Dear al,

The newest Power and SWR meter design and for sure home made, small and really accurate.
See for more information :
/g/RadioStuff

Also nice to see the one of a kind CWModem......
73' PD0LEW, Johan Holstein

Two questions:

When I tune in 10MHz WWV in LSB mode on the uBITX, the frequency reads 9.998.500.? Does it mean the rig is out of calibration or is it supposed to read like this in LSB mode?? I note that Fc-BW/2 is exactly what I'm reading on the display so it makes me suspicious.? Before I go through the calibration procedure and potentially screw things up further, I was hoping someone can confirm.

BTW, the calibration procedure on hfsignals.com just says find an AM broadcast signal and says nothing about the mode the rig is set to (USB/LSB).? Doesn't the mode matter during calibration?? Thanks!

73 Mike KK7ER

P.S. How 'bout a free PCB for the help?? I'm looking to build this: /g/BITX20/message/54034

I have a T1 its the ideal pocket sized ATU.? Excellent battery life? I replace
it once a year on general principle..? I believe it can tune?a nail on 80m.
For less than 12W its bullet proof L tuner.? It tunes up well even at 1W
and less.? It does so in less than 5 seconds.

One hard note while they rate it for a max of 20W I've blown detector
diodes?on 40M for some antenna cases.? Its related to power under
some reactive condition where the voltage at the atu output exceeds
diode tolerance voltage.? It does not show tuning a HW wire at 15W.?
It only takes out one diode of the pair.

That said for under 15W its easy to use and works very well.

I use it with the:
KNQ7A (40M) SSB
Slop bucket 20 SSB
Argonaut 505 (all bands) SSB mostly
Tempo-one QRP tube radio (modified,? 12BY7 driver as final about 4-5W)
HB 40M SSB
HB20M SSB
HB15M SSB
HB 10M SSB
Kistandparts 1W CW
WM20? SSB
PSK20 PSK31
FT817 with matching interface cable HF

Allison

Allison,

Yup, the blowby around the LPF's is at the top of the list of things to fix.
Most forum readers seem to have that one figured out.
I did say "should" not "will" for a reason.

Also, as you originally brought up long ago, those 7dBm mixers are seeing nothing like 7dBm
from the si5351, which means they are overdriven at lower signal levels than they should be.
Worth keeping in the list when talking about trouble around those IF stages.

Jerry

On Thu, Aug 30, 2018 at 11:32 AM, Gordon Gibby wrote:

And I've learned a TON!!!

I think that's what it's all about.....intended or not.?

73 Kees K5BCQ

开云体育

yup -- cheap radio, early attempts!!? ?the key is to offer constructive improvements by spotting where signals are going the wrong way.? ?Perhaps Ashar can make the needed improvements.

?

I'm a lot happier nowthat I know I can get the thing to? basically work on 80/40/30 --- the prime bands for digital emergency comms for me.? ? The ability to switch so rapidly from receiver frequency to another is a vast asset for an ALE system.? ?I may hang a LPF somewhere just above 20 M on the output and that should clobber the remaining spurs for me from 80/40/30/20 meter digital operations.??

And I've learned a TON!!!

Gordon

I can't comment on ft8, but I managed southern Ontario to northern Brazil with my bitx40 on 40cw and end fed wire

If the ATU is close to the antenna I would opt for an auto. If you use the atu close to the rig I would prefer the manual.

On Thu, Aug 30, 2018 at 11:01 AM, ajparent1/KB1GMX wrote:

Its all related to board layout and other paths like shared?
and unfiltered power distribution.? A? signal in one area presents it self at some level elsewhere
where its not wanted.

Notes are coming faster than I can read them..............

There are also simple #43 material ferrite chokes which can be added to reduce conducted RF on power source lines with no loss in DC current capability.

I still believe "there is a pony out there" .....small handful of parts and a good dual relay switched LPF board.

73 Kees K5BCQ?

On Thu, Aug 30, 2018 at 10:42 AM, ajparent1/KB1GMX wrote:

Reason is the 45mhz amp picked up stuff from the power amp
and adds it to the output creating a greater number of products related to
harmonics of the lower bands and the unfiltered products of the higher bands.

Allison,

THAT is a problem.

Since there is not much shielding between sections on a uBITX, wouldn't it help going to RD16HHF1 (or RD15) part, so at least the MOSFET Source lead can be solidly grounded vs tying it to a "heatsink antenna". I would also make those MOSFET leads ALL "REALLY short".

Another thing about RF power lead bypass caps .....100nF is good but they also ought to have a 1nF-10nF cap in parallel.

73 Kees K5BCQ

On Wed, Aug 29, 2018 at 08:53 PM, Jerry Gaffke wrote:

The strength of the spur will depend on how? loud you yell into the mike? (and thus overdrive the mixers).
I believe it is typically 30dB down or so.

The key is since there is excess IF gain yelling is not needed.? The last mixer is
over-driven by anywhere from 7 to 12 DB for openers and even pushing a smaller
amount gets you to more of same.

The closer we looks the worse it is.? Its all related to board layout and other paths like shared?
and unfiltered power distribution.? A? signal in one area presents it self at some level elsewhere
where its not wanted.

Allison

Jerry,

I also said that.? However it was assumed the 20M LPF worked as we found
out later it does not.

The big LPF (9 element at T1) however has a corner frequency of about
33mhz (33.68 mhz in mine) and that is the 3db point so below that its an
open pipe.

Rather than hash minor points the issue is below 20mhz the output filters
do not work as designed.? Warren showed a lot of work to prove that.? ?
Above 20mhz there is no filtering.? Spurs below? the cutoff for the 10M
output LPF and the other 33mhz filter have a unfiltered path.

Now we add to that high power output on the lower bands tends to couple
into the IF especially the 45mhz IF and contribute new tones to the mix
increasing the products at the output.? Several of us have seen that but?
it was not understood why.? ?Best example is 80M SSB at 10W or more,
Not only does one see harmonics leaking by the filter but there are a
host of other seemingly random products that are the result of the output
signal and harmonics plus 45mhz and OSC2.? Push just a little for say
15 to 20W and those grow alarmingly.

Allison

First SSB contact with new uBITX was with JE6EHP on 20m with an end-fed random wire. Nice long chat. Well over 8,000 Km. -Don

The Elecraft T1 seems pretty ideal, but I've never used it.? Does anyone else have experience with that tuner?

On Tue, Aug 28, 2018 at 04:25 PM, Rod Davis wrote:

WARNING: q911,q912,q92,q93,q96,q97 all dissipate at least 296 mW. That
means 250 mW transistors are not acceptable.

So, in searching for a better Ft device for the TX chain:
the BFR106 has the dissipation, but the 3.5 to 5GHz Ft invites instability
the MMBT10? ?? lists dissipation at 225 mW, so it may not be a good candidate
the MMBT2369 lists dissipation at 225 mW, so it may not be a good candidate
the DTX2222A has the dissipation, but the Ft is not better than 2n3904, and
the footprint is not compatible with the board.

I was wondering about the reasoning behind using several parallel 2N3904 transistors in the uBITX circuit.....they are inexpensive, but why not just use a single 2N2222 ?

73 Kees K5BCQ

Lower the gain of the two TX IF amps to 11db each.
There is excess gain.

Less pad and less gain.? Why? the higher gain picks up stuff out of band
and adds it to the mix, result is more and greater spurs.? The pad lowers
the carrier to signal as the carrier is leakage around the balanced
mod and filter.

The problem with padding the 45mhz filter was I tried it and no useful effect.
Lowering the gain was more productive and adding a filter to the 45mhz output?
helped as well.? Reason is the 45mhz amp picked up stuff from the power amp
and adds it to the output creating a greater number of products related to
harmonics of the lower bands and the unfiltered products of the higher bands.
The biggest reason is coupling through power leads and current loops in the
ground plane.

Short explanation is too much stuff getting into places it should not be creating
more new stuff.

Simple fixes like changing a resistor or pad does not fix that.

Allison

On Thu, Aug 30, 2018 at 08:43 AM, Chuck WB6GPO wrote:

How about adopting an informal convention of putting a TOPIC PREFIX on the thread title?

Like the already available hashtags that almost never get used?? It is a very good idea.? It just gets lost in the implementation.
?
--

New Zealand, ssb 3w qrp with the Spanish ILER20. I logged that as an ordinary qso. I was not in the States of course... But in Italy. New Zealand is exactly on the other side of planet earth from my qth. Just let me say that if you hear anything around s9 or more if you use a qrp you can have a qso, of course it will be more difficult during a pile up. So give up FT8 and come back to cw-ssb!

On 6M K9ppy and W4IMD using HB portable rig at 820mW. into the
4 element beam at 33ft.??

For HF:
For 5W using my Argonaut 505 on 40m the best was SV54rwu from W1 country.
For the Slopbucket 20, DL5ARH
These two using LNR EF-quad at 30ft.

For the KNQ7A (40M) VK3 foundation station while mobile (8ft centerloaded whip).
That radio does about 7-8W? at 13.8V.

For 10m during the last solar minimum all of South America, the carib islands,
Falklands and Antartica all using 4W SSB HB into one of two antennas the
PAR EF40/20/10? and the K6STI 10M loop with the top 20ft up.? That was
over a 5 month period.? ?I credit the K6STI 10M loop a 73" wide by 146" high
rectangle for the better part of all that as it was aimed to favor South America.
The par EF40/20/10 as set up then favored east west paths.

Antennas that are oriented in the desired direction and high enough to
be effective seem to make a difference.

Allison