[Amps] Subject: Henry hum on transmitted signal

David Gow 6146guy at gmail.com
Tue Sep 5 18:58:46 EDT 2023


The step start gizmo is a chicken brooder heater, still available in
rural supply stores.

On Tue, Sep 5, 2023 at 3:54 PM Steven Katz <stevek at jmr.com> wrote:
>
> Yeah, I wouldn’t do that.   The Henry pedestal amps were well built and built to last, although the HV choke resonating cap is a failure point…usually after 20-30 years, not a year.
>
> I never had any problems with any of them, but never owned one for 30 years.
>
> The 4K Ultra was IMO the best amateur amp ever made by anybody but didn’t cover 160 meters, so that was its primary drawback.   I had one for about ten years, zero problems and it was hard to keep it down to “legal limit.”  😊
>
> From: gudguyham at aol.com <gudguyham at aol.com>
> Sent: Tuesday, September 5, 2023 4:53 PM
> To: Steven Katz <stevek at jmr.com>; Rob Atkinson <ranchorobbo at gmail.com>; amps at contesting.com
> Subject: Re: [Amps] Subject: Henry hum on transmitted signal
>
> Steve, I won’t mention any names, but somebody bought quite a few Henry amps and stripped out the ENTIRE power  supply guts, plate transformer , choke, HV cap, and the tuning caps  even the wire would step start gizmo.  Sold off all that stuff and put in a cap input supply using PD transformer like Ilona the big Ameritrons.
>
> Sent from the all new AOL app for iOS<https://apps.apple.com/us/app/aol-news-email-weather-video/id646100661>
>
>
> On Tuesday, September 5, 2023, 5:26 PM, Steven Katz <stevek at jmr.com<mailto:stevek at jmr.com>> wrote:
> Lou, I've seen that, too.
>
> I've also seen the resonating cap short out (choke is still fine) and B+ soar to 6kV and they just keep operating.
>
> Something will eventually fail, but those big oil-filled caps can often handle 6kV for quite a while, and so can the tubes in many cases.
>
> -----Original Message-----
> From: Amps <amps-bounces at contesting.com<mailto:amps-bounces at contesting.com>> On Behalf Of gudguyham--- via Amps
> Sent: Tuesday, September 5, 2023 4:24 PM
> To: Rob Atkinson <ranchorobbo at gmail.com<mailto:ranchorobbo at gmail.com>>; amps at contesting.com<mailto:amps at contesting.com>
> Subject: Re: [Amps] Subject: Henry hum on transmitted signal
>
> Rob, it seems as though is not “if” but “ when” the choke craps out in those Henry amps.  I’ve seen where many chokes shorted to the core and guys mounted the choke on insulated material instead of getting a new one. Lou
>
>
> Sent from the all new AOL app for iOS
>
>
> On Tuesday, September 5, 2023, 7:14 AM, Rob Atkinson <ranchorobbo at gmail.com<mailto:ranchorobbo at gmail.com>> wrote:
>
> I think the resonant choke design is clever by a half.  It's just too finicky and failure prone for my liking.  Also, I've seen a choke Henry used in one of their amps, I forget which one but it was supposedly rated for 700 ma.  I have  a 700 ma filter choke out of a 1 KW broadcast rig intended to run continuously and it's at least twice as big and heavy as the dinky thing Henry used.  I've seen I don't know how many RF power amplifiers designed for volatile loads like SSB and CW and they did fine with nothing but around 40 mfd capacitance for a filter.  I would only use a choke input for power supplies serving transmission modes that put the supply under continuous load, such as AM and RTTY.  I would rebuild that power supply for whatever xmission mode is intended and ditch that resonant choke scheme.
>
> 73
>
> Rob
> K5UJ
> _______________________________________________
> Amps mailing list
> Amps at contesting.com<mailto:Amps at contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com<mailto:Amps at contesting.com>
> http://lists.contesting.com/mailman/listinfo/amps
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps


More information about the Amps mailing list