|
Well, that didn't go well.
Looking at it, the two toroids on the left are a little close.
I have a layer of grounded copper foil between
the PCB and the filter (insulated of course).
I might rebuild the filter lying flat.
It looks like I only have 40m and 30m for SSB now.
Input is 1KHz 50mv p-p.
Harmonics on CW follow the spur tables.? Only 80m is not usable
there.
Before
After
|
Ok, I have mounted the LPF filter in a Manhattan style without any glue so I had more flexibility in positioning the toroids, which are very light. I am not sure I understood your spreadsheet. The filter was assumed to reduce some spurs above the 17m band. I'd tuned at 28mhz you should see a 17mhz spur quite attenuated than without this filter (28+17=45mhz). At 21mhz the spur at 28mhz should be attenuated (21+24=45mhz), so on and so forth for any frequency above the 17m band. You show spurs that are not related in this way.
Il 13/apr/2019 11:55, "John Sutter" < jds@...> ha scritto:
Well, that didn't go well.
Looking at it, the two toroids on the left are a little close.
I have a layer of grounded copper foil between
the PCB and the filter (insulated of course).
I might rebuild the filter lying flat.
It looks like I only have 40m and 30m for SSB now.
Input is 1KHz 50mv p-p.
Harmonics on CW follow the spur tables.? Only 80m is not usable
there.
Before
After
|
|
|
I was about to dig into my parts bin searching for toroids and
I remembered I had those left over.
I'll probably have to order some 30 uH parts.? 27 and 33 are easy to get locally, 30 maybe not.
Sounds like the way to go, thanks.
John
toggle quoted message
Show quoted text
On 4/13/2019 6:28 AM, Raj vu2zap wrote: John,
Very neat job on L5 and L7.
Make the 45MHz IF new filter with SMD parts. What seems to be the culprit is any vertical wire leads in that area
causes trouble. Solder the SMDs directly on the board.
When I get back to town tomorrow I will try it.
Raj
|
John
You aren't clear in this message which spurs you are trying to solve, nor where you are putting this new filter?
If this is an added 45 MHz filter, adjacent to the mix to and from RF, then its objective is to reducing non harmonic mixing spurs typically found on 15, 12, and 10 meters. A common problem with v3 and v4, maybe less so on v5. Note this mixing only happens on ssb. In the last dB or to audio drive is a big deal. If my rig measured say 41 dB down at full output, note if I ran digital at less output I would likely be okay. For voice one might debate the last dB since our voices don't stay at peak amplitude.
Curt
|
Good point.? Earlier in this thread it
was recommended that I add
a LPF to get rid of the spurs on 15, 12, and 10m.
It was my understanding that the following (from Ashar I believe)
is the one (though #1 is backwards).
I've picked up some 0.33 uH SMD inductors I'll try today.
If that's not the right one, I could use a pointer to it.
On 4/13/2019 12:45 PM, Curt via Groups.Io wrote:
toggle quoted message
Show quoted text
John
You aren't clear in this message which spurs you are trying to
solve, nor where you are putting this new filter?
If this is an added 45 MHz filter, adjacent to the mix to and from
RF, then its objective is to reducing non harmonic mixing spurs
typically found on 15, 12, and 10 meters. A common problem with v3
and v4, maybe less so on v5. Note this mixing only happens on ssb.
In the last dB or to audio drive is a big deal. If my rig measured
say 41 dB down at full output, note if I ran digital at less
output I would likely be okay. For voice one might debate the last
dB since our voices don't stay at peak amplitude.
Curt
|
John
very good - I am interested in your results on this, and which ubitx version you have.?
on 12m you might notice 2 spurs on either side of the carrier about 5 MHz apart,? the v5 comes with a LPF similar to you have drawn already installed.? I tried one using SMT inductors on my v4 -- not much change -- not surprising since the spurs are close to carrier.? I did change R26 on mine, but I still have stock 2n3904 transistors (if I were bored I might see what better old stock transistors I might have for 45 MHz - but that might be an adventure).?
on your 12 and 10m readings you are mostly focused on harmonics of the RF output.? either your close-in spurs are good -- or you didn't notice them??
you could be a little confused as this LPF is described as filtering harmonics of 45 MHz.? one of those 2 spurs I mentioned seems to be 90 MHz - the LO frequency.? the other spur I think is the PA signal leaking back to the mixer, and mixing again. ?
with any changes you make in this part of the circuit - do see if you get any reduction of CW output power -- mine does a bunch on 40 and 80 meters. ?
73 Curt
?
|
This is a V3 that has new relays and
the L5/L7 fix and working on the LPF
that I believe is before the mixer, but I'm not sure.
I've been taking measurements at each step.? So far not
significant drops.
I had some crazy readings which where later explained by one of
the techs saying,
"don't use that one..." but at least it was consistent in relative
readings.
That said, I do see power go down with frequency across all
changes regardless of mods.
I think I saw a mod for that, but that one's probably not for me.?
We'll see.
On 12m I saw 32, 16, and 12Mhz
On 10m, I had 32, 16, and 12MHz and then 7.86 MHz
On 4/13/2019 3:22 PM, Curt via Groups.Io wrote:
toggle quoted message
Show quoted text
John
very good - I am interested in your results on this, and which
ubitx version you have.?
on 12m you might notice 2 spurs on either side of the carrier
about 5 MHz apart,? the v5 comes with a LPF similar to you have
drawn already installed.? I tried one using SMT inductors on my v4
-- not much change -- not surprising since the spurs are close to
carrier.? I did change R26 on mine, but I still have stock 2n3904
transistors (if I were bored I might see what better old stock
transistors I might have for 45 MHz - but that might be an
adventure).?
on your 12 and 10m readings you are mostly focused on harmonics of
the RF output.? either your close-in spurs are good -- or you
didn't notice them??
you could be a little confused as this LPF is described as
filtering harmonics of 45 MHz.? one of those 2 spurs I mentioned
seems to be 90 MHz - the LO frequency.? the other spur I think is
the PA signal leaking back to the mixer, and mixing again. ?
with any changes you make in this part of the circuit - do see if
you get any reduction of CW output power -- mine does a bunch on
40 and 80 meters. ?
73 Curt
?
|
The power mod is easier then figuring out spurs and harmonics. ?You certainly don’t need that expensive scope for it :) I just did mine and I guess I’m getting the 14w on 80 and 6w on 10 like Allison mentioned. She does best power wise on 20 meters for me, not Alison but my uBitx :)
I’m watching your work here though as I want to do the filtering Farhan mentions and use my poor mans analyzer to see if I notice a difference.?
And....I don’t mean to hijack the post by hey Raj what do you think about my L5, L7 work? :)?
 ?
Can someone tell me what C215 does? Mine went bad on me from attaching the IF out for SDR so for a while I was getting poor performance until I replaced it. I didn’t have a 1206 and not the right value of 0805 so I used a 22uf pin hole ceramic cap. Just curious what that part dose right before it goes into the filter. ?Now with the new, part my SSB audio is peaking to full wattage nicely.?
Joe? KD2NFC?
toggle quoted message
Show quoted text
On Apr 13, 2019, at 6:50 PM, John Sutter < jds@...> wrote:
This is a V3 that has new relays and
the L5/L7 fix and working on the LPF
that I believe is before the mixer, but I'm not sure.
I've been taking measurements at each step.? So far not
significant drops.
I had some crazy readings which where later explained by one of
the techs saying,
"don't use that one..." but at least it was consistent in relative
readings.
That said, I do see power go down with frequency across all
changes regardless of mods.
I think I saw a mod for that, but that one's probably not for me.?
We'll see.
On 12m I saw 32, 16, and 12Mhz
<pjeijlfghkjpbbdb.jpg>
On 10m, I had 32, 16, and 12MHz and then 7.86 MHz
<cpmofleofcibhidm.jpg>
On 4/13/2019 3:22 PM, Curt via Groups.Io wrote:
John
very good - I am interested in your results on this, and which
ubitx version you have.?
on 12m you might notice 2 spurs on either side of the carrier
about 5 MHz apart,? the v5 comes with a LPF similar to you have
drawn already installed.? I tried one using SMT inductors on my v4
-- not much change -- not surprising since the spurs are close to
carrier.? I did change R26 on mine, but I still have stock 2n3904
transistors (if I were bored I might see what better old stock
transistors I might have for 45 MHz - but that might be an
adventure).?
on your 12 and 10m readings you are mostly focused on harmonics of
the RF output.? either your close-in spurs are good -- or you
didn't notice them??
you could be a little confused as this LPF is described as
filtering harmonics of 45 MHz.? one of those 2 spurs I mentioned
seems to be 90 MHz - the LO frequency.? the other spur I think is
the PA signal leaking back to the mixer, and mixing again. ?
with any changes you make in this part of the circuit - do see if
you get any reduction of CW output power -- mine does a bunch on
40 and 80 meters. ?
73 Curt
?
<cpmofleofcibhidm.jpg>
|
Joe
C215 is part of the matching circuitry used with the 45 MHz xtal filter -- 0.1 uF is a pretty large value at 45 MHz -- and it is large enough that it resonates with the coil way above this.? it seems to be a capacitive voltage divider to aid in impedance matching the filter.? possibly what you used is just fine -- I don't fret if I have to replace a SMT with a leaded part.? at these low frequencies the physical size of the cap isn't a big deal - when it fits the space.?
John
FB on your mods - those relays are said to often to fix the harmonics, and sometimes also help with mixer spurious.? the new filter you added is intended to fix SSB spurs on 15/12/10m.?
on 12m I think I see your spurious down at - 39 dBc.? that is ever so close to the goal (much better than my - 34 dBc) that if you experiment with slightly less audio drive you may be compliant enough.?
I think what you did was adding a new LPF placing it between the 'bi-directional amplifier' and the 'final mixer on transmit' (aka first receive mixer) - juslike v5.? I am especially curious with this result - and if you think it gave you some spur reduction - great news.? Raj is doubting the vertical orientation but your results seem to be good.? check your CW output now especially on 40 and 80 meters -- hopefully at least 5w on 40m and more on 80m.? (my rig and some v4's appear to be 'haunted' on CW whenever parts are added here to fix the SSB spurs).?
possibly your rig is doing well.? nice instrument you have there.? enjoy your work.
Curt
|
Thanks Curt. I probably meant C212 which is 22pf. Gets a little rough remembering component numbers when youre trying to recount. :) ?
toggle quoted message
Show quoted text
On Apr 13, 2019, at 8:56 PM, Curt via Groups.Io < wb8yyy@...> wrote:
Joe
C215 is part of the matching circuitry used with the 45 MHz xtal filter -- 0.1 uF is a pretty large value at 45 MHz -- and it is large enough that it resonates with the coil way above this.? it seems to be a capacitive voltage divider to aid in impedance matching the filter.? possibly what you used is just fine -- I don't fret if I have to replace a SMT with a leaded part.? at these low frequencies the physical size of the cap isn't a big deal - when it fits the space.?
John
FB on your mods - those relays are said to often to fix the harmonics, and sometimes also help with mixer spurious.? the new filter you added is intended to fix SSB spurs on 15/12/10m.?
on 12m I think I see your spurious down at - 39 dBc.? that is ever so close to the goal (much better than my - 34 dBc) that if you experiment with slightly less audio drive you may be compliant enough.?
I think what you did was adding a new LPF placing it between the 'bi-directional amplifier' and the 'final mixer on transmit' (aka first receive mixer) - juslike v5.? I am especially curious with this result - and if you think it gave you some spur reduction - great news.? Raj is doubting the vertical orientation but your results seem to be good.? check your CW output now especially on 40 and 80 meters -- hopefully at least 5w on 40m and more on 80m.? (my rig and some v4's appear to be 'haunted' on CW whenever parts are added here to fix the SSB spurs).?
possibly your rig is doing well.? nice instrument you have there.? enjoy your work.
Curt
|
I'd say C212 and L7 form one matching network, C214 and L5 form another matching network.
As Curt noted, the 0.1uF caps at C211 and C215 are extremely large at 45mhz, pretty much 0 ohms AC impedance.
They are there to prevent any DC across the quartz crystal, which could permanently degrade it.
Jerry, KE7ER
On Sat, Apr 13, 2019 at 06:44 PM, Joe Puma wrote:
Thanks Curt. I probably meant C212 which is 22pf. Gets a little rough remembering component numbers when youre trying to recount. :) ?
?
|
The LPF as I have understood is aimed to remove some specific spurs.
At 21.3mhz without the filter you should see a quite strong 23.7Mhz (21.3+23.7=45). If you don't even detect it, it means the LPF does its work marvellously. The other spurs you see, might be to another issue, if any.
|
toggle quoted message
Show quoted text
At 13-04-19, you wrote: I was about to dig into my parts bin searching for toroids and
I remembered I had those left over.
I'll probably have to order some 30 uH parts. 27 and 33 are easy to get locally, 30 maybe not.
Sounds like the way to go, thanks.
John
On 4/13/2019 6:28 AM, Raj vu2zap wrote:
John,
Very neat job on L5 and L7.
Make the 45MHz IF new filter with SMD parts. What seems to be the culprit is any vertical wire leads in that area
causes trouble. Solder the SMDs directly on the board.
When I get back to town tomorrow I will try it.
Raj
|
Thanks Raj.? I'll pick up some 51pF
caps Monday.? My local parts shop gets worried
if they haven't seen me in a day or two...
I'll try parts I have on hand first.? Otherwise, it'll be time to
put together another
Digikey order...? I noticed I should have some Murata
LQW2BASR33J00L unshielded
parts that I picked up for a Radioberry build.
This is the placement I'm planning, mostly because I'd already cut
the trace from R27 to C10
in two places for the previous filter and this will cover the
cuts.
- John
On 4/14/2019 12:28 AM, Raj vu2zap wrote:
toggle quoted message
Show quoted text
John,
see this earlier post of mine
/g/BITX20/message/62097
Raj
At 13-04-19, you wrote:
I was about to dig into my parts bin searching for toroids and
I remembered I had those left over.
I'll probably have to order some 30 uH parts. 27 and 33 are easy to get locally, 30 maybe not.
Sounds like the way to go, thanks.
John
On 4/13/2019 6:28 AM, Raj vu2zap wrote:
John,
Very neat job on L5 and L7.
Make the 45MHz IF new filter with SMD parts. What seems to be the culprit is any vertical wire leads in that area
causes trouble. Solder the SMDs directly on the board.
When I get back to town tomorrow I will try it.
Raj
|
47pf should be perfect but the inductor needs to be similar to
L5/7
Raj
At 14-04-19, you wrote:
toggle quoted message
Show quoted text
Content-Type: text/html;
charset=utf-8
X-MIME-Autoconverted: from 8bit to quoted-printable by
jax4mhob18.registeredsite.com id x3E8noRV134407
Thanks Raj.?? I'll pick up some 51pF caps Monday.?? My local
parts shop gets worried
if they haven't seen me in a day or two...
I'll try parts I have on hand first.?? Otherwise, it'll be time to
put together another
Digikey order...?? I noticed I should have some Murata
LQW2BASR33J00L unshielded
parts that I picked up for a Radioberry build.
This is the placement I'm planning, mostly because I'd already cut the
trace from R27 to C10
in two places for the previous filter and this will cover the
cuts.
- John
![[]](/g/BITX20/attachment/67806/)
On 4/14/2019 12:28 AM, Raj vu2zap wrote:
John,
see this earlier post of mine
/g/BITX20/message/62097
Raj
At 13-04-19, you wrote:
I was about to dig into my parts bin searching for toroids and
I remembered I had those left over.
I'll probably have to order some 30 uH parts.? 27 and 33 are easy to
get locally, 30 maybe not.
Sounds like the way to go, thanks.
John
On 4/13/2019 6:28 AM, Raj vu2zap wrote:
John,
Very neat job on L5 and L7.
Make the 45MHz IF new filter with SMD parts. What seems to be the culprit
is any vertical wire leads in that area
causes trouble. Solder the SMDs directly on the board.
When I get back to town tomorrow I will try it.
Raj
|
I think I'll need to find some shielded
inductors for this filter as recommended by Raj.
I used the ones I mentioned previously.
I also noticed that I had the function generator set up
incorrectly to drive 50 Ohms
as opposed to high impedance so the actual voltage at the Mic pin
on the uBitx was
more than 100mV instead of 50mV.? The power output at 50mV is very
low, just 10s of mW.
What would be a good max drive voltage for the Mic?
I'll try at different levels to see which spurs move too when I
get a chance.
For CW, all bands were clear though I didn't get a chance to test
80m which seems to be the
worst for me historically.? I updated the FW and didn't figure out
why it didn't want to operate on 80m.
On 4/14/2019 3:33 AM, Raj vu2zap wrote:
toggle quoted message
Show quoted text
47pf should be perfect but the inductor needs to be similar to
L5/7
Raj
At 14-04-19, you wrote:
Content-Type:
text/html;
charset=utf-8
X-MIME-Autoconverted: from 8bit to quoted-printable by
jax4mhob18.registeredsite.com id x3E8noRV134407
Thanks Raj.?? I'll pick up some 51pF caps Monday.?? My local
parts shop gets worried
if they haven't seen me in a day or two...
I'll try parts I have on hand first.?? Otherwise, it'll be time
to
put together another
Digikey order...?? I noticed I should have some Murata
LQW2BASR33J00L unshielded
parts that I picked up for a Radioberry build.
This is the placement I'm planning, mostly because I'd already
cut the
trace from R27 to C10
in two places for the previous filter and this will cover the
cuts.
- John
![[]](/g/BITX20/attachment/68473/2)
On 4/14/2019 12:28 AM, Raj vu2zap wrote:
John,
see this earlier post of mine
/g/BITX20/message/62097
Raj
At 13-04-19, you wrote:
I was about to dig into my parts bin searching for toroids and
I remembered I had those left over.
I'll probably have to order some 30 uH parts.? 27 and 33 are easy to
get locally, 30 maybe not.
Sounds like the way to go, thanks.
John
On 4/13/2019 6:28 AM, Raj vu2zap wrote:
John,
Very neat job on L5 and L7.
Make the 45MHz IF new filter with SMD parts. What seems to be the culprit
is any vertical wire leads in that area
causes trouble. Solder the SMDs directly on the board.
When I get back to town tomorrow I will try it.
Raj
|
Raj vu2zap