Hny bill!!!
Yes I remember Ernie! Always ha a big sig on 2 m!!
Ve3fgu in fn04 had the Johnson also - I had the hi version - it used a roller
inductor for tuning -
Yep sspa with switchable filters would be excellent!!
73
Dana
Balmy -7c today and snowing
Sent from my iPhone
> On Jan 1, 2018, at 11:42 AM, Bill Olson <callbill@hotmail.com> wrote:
>
> Hi Dana and all, I meant to comment on this last year.. hah hah..
>
>
> The Henry dual band tank circuit was pretty unique. The tubes ran in parallel
> on 6M and push pull on 2.. Not hard to believe there were 3rd harmonic issues
> when transmitting on 6 though.. The old Johnson 6N2 Thunderbolt came out in
> the late 50's and had a pair of 4CX250's in parallel on both bands. It used a
> band switched pi-network tank circuit. pretty revolutionary for the day I
> guess.. I heard they had band switch reliability problems with a lot of RF
> current flowing through the switch. Ernie, W3KKN, in Philly ran the Johnson
> forever it seemed.. He was always LOUD..
>
>
> Today we have the LDMOS SS kilowatt amps that are pretty broad banded. For a
> dual band amp I always theorized a broadband circuit could be designed that
> worked well on both 6 and 2 (certainly 2 and 222) where all you would need to
> do to change bands was switch in band pass filters for each band.. Project
> way down the list I guess..
>
>
> HNY everyone, - bill k1DY
>
>
> ________________________________
> From: VHFcontesting <vhfcontesting-bounces@contesting.com> on behalf of Dana
> <ve3ds@acanac.net>
> Sent: Thursday, December 28, 2017 3:41 AM
> To: Michael Clarson
> Cc: VHF Contesting
> Subject: Re: [VHFcontesting] 6 and 2 meters
>
> I have a Tempo 6N2 here SN 50 bought it in 1980.
> Yes it works on both bands, and yes there is some interaction
> so tuning initially is tricky but once set up its fine.
> Just follow the instructions.
> The original had “specially cut” cables for each input … I suspect they
> were 1/4 wave multiples…Henry had no info on this when I e mailed them..
>
> I doubt it would work on both bands at once however….(never tried it)
> but with separate output relays it works fine, with 1000 + watts out
> on 6 or 2.
> I don’t think it makes the modern FCC emission requirements, so you need
> bandpass filters on each of 6 and 2 m to keep it clean, but otherwise
> its an interesting design concept.
>
> I also tried getting some mechanical details from henry but they lost the
> dwgs.
>
> There was an neat deisgn in QEX about 2008 using a pair of 3cx800’s instead
> of 8874’s … the layout and plate arrangement was identical!
> Of course today you might just do the same with a single solid state device …
>
> 73 Dana VE3DS
> FN03
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