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Many thanks for some great advice!? I have a dummy load and I need to get in the habit of leaving it connected until I'm really ready to go. -- Jim, KJ7EZN? ? 73!

Allison Agreed, my PLL reference was to the fact that there is a control loop but that it is slower than a conventional PLL. H&P is very useful if done properly, but can be a real nightmare if done

Mike Several years ago when I was experimenting with H&P designs I found that a Vackar VFO was better for my H&P uses. In addition to being stable, the output is low impedance and seems relatively

If you connect one end of a cable shield to ground, you create a Faraday Shield ( Google it ) and having only one end connected to ground prevents spurious current loops creating noise. You must of

Mike, I've never measured it, not having ever used it for anything except 75M AM where it was a non-issue.? I usually monitored myself on a SDR and occasionally made minor corrections to stay spot

Thanks for that Arv. I don't know about moving the yahoo group as, really, how many people are going to use a huffpuff in this age of synths? I liken my interest in this area to a kind of boat-anchor

Thanks, Allison.? I was thinking maybe 100 ohms in series with the blocking cap (to provide short circuit protection) and then 75 ohms to ground at the output of the box to recover a 50 ohm source

I would connect that shield to the ground only at one end and if the GPS kit already suggests not to use the ground plane of the GPS then you only have the rig end as an option. Both ends will give

Hi Jim, I would personally not hook the shield to to the QCX or the GPS. I have about 3 GPS units running and have never used a shield. If after using the radios and you think? that a shield would

Hi Jack, I would be interested in how the drift affects the x2 x3 and x4 multiplier for 20-10 meters on the DX-60.? What would you say the HG-10 drifts now?? From cold start and after 30 minutes? I

Hi Arv, "Consider H&P as a PLL design that locks on multiples of the reference frequency.? It? adjusts slower than a PLL but otherwise many of the PLL design formula can be used." Its not a PLL,

One more issue with the Heathkit vfo/DX-60b problem is that the vfo outputs 7 mhz for 40-10 meters.? The radio x2 x3 or x4 to get the correct frequency.....so, a 100 hz drift on 40 meters becomes a

Hi all-- ? I'm a noob here with a just completed QCX 40 on the desk and a QCX 20 just beginning construction.? I've ordered the GPS kit with the intention of connecting to the QCX's via 4-conductor

Hi Roger Where about are you?? If its doing everything except transmitting then you're probably right that the output transistors have failed because of transmitting without a load on it.? I'd be

Allison All good information, but can I politely disagree with a couple of your statements. *1)* Back when many of us were experimenting with H&P design it was common to obtain stability within 2 Hz

VFO instability and drift are symptoms of parts failure or implementation errors. Sometimes its just plain broken and needs to be fixed. If it does not have a regulated supply it will be unstable even

Mike, Looks like we are comtemplating the same problem.?? I have a highly modified DX-60A/HG-10 setup.? The HG-10 is stock and perfectly adequate for my normal 75M AM usage. However.... now I am

When time permits I will try the new code. The result with the last version was, unintelligible TX, and with tweaks and fussing it was "terrible audio can barely understand you".. Allison

An AC short at the output would be less than desirable and does increase the devices power needs and heating. Better would be 10 to 50 ohm series and then short to ground.? Or turn the oscillator off

Thank you all that took time to weigh in on this topic.? I have a few dds vfo's already (probably 5 including my Qrp-Labs arduino shield)? ?What I was trying to see was there a modern