenty good for use in front of all LM78* on the Bitx40, including the Raduino.
The combination would be cheaper than my LM2940*

But I still like the thought of an LM2940-12 up front to the main Bitx40 supply.? Dropout at 150ma is around 0.13v,
so 12.000 volts in would still give the Bitx40 11.870v.? A diode plus LM78* would lose quite a bit more than that.

I well remember how fantastic it was to have the LM309k to play with back in the early 70's.
It did everything!? And just 3 terminals!
You could power a board full of 7400's and 7490's with it!

?> The problem of shorted regulators passing full voltage through them ...

Correct me if I'm wrong, but I assume you mean the problem of a reversed supply.
?
Jerry, KE7ER



On Sun, Jun 11, 2017 at 10:28 am, Arv Evans wrote:
45 years ago in the LM340 regulator days it was conventional to always put a 1N400x in series
with the regulator input. ??? The problem of shorted regulators passing full voltage through them was?well known and accounted for with the series diode.

?
Re: BITX40 package size

 

The raduino is fine in as much as it powers up, displays frequency etc. I can't test the DDS output of it so it might not be completely fine but looking ok so far.

Raj: what voltage should I expect between base and emitter? I'm travelling for the next few days so probably want get to check until the end of the week - and there's no way I'm taking it on a plane with me, that's just asking for trouble!

Matt 2E1HNK
Re: Frequency from dds pcb

 

Just power the Raduino from a USB cable to keep all other circuitry quiet and attach a small wire to the DDS connector, you should be able to pick the signal on a nearby receiver on CW then zero beat it.
?That is if you don't have access to a frequency counter...

Dan

On Sun, Jun 11, 2017 at 1:11 PM, EA3IAV <Cesarleon@...> wrote:
is there a way to pick the actual freq from the dds in order to align it??

Thank you


Re: New BITX-40 User and Antenna Recommendations

Thomas Noel
 

¿ªÔÆÌåÓý

Both will work, and both will have similar challenges as you can¡¯t fool Mother Nature.

The (extremely) short loaded vertical will have low efficiency and narrow bandwidth, and will require a tuner.

The magnetic loop will also have extremely narrow bandwidth and require adjustment with even slight frequency changes.

Google K2MIJ and his extremely small antennas for HF, such as the 9¡± tall ¡°Limbo Stick¡±

Another idea is the spiral loop.

Thomas W Noel
KF7RSF

On Jun 11, 2017, at 11:15 AM, Syed Faisal Akber <faisal@...> wrote:

Hi Everyone,

I ordered a BITX-40 a short while ago (A3-720). ?I've finally wired it together and got it working!!

Once I have a decent small antenna I'll get on the air. ?I live in an apartment and won't be able to put up dipoles or large verticals.

I am looking at two different options:
1 - A short (2m) vertical with a loading coil.
2 - A small magnetic loop.

Have you tried the BITX-40 with any of these two types of antennae?

What are your experiences and recommendations?

Thanks and 73,
VA3SFA/W6
Re: Frequency from dds pcb

 

What works for me is to program it for the reference frequency and then use the result (read by a frequency counter) as the value to insert as your reference. For the Si5351 in the Raduino, for instance, use 25 MHz.
That eliminates the errors if you were to use a broadcast signal since it involves your BFO frequency, too.
Don, ND6T
Re: My Next Ham Radio Project

 

¿ªÔÆÌåÓý

Nice project.? Where do you source the Flux Capacitor from?

Does Doc Brown sell kits for them?

73,

Faisal VA3SFA


On 06/11/2017 11:02 AM, Jerry Gaffke via Groups.Io wrote:

Suitable for framing!
As are many of Randall's offerings.

Here's the manual: ???

Jerry, KE7ER




On Sun, Jun 11, 2017 at 10:33 am, K-Squared wrote:

Here's a schematic.? I'll try to include a complete parts list later.
?

?
New BITX-40 User and Antenna Recommendations

 

Hi Everyone,

I ordered a BITX-40 a short while ago (A3-720). I've finally wired it together and got it working!!

Once I have a decent small antenna I'll get on the air. I live in an apartment and won't be able to put up dipoles or large verticals.

I am looking at two different options:
1 - A short (2m) vertical with a loading coil.
2 - A small magnetic loop.

Have you tried the BITX-40 with any of these two types of antennae?

What are your experiences and recommendations?

Thanks and 73,
VA3SFA/W6
Frequency from dds pcb

EA3IAV
 

is there a way to pick the actual freq from the dds in order to align it??

Thank you
Re: My Next Ham Radio Project

 

Suitable for framing!
As are many of Randall's offerings.

Here's the manual: ???

Jerry, KE7ER




On Sun, Jun 11, 2017 at 10:33 am, K-Squared wrote:

Here's a schematic.? I'll try to include a complete parts list later.
?

?
Re: BITX40 package size

 

The 1n4148w is good for 300ma, plenty good for use in front of all LM78* on the Bitx40, including the Raduino.
The combination would be cheaper than my LM2940*

But I still like the thought of an LM2940-12 up front to the main Bitx40 supply. ?Dropout at 150ma is around 0.13v,
so 12.000 volts in would still give the Bitx40 11.870v. ?A diode plus LM78* would lose quite a bit more than that.

I well remember how fantastic it was to have the LM309k to play with back in the early 70's.
It did everything! ?And just 3 terminals!
You could power a board full of 7400's and 7490's with it!

?> The problem of shorted regulators passing full voltage through them ...

Correct me if I'm wrong, but I assume you mean the problem of a reversed supply.
?
Jerry, KE7ER



On Sun, Jun 11, 2017 at 10:28 am, Arv Evans wrote:
45 years ago in the LM340 regulator days it was conventional to always put a 1N400x in series
with the regulator input. ??? The problem of shorted regulators passing full voltage through them was?well known and accounted for with the series diode.

?
My Next Ham Radio Project

K-Squared
 

Here's a schematic.? I'll try to include a complete parts list later.


?

K2

Women spend more time wondering what men are thinking than men spend thinking.
Re: add yourself to the new BITX operators map

Vince Vielhaber
 

I just added myself with the firefox browser.

Vince.

On 06/11/2017 09:59 AM, Al Duncan VE3RRD wrote:
Did you try using the Chrome browser? I couldn't enter my location using
Firefox.
--
Michigan VHF Corp.

Re: BITX40 package size

 

45 years ago in the LM340 regulator days it was conventional to always put a 1N400x in series
with the regulator input.? The problem of shorted regulators passing full voltage through them was
well known and accounted for with the series diode.? Somehow we seem to have forgotten that
knowledge over the intervening 40+ years.? Doing this means that you have to account for the
additional 0.65 volts of diode voltage drop, but it is a small price to pay for the added security.

?

The datasheet also shows the shorted-input protection diode across the regulator device (Fig. 15)
and a protection diode across the output (Fig. 26).

Arv K7HKL
_._


On Sun, Jun 11, 2017 at 11:08 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
My curiosity overcame me.? Pulled the LM7805 from my Raduino (so I was sure I was working with the same manufacturer that hfsigs uses) and verified proper operation with 12v in, saw 5v out.? Reversed the 12v leads into the LM7805, put on the safety goggles, and powered up.? Was powering from a 2.5 amp 12v supply. ? The reversed LM7805 was sucking enough current to pull down my 12v switcher to -5v going into the LM7805, saw -2v going out of the LM805.? Could well be more than -2v going out if I had used a beefier 12v supply.? Regardless, -2v is sufficient to damage some parts behind the LM7805.? After a few seconds the LM7805 got hot enough to vent and stink up the room.

So, the LM78** parts offer little to no protection from reversed power supply leads.? Not surprising, they were designed 40 years ago when such niceties would have been too expensive to include.? A reversed power supply to the rig could easily blow the Nano on the Raduino.? The Nano has an internal 3.3v regulator that may or may not save the Si5351, but no guarantees.? The LM78L09 powering the analog VFO and LM78L05 for the IRF510 bias likely have the same issue.

The LM2940* family of regulators does offer reverse polarity protection and has a lower dropout voltage.? However it is twice as expensive ($1.00 vs $0.50 from mouser for 10), they recommend at least 22uf on the LM2940* output to maintain stability. ? As mentioned previously, having an LM2940-12 at the main Bitx40 supply going into the board would protect us from reversed power leads, and also avoid trouble from supplies that exceed 12v such as a stack of 4 lithium batteries.? The IRF510 should be powered separately, as we may want considerably higher voltages and currents there and the IRF510 is plenty cheap.

I am left very curious if Matt's Raduino is still functional. ? Does the display come up if you apply 12v to it?

Jerry, KE7ER


On Fri, Jun 9, 2017 at 08:27 pm, Jerry Gaffke wrote:
If the LM7805 and LM78L09 regulators avoid passing negative supplies somehow,
might not be just too much damage from reversed power.
But I don't see anything in the LM78** datasheet suggesting that is the case.
Would be interesting to see what they do.

?
Re: someone just deleted the entire BITX operators map - almost fixed

 

Maybe create a cron that exports it every hour. I tried to export but no option for .kmz. If we can grab it hourly then put in github or something?
Re: BITX40 package size

 

My curiosity overcame me. ?Pulled the LM7805 from my Raduino (so I was sure I was working with the same manufacturer that hfsigs uses) and verified proper operation with 12v in, saw 5v out. ?Reversed the 12v leads into the LM7805, put on the safety goggles, and powered up. ?Was powering from a 2.5 amp 12v supply. ? The reversed LM7805 was sucking enough current to pull down my 12v switcher to -5v going into the LM7805, saw -2v going out of the LM805. ?Could well be more than -2v going out if I had used a beefier 12v supply. ?Regardless, -2v is sufficient to damage some parts behind the LM7805. ?After a few seconds the LM7805 got hot enough to vent and stink up the room.

So, the LM78** parts offer little to no protection from reversed power supply leads. ?Not surprising, they were designed 40 years ago when such niceties would have been too expensive to include. ?A reversed power supply to the rig could easily blow the Nano on the Raduino. ?The Nano has an internal 3.3v regulator that may or may not save the Si5351, but no guarantees. ?The LM78L09 powering the analog VFO and LM78L05 for the IRF510 bias likely have the same issue.

The LM2940* family of regulators does offer reverse polarity protection and has a lower dropout voltage. ?However it is twice as expensive ($1.00 vs $0.50 from mouser for 10), they recommend at least 22uf on the LM2940* output to maintain stability. ? As mentioned previously, having an LM2940-12 at the main Bitx40 supply going into the board would protect us from reversed power leads, and also avoid trouble from supplies that exceed 12v such as a stack of 4 lithium batteries. ?The IRF510 should be powered separately, as we may want considerably higher voltages and currents there and the IRF510 is plenty cheap.

I am left very curious if Matt's Raduino is still functional. ? Does the display come up if you apply 12v to it?

Jerry, KE7ER


On Fri, Jun 9, 2017 at 08:27 pm, Jerry Gaffke wrote:
If the LM7805 and LM78L09 regulators avoid passing negative supplies somehow,
might not be just too much damage from reversed power.
But I don't see anything in the LM78** datasheet suggesting that is the case.
Would be interesting to see what they do.

?
someone just deleted the entire BITX operators map - almost fixed

 

Someone just deleted the entire layer from the map with all of the information.? This is the problem with trying to keep this open for editing for everyone.? Fortunately I saved the kmz file last night at 9:52pm central and can rebuild the map from there.? If you did anything after that you will need to add your information again.? I have said many times if you need help, just ask.? Reply to one of my messages or email me at KD9CYF At gmail DOT com? .? I am concerned keeping this open puts our data at risk of deletion again.? I am trying to keep this public and not owned by me or anyone else but if this happens again I may have to lock it down to protect it and have operators email me or a group of editors to be added.? I am very open to other suggestions.

the link is the same.? here it is again...
https://drive.google.com/open?id=1Oa_egVdStSJBF5C7mpS6MXrkces&usp=sharing
Re: add yourself to the new BITX operators map

 

Did you try using the Chrome browser? I couldn't enter my location using Firefox.
Re: W8TEE Parts List for TFT/VFO

Jack Purdum
 

Mike Nothdurft (k5ess.nothdurft@...) has done a very small PCB that is an adapter for the Type I to Type II board. It plugs directly into my PCB. I just got mine yesterday, so haven't tried it yet, but should be able to test it today. There is a trace that has to be cut, but he can point you to the directions for that...pretty simple. I think he charges $2 (or less) which is cheaper than the Type II board difference in price.

Jack, W8TEE

From: Adrian <a.futrill@...>
To: [email protected]
Sent: Sunday, June 11, 2017 9:39 AM
Subject: Re: [BITX20] W8TEE Parts List for TFT/VFO

Found most of the parts to put this together but been unable to find a supplier of the?AD9850 Type II DDS module companies that advertise them are out of stock and don't know if/when they will be back in stock

Adrian VK4KL


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