Date   
Re: Troubleshooting the CS-40

John VA7JBE
 

Thanks for the advice.  I traced back and found an old fix that I did about 2 months ago (when I last worked on the kit.)  One of the leads for the crystal in the single pole IF amp filter had broken off during shipping and I had bridged it with a jumper.  I removed the jumper and the voltages are pretty close to where they should be:

Pin   Volts
1      1.35
2      1.22
3      0
4      5.87
5      6.8
6      7.33
7      7.27
8      8

Still not sure whats up with the relays, but I'm thinking of ordering some new ones when I order a new IF filter crystal.

John VA7JBE

Re: Troubleshooting the CS-40

AA7US
 

John,

Unless I'm mis-reading the schematic, there definitely shouldn't be 8v DC on pin 1.  8v DC on pin 8 is normal.

I think now I'd carefully work back from pin 1 along the affected circuit to try and find out how (where) that 8v DC is coming from.

Question: Did the transceiver work fine for awhile then suddenly start acting up like this?  Or has this been a problem since you assembled it?

John
AA7US

---In CHINA_QRP@..., <va7jbe@...> wrote :

I'm afraid I don't have a second mixer IC, but I pulled off the one giving weird readings and measured the voltage on the pins.  All pins are 0 volts except 1 and 8, which were 8 volts.

John VA7JBE

Re: Troubleshooting the CS-40

John VA7JBE
 

I'm afraid I don't have a second mixer IC, but I pulled off the one giving weird readings and measured the voltage on the pins.  All pins are 0 volts except 1 and 8, which were 8 volts.

John VA7JBE

Re: Troubleshooting the CS-40

AA7US
 

Since many of those measurements you're getting on the NE602AN mixer IC are indeed abnormal (and seemingly impossible unless internal or external components are damaged), I think next I'd try removing the NE602AN mixer, then take voltage measurements at each pin of the exposed socket.  If you can post those measurements here maybe we can help troubleshoot.

Do you have a new NE602AN to try?

73,

John
AA7US

---In CHINA_QRP@..., <va7jbe@...> wrote :

Hi John,

I've observed this behavior while using both the microphone and shorting pins 5 and 8 of the connector without the microphone attached. 

Cheers,
John VA7JBE

Re: Troubleshooting the CS-40

John VA7JBE
 

Hi John,

I've observed this behavior while using both the microphone and shorting pins 5 and 8 of the connector without the microphone attached. 

Cheers,
John VA7JBE

Re: Troubleshooting the CS-40

AA7US
 

Hey John,

Have you ruled out if the PTT switch inside the microphone could be the cause of the problem by manually grounding the PTT line at the microphone connector?  It's pin number 5 of the 8-pin mic connector.

73,

John
AA7US


---In CHINA_QRP@..., <va7jbe@...> wrote :

1) Intermittent relay flip on PTT.

Troubleshooting the CS-40

John VA7JBE
 

Hi Folks,

Some funny things have been happening with my new CS-40 kit.

1) Intermittent relay flip on PTT.  Sometimes the relays go, sometimes they don't.  I have no idea what the issue might be here but every now and then when I trace the 8v line to the Tx/Rx relay (the one by the sandwich VFO, not the antenna) it looks like a broken relay.

2) When going through the voltages in Rx on the NE602 mixer (the one by the BFO) I also get some weird voltages.  Here are my readings:

Pin    Volt
1        8
2        3.4
3        0
4        8
5        8
6        Drops from 4 to 0 once voltmeter is applied
7        7.3
8        8

Pins 1,2,4,5, and 6 are not to spec.  Testing in Tx is quite difficult because of problem 1), but I'll try to get some voltages up soon.  If anyone has an advice or suggestions I'd really appreciate it, this is an awesome kit.

Cheers,
John VA7JBE

UPDATE: More on CS-17 and FT8 Digital Modes

AA7US
 

Tonight I made my farthest confirmed QSO yet using the CS-17 and FT8 on 17M with only 5 watts TX power...

4593 miles (7392 km) from the USA to Japan!  I received a good strong signal report too!

73,

John
AA7US

Re: Some measurements by DG8SAQ VNWA 3

AA7US
 

Adam,

Thank you for the reply.

OK, let me see if I have everything correct...

KN-Q7A and CS-Series DIY7 Filter General Rules
1. Decreasing DIY7 inductance value increases resonant frequency
2. Increasing DIY7 inductance value decreases resonant frequency
3. Lowering DIY7 adjusting slug position decreases inductance and increases resonant frequency
4. Raising DIY7 adjusting slug position increases inductance and decreases resonant frequency
5. Decreasing end capacitance values increases resonant frequency and increases insertion loss
6. Increasing end capacitance values decreases resonant frequency and decreases insertion loss
7. Decreasing center capacitor value decreases bandwidth and increases insertion loss
8. Increasing center capacitor value increases bandwidth and decreases insertion loss

Please let me know if anything is wrong with the above.

I'm finding out that trying to properly evaluate DIY7 filters using a signal generator and oscilloscope doesn't work perfectly because the added capacitance of the test leads affects the filter's characteristics.  I guess a spectrum analyzer and tracking generator would be needed to do it correctly!

73,

John
AA7US

---In CHINA_QRP@..., <rongxh@...> wrote :

John,

Although I haven't tested the BPF for CS-Series due to impedance mismatch, I can try to answer your questions:

1. The resonating frequency will be a bit lower (so you will need to tune the slug higher position to tune the frequency back) and the insertion loss will be smaller (but smaller insertion loss is not aways good if the overall gain is enough, instead, sometimes selectivity is more of a concern) if you increase the value of capacitors.

2. Same as my finding in my measurements. The bigger value, the less insertion loss, but a bit wider bandwidth. It varies with band and impedance but generally it is this trend.

3. No modification is required for 15 meter band.

Thanks,
Adam

Re: Some measurements by DG8SAQ VNWA 3

Adam Rong
 

John,

Although I haven't tested the BPF for CS-Series due to impedance mismatch, I can try to answer your questions:

1. The resonating frequency will be a bit lower (so you will need to tune the slug higher position to tune the frequency back) and the insertion loss will be smaller (but smaller insertion loss is not aways good if the overall gain is enough, instead, sometimes selectivity is more of a concern) if you increase the value of capacitors.

2. Same as my finding in my measurements. The bigger value, the less insertion loss, but a bit wider bandwidth. It varies with band and impedance but generally it is this trend.

3. No modification is required for 15 meter band.

Thanks,
Adam

于 2017-9-3 9:12, landrjoh@... [CHINA_QRP] 写道:

 

Adam,


This is great information!

I have some additional questions about using DIY7 transformers and hope you might know the answers.

1. In a twin DIY7 filter setup such as used in the KN-Q7A and CS-Series, what happens when the coupling capacitor values are decreased or increased?  By chance does changing capacitor values shift the entire passband frequency range, or does it only change the passband width?  Or both maybe?

2. What happens when the value of the single capacitor located BETWEEN the DIY7's is changed?

3. Are there any modifications you can suggest to better optimize and improve the performance of a CS-15/17 kit if used only on the 15M band?

Thank you,

John
AA7US

Re: Some measurements by DG8SAQ VNWA 3

AA7US
 

Adam,

This is great information!

I have some additional questions about using DIY7 transformers and hope you might know the answers.

1. In a twin DIY7 filter setup such as used in the KN-Q7A and CS-Series, what happens when the coupling capacitor values are decreased or increased?  By chance does changing capacitor values shift the entire passband frequency range, or does it only change the passband width?  Or both maybe?

2. What happens when the value of the single capacitor located BETWEEN the DIY7's is changed?

3. Are there any modifications you can suggest to better optimize and improve the performance of a CS-15/17 kit if used only on the 15M band?

Thank you,

John
AA7US

Some measurements by DG8SAQ VNWA 3

Adam Rong
 

Gang,

I buit a test fixture for DG8SAQ VNWA 3 (bought from
http://sdr-kits.net) yesterday and did some measurements. I finally
found the reason why my recent BITX receiver didn't sound loud enough.
Besides the audio pre-amplifier is not installed, there are other factors:

1. The insertion loss between the primary winding and the secondary
winding of a DIY series coil is 3~4 dB higher than a tri-filar coil on
FT37-43 when it is used as a wideband transformer. Now I understand that
it is not a good idea to use them to replace tri-filar coils in a diode
mixer. In the application of the detector, it might be okay if the LO is
stong enough. However, in the case of replacing bi-filar toroidal coil
by the DIY7-series primary winding and its tap in the middle, it
performs equally good in terms of insertion loss.
2. When two DIY7-7 transformers are used to replace the original BPF, it
is adivised to increase the coupling capacitor value from 15 pF to 27 pF
to reduce insertion loss by about 2 dB. This finding will not impact
KN-Q7A or CS-series, but it is a valuable finding here to save 2 dB
insertion loss at the cost of a slight wider passband.

I also measured the LPF for CS-series. The current design performs quite
good. In the CS-15/17 kit, if you only use 17 meter, you can increase
the turns of the T37-2 winding from 8 turn to 9 turn to help a bit
(maybe just about 2 dB) of 2nd and 3rd harmony suppression.

Thanks,
Adam

Re: Video Uploaded: More projects on Choc perfboard

AA7US
 

Your chocolate perf board projects are inspiring Adam!

Thank you for sharing them with us.

73,

John
AA7US


---In CHINA_QRP@..., <rongxh@...> wrote :

This video showed my recent two projects based on Choc Perfboard. You can see many details, although it is in portrait mode.

Re: More on CS-17 and FT8 Digital Modes

Adam Rong
 

When I talked about the magnetic loop antenna, I meant VK3YE's brilliant idea of tuning. See this video:

Thanks,
Adam

在 2017年8月31日,上午1:41,Adam Rong rongxh@... [CHINA_QRP] <CHINA_QRP@...> 写道:

 

Nice job. If you keep it 5 watt for 50% duty, I think the original FT37-43 toroid should be fine.

FT8 is really hot these days. I think probably it is a good idea to get a magnetic loop antenna (even in door) for this mode.

Thanks,
Adam

在 2017年8月28日,上午9:00,landrjoh@... [CHINA_QRP] <CHINA_QRP@...> 写道:

 

In less than 2 hours this afternoon I made 20 confirmed QSO's all across North America with  a new the new FT8 digital mode and a CS-17 transceiver (17M band).  Operating was done on 12.7v battery power and TX power was held at 5 watts.  Farthest contact today was 2,180 miles.  The bottom enclosure of the CS-17 barely got warm to the touch even with continuous transmit cycles calling CQ for 15 seconds then listening for 15 seconds, repeat.


With the FT50-43 toroid in place of T3, the CS-Series transceiver is turning out to be perfect for QRP digital mode operation.


I've attached a couple of pictures...


One is my setup when operating using digital modes and the other shows the larger FT50-43 toroid inside the CS-17 on the main PCB.  Note the regular size toroid in the foreground for comparison.


73,


John

AA7US

Re: More on CS-17 and FT8 Digital Modes [2 Attachments]

Adam Rong
 

Nice job. If you keep it 5 watt for 50% duty, I think the original FT37-43 toroid should be fine.

FT8 is really hot these days. I think probably it is a good idea to get a magnetic loop antenna (even in door) for this mode.

Thanks,
Adam

在 2017年8月28日,上午9:00,landrjoh@... [CHINA_QRP] <CHINA_QRP@...> 写道:

 

In less than 2 hours this afternoon I made 20 confirmed QSO's all across North America with  a new the new FT8 digital mode and a CS-17 transceiver (17M band).  Operating was done on 12.7v battery power and TX power was held at 5 watts.  Farthest contact today was 2,180 miles.  The bottom enclosure of the CS-17 barely got warm to the touch even with continuous transmit cycles calling CQ for 15 seconds then listening for 15 seconds, repeat.


With the FT50-43 toroid in place of T3, the CS-Series transceiver is turning out to be perfect for QRP digital mode operation.


I've attached a couple of pictures...


One is my setup when operating using digital modes and the other shows the larger FT50-43 toroid inside the CS-17 on the main PCB.  Note the regular size toroid in the foreground for comparison.


73,


John

AA7US

Video Uploaded: More projects on Choc perfboard

Adam Rong
 

Gang,

This video showed my recent two projects based on Choc Perfboard. You can see many details, although it is in portrait mode.

More on CS-17 and FT8 Digital Modes

AA7US
 

In less than 2 hours this afternoon I made 20 confirmed QSO's all across North America with  a new the new FT8 digital mode and a CS-17 transceiver (17M band).  Operating was done on 12.7v battery power and TX power was held at 5 watts.  Farthest contact today was 2,180 miles.  The bottom enclosure of the CS-17 barely got warm to the touch even with continuous transmit cycles calling CQ for 15 seconds then listening for 15 seconds, repeat.


With the FT50-43 toroid in place of T3, the CS-Series transceiver is turning out to be perfect for QRP digital mode operation.


I've attached a couple of pictures...


One is my setup when operating using digital modes and the other shows the larger FT50-43 toroid inside the CS-17 on the main PCB.  Note the regular size toroid in the foreground for comparison.


73,


John

AA7US

Re: 51 super Rockmite low voltage on collector of q3 on transmit.

KQ8B, Robert
 

Thanks so much, actually the schematic and assembly instructions were downloaded from your website before I put it together and I bought new toroids and rewound those to no avail. I don't know what I did wrong. Thanks again. 73 Robert N4SWD

Re: 51 super Rockmite low voltage on collector of q3 on transmit.

John Clements
 

Not sure if it will help but I worked on one with a bad transformer (t1) and also had another with bad toroids, don't remember if I saw anything on the collector of Q3 at the time with either issue.  You may want to check T2 windings, or possibly a solder bridge or wrong part around Q3/Q4 area.  Download my manual which has lots of test points, o-scope patterns, mods, etc.   http://kc9on.com/ham-radio/qrp-radios/chinese-qrp-kits-2/chinese-super-rm-rockmite-aka-octopus/

73 John kc9on

Re: UPDATE: New FT8 Digital Mode Easier on IRF510?

AA7US
 

That was funny W6LG using a "lightbulb dipole."  But he did feed it with 100 watts, so not as impressive as if he'd used 5 watts. 

Either way, his experiment adds to the near mythical reputation FT8 is developing.

73,

John
AA7US


---In CHINA_QRP@..., <rongxh@...> wrote :

Seeing the video by W6LG about Light Bulb Antenna for FT8, I start to realize that 5 watt for a regular antenna seems too much, hihi.

Thanks,
Adam