[CVARC] Re: Elecraft KPA1500 solid state amp (1500 watts) announcement

  • From: Ed Hutchinson <ehutch@xxxxxxxxx>
  • To: cvarc@xxxxxxxxxxxxx
  • Date: Sun, 23 Apr 2017 14:21:40 -0400

I think we try to forget!

My first station was a Hallicrafters S-40. I built a 6DQ7 sweep tube transmitter with a 12AT7 oscillator (bread-boarded) with a TV power supply. It had hand made coils and (junk) broadcast band variable capacitors. The 6DQ7 xmtr came from a free TV at the dump, and more or less built to a circuit in a borrowed ARRL handbook. Other expenses were for the plate/grid current meter, a code key and some switches, plus $5 (?) for used crystals from Ray Machel. There was also a roll of antenna wire and 30' of "surplus" coax. It was very ugly and didn't even win honorable mention at the science fair. I soon got a Heath DX-40, it got better signal reports.

My total cost of the S-40 was $40, and the DX-40 was $60. The S- 40 was probably about 20 years old then. I had 4 crystals, 2 for 80M and 2 for 40, but my antenna was not tuned on 40 and did not load there. With the crystals and antenna the whole station may have cost a total of $130.

An "online calculator" values $130 of 1963 to $1,030 in 2017 dollars. That's hard to believe! No wonder it took a lot of delivering newspapers, and pulling weeds to get on the air. Unfortunately I didn't get up to 13wpm and my novice call expired.

The 6DQ7 later became a "not quite legal" broadcast band transmitter in college. I bragged that I could build a clandestine station and got pressured into proving it. I switched the 12AT7 to a 12AX7, to beat two crystals to get a broadcast band frequency (and probably a lot of other frequencies!). The output was coupled to the grid of the sweep tube through a tuneable loop-stick and a capacitor. I added a lot of turns and fixed capacitors to the pi-filter. It was never "tuned" to the "way too short" random wire hanging out of a second story dorm window, but was very "loosely coupled" and radiated a few watts (grounded to the radiator and third wire of the electric supply). Car radios could hear the signal several miles away. A high-fi amplifier under-modulated the plate B+ through a large speaker transformer. I also tried screen modulation but it was too easy to drive it to distortion. It actually sounded decent on the air plate modulated.

My roommates got expelled, but more for indecent content of their "shows" than the FCC violations. One other "classical music" DJ later graduated and went on to become a long term official of a town in central VT. He may have even been elected to the state House. The station didn't last more than a few weeks of my first semester, probably about a hundred hours "on air".


On 04/22/2017 06:41 PM, GRANT D TAYLOR wrote:

How quickly some long time hams forget. My first ham station was a Halicrafters S-85 and a well used Viking Valiant...modest compared to high end stations of the day... But cost in today's dollars around $2,000. Didn't come close to what that SDR radio can do... Or even what the Lime SDR for $400 can do (which we heard about at today's NEWS VHF Conference). 6 or7 grand is actually a fair price. That Lime rig is a steal even though limited to VHF and microwave. Factor in inflation and ham gear from the 60's was mighty expensive!
De
w1aim


On Fri, 21 Apr 2017 16:20:47 +0000 (UTC)
 Catherine James <catherine.james@xxxxxxx> wrote:
At $6K, I won't be buying one of these, but there are serious hams who will be excited and lining up to grab one as soon as they're available.

Actually, I think this is a perfectly reasonable hobby for normal folks. You can get a decent HF transceiver for a few hundred dollars, and wire antennas are cheap. The last CVARC newsletter had my article showing how you can get an amp for a few hundred dollars. Like so many other products, there's a low end, a middle end, and a high end.

73,
Cathy
N5WVR

--------------------------------------------
On Fri, 4/21/17, Ed Hutchinson <ehutch@xxxxxxxxx> wrote:

Subject: [CVARC] Re: Elecraft KPA1500 solid state amp (1500 watts) announcement
To: cvarc@xxxxxxxxxxxxx
Date: Friday, April 21, 2017, 11:04 AM

It looks pretty impressive!

And it only costs four or five times what my VW is worth. This is not a hobby for poor folks.

Ed









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