- 221. Re: [TenTec] Receivability (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Wed, 30 Oct 2002 10:12:04 -0600
- To maintain dynamic range its necessary that the diode ring mixer (and surely FET mixers that switch like a diode ring) be terminated broad band. Otherwise the undesired signals and output products (
- /archives//html/TenTec/2002-10/msg00591.html (13,301 bytes)
- 222. Re: [TenTec] [OT] re: 50hz PSK filter? (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Wed, 30 Oct 2002 11:33:22 -0600
- It all depends on the dynamic range of the receiver and the DSP. If the strong signals passing through the receiver but rejected by the external DSP cause the receiver gain to drop so low as to loose
- /archives//html/TenTec/2002-10/msg00593.html (7,987 bytes)
- 223. Re: [TenTec] Define RX intercept, please. (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Fri, 02 Aug 2002 21:18:37 -0500
- You should be reading recent ARRL handbooks. There's a chapter on receiver testing and performance. There are many other useful chapters also. 73, Jerry, K0CQ -- Entire content copyright Dr. Gerald N
- /archives//html/TenTec/2002-08/msg00033.html (7,104 bytes)
- 224. Re: [TenTec] TenTec 524 (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Mon, 05 Aug 2002 20:55:56 -0500
- I'm working on the concept but I'm slow this year. May have something for future CSVHF conferences. 73, Jerry, K0CQ -- Entire content copyright Dr. Gerald N. Johnson, electrical engineer. Reproductio
- /archives//html/TenTec/2002-08/msg00100.html (7,134 bytes)
- 225. Re: [TenTec] Scout field/mobile (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Fri, 09 Aug 2002 22:46:15 -0500
- When used mobile you want fuses in both positive and ground to protect the radio when the engine to frame jumper breaks and starter current tries to pass through coax and radio. Breakers are more con
- /archives//html/TenTec/2002-08/msg00160.html (7,099 bytes)
- 226. Re: [TenTec] RF Spectrum Analyzer (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Tue, 13 Aug 2002 13:36:43 -0500
- Some of the classic spectrum analyzers from HP, such as those using the HP141 scope for display also include x y recorder outputs. Those are fairly easy to interface to a PC for display. There was an
- /archives//html/TenTec/2002-08/msg00236.html (8,167 bytes)
- 227. Re: [TenTec] Optical Encoder operation (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Tue, 13 Aug 2002 14:51:58 -0500
- There are two sensors, that are positioned so their outputs change alternately. The sequence then shows direction. In discrete logic it takes about two quad logic chips to take the two outputs and pr
- /archives//html/TenTec/2002-08/msg00244.html (8,310 bytes)
- 228. Re: [TenTec] WGA or Heil for Scout (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Wed, 14 Aug 2002 08:45:32 -0500
- There are several ways to cure microphone "bassiness." The simplest is to back away from the microphone. That enhanced bassiness is why pop singers swallow their hand microphone. Back off and it gets
- /archives//html/TenTec/2002-08/msg00270.html (8,587 bytes)
- 229. Re: [TenTec] WGA or Heil for Scout (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sun, 18 Aug 2002 12:19:20 -0500
- Capacitor shaping can work a great deal. That's all there is in the fanciest equalizer, just multiple RC and op amps to make their effects stronger. Simple RC using the circuit impedance for the R an
- /archives//html/TenTec/2002-08/msg00327.html (9,539 bytes)
- 230. Re: [TenTec] RC shaping was WGA or Heil for Scout (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sun, 18 Aug 2002 22:36:44 -0500
- The resistances need not be changed, that way the mid range level stays constant. Only the series and shunt capacitors need to change to modify the low and high roll off frequencies. With the lows an
- /archives//html/TenTec/2002-08/msg00338.html (10,279 bytes)
- 231. Re: [TenTec] Scout,Omni,TS 850 transmit (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sat, 24 Aug 2002 09:43:19 -0500
- Poor transmitter intermod is noticed first by users of adjacent frequencies as monkey chatter and splatter. IN the ault days of tube finals going for third order of -30 gave a super 5th order and the
- /archives//html/TenTec/2002-08/msg00422.html (9,359 bytes)
- 232. Re: [TenTec] Paragon VFO Problem (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sat, 24 Aug 2002 09:43:36 -0500
- Standard Tentec VFO wear. Needs a rebuild. Kit from TenTec about $23, takes about 3 hours to do the first one. Sometimes cleaning and regreasing works, but my CorsairII had a very worn ball reduction
- /archives//html/TenTec/2002-08/msg00423.html (8,441 bytes)
- 233. Re: [TenTec] Scout,Omni,TS 850 transmit (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sat, 24 Aug 2002 17:57:53 -0500
- Well 50 watts is 3 dB down from 100 watts, but a -25 dB third order intermod product is still 3 dB up from the third order intermod product from a 100 watt radio doing -31 dB third order intermod. An
- /archives//html/TenTec/2002-08/msg00441.html (9,828 bytes)
- 234. Re: [TenTec] close talking was Scout,Omni,TS 850 transmit (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Sun, 25 Aug 2002 11:58:08 -0500
- So dig into microphone or radio and find an audio coupling capacitor in the transmitter. Take it out and put on in that is half its size. That will double the roll off frequency for the bass. Close t
- /archives//html/TenTec/2002-08/msg00456.html (9,486 bytes)
- 235. Re: [TenTec] Paragon VFO Problem (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Mon, 26 Aug 2002 07:26:34 -0500
- I think he meant that the tuning slowed though the knob turned OK. But if you are going to apply OIL, apply OIL, not distilled kerosene! Water Displacer number 40 is not a permanent or quality lubric
- /archives//html/TenTec/2002-08/msg00476.html (8,765 bytes)
- 236. Re: [TenTec] Paragon VFO Problem (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Mon, 26 Aug 2002 12:24:23 -0500
- The other component of a spray can of WD-40 is the propellant, propane. 73, Jerry, K0CQ -- Entire content copyright Dr. Gerald N. Johnson, electrical engineer. Reproduction by permission only.
- /archives//html/TenTec/2002-08/msg00488.html (8,411 bytes)
- 237. Re: [TenTec] close talking was Scout,Omni,TS 850 transmit (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Mon, 26 Aug 2002 17:17:53 -0500
- Soldering isn't a tough task if done properly with good tools. Poking around a radio with poor tools and techniques can turn a fixable radio into trash. The Heathkit assembly manuals had a good secti
- /archives//html/TenTec/2002-08/msg00517.html (9,279 bytes)
- 238. Re: [TenTec] Re: synthesizers was Omni C (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Mon, 26 Aug 2002 22:15:30 -0500
- Tentec designed the Omni V, and VI (and I don't know about the Paragon) with the synthesizer at VHF and divided it down to reduce the phase noise. Its not perfect but its better than most rice boxes
- /archives//html/TenTec/2002-08/msg00530.html (8,680 bytes)
- 239. Re: [TenTec] Re: synthesizers was Omni C (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Tue, 27 Aug 2002 02:09:26 -0500
- DDS can be good close in and when not stretched too far, but DDS is not at all clean, there are so many spurs it usually takes a PLL (with the attendant noisy VCO) to act as a spur filter. I'm going
- /archives//html/TenTec/2002-08/msg00532.html (8,817 bytes)
- 240. Re: [TenTec] Re: synthesizers was Omni C (score: 1)
- Author: "Dr. Gerald N. Johnson, electrical engineer" <geraldj@isunet.net>
- Date: Tue, 27 Aug 2002 08:10:23 -0500
- The DDS has outputs at DC + desired frequency and clock - desired frequency of equal amplitude. Then there can be many others depending on the quality of the D/A and the number of bits in the D/A and
- /archives//html/TenTec/2002-08/msg00535.html (10,004 bytes)
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