Date   
Re: New Facebook Group for D4D

Adam Rong
 

Don’t worry. I meant Facebook group is a new one, but it won’t replace here.

Thanks,
Adam

在 2019年8月7日,下午11:14,bleepingbeep <bleepingbeep@...> 写道:

I agree with Mr. Brauer.  Groups.io is an international venue, is it not?

Jerry AA6KI
Tucson

D4D 20m kit for sale

bleepingbeep
 

I am offering my unbuilt D4D kit for sale.  It is the 20m version, and the price is $35 shipped.  U.S. addresses and PayPal only, please.

Jerry AA6KI
Tucson

Re: New Facebook Group for D4D

bleepingbeep
 

I agree with Mr. Brauer.  Groups.io is an international venue, is it not?

Jerry AA6KI
Tucson

Re: d4d off frequency

ron mcmurray
 

dont know what i did but its working on frequency now.
thanks for your help.
ron, kc0tdj

Re: d4d off frequency

Adam Rong
 

Ron,

Since the info is limited, I have to guess.

I suppose you have calibrated K2 frequency. Please confirm you did like one of these ways:
1. Use zero beat to test the carrier leakage from the D4D oscillator.
2. If you send 1500 Hz audio into D4D and triggered VOX, your K2 should zero beat two most strong frequencies at 14.0755 and 14.0725 MHz.
3. Send FT8 signal and receive in K2 and compare the audio frequency delta.

Thanks,
Adam


On Tuesday, August 6, 2019, ron mcmurray <hamshack@...> wrote:
i used my k2 to measure it.



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Thanks,
Adam Rong

Re: New Facebook Group for D4D

Adam Rong
 

Bryan,

I have a WECHAT group for domestic hams to real time discuss about D4D kit building, modification and application. Facebook group will serve as the same function for international hams.

I will still keep this groups.io group the major area for announcements and file keeping.

Thanks,
Adam

在 2019年8月7日,上午12:21,Bryan Brauer <bryan@...> 写道:

Adam,

I surely hope that this will not be the sole, or even primary venue for information exchange.  I do not do, and never will do, Facebook.

Bryan B. Brauer, PE
Consulting Engineer


On Mon, Aug 5, 2019 at 8:47 PM Adam Rong <rongxh@...> wrote:
Folks,

You are invited to join the new group.
https://www.facebook.com/groups/487925331780070/

Thanks,
Adam

Re: New Facebook Group for D4D

Bryan Brauer
 

Adam,

I surely hope that this will not be the sole, or even primary venue for information exchange.  I do not do, and never will do, Facebook.

Bryan B. Brauer, PE
Consulting Engineer


On Mon, Aug 5, 2019 at 8:47 PM Adam Rong <rongxh@...> wrote:
Folks,

You are invited to join the new group.
https://www.facebook.com/groups/487925331780070/

Thanks,
Adam

Re: d4d off frequency

ron mcmurray
 

i used my k2 to measure it.

New Facebook Group for D4D

Adam Rong
 

Folks,

You are invited to join the new group.
https://www.facebook.com/groups/487925331780070/

Thanks,
Adam

Re: d4d off frequency

Adam Rong
 

Ron,

If you measure by a frequency counter or other devices with a probe, the capacitance introduced by the probe will pull low the oscillator frequency, and 2kHz is a reasonable number.

You can receive the same station using D4D and a known calibrated commercial radio to know the difference.

Thanks,
Adam

在 2019年8月6日,上午7:44,ron mcmurray <hamshack@...> 写道:

my d4d is off frequency, low by 2khz . do i decrease or increase capitance. it's at 14.272.
thanks, ron
kc0tdj

d4d off frequency

ron mcmurray
 

my d4d is off frequency, low by 2khz . do i decrease or increase capitance. it's at 14.272.
thanks, ron
kc0tdj

Re: D4D mods

Adam Rong
 

In my test, I used 1N4148 but any diode will do, like 1N914, 1N4001-4007, 1N5817 and etc.

On Mon, Aug 5, 2019 at 8:12 AM Simon C via Groups.Io <symen79=yahoo.com@groups.io> wrote:
What diode is recommended for Steve's Mod?



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Thanks,
Adam Rong

Re: D4D mods

Simon C <symen79@...>
 

What diode is recommended for Steve's Mod?

Re: dB level and TX timings

Adam Rong
 

Hi Conor EI6GSB,

Thanks for reporting this. I have never met this before. If you have spare part, you can try to swap NE602 to see if it is better. Also, check if you have properly attach the final transistor to the rear cover to help heat sink.

Thanks,
Adam

Thanks,
Adam


On Mon, Aug 5, 2019 at 2:32 AM <conchobhair.ofearghail@...> wrote:
Hi all again,

After some more investigation I believe this simply may be a case of the transceiver overheating. I opened the case to inspect the board to see if there were any signs of component damage, and everything looked fine. I powered up the transceiver and I still experienced the original problem, but after a few minutes the TX timings returned to normal and the dB level dropped down to about 23dB.

My radio shack got very warm over the last couple of days (over 30 degrees C) and I while troubleshooting I opened the door to let the room cool down for my own personal comfort. I think that this, combined with the black, heat-absorbing enclosure of the transceiver caused the components on the board to overheat and not function correctly.

Thanks to the nature of the enclosure and the board, the D4D transceiver may lend itself to a cooling system modification for people operating in unusually warm climates.

Thank you, too, to Adam for developing the kit: it was fun to assemble and I'm looking forward to making some QRP contacts!

73,
Conor EI6GSB



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Thanks,
Adam Rong

Re: dB level and TX timings

conchobhair.ofearghail@...
 

Hi all again,

After some more investigation I believe this simply may be a case of the transceiver overheating. I opened the case to inspect the board to see if there were any signs of component damage, and everything looked fine. I powered up the transceiver and I still experienced the original problem, but after a few minutes the TX timings returned to normal and the dB level dropped down to about 23dB.

My radio shack got very warm over the last couple of days (over 30 degrees C) and I while troubleshooting I opened the door to let the room cool down for my own personal comfort. I think that this, combined with the black, heat-absorbing enclosure of the transceiver caused the components on the board to overheat and not function correctly.

Thanks to the nature of the enclosure and the board, the D4D transceiver may lend itself to a cooling system modification for people operating in unusually warm climates.

Thank you, too, to Adam for developing the kit: it was fun to assemble and I'm looking forward to making some QRP contacts!

73,
Conor EI6GSB

Re: D4D mods

Adam Rong
 

Modification is not necessary if you want to get it work first. After you have time, you can consider these two modifications:
1. Replace C5 by a 105 monolithic cap (tolerance < 20%) to improve IMD at the cost of half RF power at the same audio input.
2. Add a diode per KD1JV to improve carrier leakage.

If your sound card output is too low to drive VOX, consider KD1JV improvement to add a 150k resistor. This mod will not become standard as it is related with transistor parameter and power supply voltage. You make your call to modify it or buy a USB sound card along.

Thanks,
Adam

On Mon, Aug 5, 2019 at 12:29 AM Bryan Brauer <bryan@...> wrote:
I just received my d4d kit this week, and wish to incorporate all recommended mods.  Will there be a file that lists all mods, or an update to the instructions that includes all?

Bryan B. Brauer, PE
Consulting Engineer


On Sun, Aug 4, 2019 at 8:21 AM Adam Rong <rongxh@...> wrote:
Steve,

Thanks for reminding. We studied the spec while we apply the 4.3V power supply. The main impact parameters are:
Conversion gain, Noise figure, and IP3i

I believe the major impact is IP3i which will cause worse BCI.

With your modificaiton, I think it is okay not to add BH4DCL diode mod to avoid the impact to the receiver performance. The carrier leakage is now about 10 dB under USB and LSB signals even I applied 10 dB attenuation to the audio input.

Thanks,
Adam



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Thanks,
Adam Rong

Re: D4D mods

Bryan Brauer
 

I just received my d4d kit this week, and wish to incorporate all recommended mods.  Will there be a file that lists all mods, or an update to the instructions that includes all?

Bryan B. Brauer, PE
Consulting Engineer


On Sun, Aug 4, 2019 at 8:21 AM Adam Rong <rongxh@...> wrote:
Steve,

Thanks for reminding. We studied the spec while we apply the 4.3V power supply. The main impact parameters are:
Conversion gain, Noise figure, and IP3i

I believe the major impact is IP3i which will cause worse BCI.

With your modificaiton, I think it is okay not to add BH4DCL diode mod to avoid the impact to the receiver performance. The carrier leakage is now about 10 dB under USB and LSB signals even I applied 10 dB attenuation to the audio input.

Thanks,
Adam

Re: D4D mods

Adam Rong
 

Steve,

Thanks for reminding. We studied the spec while we apply the 4.3V power supply. The main impact parameters are:
Conversion gain, Noise figure, and IP3i

I believe the major impact is IP3i which will cause worse BCI.

With your modificaiton, I think it is okay not to add BH4DCL diode mod to avoid the impact to the receiver performance. The carrier leakage is now about 10 dB under USB and LSB signals even I applied 10 dB attenuation to the audio input.

Thanks,
Adam

Re: D4D mods

Steven Weber
 

I would remove the diode in series with the 5V to the SA602. The minimum operating voltage for the SA602 is 4.5V and performance degrades quickly below 4.5V.

 

 

Thank you, Steve. Your diode mod is effective. In my test, the carrier leakage improved by about 5 dB, as a side effect, both USB and LSB signals increased about 1 dB which is a surprise to me. I also applied the BH4DCL diode mod, and it improved the carrier leakage further for another 3 dB, and there was no noticeable difference on the USB and LSB signal level.

I did try to change the emitter resistor from 1.5k to half and it won't help too much, so I will not change it.

So, my recommendation is that we apply both diode mods, hihi.

 

Thanks,

Adam

 

On Wed, Jul 31, 2019 at 4:36 AM Steven Weber <steve.kd1jv@...> wrote:

Yes, Q1’s collector should stay above 5V when 12_V is applied.

Steve

 

 

From: Adam Rong
Sent: Tuesday, July 30, 2019 10:33 AM
To: crkits@groups.io
Subject: Re: [crkits] D4D mod

 

Hi Steve,

Thanks for your sharing. I will test them. One thing to confirm: If we add a diode between +5V and the collector of Q1, when 12V_R is present, the diode will be reverse biased? If not, I suppose it will mute the audio output.

Thanks,
Adam

 



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Thanks,

Adam Rong

 

Re: D4D mods

Adam Rong
 

And the photo follows. The left side is the KD1JV diode mod, and the right side is the BH4DCL diode mod.
微信图片_20190804230531.jpg


On Sun, Aug 4, 2019 at 10:59 PM Adam Rong via Groups.Io <rongxh=gmail.com@groups.io> wrote:
Thank you, Steve. Your diode mod is effective. In my test, the carrier leakage improved by about 5 dB, as a side effect, both USB and LSB signals increased about 1 dB which is a surprise to me. I also applied the BH4DCL diode mod, and it improved the carrier leakage further for another 3 dB, and there was no noticeable difference on the USB and LSB signal level.

I did try to change the emitter resistor from 1.5k to half and it won't help too much, so I will not change it.

So, my recommendation is that we apply both diode mods, hihi.

Thanks,
Adam

On Wed, Jul 31, 2019 at 4:36 AM Steven Weber <steve.kd1jv@...> wrote:

Yes, Q1’s collector should stay above 5V when 12_V is applied.

Steve

 

 

From: Adam Rong
Sent: Tuesday, July 30, 2019 10:33 AM
To: crkits@groups.io
Subject: Re: [crkits] D4D mods

 

Hi Steve,

Thanks for your sharing. I will test them. One thing to confirm: If we add a diode between +5V and the collector of Q1, when 12V_R is present, the diode will be reverse biased? If not, I suppose it will mute the audio output.

Thanks,
Adam

 



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Thanks,
Adam Rong



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Thanks,
Adam Rong