Thanks Raj.? I already replaced all 5 relays just to be safe with axicom ones and now also the L5 and L7 fix.? Would it be possible to add a low pass filter into the transmit chain somewhere to prevent that mixer product?



On Fri, Feb 1, 2019 at 10:14 PM, Raj vu2zap wrote:

What inductors did you use, please share a pic.

There is always a carrier leak at 12Mhz and 12-7 = ~5 Mhz could be what you see.

Most spurs are created by the harmonics of the carrier feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes.

Raj



At 02-02-19, you wrote:

Thanks I'll try the two tone test next. Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences. Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter. Wonder what could be producing around 5 MHZ.

I wonder if the v5 board redesign changes next might help. Might see if I can figure out where on the board that could be introduced.

What inductors did you use, please share a pic.

There is always a carrier leak at 12Mhz and 12-7 = ~5 Mhz could be what you see.

Most spurs are created by the harmonics of the carrier feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes.

Raj



At 02-02-19, you wrote:

Thanks I'll try the two tone test next. Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences. Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter. Wonder what could be producing around 5 MHZ.

I wonder if the v5 board redesign changes next might help. Might see if I can figure out where on the board that could be introduced.

What inductors did you use, please share a pic.

There is always a carrier leak at 12Mhz and 12-7 = ~5 Mhz could be what you see.

Most spurs are created by the harmonics of the carrier feeding back to the first BiDi amp. Changing to Axicom relays
eliminates a lot of these dancing dervishes.

Raj



At 02-02-19, you wrote:
>Thanks I'll try the two tone test next.? Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences.? Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter.? Wonder what could be producing around 5 MHZ.
>
> I wonder if the v5 board redesign changes next might help.?? Might see if I can figure out where on the board that could be introduced.

Are they a special type, as I see them on eBay for ?1.11 each? Am I missing something? Postage was just over a pound too.
Have you tried mouser.co.uk <>?
Keith M6OLP
On Fri, 1 Feb 2019 at 14:23, Peter Russell <peter.russell@... <mailto:peter.russell@...>> wrote:
Can someone help me with the part number and supplier ( UK ) for the
680nH smd inductors used to replace L5 and L7.
Just found some on Digikey but they were very small (0603) and they
wanted ?12 for shipping!
Peter G8FWY.
---
This email has been checked for viruses by AVG.

--
Keith Baker - Communications technician (retired)

sorry for wrong typing Raj sir.

regards
sarma
vu3zmv

Thanks I'll try the two tone test next. Tonight I replaced L5 and L7 Raj's fix to see if I noticed any differences. Using LSB on 7.15 into 40db attenuator get-55db main signal and I see some sort of spur at around 5MHZ that is about -85db, doesn't fluctate with voice it's constant when I key the transmitter. Wonder what could be producing around 5 MHZ.

I wonder if the v5 board redesign changes next might help. Might see if I can figure out where on the board that could be introduced.

I did not measure with no sound, as that should be almost 43 db down already (no audio).? At that low of a level you may see things relative to the carrier that leaks through.? I would not expect to see harmonics.? Wonder if the BFO is off so that the crystal filter is not removing the BFO that becomes the "carrier"??

Can you do the test with a dual tone input to the mic?? There is a simple PC 2 tone generator that you can use through the mic to run the test:?


I did a quick test that way before I completed the 2 tone audio circuit from Peter Rachow, DK7IH.

Ran it with a 9v battery.??



Not Pretty, but it works

I also used the "multi tone" setting on my Koolertron signal generator and got the same general results.

To be able to keep the transmitter on, I added a slide switch to the tone board and connected through the 3.5mm plug to the PTT and the tone out to the mic input on the ubitx.? I was careful and monitored the temps on the finals (they did get warm when I had the audio drive too high).

As I stated in the prior email, I used the CW power output reading on my Nissei SWR/Power meter to set the audio drive to get the same power out.? I had adjusted the two tones relative amplitude to each other using the audio spectrum analyzer program that I listed before.? Would like to know the design value for the audio input of the ubitx, would be easy to set that up with a scope.

Net result is that there is a spur issue, though not high enough, nor on a band that I use.? CW harmonics are out of compliance, however there were not above the -43db with the two tone input.? Became just as bad if audio drive was increased to an above CW power level (8.5 watts for me on 40 meters with 13.5 volts to PA only, 12v to rest of rig)

Still learning how to use the tools.? Not exactly as I expected, need to adapt to what is available.? Still think a Siglent or Rigol is in my future shack.

Waiting on the QSX to become available to do comparison testing.

Above are my interpretations of my experiences.? Yours may differ
73
Evan
AC9TU

Can someone help me with the part number and supplier ( UK ) for the 680nH smd inductors used to replace L5 and L7.

Just found some on Digikey but they were very small (0603) and they wanted ??12 for shipping!

Peter G8FWY.