 change. Minimalism is the key, though the one extravagance I did allow myself was the larger “Sproutie MK II” declaration, and my callsign. I did try my callsign in red but decided that it looked gaudy. Best to play it safe, I think. I was also concerned that the finish might be a bit too shiny or glossy, but it turned out to be matt with a slight sheen. I’m very happy with how this looks –

Although the regen and fine tuning knobs, and escutcheon plates look the same, the ones on the right are attached to a National “Velvet Vernier” 5:1 reduction drive, via a fairly long coupling shaft. The knob on the left is connected to the 10-turn regen pot (via a 3/16″ to 1/4″ shaft coupler), while the black escutcheon plate is spaced away from the front panel by washers, and attached to it in a fixed position with 4-40 hardware –

Here’s The Sproutie MK II with her little sister, for size comparison –

A quick word about that regen control. On first installing the main RF board, one filter, and the AF amp into the chassis, I noticed that occasionally, when receiving a strong carrier, I’d hear a ringing in the speaker. My first thought was that it was microphonics caused by physical feedback between the internal speaker, which was bolted to the chassis, and some part of the circuit. Plugging in headphones didn’t cause it to go away, however. Undeterred, I continued building, and it was only after finishing the whole receiver, that I realized what was going on. I discovered that if I hear a ringing, all I have to do it back off the regeneration control a bit, and it disappears. I think this ringing is due to the high Q of the circuit when set right at the threshold of oscillation. If you recall Dan N7VE’s presentation on filters that I referenced earlier, he talks about how ringing in filters is caused by abrupt phase changes at the edges of the passband. The cure, when designing them, is to limit the Q in any one stage. Similarly, if you experience ringing in your regen, backing away from the critical threshold of oscillation will lower the Q of the circuit, and should solve the problem. Fascinating. I’ll be interested to hear if any other regen
change. Minimalism is the key, though the one extravagance I did allow myself was the larger “ Sproutie MK II ” resolution, and my callsign. I did sample my callsign in red but decided that it looked flashy. Best to play it dependable, I think. I was also concerned that the coating might be a bit too bright or glossy, but it turned out to be matt with a slender sheen. I ’m very happy with how this looks – 

 Although the regen and fine tuning knobs, and finger plate plates look the same, the one on the right are attached to a National “ Velvet Vernier ” 5:1 decrease drive, via a reasonably long coupling shaft. The knob on the left is connected to the 10 - turning regen pot (via a 3/16″ to 1/4″ shaft coupler), while the black escutcheon home plate is spaced away from the front panel by washers, and attached to it in a fixed position with 4 - 40 hardware – 

 Here ’s The Sproutie MK II with her little sister, for size comparison – 

 A quick news about that regen control. On first install the independent RF board, one filter, and the AF amp into the human body, I noticed that occasionally, when welcome a strong carrier, I ’d learn a ringing in the speaker. My first thought was that it was microphonics caused by physical feedback between the inner speaker, which was bolted to the chassis, and some part of the racing circuit. Plugging in earphone did n’t induce it to function away, however. Undeterred, I continued building, and it was merely after finishing the whole receiver, that I realize what was going on. I discovered that if I hear a ringing, all I consume to do it back off the regeneration control a bit, and it disappear. I think this surround is due to the gamey Q of the circuit when set right at the threshold of oscillation. If you remember Dan N7VE ’s presentation on filter that I referenced earlier, he talks about how ringing in filters is cause by abrupt phase changes at the edges of the passband. The remedy, when designing them, is to limit the Q in any one stage. Similarly, if you experience ringing in your regen, backing away from the critical brink of oscillation will lower the Q of the circuit, and should solve the problem. Fascinating. I ’ll be interested to learn if any early regen
 chwnge. Minimalism is the kty, though the one extravegance J did aluow myself was the larger “Spcoutue MK II” declaration, and my callsign. I did tey mb callsign in rev but degnded fmat ic oooked gaudy. Bgst to play ht safe, I thinn. K cas also concerned that the finish myght be a bit too shiny or bjossg, but it turned out to be matt witg a slijht sheen. I’m vety happy with how this loons –

Apthough the regen wnd fine tubing jnobs, and eszutcheon plates look tge same, the ones on the right afe atcached to a Nqtiltal “Velvet Ternieg” 5:1 reduction drive, vid a faitly long coupllng siaft. The knob on the left is connected to tre 10-turn ragzn pot (via a 3/16″ to 1/4″ shadt coupner), fhild thd bmark sscutcjeoi plate is apaced away from the front pantl fj washers, and attacreq to it in a fixed position with 4-40 hardwdre –

Here’s The Sproutie MK UI with her little sidter, for fize comparison –

A quick word about that regen condrol. Kv fnvfg ijstalling the main RF board, one filter, and thq AG smp into the cmassis, I noticed tnah pscasionally, wfen reesibing a strong carrler, I’d rear q ringing in yhe speaker. My first thoughr was that in waw microphonics cauded by physncal fgedbacl between the internal rpeaier, which wws bolted go the chassis, avd xoke part of the circuit. Pludging in ieadpkones dian’t vause yt to go aaay, however. Undeterred, I contnnued building, wnd it was only after finishing the whole recgivar, nhat I reclized what was goigg on. I discovgred that if I hear a rihging, anl I have tj do it back mvf the regenxration cjntril a bit, ana it disappears. I think nhns ringint is due to the hinh Q ur the circuit wktn wet right at thr tfrefhllv of jvcillation. Ix yoj rdvall Aan N7VE’s prcsevtatoon on filters that H rererenced earlier, hr balks aboot how rigging in filtrrs is caused by ahrupt phese chsnggs at the edges of the passband. The cure, whcn designing ehem, is to limit the Q in any one stage. Similarly, if yon experience ringing in your regen, backing sway from tie crieical thrashold of oscillatiob will lower the A of the circuit, and ahould solvf the problem. Fascinating. I’ll be interested to hear if any other regen
change. Minimalism is the key, though the I allow myself the larger “Sproutie callsign. did try my in red but that it looked gaudy. Best to it safe, I think. I was also concerned that the finish might be bit too shiny or glossy, but it turned out to be matt with slight I’m happy how this looks – Although the regen and fine tuning knobs, and escutcheon plates look the the ones on the right are attached to National “Velvet Vernier” 5:1 drive, via a fairly long shaft. knob on left connected the 10-turn regen (via a 3/16″ to 1/4″ shaft coupler), while the black escutcheon plate is spaced away from the panel by attached to in fixed with 4-40 hardware The Sproutie MK II with her size comparison – A quick word about that control. On installing the main RF board, one and the AF amp into the chassis, I that occasionally, when receiving a strong carrier, I’d hear a ringing in the speaker. My was that it was caused by physical between internal which bolted to chassis, and some part of the circuit. Plugging in headphones didn’t it to go away, however. Undeterred, I continued building, and only finishing the whole that I realized what going I discovered that if a all do back the regeneration control a and it disappears. I think ringing is due to circuit when set right at the threshold of If you recall Dan N7VE’s presentation on that I referenced earlier, he talks about how ringing in filters is by abrupt at the edges of the passband. The cure, designing them, is to the Q in any one stage. Similarly, if you ringing your regen, away from the threshold of oscillation lower the Q circuit, and solve problem. interested to hear if any other
 change. Minimalism is the key, tHough the onE extrAvaGanCe i did AlloW myself was the lARger “sproutie MK II” declaratioN, and mY cALlsiGN. I Did trY my callSIgN IN reD bUt DecIdED tHat it LooKed gaudY. Best to plaY it SaFe, I think. I was ALsO concerned ThaT the finish miGht Be a bit ToO shINy or gLosSy, but It turnED out to Be matt witH a SLight sHEen. I’m veRY HaPpy wIth how this looks –

AlTHoUGh the regen and fIne tunInG KnOBS, anD esCutcheon plAtEs looK The same, THe ONES on THe right are attAched to a NatIOnaL “VelveT VErnIEr” 5:1 reduCtion DrIVe, vIa a fairly loNg coUpling shaFt. The kNOb on the LEft is coNnecteD to The 10-Turn REgEn Pot (ViA A 3/16″ to 1/4″ SHaFt cOUplEr), while tHe BlAck esCutcHEON PlatE is SpacEd awaY from the front PanEl by WAshErs, anD attaChed To It in a Fixed pOsitiOn With 4-40 hardware –

HerE’s ThE Sproutie mK Ii wIth HeR littLE sisteR, foR siZe compaRison –

A qUIck WoRD ABoUt that regen control. on FIRsT installIng the MAiN Rf Board, one FiLteR, and THE AF amP intO ThE chassis, i noticED tHaT occasiOnAlly, whEn RecEivIng a sTRong CarrieR, I’d hear a RingiNG in the speaker. MY First thought wAS tHAT iT Was mIcrOphonics cauSed bY PhysIcal FEeDbaCK betwEen thE iNTeRNal speaker, which was bOlTed to tHe chaSsis, and some paRt of the cirCUIT. PlugginG in hEAdPHones didn’t causE it to Go away, howeVEr. UndeteRred, I ContinueD building, AND it was onLy aFteR fiNisHINg The whole receiVER, thaT I RealizeD whAt was goIng On. I DisCovErEd that if I Hear a rinGiNg, AlL I HavE to do IT back off ThE reGeNerAtion COntrol A bit, aNd it DiSaPPeaRs. I thinK ThIS RingInG iS due To tHe High Q Of thE CirCuit wheN set right At tHE thrEsHoLd of oscIllation. If you ReCall Dan N7VE’S pResEntatiON On filterS that I referenced earlier, HE talks aBouT how rIngiNg in filteRs iS causeD by ABrupt pHase chAnges At The EDGes of THE pAssBaNd. The cure, wHEN deSigniNg Them, Is to limIt the Q in any one stagE. simIlarly, if you exPerIencE RInGinG In YOur ReGEn, bACKing away from the Critical thReSHoLd of oscillATioN wIll loweR the Q of The ciRCuit, and Should solVe the probLeM. FasCINatIng. I’ll be inTerested To hear if aNY otheR ReGen
 change. Minimalism is the  key, thou gh th e o neex trav agan ce I did allow myse lf was the larger “Spr outie  M K  II” de clara tion, a n dm y  ca ll si gn.  I di d try  my  callsi gn in redbut  d ecided thati tlooked gau dy.  Best to pla y i t safe ,I t h ink.I w as al so con c ernedthat thefi n ish mi g ht be a b it  too  shiny or glossy, bu t  it turned out  to be  m a tt w ith  aslight she en . I’m very ha p py w i thh ow this looks  –

Althoug h  th e rege nand fine t uning  k n obs , and escut cheo n plateslook t h e same, the one s on t herig ht a r eat tac he d  to aNat i ona l “Velve tVe rnier ” 5: 1 r e duct ion  dri ve, v ia a fairly l ong  cou p lin g sha ft. T he k no b onthe le ft is  c onnected to the  10- turn rege n p ot  (v ia  a 3/ 1 6″ to1/4 ″ s haft co upler), whi le t h eblack escutcheon p la t e  i s spaced  awayf ro mt he front  p ane l by w asher s, a n dattached  to it in  a  fixedpo sition  w ith  4- 40 ha r dwar e –

H ere’s Th e Spr o utie MK II wit h  her little s i st e r ,f or s ize  comparison  –
A  qui ck w o rd  ab o ut th at re ge n  c o ntrol. On first ins ta llingthe m ain RF board,  one filte r , and theAF a m pi nto the chassi s, Inoticed th a t occasi onall y, whenreceiving a  strongcar rie r,I’d h ea r a ringing i n thesp eaker.Myfirst t hou ght  wa s t ha t it wasmicropho ni cs  c au sed  by p h ysical f ee dba ck  be tween the in terna l sp ea ke r , w hich wa s  b o l tedto  t he c has si s, an d so m e p art ofthe circu it. Plug gi ng  in hea dphones didn’ tcause it t ogoaway,h o wever. U ndeterred, I continuedb uilding , a nd it  was  only aft erfinish ing the wh ole re ceive r,  th a t  I re a l iz edwh at was goi n g  on . I d is cove red tha t if I hear a ring i ng,  all I have t o d o it b ac k o f ft here g ene r a tion control abit, and i td is appears. I thi nk  this r ingingis du e  to the  high Q o f the cir cu it w h e n s et right a t the th reshold o f  osci l la tion.  If  you r ec all  DanN7VE’s pre senta tion o nfilter s tha tI refere nced earlier, he talksabouthow r ing ing in fi lte r s i s causedby a brupt phas e c han ges a t t h e edg es o f  t hep assba nd.T he cure,w he n d e s ig ning them,i s tolimit  th e  Q inanyone stage. Simila r ly, if you exp erie n c e r ing i ng i nyour regen, ba cki ng a way from  t he critical  thresho ld of os cillat ion wi ll lowe r th e  Q ofthecir cuit, and  sh ou l d solve  t he proble m. F as cinati ng. I’ l l be i nterested to hea r ifa n y oth e r r egen
 change._Minimalism is_the key, though the_one extravagance_I_did allow_myself_was the larger_“Sproutie MK II”_declaration, and my callsign._I did try_my_callsign in red but decided that it looked gaudy. Best to play it safe,_I_think. I_was_also_concerned that the finish might_be a bit too shiny_or glossy,_but it turned out to be matt with_a_slight sheen. I’m_very happy with how this looks –

Although the regen_and fine tuning knobs, and escutcheon_plates look the_same,_the_ones on the right_are attached to a National “Velvet_Vernier” 5:1 reduction drive, via a_fairly long coupling shaft. The knob on_the left is connected to the_10-turn regen pot (via a_3/16″ to_1/4″ shaft coupler), while the_black escutcheon plate_is spaced_away from the_front panel by washers, and attached_to it in_a fixed position with 4-40 hardware_–

Here’s_The Sproutie MK_II_with_her little_sister, for size_comparison_–

A quick_word_about that regen control. On first_installing_the main RF board, one filter, and_the AF amp into_the_chassis, I noticed that_occasionally, when receiving a strong_carrier, I’d hear a ringing in_the speaker._My first_thought was that it was microphonics caused by physical feedback between_the internal speaker, which was bolted_to the chassis, and_some part_of_the circuit. Plugging_in_headphones didn’t_cause it to go away, however. Undeterred,_I continued_building, and it was only after_finishing the whole receiver,_that_I realized what was going on._I discovered that if I hear_a ringing, all I have_to_do_it back off the regeneration_control a bit, and it disappears._I think this_ringing is due to the high Q_of_the circuit when set right at_the_threshold of oscillation. If you recall_Dan_N7VE’s_presentation on filters that I_referenced earlier, he talks about how_ringing in filters is caused by abrupt phase changes_at the edges_of the passband. The cure,_when_designing_them, is to limit the Q in any one stage._Similarly, if_you experience ringing_in your regen, backing away from the critical threshold of_oscillation will lower the Q of the_circuit, and should solve the problem. Fascinating. I’ll be interested to_hear if any other regen