Tim
If you don't get an answer, there is a QRP Labs group on this system that he monitors.
73 Howard

This is a question on the output transformer on the 50W PA from Hans (who appears to read these posts).? This uses a phasing transformer as the power feed.? It seems that the Phasing choke adds an AC? copy of the supply voltage to the supply voltage? on the currently supply leg of the output transformer's primary.?

But this suggests that an amplifier using a phasing choke can't be more than 66 percent efficient? just on the basis of that topology regardless of the basic amplifier (semiconductor ) efficiency.? ?Is that correct or am I missing some vital point ?? ?I realise that the other main RF power transformer topology with a split winding transformer has issues with efficient use of the magnetic core? and? with getting a true RF centre tap (with an assymetric waveform if it is not dead on centre ) so the the phasing choke may be the best of a bad bunch.? ?Comment invited on the efficiency question.

Cheers, Tim F

Thanks, Hans
73 Howard K4LXY

Hi Adam,

Short circuiting X1 did it. The receiver is back to life with the usual performance.

Regards, Pedro LU7DID

I'm guessing that a MOSFET solid state relay will be the way to go. ?The DC line to the transmit LED provides a little over 4v. ?I've not used MOSFET relays before but I plan to experiment with one.
73 Howard

A reed relay is very responsive so it should work, though I'd really like to get rid of the relay. ?Maybe my next project. ?Be sure to put a reverse diode across the relay to prevent damage.
The amp is QSK and Hans, who is the designer, doesn't like relays and has built it without any.?

73 Howard

Folks,

Recently I focus on supply chain and manufacturing in my professional work, and I visited 10 OEM factories in the past two weeks. In my piece, I wrote that it might be good training material to improve skills of technicians if HeathKit still supplies those nice kits for amateur radio, audio, computer and education.



Thanks,
Adam

开云体育

Thanks for sharing this, Howard.

The QRP-Labs 50W amplifier makes a great (and inexpensive) single-band amp for the HT-1A.
To key the amp, a 5v keying line is needed from the HT-1. ?On the HT-1 display board I tapped into the line supplying voltage to the red transmit LED and used that to feed a small reed relay mounted inside the rig's case (with a diode across it), connected to a 1/8" phone jack on the back.

I'll attach the interface circuit I used to provide 5v to key the amp.

73 Howard K4LXY

Folks,

1000 members for the first time.

During the lockdown period, let's build something.

Thanks,
Adam

开云体育

The tracking at??says it departed Shanghai on March 20.

开云体育

Hello Adam

If you feel weird to turn Gain pot in reversed direction, you can de-solder the gain pot and turn 180 degree and use jumper wires to connect like III

I am looking forward to your progress of the building of CS-40V and CS-15V.

Thanks,
Adam

Hi Adam,

Thank you for your kind reply.

Relay seems to be good. Will try during the afternoon the other two tips.

73 de Pedro, LU7DID

开云体育

Hi Dr. Pedro,

Hello,

I've been using the D4D as part of my FT8/WSPR beacon and monitoring station for several months now, very good performance I must say.

However, recently, it stopped working.

It was not able to either transmit nor receive. Replacing the NE602 restored transmission back to life, and reception is working as well.

Transmission chain seems to be Ok. monitoring the signal yield a strong level, or at least compatible with what used to be.

However testing the reception it's able to hear and decode another transmitter at the shack in FT8 with only 4 dB SNR (normal yield should be more like 15 dB), and in fact isn't hearing anything else, even strong signals present in the band.

Any suggestion on a trace and/or test to perform in order to identify which other component might be operating in a faulty way?

Thanks in advance, Pedro, LU7DID

Adam and All,

Yes, I wrote the HT-1A article to Japanese CQ magazine.
The reputation of this small gem rapidly spread in nation wide and this is faster than the damned virus.
My preparation stock in Japan domestic evaporated immediately after the issue. Though IC-705 delivery is postponed, we are still supplying HT-1A.?
I appreciate readers and builders highly praise our voluntary activity to amateur radio society in this severe moment stay inside house.

Both HT-1A kit and assembled are popular. For those who chose the kits, they enjoy winding? toroidal, soldering and adjustment.
They are?able to have transceivers which they build themselves. Beginners only own Yae-com-woods are very impressed?
their homebrew experience. As for who purchased assembled, they enjoy the single super smooth and mild sound
never heard in recent Yae-com-wood transceiver in market.? Even CW keener often agressively evaluate commercial transceiver
prefers the HT-1A. This is the real performance price radio (PPR).?

As my observation, HT-1A looks close to original design of SST. Once we surprised the parts reduced design minimal concept.
Its essential performance is now enhanced to 2-band?a full coverage by digital VFO?and an IRF-510 full gallon final.
USB/LSB-receiving capability make this transceiver?more usable flavor in ham band. Well thought out idea totally changed the shape of radio to a new one.
Strudy chassis is usable in field.?Remembering NorCal design, no harness are inside at all except speaker and battery.
Though I don't have too much expect as SWL radio because it is less sensitivity outside ham band.

See my HT-1A introduction site through your translation site.


Junichi JL1KRA

开云体育

Folks,

Mr. Nakajima

The other day, I received HT-1 at Kinoshita in Obama City, Fukui Prefecture.

HT-1 is complete. But 95% is a finished product? It is not something to be able to say proudly because it did.　Lol

【Production impression】

· The SMD parts were fitted, so it was helpful.

· It is wonderful that the attention points and the mounting order were made appropriate manual using the photograph.

· The idea of switching AF and RF volume is Good.

· It is good to know the adjustment point by the LED of the inside.　

· I was surprised that you put VR for RF.

【Impression of use】

· Receiving sensitivity is very good. I put -120dB from SG and tested it, but i was able to receive it.

· I was surprised to see that the maximum that two buttons and three main dials could do all the control.

· It is good to be able to receive LSB.

· The Auto function of the backlight is indispensable at the time of mobile use.

· I wanted the Elekey Off function so that i could use the straight key if possible.

· The card operation manual is good because it can be pasted on the main body.

HT-1 is probably it! Operability & functionality I guess that Nakajima-san was involved because I feel a considerable part of the Japanese idea in each manual.

I think you can call it <HT-1 Little Giant>.

Thank you very much for your efforts to be able to purchase at this amount of money.

The enjoyment has increased in the coming summer.

* An external speaker connection jack is installed from the RF volume and the internal speaker on the back (which will be drilled into the housing at a later date).

I'll send you two completed pictures of the little giant.

Yoshio Kinoshita, Obama City, Fukui Prefecture

Hello,

This email message is a notification to let you know that the following files have been uploaded to the Files area of the [email protected] group.

• /D4D Kit Documentations/D4D.pdf

Uploaded By: Adam Rong <rongxh@...>

Description:
D4D Kit Assembly Manual Rev. D French translation by Gilles Delpech F1BFU / FR. Many thanks!

Cheers,
The Groups.io Team