[WSWSS] For Sale - Partially Completed 2 Meter Kilowatt Amp & Pwr Supply
Bob Kocisko
[email protected]
Sat, 19 Jan 2002 14:38:41 -0800
Peter,
I'm doing vy weak signal work on 2m EME & soon on 70cm EME. I'm currently
QRP on 2m running 400 watts output. Even with legal limit pwr, EME is the
ultimate weak signal work in amateur radio in my opinion. In addition, I've
done a lot of 2m MS over long hauls & pwr is helpful for that also. "Weak
Signal" is not synonymous with "QRP".
73,
Bob, K6PF
----- Original Message -----
From: "Peter Shores" <[email protected]>
To: "Bob Kocisko" <[email protected]>
Sent: Saturday, January 19, 2002 2:21 PM
Subject: Re: [WSWSS] For Sale - Partially Completed 2 Meter Kilowatt Amp &
Pwr Supply
Hi Bob,
Each time that I read about someone selling "high power amplifiers" on
this reflector I cant help but think isn't this the "weak signal society"
group? Maybe the name should reflect something other than weak since the
amount of energy that is going to be radiated is far from what I thought the
term implied. However, I guess if one is doing some kind of EME or long haul
the signal at some point is going to become weak; at least to someone
somewhere.
73's
Peter AD6TN
----- Original Message -----
From: "Bob Kocisko" <[email protected]>
To: "WSWSS" <[email protected]>; "Moon-Net posting msgs"
<[email protected]>; "Forsale-Swap Net" <[email protected]>; "Bob
Kocisko" <[email protected]>
Sent: Friday, January 18, 2002 11:06 PM
Subject: [WSWSS] For Sale - Partially Completed 2 Meter Kilowatt Amp & Pwr
Supply
> Hello:
>
> Two days ago, I posted a message that I hv for sale a partially completed
> K2RIW design 432 MHz kilowatt amp & pwr supply. This message pertains to
a
> similar situation but for 2 meters instead. In the May 1975 QST, W9OJI
> described a 2 meter version of the K2RIW amp using 2 x 4CX250B's in
parallel
> with a 0.25 WL stripline for the anode & a 0.5 WL stripline for the grid
> ckts. I purchased this partially completed project fm a different ham
with
> the intent of using much of the RF deck & many parts of the HV, screen &
> bias supplies but rebuilding them so they will look vy professional in my
6
> foot rack cabinet. The quality of the construction of this PA & PS are no
> where near the quality of the 432 MHz PA & PS that I offered 2 days ago.
I
> intended to re-build a heavy duty HV pwr supply (using the big & heavy
xfmr
> included), & screen, bias & filament supplies that would pwr this tetrode
PA
> on 2m + the 70cm tetrode PA. I purchased this partially completed PA & PS
> for $300 abt 4 years ago strictly for the parts & am offering it in the
same
> condition as when I purchased it for the same $300. This will need to be
a
> pick-up only. It's too big & heavy to ship. Based on the value of the
> parts alone, I think this price represents a very gud value. I do hv a
> couple of people in Southern Calif. interested in the 432 MHz PA & PS I
> offered & rcv'd a couple of emails saying at $350, it was a "gift". So,
if
> you're interested in this project & hv the ability & desire to complete
it,
> pse read on for a detailed description. Otherwise, tnx for reading & go
> ahead & delete this long message now.
>
> 73,
> Bob, K6PF
> DM13ar
>
> Detailed information for those of you who are interested follows.
>
> WHAT IS INCLUDED:
>
> The RF deck consists of two 17x7x3" aluminum chassis mounted back to back.
> The 2 tube sockets are part of an assembled unit which was removed fm some
> other equipment. It is mounted along with 2 x 4CX250B's. The 0.25 WL
brass
> stripline plate circuit & plate blocking cap are mfg'd & installed. The
> plate tuning vane (cap) is also mfg'd & mounted with a large venier & knob
> on the exterior of the chassis. The RFC is wound but not installed. The
> output coupling probe has not been made yet & the output coaxial connector
&
> HV connector & feedthru cap need to be installed. The 0.5 WL brass
> stripline for the grid ckt has bn mfg'd & installed & attached to a tuning
> cap. The capacitive input probe needs to be mfg'd & the tube sockets need
> to be wired up. THe input coaxial connector, RFC & feedthru cap all need
to
> be installed yet. I would estimate that the RF deck is abt 65 to 70%
> completed. Agn, the hard part has bn done. A blower was not included but
> will be needed & the airflow system will need to be completed. The
quality
> of construction of the chassis (extra holes, etc) is not that pretty. I
> think attaching this RF deck to a rack mount panel would add a nice touch
&
> any extra holes in the chassis can be plugged up.
>
> A copy of the May 1975 QST article is included along with another article
by
> W2GN in October 1977 which described another version of the K2RIW PA for
2m.
> That article included a pwr supply schematic.
>
> There is a separate 17x6x3 chassis & cover plate that has 3 meters mounted
> on it. One is 0-6V & labelled filaments, another meter is 0-1ma. for grid
> current & the third meter is a 0-50ma. for screen current. There are
> connectors on the rear of the chassis & some interconnecting cables. If
the
> RF deck is rack mounted, I think these 3 meters could all neatly be
mounted
> on the same panel. Again, this chassis with the 3 meters is not vy
pretty.
>
> The pwr supplies are mounted on a 17x13x3" chassis attached to a 12" rack
> panel. On the panel are 3 additional meters labelled 0-2.5KV plate
voltage,
> 0-500ma. plate current & 0-10v filament voltage. Thr are also 2 toggle
> switches (one is on/off & one is unlabeled), a rheostat to adjust the
> filament voltage & a pot to adjust the grid bias. There is another pot
> unlabeled & not connected to anything. Mounted on top of this chassis are
> the HV diodes, electrolytic caps, HV metering ckt, screen supply & 2
relays
> (one is a time delay). Another hvy duty relay & small xfmr(bias supply?)
> are located underneath the chassis. I never traced this ckt out since I
> never intended to use this pwr supply as constructed since the quality of
> construction was not up to my standards. My intent was to use it as an
xlnt
> & inexpensive source of parts to rebuild it the way I wanted.
Potentially,
> all of the pwr supplies are completed but I hv no idea whether they work
> properly or not.
>
> An old 36"Hx20.5"Wx15"D standard rack cabinet on castors is included. It
> needs paint & does not hv a rear door. A huge plate xfmr (14"Lx9"Wx7"H)
is
> mounted on the bottom of the rack cabinet. It probably weights 75-100 lbs
&
> needs a coat of paint also. This xfmr is labeled 230 VAC primary & 2260V
> secondary @ 2.1 KVA (almost 1 amp). There are some interconnecting cables
> included. There are 2 of old pieces of aluminum with various holes that
> serve as panels to fill up the space on the front of the rack cabinet.
>
> All of the above is being offered for $300 on a pickup only basis.
>
> I do hv a couple of optional item I can sell if someone is interested. I
> was going to build a vy well regulated HVPS using choke input filtering.
I
> purchased the following additional parts for the HVPS & will sell them for
> what I paid. THey include: 2 separate 35uf, 4KV oil filled caps that look
> brand new ($30 each) + a used swinging choke (5-30 Hy, 750-75 ma., 10KV
> test) for $40. The choke also is vy heavy. So, if interested, I will
> include these 3 additional HVPS items for an additional $100 but they are
an
> option. I won't sell them separately unless the PA & PS sell first & the
> buyer doesn't hv an interest in these optional items. I also was thinking
> of using 2 x 4CX350A's instead of the 4CX250B's. WOuld get a little
higher
> pwr out with higher anode voltage. I may hv 2 or 3 of these tubes
available
> for sale if interested.
>
> I just took a few photographs & will try to get them developed on
Saturday.
> If they turned out ok, I should be able to email any interested parties a
> few photos by Sunday.
>
> Pse let me know if you hv any interest. Agn, if you got this far, many
tnx
> for reading this message.
>
> 73,
> Bob, K6PF
> DM13ar
>
>
>
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