Topics

#bpf #t1 #alignment #filter #t1 #filter #bpf #alignment

bruisedreed@...
 

Figured it was worth a quick message post…#3793 is built and fired up as expected.  I am having some trouble in the alignment process.  I was initially not able to peak BPF in the expected ranges (scale for BPF never higher than 5 or so) so I made some adjustments to T1 as per build instructions.  Nothing really changed so just as a precaution I rewound the T1 entirely.  Still no change so I will have to do some more digging.  Since I did not have a working oscilloscope anymore, I have an el cheapo Chinese wonder on the way to do some rudimentary signal tracing to hopefully solve the problem.  With any luck, I won’t get in a hurry and really foul something up and I’ll have her singing in a week or so!  THANKS A BUNCH to Hans and the crew.  This is head and shoulders above any kit I’ve built in my ham career and the documentation alone is worth as much as the cost of a kit.  Thanks much!

Andrew Lenton
 

Hi, just a quick reply from my phone while on holiday.

 

Setting up band pass filters is tricky with out good test equipment. idealley you want a narrow pass band with just enough to coupling for the two parallel tuned circuits yo intereact . And steep roll off out of band.

 

Hans has some good plots and I have replicated  them. I did notice the tuning was very critical.

 

I do have access to a network analyser, but I look for a way to tune without.

 

73

 

Andrew

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 15:34
To: QRPLabs@groups.io
Subject: [QRPLabs] #bpf #t1 #alignment #filter

 

Figured it was worth a quick message post…#3793 is built and fired up as expected.  I am having some trouble in the alignment process.  I was initially not able to peak BPF in the expected ranges (scale for BPF never higher than 5 or so) so I made some adjustments to T1 as per build instructions.  Nothing really changed so just as a precaution I rewound the T1 entirely.  Still no change so I will have to do some more digging.  Since I did not have a working oscilloscope anymore, I have an el cheapo Chinese wonder on the way to do some rudimentary signal tracing to hopefully solve the problem.  With any luck, I won’t get in a hurry and really foul something up and I’ll have her singing in a week or so!  THANKS A BUNCH to Hans and the crew.  This is head and shoulders above any kit I’ve built in my ham career and the documentation alone is worth as much as the cost of a kit.  Thanks much!

 

bruisedreed@...
 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

Andrew Lenton
 

Check you coil windings are in the correct rotation as it is easy to be 180 out of phase

 

BR Andrew

 

If you send me a pile of filters I can align for free of charge

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 18:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

 

Andrew Lenton
 

Please find enclosed Plot of BPF 14 MHz after careful tuning

 

73 Andrew

 

 

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 18:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

 

Hans Summers
 

Hi Andrew

I think you and "bruisedreed" are not netted on the same QRG!

If I am not mistaken: you are talking about the BPF kit http://qrp-labs.com/bpfkit whereas "bruisedreed" is talking about the different BPF in the QCX kit.

73 Hans G0UPL 

On Mar 10, 2018 1:58 AM, "Andrew Lenton" <a@...> wrote:

Please find enclosed Plot of BPF 14 MHz after careful tuning

 

73 Andrew

 

 

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 18:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

 

Andrew Lenton
 

Thanks Hans, noted, does the QRG use a similar BPF Circuit?

 

I will look it up

 

BR Andrew

 

Sent from my Windows 10 phone

 

From: Hans Summers
Sent: 10 March 2018 05:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

Hi Andrew

 

I think you and "bruisedreed" are not netted on the same QRG!

 

If I am not mistaken: you are talking about the BPF kit http://qrp-labs.com/bpfkit whereas "bruisedreed" is talking about the different BPF in the QCX kit.

 

73 Hans G0UPL 

 

On Mar 10, 2018 1:58 AM, "Andrew Lenton" <a@...> wrote:

Please find enclosed Plot of BPF 14 MHz after careful tuning

 

73 Andrew

 

 

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 18:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

 

 

bruisedreed@...
 

That is correct Hans. I will get it going sometime soon here. It does hear a little now but alignment isnt coming together in the expected ranges. BPF peaks somewhere around 5 on the scale max which makes everything else a little off too. Everything seems to work just pretty deaf. Thanks again for the kit. It is what we have been waiting for a long time!

73 de WZ2N
Greg

 

Greg, it sounds like you are seeing a peak when adjusting C1. That being the case, it seems unlikely that T1 has the wrong values. I suggest verifying that all windings are in correct phase on T1. Then check that the correct components are installed.in the audio path. I have seen some problems in that area with some builds. I think that tTo some degree the actual level reached in the 8.7 Peak BPF step will depend on the alignment of the audio path in steps 8.8, 8.9 and 8.10.
--
> I finally got it all together...now I can't remember where I put it<

Wes

AE6ZM

Hereford, AZ

 

Andrew Lenton
 

Hi Hans, is an ssb qrp kit on the drawing board?

 

73 Andrew

 

Sent from my Windows 10 phone

 

From: Hans Summers
Sent: 10 March 2018 05:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

Hi Andrew

 

I think you and "bruisedreed" are not netted on the same QRG!

 

If I am not mistaken: you are talking about the BPF kit http://qrp-labs.com/bpfkit whereas "bruisedreed" is talking about the different BPF in the QCX kit.

 

73 Hans G0UPL 

 

On Mar 10, 2018 1:58 AM, "Andrew Lenton" <a@...> wrote:

Please find enclosed Plot of BPF 14 MHz after careful tuning

 

73 Andrew

 

 

 

Sent from my Windows 10 phone

 

From: bruisedreed@...
Sent: 09 March 2018 18:23
To: QRPLabs@groups.io
Subject: Re: [QRPLabs] #bpf #t1 #alignment #filter

 

My assumption is that there is more going on than just alignment issues.  Things are far enough out of the expected ranges that the receiver is totally deaf.  I'll follow the receive path as soon as I have some way of doing so (thanks to a PHENOMENAL troubleshooting guide) and I'm pretty sure I'll find something that I have missed so far.  Or I'll end up with a smoldering pile of ashes...either way will be educational hopefully.

 

 

bruisedreed@...
 

Thanks Wes! I am about to start verifying all tge components. I have completely redone T1 even though ai was sure it was right and have added turns as prescribed in the manual. No changes. I am going to verify everytthing in the audio path and then when my scope gets here will probe around a bit. 

bruisedreed@...
 

OK...so I followed the entire receive path and verified components...then only thing I found wrong was I had swapped R14 and R15 inadvertently.  I replaced both with the proper value.  It didn't make any change to the alignment issue I'm having. I still can't get a higher scale reading than around a 5 when peaking the BPF (allignment menu 8.7) and then in the 8-9 range on IQ bal (menu 8.8) Phase lo around 8 and phase high is around 7 on the scale. I am able to adjust all and get peaks just the scale is not where it should be.  I am 99% sure there is no torroid problem as I have done it several times and had the same result nothing changes even when adding/removing turns...I also do have continuity across each winding once installed. Hopefully something will pop up on the scope once I get it later this week but I really am not seeing anything I've screwed up so far.

bruisedreed@...
 

OK so just by way of closing this out...I went over the rig with a fine tooth comb today.  I really couldn't find any problems.  I did retouch most of the solder joints just to be sure everything was making good connections.  No change when in alignment so i did some tests with the receiver on the air.  After a couple of hours peaking and repeaking the alignment I decided to just experiment a little.  after reading some comments about C1 and rereading the manual about C5 and C8 adding some parallel capacitance to C1 I decided what the heck and started adding some capacitors to the bland C8 slot on my circuit board.  right away I started noticing signals getting louder.  I also had to get the feel of the receiver...that is not a wide filter to work with so carefully tuning a station in makes a huge difference.  My first CQ's went unanswered, but I have made about 6 QSO's so far.  Output power with 13v power supply is right under 4 watts by my uncalibrated Chinese wattmeter.  I think we'll call her good.  Thanks again to Hans and the crew for the kit, tech support, and just being all around good guys.  I think I can speak for a lot of hams when I say you have really put the fun back into ham radio for a lot of us!