Date   
Re: Winding and installing bilfilar transformer T1 and T2

Jerry Haigwood
 

When I wind toroid transformers, I always twist the wire together before winding.  On the cores for this project, I used #30 wire twisted about 6-8 turns per inch.  Wind the wire tight on the core.  Cut the leads and separate them.  I use low temp insulation wire so I can melt the insulation with my soldering iron and tin the leads at the same time.  Once all four wires have been tinned, I measure the resistance with my ohm meter to find P, P' and S, S'.  I then twist P' with S and insert the transformer into the board and solder them down.  I always check the connection to the board with an ohm meter to insure I do not have a bad connection.

Jerry W5JH

"building something without experimentation is just solder practice"



---In phsna@..., <n5ib@...> wrote:

Just posted a pictorial and description of how to wind and install the transformers. Look in the Files section for a PDF.

Jim, N5IB

Hole Size for R7

Jerry Haigwood
 

I used a 270 ohm 1W resistor for R7 on the ERA-3 combo board.  The hole sizes on the board are not large enough for the 1W resistor leads.  I had to drill out the holes using a #60 drill bit.  When installing R7, you will have to solder the top and bottom of the board since you drilled out the through plating.

Jerry W5JH

"building something without experimenting is just solder practice"

 

Re: Hole Size for R7

N5IB
 

The 1 watter for R7 could be a good idea. The ERA is supposed to be drawing about 35 mA at 12V with a 251 ohm resistor. At 13 V,  280 ohms is called for.  35 mA through 270 ohms is 0.33 watt, a little warm for a half watt part. If you use 1/2 W perhaps elevating it a mm or so above the board would be a good idea.


If you want more robust than 1/2 W... two alternatives to drilling out the hole...


Use 1 W, trim leads to length, then file the leads to a point and poke 'em in as far as they'll go, then solder top and bottom. The through-plating will make contact on both sides


Solder a pair of 560 ohm parts in parallel using the leads of one of them in the holes. That gives you 280 ohms and will compensate for supplies a bit above 12 V.


Jim, N5IB


---In PHSNA@..., <w5jh@...> wrote:

I used a 270 ohm 1W resistor for R7 on the ERA-3 combo board.  The hole sizes on the board are not large enough for the 1W resistor leads.  I had to drill out the holes using a #60 drill bit.  When installing R7, you will have to solder the top and bottom of the board since you drilled out the through plating


Attaching the counter cable

Jerry Haigwood
 

On the ERA-3 board the counter cable (I use RG-174U) attaches next to R19 but there isn’t a place to attach the ground braid.  So, I scraped a small amount of solder mask off of the board next to the counter pad and attached the ground braid there.  Also, the reset pad does have a ground either.  I attached the ground to the braid of CH0.  I am about ready to give my ERA-3 board the smoke test.  I’ll let everyone know if it “plays.”

Jerry W5JH

"building something without experimenting is just solder practice"

 

Re: Attaching the counter cable

N5IB
 

Lack of ground pads...  Shucks, that's another oversight on my part....


You can leave the grounded leads of R14 and R12 a little long and bend a loop or hook in them, then use that to attach the ground wires for the counter and reset lines.


Jim, N5IB





---In PHSNA@..., <w5jh@...> wrote:

On the ERA-3 board the counter cable (I use RG-174U) attaches next to R19 but there isn’t a place to attach the ground braid.  So, I scraped a small amount of solder mask off of the board next to the counter pad and attached the ground braid there.  Also, the reset pad does have a ground either.  I attached the ground to the braid of CH0.

Got the 2N5109 amplifier going

Nick Kennedy
 

I built the amplifier strip portion today. I made several changes to deal with not having the right parts and to boost the output a bit. Didn't find any problems with the board or circuit.  I'm getting -1 dBm out and see a good sine wave on the scope and about 0.56 Vpp on 7.040 MHz.
Turns out I was out of T37-6 toroids so I after some soul searching, I used T37-2 with number of turns adjusted.  For a wide band signal generator like this one, it's hard to prefer one over the other.
The 2N5109 is a little warm but I can hold my finger on it without hollering, so it should be OK with no heat sink.  If I have one that fits I may put it on anyway. It draws about 21 mA so that's about 1/4 watt dissipation.
On the 2N5109, it will fit down flat onto the board, but the lead and hole for R8 are just about under the body, so you might want to space it off about 1/8 inch.
I've had some issues with the unit not wanting to start.  I take multiple presses of the reset button or re-powering the board and then it takes off.  Maybe I've got something intermittent somewhere.

73-

Nick, WA5BDU

ERA-3+ Version passes the smoke test

Michael McShan <n5jky@...>
 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City

C7 Connection to 2N5109 Emitter

W0PWE
 

I have been troubleshooting low output ~15mv into 50 ohms and I believe I have found the culprit. It appears as though the connection between C7 and the emitter is missing. I put a jumper on the back side of the board and now the output is good. In fact it is a bit strong at 115mv RMS. 

Jerry - W0PWE

Re: C7 Connection to 2N5109 Emitter

Nick Kennedy
 

Wow, nice catch, Jerry.  I thought my output was a little low, but wasn't sure since I'd changed several things.  I added your jumper and went from -1 dBm to +8 dBm output.  

73-

Nick, WA5BDU

Builder Alert !! - 5109 SSNA C7 - Alert!

N5IB
 

Thanks for the catch, Jerry.

Indeed, I left off the trace between the bottom pad of C7 and the emitter pad of Q1.

When installing C7 just bend the lead over to Q1's emitter pad.

I've updated the Builder Alert PDF with a diagram (rev09NOV13)

Jim, N5IB

Re: ERA-3+ Version passes the smoke test

Jerry Haigwood
 

Mike,

    I finished a ERA-3 version tonight.  I measured the output level before installing the final attenuator and found that I had +7.4 dbm output.  So, my final attenuator value is -17 db.  I am surprised that there is that much difference in the output levels.  Did you remove the DDS low pass filter?  I would really like to see where the output level difference is coming from.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 8:18 PM
To: PHSNA@...
Subject: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City

Re: ERA-3+ Version passes the smoke test

Michael McShan <n5jky@...>
 

No, I have not hacked the DDS yet.  I'll give it a try tomorrow and see what happens.

Mike N5JKY


On Nov 8, 2013, at 9:45 PM, Jerry Haigwood <w5jh@...> wrote:

 

Mike,

    I finished a ERA-3 version tonight.  I measured the output level before installing the final attenuator and found that I had +7.4 dbm output.  So, my final attenuator value is -17 db.  I am surprised that there is that much difference in the output levels.  Did you remove the DDS low pass filter?  I would really like to see where the output level difference is coming from.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 8:18 PM
To: PHSNA@...
Subject: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City

Re: ERA-3+ Version passes the smoke test

Jerry Haigwood
 

Mike,

    Once you check out the DDS fix, you will need to put your power meter calibration into the program at line 125.  Also, you will need to run a sweep from 1-30 MHz with the generator output connected to the power meter and the power meter feeding back into the SSNA.  You will need to record the data using a step size of 100000 Hz (TERM232 allows you to capture a file).  You can send this file to Jim and he will do a curve fit for you (to flatten the response of the DDS).  He will send you 6 coefficients that you will enter into the program at lines 29-34 (C0 through C5).  Then you should be all set to go!

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 9:57 PM
To: PHSNA@...
Subject: Re: [PHSNA] ERA-3+ Version passes the smoke test

 

 

No, I have not hacked the DDS yet.  I'll give it a try tomorrow and see what happens.

 

Mike N5JKY


On Nov 8, 2013, at 9:45 PM, Jerry Haigwood <w5jh@...> wrote:

 

Mike,

    I finished a ERA-3 version tonight.  I measured the output level before installing the final attenuator and found that I had +7.4 dbm output.  So, my final attenuator value is -17 db.  I am surprised that there is that much difference in the output levels.  Did you remove the DDS low pass filter?  I would really like to see where the output level difference is coming from.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 8:18 PM
To: PHSNA@...
Subject: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City

Re: ERA-3+ Version passes the smoke test

Michael McShan <n5jky@...>
 

One thing I should mention - I chose to wire mine for a 12V supply.  How are you powering your unit?  If you're using the Arduino USB, is it possible that the output is affected?

Mike N5JKY

On Nov 8, 2013, at 10:28 PM, Jerry Haigwood <w5jh@...> wrote:


Mike,

    Once you check out the DDS fix, you will need to put your power meter calibration into the program at line 125.  Also, you will need to run a sweep from 1-30 MHz with the generator output connected to the power meter and the power meter feeding back into the SSNA.  You will need to record the data using a step size of 100000 Hz (TERM232 allows you to capture a file).  You can send this file to Jim and he will do a curve fit for you (to flatten the response of the DDS).  He will send you 6 coefficients that you will enter into the program at lines 29-34 (C0 through C5).  Then you should be all set to go!

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 9:57 PM
To: PHSNA@...
Subject: Re: [PHSNA] ERA-3+ Version passes the smoke test

 

 

No, I have not hacked the DDS yet.  I'll give it a try tomorrow and see what happens.

 

Mike N5JKY


On Nov 8, 2013, at 9:45 PM, Jerry Haigwood <w5jh@...> wrote:

 

Mike,

    I finished a ERA-3 version tonight.  I measured the output level before installing the final attenuator and found that I had +7.4 dbm output.  So, my final attenuator value is -17 db.  I am surprised that there is that much difference in the output levels.  Did you remove the DDS low pass filter?  I would really like to see where the output level difference is coming from.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 8:18 PM
To: PHSNA@...
Subject: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City



Re: C7 Connection to 2N5109 Emitter

W0PWE
 

Wow that's a pretty strong output Nick. I increased the emitter resistor (R11) and got it down to around -10dBm at 10MHz.


Mine has noticable roll off above 10MHz also. The numbers below are with the original R11 = 5.6 ohms:

Freq(MHz)  Output(dBm)

1.8             -5.6

5.1             -5.6

10.0           -6.3

19.8           -9.7

29.7           -14.9


DDS output drops about 1.7dB and my filter attenuation increases by about 6.5dB over that frequency range.



---In phsna@..., <kennnick@...> wrote:

Wow, nice catch, Jerry.  I thought my output was a little low, but wasn't sure since I'd changed several things.  I added your jumper and went from -1 dBm to +8 dBm output.  

73-

Nick, WA5BDU

Curve Fitting Instructions

N5IB
 

This morning I dashed of a first cut at instructions for determining the compensation for the frequency response of the SSNA. Look in the Files section for a new PDF file..

I'll probably refine this later, but wanted y'all to have something to start with, since I'll be out of pocket for most of today and tomorrow.

Jim, N5IB

Re: C7 Connection to 2N5109 Emitter

Jerry Haigwood
 

Increasing the emitter resister is not recommended since it will affect the input impedance.  The input/output is designed for 50 ohms.  It would be much better to adjust the attenuator values.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of j.b.hall@...
Sent: Saturday, November 09, 2013 8:42 AM
To: PHSNA@...
Subject: [PHSNA] RE: C7 Connection to 2N5109 Emitter

 

 

Wow that's a pretty strong output Nick. I increased the emitter resistor (R11) and got it down to around -10dBm at 10MHz.

 

Mine has noticable roll off above 10MHz also. The numbers below are with the original R11 = 5.6 ohms:

Freq(MHz)  Output(dBm)

1.8             -5.6

5.1             -5.6

10.0           -6.3

19.8           -9.7

29.7           -14.9

 

DDS output drops about 1.7dB and my filter attenuation increases by about 6.5dB over that frequency range.



---In phsna@..., <kennnick@...> wrote:

Wow, nice catch, Jerry.  I thought my output was a little low, but wasn't sure since I'd changed several things.  I added your jumper and went from -1 dBm to +8 dBm output.  

 

73-

 

Nick, WA5BDU

Re: ERA-3+ Version passes the smoke test

Jerry Haigwood
 

Mine is also powered by +12V.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 11:05 PM
To: PHSNA@...
Subject: Re: [PHSNA] ERA-3+ Version passes the smoke test

 

 

One thing I should mention - I chose to wire mine for a 12V supply.  How are you powering your unit?  If you're using the Arduino USB, is it possible that the output is affected?

 

Mike N5JKY

 

On Nov 8, 2013, at 10:28 PM, Jerry Haigwood <w5jh@...> wrote:



 

Mike,

    Once you check out the DDS fix, you will need to put your power meter calibration into the program at line 125.  Also, you will need to run a sweep from 1-30 MHz with the generator output connected to the power meter and the power meter feeding back into the SSNA.  You will need to record the data using a step size of 100000 Hz (TERM232 allows you to capture a file).  You can send this file to Jim and he will do a curve fit for you (to flatten the response of the DDS).  He will send you 6 coefficients that you will enter into the program at lines 29-34 (C0 through C5).  Then you should be all set to go!

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 9:57 PM
To: PHSNA@...
Subject: Re: [PHSNA] ERA-3+ Version passes the smoke test

 

 

No, I have not hacked the DDS yet.  I'll give it a try tomorrow and see what happens.

 

Mike N5JKY


On Nov 8, 2013, at 9:45 PM, Jerry Haigwood <w5jh@...> wrote:

 

Mike,

    I finished a ERA-3 version tonight.  I measured the output level before installing the final attenuator and found that I had +7.4 dbm output.  So, my final attenuator value is -17 db.  I am surprised that there is that much difference in the output levels.  Did you remove the DDS low pass filter?  I would really like to see where the output level difference is coming from.

Jerry W5JH

"building something without experimenting is just solder practice"

 

From: PHSNA@... [mailto:PHSNA@...] On Behalf Of Michael McShan
Sent: Friday, November 08, 2013 8:18 PM
To: PHSNA@...
Subject: [PHSNA] ERA-3+ Version passes the smoke test

 

 

Well, my build seems to have passed the smoke test OK. I was able to program it to sweep between 2000 khz and 10000 khz with 500 hz steps and watch the output on my O-scope and frequency counter. The output looks like an OK sine wave. The -10 dBm output is exactly that on my W7ZOI/W7PUA power meter and the output before R19 is 0 dBM. My little homebrew bench frequency counter is a bit "deaf," so I probably will remove this resistor for the counter output (unless there is a compelling reason not to).

I noticed that R7 did get kind of warm, so I may replace the 1/2W one with a 1W version. Seems like a good idea.

Now I have to start thinking about making a case for this FB project.

Thank you, Jim and Jerry! Well done, gentlemen.

73, Mike N5JKY
OK City

 

 

Re: C7 Connection to 2N5109 Emitter

Nick Kennedy
 

Yeah, I did several things to bring the output up:

I eliminated the first 3 dB attenuator at the input to the filter.
I changed the attenuator at the input to the amplifier to -3 dB from -10 dB
I changed the output attenuator from -12 dB to -3 dB

But I didn't realize all this gain in the output because I also increased the size of R11 from 5.6 ohms to 18 ohms to reduce the amplifier gain and extend its BW.

Checking my output just now with my old AD8307 log power meter, it's looking pretty flat:

MHz      dBm
1            8
4            8
8            8
14         8
21         7
30         6

73-

Nick, WA5BDU



On Sat, Nov 9, 2013 at 8:42 AM, <j.b.hall@...> wrote:
 

Wow that's a pretty strong output Nick. I increased the emitter resistor (R11) and got it down to around -10dBm at 10MHz.


Mine has noticable roll off above 10MHz also. The numbers below are with the original R11 = 5.6 ohms:

Freq(MHz)  Output(dBm)

1.8             -5.6

5.1             -5.6

10.0           -6.3

19.8           -9.7

29.7           -14.9


DDS output drops about 1.7dB and my filter attenuation increases by about 6.5dB over that frequency range.



---In phsna@..., wrote:

Wow, nice catch, Jerry.  I thought my output was a little low, but wasn't sure since I'd changed several things.  I added your jumper and went from -1 dBm to +8 dBm output.  

73-

Nick, WA5BDU


Attaboys

N5IB
 

Just wanted to send out a set of "Official Alpha Tester Attaboys" to these guys who have found my mistakes and saved the rest of y'all much weeping and gnashing of teeth. Perhaps certificates are warranted  :^))

Don Lweis
Jerry, W5JH
Nick, WA5BDU
Michael, N5JKY
Jerry, W0PWE

Thanks to them I can now build my own SSNA confident the blessed thing will work!

73
Jim, N5IB