Re: HT20 - Nice Rig

Charles W. Powell

QCX is a radio designed by Hans Summers, G0UPL, and marketed through his company QRP-labs.  It is an innovative design with an I-Q quadrature/Taloe detector circuit.  Very high sensitivity on receive, with < 1 dB of loss in the front end of the radio.  Typically a superhet has something on the order of 3 dB or more of signal loss in the IF stage. Transmitter is similar to the Hilltopper, although supposedly class E.  Hilltopper is reported by Dave K1SWL (designer) to be class C.  In my experience, the Hilltoppers consistently put out more power than the QCX, using the same BS170 MOSFETs.  As noted, QCX is not readily hackable, whereas the Hilltopper code could be completely re-written if you were that ambitious.  Not to take a thing away from Hans Summers on a fine little radio, the Hilltopper has a fun factor that the QCX lacks.  It’s also quite a bit lighter than a QCX with its aluminum case.


Chas - NK8O

On Apr 9, 2019, at 9:10 AM, Leland Lannoye <wa9aoe@...> wrote:

What is a QCX rig?

Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------
From: "Charles W. Powell via Groups.Io" <doctorcwp@...> 
Date: 4/8/19 19:00 (GMT-05:00)
Subject: Re: [HilltopperKit] HT20 - Nice Rig

Congrats Stan.  Yes, the HTs put out over 5 watts for the most part.  I think my HT 20 put out 5.1 watts and the HT 40 put out 5.9 watts.  Or maybe it was the other way around.  That was measured with a scope into a dummy load.

You sound like me - I’ve built quite a few QCXs and just about to start on HT #4.  The difference between the QCX and the HT is that you can hack the Hilltopper, add a display, add CAT control, change the tuning step intervals, etc., or if you are clever enough, do whatever you like.  With the QCX, it is what it is and there’s not anything you are going to change.


Chas - NK8O  

On Apr 8, 2019, at 5:48 PM, StanWB2LQF <sjl219@...> wrote:

Just finished my HT20 a couple hours ago.  I presently do not have any other radio in the house so I couldn't make the initial adjustments.  In spite of this situation, I managed to make my first contact within 5 minutes of connecting my antenna - Spain. Then I tuned down to the low end of the band and heard VK2KM in Sydney - long path to NY.  He sounded real nice through this little HT20.  Pileup was too severe for me to try.

I've built five (5) QCX transceivers and they are also very, very nice radios but none of them put out 5 watts on a 12 volt battery - I measured 5.6 watts from my new HT20 using an Elecraft dummy load, my Fluke DMM and some arithmetic.

Think I better order the HT40 real soon. 
72, Stan WB2LQF

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