Article: 96891 of rec.radio.amateur.homebrew From: Ken Scharf Subject: Re: Any receiver IC's? References: <4db24$441c7a6d$d135c4af$17969@MDI.CA> <1142720911.911739.64900@g10g2000cwb.googlegroups.com> <1cc48$441c9894$d135c4af$31146@MDI.CA> <1142739604.228527.151510@e56g2000cwe.googlegroups.com> Message-ID: Date: Sun, 19 Mar 2006 19:17:04 -0500 Leon wrote: > JJ wrote: > >>"Leon" wrote in news:1142720911.911739.64900@ >> >>>Bus switches like the FST3125 make very good mixers and quadrature >>>sampling detectors, as in the SoftRock SDRs. >>> >>>Leon >>> >>> >> >>And how about the IF amp? And VFO? >>DDS like AD9850 look interesting. > > > ADI makes some very nice VCAs, like the AD603. They are probably the > best IF devices available, now. Racal was using FETs for IF amplifiers > in their military radios when I worked for them a few years ago. > > PLLs are better than DDSs, but it can be diificult to make a good one. > A DDS may be used to provide a reference for a PLL, of course, for fine > tuning. > > Leon > Actually there is nothing really wrong with a DDS all by itself. They are capable of very low phase noise. The new AD995x series have 14 bit D/A's and are therefore VERY clean. They are rated at up to 400mhz clock, but if you don't use the built in clock multiplier and provide a 1:1 external clock they have been over clocked to as high as 600mhz! Running with a clock rate of 10x the desired output frequency this chip should have VERY low spurs! Instead of using the DDS as a reference for a PLL, consider using it AS the divider in a pll. This will give fractional N divide ability allowing you to tune to the nearest hertz without using dual loops. The math to calculate the DDS tuning word, might be a bit heavy on a pic though.... Article: 96892 of rec.radio.amateur.homebrew From: "Jim, KK1W" Subject: FA: Lots of old and new parts for BA gear Message-ID: <16oTf.162$ny5.20@fe07.lga> Date: Sun, 19 Mar 2006 21:05:48 -0500 Hi, Take a look at these auctions: http://search.ebay.com/_W0QQsassZkk1w2000. Lots of old and new parts, caps, resistors, pots, coils, meters, crystals and more. Low starting bids and good feedback rating. Jim, KK1W Article: 96893 of rec.radio.amateur.homebrew Subject: Ink From: mshawjr@frontiernet.net Message-ID: Date: Mon, 20 Mar 2006 04:23:01 GMT Man I have found this site that has the cheapest ink for any printer. You can compare prices and then review the companies on service and quality. Let me know what you think Article: 96894 of rec.radio.amateur.homebrew From: "Dave Turner" References: Subject: Re: Ink Date: Mon, 20 Mar 2006 12:27:48 +0800 Message-ID: <441e2f14@quokka.wn.com.au> > whois imagraphix.com Registrant: Murphey Shaw 12 Blackwatch Trail Fairport, NY 14450 , United States Registered through: GoDaddy.com Domain Name: IMAGRAPHIX.COM Created on: 09-Dec-04 Expires on: 09-Dec-07 Last Updated on: 14-Feb-06 Administrative Contact: Shaw, Murphey mshawjr@frontiernet.net 12 Blackwatch Trail Fairport, NY 14450 , United States 5854148735 Technical Contact: DNS, Administrator administrator@siteprotect.com 1 N State Street 12th Floor Chicago, IL 60602 , United States +1.3122362132 Fax -- +1.3122361958 Domain servers in listed order: NS3.SECURESERVER.NET NS4.SECURESERVER.NET Article: 96895 of rec.radio.amateur.homebrew Subject: Ink From: mshawjr@frontiernet.net Message-ID: <%WwTf.3014$tT.1641@news01.roc.ny> Date: Mon, 20 Mar 2006 12:08:27 GMT Sorry guys. The spam stuff was not my intent. I do oppoligies and won't happen again. I have never been on newsgroups before and not sure how to work them. I hope you guys can forgive a bad choice. Murphey Article: 96896 of rec.radio.amateur.homebrew From: "Dave Turner" References: <%WwTf.3014$tT.1641@news01.roc.ny> Subject: Re: Ink Date: Mon, 20 Mar 2006 21:02:17 +0800 Message-ID: <441ea7aa@quokka.wn.com.au> wrote in message news:JTwTf.2739$tT.1678@news01.roc.ny... > Sorry guys. The spam stuff was not my intent. Yes it was, your header is still the same, and you've now re-spammed every newsgroup again with your 'apology'. It doesn't get any dumber. > I have never been on newsgroups before and not sure how to > work them. Yet you know how to spam them. Did you also learn to run before you could walk? > I hope you guys can forgive a bad choice. "You go to hell! You go to hell and you die!" - Mr Garrison Article: 96897 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Any receiver IC's? Message-ID: References: <4db24$441c7a6d$d135c4af$17969@MDI.CA> Date: Mon, 20 Mar 2006 15:00:24 GMT On Sat, 18 Mar 2006 16:23:57 -0500, JJ wrote: >What are some modern IC's to build a sensitive and strong HAM receiver? >Mixers and IF amps recommended? >Not looking for NE602 but higher performance. > >JJ The answer is basically no. There are ICs that may perform well for subsystems like mixers or IF amplifiers but not a single chip or limited number of them. I my experiements with the likes of LM172, LM373 and MC33xx the closeness of input and output pins made filter blow by a problem. It's hard to beat individual circuits and lots of shielding between them when going for high performance. History shows all of the past excellent radios were heavy. The values of shielding is performance and the cost is weight. Allison Article: 96898 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: Any receiver IC's? Message-ID: References: <4db24$441c7a6d$d135c4af$17969@MDI.CA> <1142720911.911739.64900@g10g2000cwb.googlegroups.com> <1cc48$441c9894$d135c4af$31146@MDI.CA> <1142739604.228527.151510@e56g2000cwe.googlegroups.com> <1142864946.548229.300970@u72g2000cwu.googlegroups.com> Date: Mon, 20 Mar 2006 16:23:16 +0000 On Mon, 20 Mar 2006 06:29:06 -0800, Giancarlo Gian Moda, I7SWX wrote: > http://www.radioamatore.it/i0cg/add9951.html I am not the OP, but thanks Leon and Gian. That DDS looks like the final building block for my new rig. 73, Ed. EI9GQ. -- Linux 2.6.15 Remove 'X' to reply by e-mail. Yes, my username really is: nospam Article: 96899 of rec.radio.amateur.homebrew From: safemale Subject: Re: website Date: Mon, 20 Mar 2006 13:20:07 -0500 Message-ID: References: <42a431eb$1_2@newspeer2.tds.net> thanks for the web site On Mon, 6 Jun 2005 06:23:11 -0500, "steve carey" wrote: >www.k9yk.com > Article: 96900 of rec.radio.amateur.homebrew Subject: Re: mixer: DBM or dual gate mosfet? From: JJ References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> Message-ID: Date: Mon, 20 Mar 2006 13:24:28 -0500 What is the IP3 of a typical dual gate MOSFET mixer? One can also use HC4066 or 4053 as the switching element at lower freqs. JJ Article: 96901 of rec.radio.amateur.homebrew From: safemale Subject: Re: Looking for 12V tube Rx project info Date: Mon, 20 Mar 2006 13:31:45 -0500 Message-ID: References: <1119556572.530653.109680@f14g2000cwb.googlegroups.com> hay dont forget the r392 it was a 24 volt plates On 23 Jun 2005 12:56:12 -0700, LenAnderson@ieee.org wrote: > > Setchell-Carlson managed to do it with loctal-base tubes running > off of a 24/28 VDC aircraft bus back in WW2 times. No dynamotor, > just that cute little box referred to as a "range receiver" or > BC-1206. > > I bought a couple of them many years ago, surplus, principally > to get the nice compact 3-gang variable capacitor. Fired one > up in the company lab at 26 VDC and it was still in-spec although > those specs weren't the best. At 24 VDC the spec rating was > marginal. At 22 VDC it was below spec...but then the filaments > were also running cooler at 11 V each. > > Don't remember what the IF (135 KHz) BW was, but, running with > a crystal-controlled converter ahead of it, the 195 to 500 KHz > tuning range could cover 75 or 40 meters no problem. A thought. > > LenAnderson@ieee.org Article: 96902 of rec.radio.amateur.homebrew From: safemale Subject: Re: Parts at Hamfests Date: Mon, 20 Mar 2006 13:53:23 -0500 Message-ID: References: are you thinking of Jim Pembleton Pembleton Electronics fort wayne ind On Sun, 31 Jul 2005 16:53:38 GMT, Richard <"\"delete.this.\"rf.gillette"@ieee.org> wrote: >At Midwest hamfests there is a guy that has a large collection of >semiconductors. Anybody know his name or email address? try pemparts@ctlnet.com phone: (260) 484-1812 fax: (260) 484-0163 addy on web site is out or date he moved 5 or 5 blocks one black north and 2-3 west pemparts@ctlnet.com http://yellowpages.superpages.com/profile~SRC_google~T_Fort+Wayne~S_IN~PP_N~L_Fort+Wayne+IN~C_Televisions+Retail~CID_00000515778~LID_eLY3b+kM29Cy82pCa%2FpnXw%3D%3D.htm Article: 96903 of rec.radio.amateur.homebrew From: safemale Subject: Re: Remote Car Battery Voltage Monitoring Date: Mon, 20 Mar 2006 14:40:29 -0500 Message-ID: References: <441019FA.20604@bloomer.net> hay would 2 of the vw solar panel.s help charge the wheel chair battery?????????????????? safe male On Fri, 10 Mar 2006 02:43:25 -0500, "Robert Green" wrote: >"Scott" wrote in message >news:441019FA.20604@bloomer.net... >> Why go through all that bother? Look on ebay for a solar panel. There >> are a ton on small units that VW uses to keep the batteries topped off >> while the cars are in transit. They are small 5-10 Watt units. Usually >> go for about $10. Lay one on the dash and park the vehicle so the >> windshield is facing south. The unit has a cigarette lighter adapter >> and you just plug it in. > >That's the plan for now. Hopefully it will end the problem of run-down >batteries. I may still need to go the "plug in" route because I want to >also be able to charge my Dad's 24VDC scooter while it's loaded in the van. Article: 96904 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Looking for 12V tube Rx project info Message-ID: References: <1119556572.530653.109680@f14g2000cwb.googlegroups.com> Date: Mon, 20 Mar 2006 19:50:42 GMT On Mon, 20 Mar 2006 13:31:45 -0500, safemale wrote: >hay dont forget the r392 it was a 24 volt plates >On 23 Jun 2005 12:56:12 -0700, LenAnderson@ieee.org wrote: > >> >> Setchell-Carlson managed to do it with loctal-base tubes running >> off of a 24/28 VDC aircraft bus back in WW2 times. No dynamotor, >> just that cute little box referred to as a "range receiver" or >> BC-1206. >> >> I bought a couple of them many years ago, surplus, principally >> to get the nice compact 3-gang variable capacitor. Fired one >> up in the company lab at 26 VDC and it was still in-spec although >> those specs weren't the best. At 24 VDC the spec rating was >> marginal. At 22 VDC it was below spec...but then the filaments >> were also running cooler at 11 V each. >> >> Don't remember what the IF (135 KHz) BW was, but, running with >> a crystal-controlled converter ahead of it, the 195 to 500 KHz >> tuning range could cover 75 or 40 meters no problem. A thought. >> >> LenAnderson@ieee.org There are a number of available tubes like 12ek6 and friends from the late 50s early 60s broadcast (US) auto radio application in 7pin bases design for plate voltages of 12V. They work well in most designs seen using higher voltages only reduced to 12V. Those radios used either 455khz or 262khz IF. I did a crystal controlled 20m to 80m converter using them. The line up was 12ek6 rf amp and 12ad6 converter. Circuit was >from the ARRL Mobile Manual from the late 60s but I'd bet a 'Hanbook from the mid 60s would also have it. Allison Article: 96905 of rec.radio.amateur.homebrew Subject: Re: Amateur Radio Control Shifts References: From: dougmc@frenzy.com (Doug McLaren) Message-ID: <5hETf.6838$1Z5.4822@tornado.texas.rr.com> Date: Mon, 20 Mar 2006 20:29:53 GMT In article , Tim Wescott wrote: | For radio control on 6 meters using PPM -- what is the amount of | frequency shift, and which direction is it (please don't just say | 'positive' or 'negative' -- I need to know which direction is 'pulse' | and which direction is 'not pulse'). http://www.nobugs.org/engineer/uav/futaba-rx.html and http://users.belgacom.net/TX2TX/tx2tx/english/tx2txgb1.htm may be of some assistance, or at least there will be some pretty pictures. Positive shift means that the frequency increases during a pulse, and negative means it decreases. I don't think the exact amount of the frequency change really matters, but I think it's normally around 1.5 KHz to 2.5 KHz. Or, to make it really simple, for positive shift, `pulse' is about 2 KHz higher than `not pulse', and reverse it for negative shift. And modern 6m stuff is positive shift. | Yes, I know there's no standard -- what do manufacturer's do these days? >From http://www.fmadirect.com/detail.htm?item=1739§ion=1 -- SPECIAL NOTE CONCERNING HAM BAND TRANSMITTERS: All current transmitters use positive shift modulation. When you order for current transmitters, your invoice will list the purchased item as 805FM50V2FJ or 805FM53V2FJ. This receiver will work with all recently manufactured transmitters. If you have an ACE transmitter or an old Futaba (prior to around 1990), you will require an ACE version. Your invoice will list the 805FM50V2ACE or 805FM53V2ACE. Please be advised, it is unclear when Futaba changed from negative to positive shift modulation. Unfortunately, unless you have access to test equipment, you may not know if your old Futaba requires negative or positive shift. ... so it looks like there IS a standard now, at least on the six meter band stuff. I've heard some say that this isn't true, that brand X 6m RX didn't workt with brand Y 6m TX, but details were never really given. -- Doug McLaren, dougmc@frenzy.com Nine out of ten doctors agree that one out of ten doctors is an idiot. Article: 96906 of rec.radio.amateur.homebrew Subject: Re: Amateur Radio Control Shifts References: <5hETf.6838$1Z5.4822@tornado.texas.rr.com> <2ZCdnfE214aah4LZ4p2dnA@web-ster.com> From: dougmc@frenzy.com (Doug McLaren) Message-ID: Date: Mon, 20 Mar 2006 21:20:46 GMT In article <2ZCdnfE214aah4LZ4p2dnA@web-ster.com>, Tim Wescott wrote: | That was useful, but I forgot to ask: | | Is the space (no pulse) frequency the nominal frequency, or is it (more | sensibly IMHO) 1/2 the shift below -- or at least _some_ amount below | the nominal? Do not know. -- Doug McLaren, dougmc@frenzy.com We can hike anytime. This is our chance to see cars driving. --Homer Simpson Article: 96907 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> Date: Tue, 21 Mar 2006 14:02:13 GMT On 21 Mar 2006 01:41:49 -0800, "Giancarlo Gian Moda, I7SWX" wrote: >What is the IP3 of a typical dual gate MOSFET mixer? Depening on the fet and circuit values around +3dbm. >One can also use HC4066 or 4053 as the switching element at lower >freqs. True. Doesn't work well at 6M at all. >JJ > > >I really do not know what is the IP3 of a DG Mosfet as I never have >seen any value reported. I hope some readers may have data on this. >Certainly we have to look at IIP3 and OIP3 as the DGM mixer may have >high conversion gain 15-20dB and is somewhat limited in dynamic range. >Maybe it could have an OIP3 around +5dBm equivalent to an IIP3 of -10 >to -20dBm .... more or less similar to the NE602. Much better than NE602 on IP3, lower on conversion gain (6-10db). The big differnce is the DGFET mixer is lack of balance so feed through is an issue. However a pair used in a balanced arrangement can be a very good low noise mixer. Many of the balanced FET designs in past issues of Ham Radio and were from hams in Europe where strong SW broadcast is the normal environment. A thought on comparing mixers: NE602, Low power needed around 2-3ma at 6V, IP3 -10dbm. (for 18mW of power this gilbert cell offers good perfomance). Low power needed is very small to nonexistant due to internal OSC. Low NF of <5db at 45mhz. High conversion gain (typicall 15-17DB). DGmosfet power needed around 4-6ma/12V, IP3 0 to 3dbm Also low to no LO power needed. Conversion gains of 5-8db typical. Properly matched, low noise. Balanced DGmosfet(2) power needed ~8-10ma/12V, Ip3>3dbm Low to minimal LO power needed. Low conversion gains but low noise as well. Ad831 high power needs but all the advantages of Gilbert cell mixer with very high IP3s (variable with power consumption setting). DBM power needed zero (however 10mW of LO required!) IP3 around 0DBM, requires post mixer IF amp or termination and has 6-8db loss. System power required for mixer is usually around 100mW or higher. Fet switching mixers are all over the map on power required some requiring little and some needed a great deal of LO power to drive correctly, they may also require supporting pre and post amps to insure noise figure and system gain. Generally the more power, the better the IP3. In cases where power is available this may not be an issue. Balanced designs regardless of devices are more robust than single ended. For portable systems where battery lifetime is a consideration that can be a determining factor. >The DGM mixer was a common mixer in the first series of transistorized >RTX with valves PA (FT101Z, TS820 etc). The DGM has a good square law, >better than JFET. JFETS in balanced active mixers do very well. It's also possible to use two Jfets to replace a DG mosfet and in most designs that will perform the same as the DGFET. >74HC4066 is OK at low frequency conversion but it has a haigh >conversion loss, around 8-10dB and so associated noise figure. Old device and higher series on resistance. >Today the switched mixer should use fast bus switches like the FST3125 >family when looking at high performance mixers. The examples are the >CDG 2000 and STAR (Pic-A-Star) projects with IP3 around +40dBm and >+36dBm, where the H-Mode Mixer with FST3125 is used. All of that is good but unless the post mixer amp, IF and filters following it are up to the task and well matched the results can be very disappointing. When going to that level of performance one needs to look at the recieving system and examine carefully. Allison Article: 96908 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Amateur Radio Control Shifts Message-ID: <2k5022tcfogcmmvh4akbj68v1oas2gslc3@4ax.com> References: <5hETf.6838$1Z5.4822@tornado.texas.rr.com> <2ZCdnfE214aah4LZ4p2dnA@web-ster.com> <1142950470.816333.111280@i39g2000cwa.googlegroups.com> Date: Tue, 21 Mar 2006 15:30:20 GMT On 21 Mar 2006 06:14:30 -0800, "Tim Shoppa" wrote: >Tim Wescott wrote: >> Doug McLaren wrote: >> >> > In article , >> > Tim Wescott wrote: >> -- snip -- >> >> > ... so it looks like there IS a standard now, at least on the six >> > meter band stuff. I've heard some say that this isn't true, that >> > brand X 6m RX didn't workt with brand Y 6m TX, but details were never >> > really given. >> > >> That was useful, but I forgot to ask: >> >> Is the space (no pulse) frequency the nominal frequency, or is it (more >> sensibly IMHO) 1/2 the shift below -- or at least _some_ amount below >> the nominal? > >With 2kHz shifts I'm not sure that this is particularly relevant. Most >of the receivers probably have bandwidths of 10kHz or more. > >Ideally the center frequency would fall in the center of the passband >of the receiver, following your "1/2 the shift below" if the center >frequency were truly accurately calibrated. And the receiver bandwidth >would be simlar to the FSK spacing. But things have always been much >looser than this. > >> If I were designing such a rig I would have the space frequency (off, no >> pulse, whatever) be 1/2 of the shift _below_ the nominal frequency, and >> the mark frequency be 1/2 of the shift _above_. I may shade the space >> frequency to be a bit closer to the nominal frequency to balance out the >> spectrum, but I doubt that I'd stick it right onto the nominal frequency. > >1kc at 50MHz is 20 ppm, and 30 or 40 years ago when I did 6M remote >control I'm pretty sure that most of the crystals would've truly >struggled to meet this spec. Some of the transmitters used LC circuits >for tuning (I am not kidding!) and receive bandwidths were as wide as >100kHz or more. But that kind of slop was going away as the tube >transmitters disappeared :-). > >Of course the Gonset portable sets (transmitter and regen receiver both >tuned only by LC's) set truly abysmal standards for stabilities and >bandwidths. Maybe I'm being too pessimistic in extrapolating their >specs to today! > >Tim. Before that superregens and tone modulated AM were used with escapements (trigger, right, triger again neutral, again left, again neutral). Then came multifrequency tone systems using reeds. Around the same time was the GallopingGhost (wagwag) where the carrier was tone modulated and repetitive the duty cycle of on/off time varied. A simple magnetic actuator followed the state (full one way or other) and averaging of the rudder position was "proportional". The 1960s and in groth of "CB" used forced the introduction of superhets for 11m use in RC and 6M (less interference). Three things came out from the 50s and 60s important to RC, transistors, reliable nicads and multichannel proportional systems. The 1970s transmitters for RC use on 11m/6m and 72mhz were AM modulated and typically use 50ppm rocks with wide (20kc) bandwidths for superhets. (1970s and later). Impulse noise and cochannel interference were problems with AM systems. It was in this era (mid 60s) that the first PPM (really PWM) systems emergend from Craft and others. Then in the 80s the RC community started going FM for noise immunity though the encoding was still PWM. Again after a few years and emergence of real digital system the encoding was FM with digital PSK. My first RC flight was a TX using wet nicads and a pair of 3A5s on 11M and the RX was a three transistor regen using escapment. I stopped flying when FM became the standard. Though I still drag out the old CB (yep 27mhz!) .020 powered 1/4A ugly stick flying gallopingghost (ACE RC). The freq flag for that is a large 6x6" square white sheet, different from all the rest still flying! Allison Article: 96909 of rec.radio.amateur.homebrew Subject: Re: Amateur Radio Control Shifts References: <2ZCdnfE214aah4LZ4p2dnA@web-ster.com> <1142950470.816333.111280@i39g2000cwa.googlegroups.com> From: dougmc@frenzy.com (Doug McLaren) Message-ID: Date: Tue, 21 Mar 2006 16:05:59 GMT In article , Tim Wescott wrote: | Current spec is 20kHz channels, so you have to be better than that. Current spec is _10_ KHz channels. Sure, our (72 MHz) channels are 20 KHz apart, but that's because there's channels for other things (pagers, industrial R/C, wireless microphones) in between our channels. -- Doug McLaren, dougmc@frenzy.com "Give me ambiguity, or give me something else!" Article: 96910 of rec.radio.amateur.homebrew Subject: Re: mixer: DBM or dual gate mosfet? From: JJ References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> Message-ID: <49b6d$44202753$d135c4af$21489@MDI.CA> Date: Tue, 21 Mar 2006 11:18:27 -0500 Anyone remember the CA3028 singly balanced mixer? It was just 2 transistors as difference amp and current source transistor. What would the IP3 be for it? JJ Article: 96911 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> <49b6d$44202753$d135c4af$21489@MDI.CA> Date: Tue, 21 Mar 2006 17:39:01 GMT On Tue, 21 Mar 2006 11:18:27 -0500, JJ wrote: >Anyone remember the CA3028 singly balanced mixer? >It was just 2 transistors as difference amp and current source transistor. >What would the IP3 be for it? > >JJ I've used it and have a box load of them (3028, 3026 and related parts) still. IP3 depends on bias applied and load it's decent and far above the single transistor mixer. If the input and output are balanced the IP3 is around the -10 to 0dbm range depending on bias current and specific circuit. It's advantage is the LO power needed is quite low as well as low DC power needs. It's still possible to find the parts or related differential pair with current source parts (RCA had a whole series of them). They also make decent AGC If amps. Allison Article: 96912 of rec.radio.amateur.homebrew Subject: Re: mixer: DBM or dual gate mosfet? From: JJ References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> Message-ID: Date: Tue, 21 Mar 2006 14:53:33 -0500 For completeness what are the IP3 for a single BJT and single FET mixer? The ARRL handbook recommended a source resistor voltage of 1V as optimum bias. JJ Article: 96913 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: References: <1141203801.248815.322050@e56g2000cwe.googlegroups.com> <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> Date: Tue, 21 Mar 2006 20:46:38 GMT On Tue, 21 Mar 2006 14:53:33 -0500, JJ wrote: > >For completeness what are the IP3 for a single BJT and single FET mixer? >The ARRL handbook recommended a source resistor voltage of 1V as optimum >bias. > >JJ Source resistor has to be correct for the device and 1V [often] may not be it. Also LO drive will require tailoring for best IP3 and conversion gain. Single ended BJT mixers are pretty weak but can offer good conversion gain. Fets in general are much better but tend to be low conversion gain. However specific numbers are hard to appraise as circuits vary considerably. Either would only be considered for low end or where IP3 is not a consideration or are overridden by other considerations. The mid 80s low to mid range radios did use Jfets as mixers often with enough preselection to keep out the offending signals. Allison Article: 96914 of rec.radio.amateur.homebrew From: Ted Subject: Re: Data needed on RF2065 MMIC - similar to MAR-3 Message-ID: References: Date: Tue, 21 Mar 2006 17:37:07 -0500 Allison, I got the RF2065s as substitutes for the MAR-3/MSA-0385, so that's my problem. I was able to actually get some real MAR-6s, but I need a couple of the MAR-3 or substitutes. Not a bad deal on the RF2065s; 25 of them for $9.95 plus a little for shipping. I needed the data sheet just to convince myself that they'll really work. I have another problem...now I can't find the ten MAR-6s that I bought earlier! Creeping old age, or something I guess! Unfortunately, they were shipped in a plain white business envelope, and they could very well be hiding in plain sight. I like your point on the discrete transistor substitution as well. I'll keep that in mind. I have plenty of room on the board, as I'm building only the transmitter and PA chain (for 21 MHz), not the VFO and receiver as shown in the figure. Thanks, Ted On Sat, 18 Mar 2006 03:58:30 GMT, Allison-nospam@nouce.bellatlantic.net wrote: >On Fri, 17 Mar 2006 18:48:51 -0500, TW >wrote: > >>I need a datasheet on the RF2065 MMIC, or more specifically, >>RF2065TR7M. Supposed to be similar to the MAR-3, but I can't prove >>it. The guy I bought some from tested it as if it were a MAR-3, he >>says. ---snip--- > >For that application at 18mhz there is plenty of room for subs. The >mar3 or something reasonably close will be fine. You only need >enough gain to set the noise figure byb offsetting the losses in the >DBMs and image stripping filters. > --snip--- >Or it's so old everyone forgot they made it! Really, it does >happen!!! > >For circuits in EMRFD using MIMICs all you need to substitue them is: > > Gain > Max power out > Noise figure > >Then order the nearest MAR or ERA part from Minicircuits. > >Or as I've done in many cases is use a 2n3904 (2n5109 >if more bandwidth is needed) in a broadband 50ohm amp >circuit (from earlier in the book). Same performance >and I can build from my parts bin and tweek it for my usage. >I save the mmics for where space or frequencies greater than >100mhz are important to me. > >Most cases the lattitue is fairly wide and the specific circuit >details will call out the needed info to apply it. > > >Allison Article: 96915 of rec.radio.amateur.homebrew From: Ted Subject: Re: Any receiver IC's? Message-ID: References: <4db24$441c7a6d$d135c4af$17969@MDI.CA> Date: Tue, 21 Mar 2006 17:50:18 -0500 You might take a look at the National LMH6502, LMH6720, and LMH6657 trio. The are the recommended replacement IF/AGC components for the obsolete CLC520 shown in the 2005 ARRL Handbook. Ted Article: 96916 of rec.radio.amateur.homebrew From: David Harmon Subject: Re: focus group question for new products Message-ID: <444a8f1b.17577250@news.east.earthlink.net> References: <1142529061.429608.10260@j52g2000cwj.googlegroups.com> <1142535080.772184.106510@p10g2000cwp.googlegroups.com> <1142558910.394369.77220@i39g2000cwa.googlegroups.com> <1142608240.785602.114430@i39g2000cwa.googlegroups.com> <1142801286.340107.220430@u72g2000cwu.googlegroups.com> <1142866153.445666.80410@i39g2000cwa.googlegroups.com> <1142868008.916654.67200@g10g2000cwb.googlegroups.com> <1142872207.674651.51130@g10g2000cwb.googlegroups.com> Date: Tue, 21 Mar 2006 23:47:21 GMT On 20 Mar 2006 08:30:07 -0800 in rec.radio.amateur.homebrew, "Tim Shoppa" wrote, >Working sheet metal in a mill or a drill press has caused some, um, >near-disasters in many amateur shops. Poor clamping resulting in >spinning sheets with sharp edges are the most common That is deadly true; but I would think if you are going to make a business of it that you would set up some _good_ clamping fixture that would hold your sheet with no slipping. How is PC Board milling done? Article: 96917 of rec.radio.amateur.homebrew From: "Reg Edwards" Subject: New Program. Transmission Line Transformers Date: Wed, 22 Mar 2006 00:41:27 +0000 (UTC) Message-ID: There are two transmission lines in cascade plus a load impedance. The first line can be considered to be the main line from the transmitter. The second line can be considered to be an impedance matching transformer between the first line and the antenna. What is the impedance and length of line in the transformer if the antenna feedpoint impedance is not purely resistive? What are the input impedances of the two lines, R+jX ? What percentage of transmitter power is dissipated in the two lines? What is the overall power efficiency? The answers can be found in new program TWOLINES. SWR is not involved. Download program TWOLINES from website below in a few seconds and run immediately. -- ........................................................... Regards from Reg, G4FGQ For Free Radio Design Software go to http://www.btinternet.com/~g4fgq.regp ........................................................... Article: 96918 of rec.radio.amateur.homebrew From: "jack leishman" Subject: SK-506 chimney clips Message-ID: Date: Wed, 22 Mar 2006 05:05:50 GMT I am trying to locate the "U" shaped spring clips that properly space the SK 506 chimney and ground the base of the 4-1000A tube. If anyone knows a source, I would like to hear from you. Thanks jack k8xx. Article: 96919 of rec.radio.amateur.homebrew From: John Wilkinson Subject: Dual gate mosfet Date: Wed, 22 Mar 2006 10:24:49 +0000 Message-ID: <123y36rrc4q8f.v0odur2lszz6$.dlg@40tude.net> Hi, Is there any problem using a 50 Ohm resistor to set the input impedance of a BF998 dual gate mosfet, at 45MHz. Will this degrade noise etc? Thanks, John. Article: 96920 of rec.radio.amateur.homebrew From: John Wilkinson Subject: 45MHz crystal filters Date: Wed, 22 Mar 2006 10:29:56 +0000 Message-ID: Hi, I am using a couple of 45MHz crystal filters in my first IF amp. Has anyone any experience of using these, and give me any advice on problems they encountered. I think I have a problem with screening, as they require 700 Ohms termination resisistance. When the manufacturers spec a termination resistance, do the filters themselves look like say 700 Ohms, or do I need to set this externally with a resistance? Best regards, John. Article: 96921 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Dual gate mosfet Message-ID: References: <123y36rrc4q8f.v0odur2lszz6$.dlg@40tude.net> Date: Wed, 22 Mar 2006 12:32:09 GMT On Wed, 22 Mar 2006 10:24:49 +0000, John Wilkinson wrote: >Hi, >Is there any problem using a 50 Ohm resistor to set the input impedance of >a BF998 dual gate mosfet, at 45MHz. >Will this degrade noise etc? > >Thanks, >John. Yes, 50 ohms is well below optimum for gain and noise. For best noise and gain the fet seems to be in the 2k region. Allison Article: 96922 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: 45MHz crystal filters Message-ID: References: Date: Wed, 22 Mar 2006 12:45:53 GMT On Wed, 22 Mar 2006 10:29:56 +0000, John Wilkinson wrote: >Hi, >I am using a couple of 45MHz crystal filters in my first IF amp. >Has anyone any experience of using these, and give me any advice on >problems they encountered. >I think I have a problem with screening, as they require 700 Ohms >termination resisistance. > >When the manufacturers spec a termination resistance, do the filters >themselves look like say 700 Ohms, or do I need to set this externally with >a resistance? > >Best regards, >John. It means looking from the filter into the next stage it should see a 700ohm resistive load. How you get from 700 to the optimum for the stage is up to you but FETs are higher input impedence for noise and gain and transistors (BJT) are generally lower. Devices like NE602, MC1350 and similar differential inputs are around 1.5k. Allison Article: 96923 of rec.radio.amateur.homebrew From: John Wilkinson Subject: Re: Dual gate mosfet References: <123y36rrc4q8f.v0odur2lszz6$.dlg@40tude.net> Date: Wed, 22 Mar 2006 13:21:46 +0000 Message-ID: <1k0uiegvyrme$.mw1lzf8i0ysc$.dlg@40tude.net> On Wed, 22 Mar 2006 12:32:09 GMT, Allison-nospam@nouce.bellatlantic.net wrote: > On Wed, 22 Mar 2006 10:24:49 +0000, John Wilkinson > wrote: > >>Hi, >>Is there any problem using a 50 Ohm resistor to set the input impedance of >>a BF998 dual gate mosfet, at 45MHz. >>Will this degrade noise etc? >> >>Thanks, >>John. > > Yes, 50 ohms is well below optimum for gain and noise. > For best noise and gain the fet seems to be in the 2k region. > > Allison Thanks for the help so far. So, I was hoping to make this a good 50 Ohms input match. Looking at the Philips datasheet for the BF998, for the agc and cross mod test, they show a fully biased Mosfet, and an ac coupled 50 Ohm resistor across the input. the input is from a 50 Ohm sig gen. So does this mean if I set the gate resistance to say 2K, and ac couple a 50 Ohm input resistance, is that better? If so why? Best regards, John. Article: 96924 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: Dual gate mosfet Message-ID: <5um2225dm84lb5i47qfgqbfat3354vpuru@4ax.com> References: <123y36rrc4q8f.v0odur2lszz6$.dlg@40tude.net> <1k0uiegvyrme$.mw1lzf8i0ysc$.dlg@40tude.net> Date: Wed, 22 Mar 2006 14:24:01 GMT On Wed, 22 Mar 2006 13:21:46 +0000, John Wilkinson wrote: >On Wed, 22 Mar 2006 12:32:09 GMT, Allison-nospam@nouce.bellatlantic.net >wrote: > >> On Wed, 22 Mar 2006 10:24:49 +0000, John Wilkinson >> wrote: >> >>>Hi, >>>Is there any problem using a 50 Ohm resistor to set the input impedance of >>>a BF998 dual gate mosfet, at 45MHz. >>>Will this degrade noise etc? >>> >>>Thanks, >>>John. >> >> Yes, 50 ohms is well below optimum for gain and noise. >> For best noise and gain the fet seems to be in the 2k region. >> >> Allison > >Thanks for the help so far. >So, I was hoping to make this a good 50 Ohms input match. Looking at the >Philips datasheet for the BF998, for the agc and cross mod test, they show >a fully biased Mosfet, and an ac coupled 50 Ohm resistor across the input. >the input is from a 50 Ohm sig gen. that is a test fixture for s specific set of parameters not a working circuit. Depending on frequency and other factors it will work but optimum? >So does this mean if I set the gate resistance to say 2K, and ac couple a >50 Ohm input resistance, is that better? If so why? At 50 ohms the source voltage is that impressed across 50 ohms. If you transform that impedence to 2k the voltage will be sqrt(2000/50) or around 6.32 times the signal voltage at the gate of the fet with no increase in noise from the resistor. Net signal to noise ratio is then improved. This is simplified and second order stuff trivialized. At 6m I used a tapped LC to transform the 50 ohm to 2k and used a resistor of 2.2k to terminate it. Better transducer gain and much lower noise. Allison Article: 96925 of rec.radio.amateur.homebrew From: "Dale Parfitt" Subject: OCEAN STATE ELECTRONICS? Message-ID: <6BfUf.5199$I7.481@trnddc03> Date: Wed, 22 Mar 2006 17:13:38 GMT Anyone else having difficulty getting these folks on the phone? Been busy for 3 days now. A friend ordered via the net 6 weeks ago and never has been billed nor parts received. Tnx, Dale W4OP Article: 96926 of rec.radio.amateur.homebrew From: - exray - Subject: Re: OCEAN STATE ELECTRONICS? Date: Wed, 22 Mar 2006 13:42:04 -0400 Message-ID: <122333da7ejbg2a@corp.supernews.com> References: <6BfUf.5199$I7.481@trnddc03> Dale Parfitt wrote: > Anyone else having difficulty getting these folks on the phone? Been > busy for 3 days now. > A friend ordered via the net 6 weeks ago and never has been billed nor parts > received. > Tnx, > > Dale W4OP > > They have a nasty habit of simply cancelling an order without notification if the item is not in stock. Been there, done that. -Bill Article: 96927 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: 45MHz crystal filters Message-ID: References: Date: Wed, 22 Mar 2006 19:02:42 GMT On Wed, 22 Mar 2006 08:25:24 -0800, Tim Wescott wrote: >Allison-nospam@nouce.bellatlantic.net wrote: > >> On Wed, 22 Mar 2006 10:29:56 +0000, John Wilkinson >> wrote: >> >> >>>Hi, >>>I am using a couple of 45MHz crystal filters in my first IF amp. >>>Has anyone any experience of using these, and give me any advice on >>>problems they encountered. >>>I think I have a problem with screening, as they require 700 Ohms >>>termination resisistance. >>> >>>When the manufacturers spec a termination resistance, do the filters >>>themselves look like say 700 Ohms, or do I need to set this externally with >>>a resistance? >>> >>>Best regards, >>>John. >> >> >> It means looking from the filter into the next stage it should see a >> 700ohm resistive load. >> >> How you get from 700 to the optimum for the stage is up to you >> but FETs are higher input impedence for noise and gain and >> transistors (BJT) are generally lower. Devices like NE602, >> MC1350 and similar differential inputs are around 1.5k. >> >> Allison >> >It means that the source impedance of the amplifier driving the filter, >_as well as_ the input impedance of the amplifier following need to be >700 ohms, resistive. Get this wrong and the filter shape will be off. Ah, I've done a few filters in life. While your right your way to fast to audit. >> It means looking from the filter into the next stage it should see a >> 700ohm resistive load. Maybe that should have been for the pendantic. It means looking from the filter into the adjacent stages it should see a 700ohm resistive load. There the use of "adjacent" rather than "next" should satisfy. Allison Article: 96928 of rec.radio.amateur.homebrew From: "Dale Parfitt" References: <1143049636.448285.24980@j33g2000cwa.googlegroups.com> Subject: Re: Eddystone dial Message-ID: Date: Wed, 22 Mar 2006 19:16:51 GMT "Doc" wrote in message news:1143049636.448285.24980@j33g2000cwa.googlegroups.com... > Does anyone in the group have any idea of what an Eddystone dial, Model > 898, is worth. I bought a new one, along with the parts for the Ted > Crosby HBR receiver many years ago, but never got around to building > it. The XYL is pushing me to downsize and I need to start somewhere. I > may have an interested party, but can list it on e-Bay if this falls > through. I'd like to get some idea of where to start. > Doc, W4ITJ > If this is the 898: http://www.parelectronics.com/pics/w7zoi14.jpg I bought mine on EBay for around $10. Dale W4OP Article: 96929 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: 45MHz crystal filters Message-ID: References: Date: Wed, 22 Mar 2006 22:42:08 GMT On Wed, 22 Mar 2006 11:22:32 -0800, Tim Wescott wrote: >Yes, I think you have more experience than me, and I suppose I was being >pedantic -- but they do want good termination on both ends. > >I forgot to add the part that would always happen in my lab: make sure >to do a few sweeps, because no matter what my design looks like on paper >I always get it wrong the first few times. Hey, every paper design goes on the test bench. That's where the real world strikes back. Little things like sneak paths, shielding, and plain parts that do not meet tolerence make best cranked numbers meaningless. Allison Article: 96930 of rec.radio.amateur.homebrew From: John Wilkinson Subject: 45 MHz IF breakthrough Date: Thu, 23 Mar 2006 07:50:41 +0000 Message-ID: <1jimvb5qzpfuz.eqwrplvmo554$.dlg@40tude.net> Hi, OK I have a 45MHz crystal filter for my first IF. The first LO ranges from 45-75MHz. To test I am using a 45.455MHz LO, which is a pll design. When I connect up the LO to the mixer, with no input signal I get a -80dBm level out of my IF stage!! The PLL is clocked off 1MHz ref divided down to 5KHz. The 1MHz ref is a TTL signal. Could this be the cause of the problem, and if so how do I get around it? Thanks, John. Article: 96931 of rec.radio.amateur.homebrew From: Eamon Skelton Subject: Re: 45 MHz IF breakthrough Message-ID: References: <1jimvb5qzpfuz.eqwrplvmo554$.dlg@40tude.net> Date: Thu, 23 Mar 2006 11:54:29 +0000 On Thu, 23 Mar 2006 07:50:41 +0000, John Wilkinson wrote: > Hi, > OK I have a 45MHz crystal filter for my first IF. The first LO ranges from > 45-75MHz. > To test I am using a 45.455MHz LO, which is a pll design. When I connect > up the LO to the mixer, with no input signal I get a -80dBm level out of > my IF stage!! -80 dBm at the IF output sounds pretty good. Are you using a high gain, wide bandwidth IF amplifier? How good is the stopband rejection of your IF filter? Two pole roofing filters are often not much better than -20 to -25dB. What kind of mixer are you using? A well balanced or double-balanced mixer will help to keep the local oscillator signal out of the IF. > The PLL is clocked off 1MHz ref divided down to 5KHz. The 1MHz ref is a > TTL signal. Could this be the cause of the problem, and if so how do I get > around it? > > Thanks, > John. PLL oscillators can be very noisy, but it would take a very poor design to produce strong spurious signals at +/- several hundred kHz. Designing a PLL from scratch is not easy unless you have a spectrum analyser or a good receiver that covers the VCO frequency +/- a few MHz. Pay careful attention to grounding and screening, especially around the VCO and loop filter. You must keep those nasty TTL square waves away from the VCO. Make sure the DC supply to the VCO and loop filter is very clean and stable. 73, Ed. EI9GQ. -- Linux 2.6.15 Remove 'X' to reply by e-mail. Yes, my username really is: nospam Article: 96932 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: 45 MHz IF breakthrough Message-ID: References: <1jimvb5qzpfuz.eqwrplvmo554$.dlg@40tude.net> Date: Thu, 23 Mar 2006 13:58:59 GMT On Thu, 23 Mar 2006 07:50:41 +0000, John Wilkinson wrote: >Hi, >OK I have a 45MHz crystal filter for my first IF. >The first LO ranges from 45-75MHz. >To test I am using a 45.455MHz LO, which is a pll design. >When I connect up the LO to the mixer, with no input signal I get a -80dBm >level out of my IF stage!! >The PLL is clocked off 1MHz ref divided down to 5KHz. The 1MHz ref is a TTL >signal. Could this be the cause of the problem, and if so how do I get >around it? > >Thanks, >John. Before I go into other suggestions most of the 45mhz filters I've played with only had a 40db or so stopband. So it was easy to get a stong signal through them or if the gain was high after them couple around the filter via radiation. For the mixer use a balanced (Better doubly balanced) design to keep the LO from the IF. Believe it or not the NE602 qualifies as a good device for this. Then shield everything can interconnect with coax. Double sided (or multilayer) boards can help if the top layer is a groundplane and everything is grounded to that. If everything is on one board the ideal layout is straight line as that puts the input at the greatest possible distance from the output. My experience with PLLs is if not carefully designed you can have noticeable sidebands of the locked frequency spaced every Fref to either side. The PLL control voltage low pass filter has to be well executed to keep them 60 or more DB down. Those sidebands will appear as spurs and added noise. Sounds like your doing a double (or more) conversion receiver and a better choice for the 45mhz to .455khz conversion would be a crystal (much cleaner). However _if_ the 45mhz filter is wider than a few hunderd kilohertz I'd consider a higher IF to avoid images. Allison Article: 96933 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: 45 MHz IF breakthrough Message-ID: References: <1jimvb5qzpfuz.eqwrplvmo554$.dlg@40tude.net> <1143127018.329411.87140@j33g2000cwa.googlegroups.com> Date: Thu, 23 Mar 2006 16:23:21 GMT On 23 Mar 2006 07:16:58 -0800, eternalsquire@comcast.net wrote: >I've been seeing your postings for a while now. How you thought of >writing a book? >Seriously. > >The Eternal Squire Hi, In a word no. I'd never considered it. Between ham radio, old computers (DEC and CP/M hardware/software) it's just one more aspect of electronics that I've been involved with. FYI: I've been on the internet posting for the last 20+ years and changed posting addresses to foil spammers. Allison Article: 96934 of rec.radio.amateur.homebrew Subject: Re: mixer: DBM or dual gate mosfet? From: JJ References: <4406fe2e$0$25339$39db0f71@news.song.fi> <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> <49b6d$44202753$d135c4af$21489@MDI.CA> Message-ID: Date: Thu, 23 Mar 2006 12:35:41 -0500 Allison-nospam@nouce.bellatlantic.net wrote in news:grd022teq37o91uead7rd0tt44pdcj56v4@4ax.com: > I've used it and have a box load of them (3028, 3026 and related > parts) still. IP3 depends on bias applied and load it's decent and > far above the single transistor mixer. If the input and output are > balanced the IP3 is around the -10 to 0dbm range depending on > bias current and specific circuit. It's advantage is the LO power > needed is quite low as well as low DC power needs. > > It's still possible to find the parts or related differential pair > with current source parts (RCA had a whole series of them). > > They also make decent AGC If amps. > > Allison The singly balanced mixer using 2 DG MOSFETs seem to be better still. Does it have a higher IP3 than a single ended mixer? Why use a AD831 if the noise figure is 10dB? JJ Article: 96935 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: <7ar5225be775ao2v1i69ul4qbn27av7i9n@4ax.com> References: <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> <49b6d$44202753$d135c4af$21489@MDI.CA> Date: Thu, 23 Mar 2006 18:51:58 GMT On Thu, 23 Mar 2006 12:35:41 -0500, JJ wrote: >Allison-nospam@nouce.bellatlantic.net wrote in >news:grd022teq37o91uead7rd0tt44pdcj56v4@4ax.com: > >> I've used it and have a box load of them (3028, 3026 and related >> parts) still. IP3 depends on bias applied and load it's decent and >> far above the single transistor mixer. If the input and output are >> balanced the IP3 is around the -10 to 0dbm range depending on >> bias current and specific circuit. It's advantage is the LO power >> needed is quite low as well as low DC power needs. >> >> It's still possible to find the parts or related differential pair >> with current source parts (RCA had a whole series of them). >> >> They also make decent AGC If amps. >> >> Allison >The singly balanced mixer using 2 DG MOSFETs seem to be better still. >Does it have a higher IP3 than a single ended mixer? Balanced mixers generally perfom far better than single ended. FETs as a balanced mixer do well and if the FETs used are high IDSS types (J310 or others) the IP3 can be excellent. >Why use a AD831 if the noise figure is 10dB? It has gain, high IP3 and 10db my mixer standard is not that bad. A low gain RFamp with low noise figure will override mixer noise. Of course the RFamp must have a good IP3 as well. Allison Article: 96936 of rec.radio.amateur.homebrew From: "Jim, KK1W" Subject: FA: XR IC's, old parts, Sprague caps, builders stuff & more! Message-ID: Date: Thu, 23 Mar 2006 22:07:50 -0500 Hi, Just a few days left on some good stuff cheap! Low starting bids, no minimums, good feedback rating. A super chance to stock the parts bin and save space in the landfills for more deserving stuff. Take a look at these auctions: http://search.ebay.com/_W0QQsassZkk1w2000. Lots of old and new parts, caps, resistors, pots, coils, meters, crystals and more. Low starting bids and good feedback rating. Thanks for looking, Jim, KK1W Article: 96937 of rec.radio.amateur.homebrew Subject: Re: mixer: DBM or dual gate mosfet? From: JJ References: <120ei436906hh32@corp.supernews.com> <2F7Of.879$s8.113@bignews7.bellsouth.net> <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> <49b6d$44202753$d135c4af$21489@MDI.CA> <7ar5225be775ao2v1i69ul4qbn27av7i9n@4ax.com> Message-ID: Date: Fri, 24 Mar 2006 11:36:11 -0500 >>Why use a AD831 if the noise figure is 10dB? > > It has gain, high IP3 and 10db my mixer standard is not that bad. > A low gain RFamp with low noise figure will override mixer noise. > Of course the RFamp must have a good IP3 as well. > > Allison Ok, I like to try the AD831. When is dual supply better than single ended? There must be a socket to fit the package but is it all right to solder tiny leads to it for prototyping? JJ Article: 96938 of rec.radio.amateur.homebrew From: Allison-nospam@nouce.bellatlantic.net Subject: Re: mixer: DBM or dual gate mosfet? Message-ID: <7ro822p9jj8fb10rgte1dat8ij7mceqqmf@4ax.com> References: <1142724825.475143.34810@v46g2000cwv.googlegroups.com> <1142934109.266286.184930@e56g2000cwe.googlegroups.com> <9fvv12lkd8qcghig78dcjpitlg2s37bm1k@4ax.com> <49b6d$44202753$d135c4af$21489@MDI.CA> <7ar5225be775ao2v1i69ul4qbn27av7i9n@4ax.com> Date: Fri, 24 Mar 2006 21:26:31 GMT On Fri, 24 Mar 2006 11:36:11 -0500, JJ wrote: > >>>Why use a AD831 if the noise figure is 10dB? >> >> It has gain, high IP3 and 10db my mixer standard is not that bad. >> A low gain RFamp with low noise figure will override mixer noise. >> Of course the RFamp must have a good IP3 as well. >> >> Allison >Ok, I like to try the AD831. >When is dual supply better than single ended? >There must be a socket to fit the package but is it all right to solder >tiny leads to it for prototyping? > >JJ It's better to avoid the socket, unless its a specially designed to be RF complient. The circuit is simpler with dual supply, fewer resistors. Allison