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I heard Bill N2CQR and a couple others. I called CQ but got no responses (that I could hear).

John
KC9OJV

If you are running Allard's latest code, frequency should be reasonably stable.
If it's not stable, you should probably address it rather than hide it.
Though once that's cleaned up, the additional measures I mentioned in my previous post are worth considering.

The unstable freq and the buzz are likely related.
Perhaps trash on the power into the raduino, trouble around the raduino regulator, or all them wire connections talking to each other.
If you have long antenna connection wires and/or long tuning pot wires, try shortening those and twisting up each cable so ground and signal are well coupled.
Maybe use coax.?

Hi Graham,
I got stung by DHL when I ordered an AirSpy SDR receiver shipped by them rather than China mail -? that added ?50 to the cost! My BITX arrived very quickly via India post and no claim for VAT or other charges. Very well packed in its own box for the board and components.
73,
Ian
G3TVU

I have the same bad experience with DHL here in Sweden.

I will never use term again.

With India post there was no problem, fast and no extras..

SM6ERS / Ingvar

Add a cap to ground at the raduino end of the tuning pot wire if you have not already done so, same 0.1uF as the WireUp instructions say to put at the pot.
Allard has made a number of improvements to freq stability with his sketch, including oversampling of the pot and the flutter fix.
He also disables freq changes while transmitting.
Could go into Allard's settings menu and reduce the size of the pot tuning range, that would help reduce the tendancy to jump around.
Could adjust the sketch to disable any frequency changes (except rit) once you hit the ptt button, this ptt freq lock ?gets turned off when you try to move the tuning knob more than a khz or so.
Or could add a lock switch, adjust the code so when the sketch sees this switch on it ignores the tuning pot and leaves the operating freq where it's at.

I added 0.1 uF caps between pin 7 and ground, +12 and ground and PTT and ground with no improvement to the buzz noise on tx.

I put resistors in line of the +12 to the mini board, and found that the mute did not function above 3.3k.? The mute did function at 390 ohm and there was a delay of a second or two before the buzz started.

So no real improvement yet.

I can fix the buzz problem with a relay, which may also fix the keyup pop after transmit.

The unstable frequency on transmit is a bigger problem so I will shift my attention to that.? Any ideas for what to try?

just normal for DHL?
I will never use them again

I just successfully integrated a SOTABEAMS Laserbeam DSP Audio filter module into my BITX40.?

http://www.sotabeams.co.uk/dual-bandwidth-filter-modules-ssb-cw/

I am using Raduino V 1.20.1 with the CW mods suggested by Allard in the accompanying documentation and up to now have been
using the same filter (the General Purpose Module with 2.4 Khz WIDE and 300 Hz NARROW passbands) externally mounted into a small
box. I decided that it worked well enough and is cheap enough ($US32) that it warranted installing one directly into the rig for convenience.

I inserted the filter into the circuit at label M2, by removing the wire on pin 1 of ?the VOLUME POT and connecting that to the DSP Filter input and then
connecting the?Filter output back to Pin 1 of Volume control. ?I did need to put a 0.1uF coupling capacitor in series with the output of the filter as I experienced
some weird interactions between the filter and the Volume control / LM386 operation (audio was cutting out with Volume control rotated past 11 o'clock).
The coupling capacitor in series fixed that. ?I also opted to provide ?Bypass switching for the filter via a DP3T switch, simply moving M2 between the input and output of the?filter while keeping the filter powered (not enough poles on my switch to also control the filter power). The filter only draws 30mA of current.
What I discovered ?with the filter bypassed?yet still powered, is that it was generating some hash on its power leads that was getting back into the BITX40 audio.
With the filter in-line it conveniently seems to?filter out its own hash ;-) ?I resolved this issue by using VK3YEs ?Digital VFO?power lead filter in series with the power leads going to the filter. It ?consisting of two 220 uF?electrolytic caps to ground with a 12 Ohm resistor connected in series between the + leads of the caps. ?

In the WIDE setting the filter does cleanup the SSB audio making it sound better, but where it really shines is for CW. ?
The 300 Hz passband is centered at 700Hz?so it is necessary to set the Raduino Sidetone frequency to be the same value (this also controls the TX offset).
Installing the optional ?signal LED gives you visual?indication that the CW signal you are tuned to is in the middle of the filter passband, making CW ?tuning very simple. ?The end result is a much more?pleasant experience for operating CW on the BITX40. ?
Also if you have any remnants of clicks from tuning etc, the filter does a great job of stripping those?out of the RX audio.?

This is by far he best audio filter I have encountered. It outperforms any analog audio filter I have ever used.?

The only minor issue that I still have is that the filter will sometimes overload on very strong signals. The filter input is internally protected from overload but it will
cause some audio distortion, it seems mostly on SSB. I am using the default gain setting on the filter (RB12 floating not grounded) and this works well.
At this point I am simply?using the switch to BYPASS the filter on exceptionally strong signals but I am thinking as a future enhancement perhaps a
properly adjusted audio-derived AGC circuit?inserted ahead of the DSP filter would resolve this and eliminate the need for bypassing.

Cheers?

Michael VE3WMB / VA2NB?

P.S. SotaBeams also makes a similar SSB-specific filter with WIDE=2.4 Khz and Narrow = 2.1 Khz and another version with a continuously variable
bandwidth and passband centre frequency, that is controlled via a rotary encoder.?This would be a little more versatile.?

P.P.S. The usual disclaimer .. I have no connection to SOTABEAMs, financial or otherwise, I am just a very satisfied customer.?

hi

there have been various posts on this subject - the general opinion is DO NOT USE DHL

i received my bitx40 via india post and royal mail and did not pay vat but royal mail may have recently changed their policy cos my wife received a gift from daughter in new zealand and had to pay vat plus ?8 handling charge.

at least if you do have to pay vat to royal mail it will be less than dhl

terry gm4dso

Look for a knob for a 1/8" shaft. I think that works.
--
John - WA2FZW

I know that many people have been adapting the original on/off volume knob using a drilled out 1/4" standoff or replacing the entire control with something that takes a standard size knob but has anyone found a knob that natively fits that shaft?

Curt

On Mon, Jul 31, 2017 at 03:42 am, Graham Coltman wrote:

I recently received my BitX40 but was a bit surprised to be charged VAT+DHL fee (of a similar amount) for handling the VAT

Didn't have that problem here in the US. Just the $10 for DHL shipping.
?
--
John - WA2FZW

Hello Graham, not exactly UK, but I had a similar experience receiving the bitx to Italy, just that the added cost (taxes+dhl duties) were almost 40€.

I believe that in general, for Europe, receiving the bitx with dhl is not worth, unless you wanna end up paying double.

73 de IU2HXT Paolo

Lots of QSB and QRM, but worked Tom VE3THR and Paul KC8WBK. Heard N2CQR, KC1FSZ and KI4PSR plus a couple of others.
Conditions didn't start to improve until about 7:30 or 8pm.
AL - VE3RRD

Hi All (in the UK)

?

I recently received my BitX40 but was a bit surprised to be charged VAT+DHL fee (of a similar amount) for handling the VAT. These added 40% to the total cost (including the extra shipping charge). I just wanted to check that others had the same charges applied?

?

73, Graham M6LSO