[Drakelist] Drake 2-NT to Heathkit VF-1 VFO
I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot. Could that be somewhat remedied by replacing some of the components with newer ones? TNX in advance for any advise! Gary N2UM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Gary - there are a couple of alternatives to consider. There was an addendum to the 2-NT manual that identified the Heathkit HG-10B and the Hallicrafters HA-5 as being suitable VFOs. I was lucky and found a nice Hallicrafters HA-5 VFO on eBay. I had a HG-10B but the problems with that VFO (and I imagine the VF-1) is that you'll have to provide it with power and modify it for grid-block keying; the HA-5 has it's own AC supply and is easily modified for grid-block keying. Once you have the VFO set up you can put together a connecting cable with RG-174 coax and sacrifice an old FT-243 crystal to create a plug-in for the front panel crystal jack. Here are instructions for converting the HG-10B for use with the 2-NT per Roy KF5YU: In order to connect the 2-NT to the HG-10B we need to supply the HG-10B with B+ and 6.3 VAC filament voltage. We must also connect the RF Out from the HG10B to the backside of the xtal holder and key the HG-10B from the VFO Key of the 2-NT. I accomplished this by building a cable using a 4-pin connector and plug similar to the one used on PC power supplies, in fact if you have an old PC power supply you can use the connector and wires to build the cable. I built my cable using the same color coding of the original Heathkit cable to avoid accidents and confusion. The cable will have a red wire going to +250v, white wire going to 6.3 VAC filament, green wire going to the backside of the xtal jack and a black wire going to ground. These wires will correspond to the octal plug wiring on the HG-10B. I then made another cable to connect the 2-NT/VFO Key to the HG-10B Key jack. I then modified the HG-10B by moving the green wire from terminal strip A to the center connection on the RF Out jack. I then plugged my CW key into the front jack of the 2-NT. There is a chart in the HG-10B manual that tells you what value of R11 is needed to drop the B+ voltage down to 108 VDC. My HG-10B already had a 10k/10w resister so I tried that first and it worked even though the manual said I needed a 6k/5w resister. The 2-NT theoretically produces 250 VDC but my meter measured 280 volts so R11 will require some experimentation. 4 Pin Accessory Jack 2-NT (xtal block) - green wire - HG-10B (RF Out Jack) 2-NT (250 VDC) - red wire - HG-10B (terminal strip A pin 6 to R11) 2-NT (6.3 VAC )- white wire - HG-10B 2-NT (gnd) - black wire - HG-10B (gnd) 2-NT VFO Key - HG-10B Key Jack 2-NT Key Jack - CW Key The key to everything working is to consult the schematics of both units and check the wiring. The procedure I just set forth worked for me but you never know the history of the units you're working on, their wiring could be different than the original. Good Luck Roy Vickers KF5YU - Another way to skin this cat is to build yourself up a digital VFO like the NORCAL FCC-1/2 combination: http://www.norcalqrp.org/fcc2mkii.htm (although temporarily out of stock) But you'll have to kludge together a buffer amp to raise the drive level sufficiently for use on the higher bands (it does work on 80m as is with mine); alternatively you may be able to simply use a transformer system to boost up the drive: From: Bob Okas vinta...@earthlink.net Date: April 17, 2008 2:55:16 PM EDT To: 'Dino Papas' k...@cox.net Subject: RE: Using the FCC-1/2 with a Tube Type Transmitter Greetings Dino, The matching network is a simple L-network that matches the 50 Ohm output impedance of the FCC-2 to a higher impedance transmitter input. The inductor is in series with the FCC-2 output and the cap shunts the TX side of the network. The trick is determining what the 2-NT’s input impedance is. A good starting point is to guess around 1K. The network will offer roughly a 20x voltage step-up, which should be adequate to drive the TC on the higher bands. To determine what component values to use for the L-network, look at: http://bwrc.eecs.berkeley.edu/Research/RF/projects/60GHz/matching/ImpMatch.html Use a Q value of 7 and you should get some reasonable values. 73, Bob – W3CD Finally, if you're really into building from scratch you may want to consider starting with a PAL CB VFO unit which are readily available on eBay and creating a multiband VFO on your own. The box and tuning mechanism and capacitor would make a good base for such a unit (I have one over in the project queue myself). Hope some of this is useful. 73 -- Dino KL0S --- On 5Jan2010, at 9:25 AM, Gary Winkelman wrote: I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot.
[Drakelist] High Performance Mixers for Drake R4-C
Hi to all the Drake Fans: Can anyone recommend replacement high performance mixers for the late model Drake R4-C, serial number 27k+? Characteristics of Mixers desired: (1) Double Balanced Mixer or (2) Two doubly balanced mixers phased together (3) Hard Swithching Mixer (4) Voltage method of multiplication Thank you for all: 73, Chuck Pool - AA5WG Cedar, Michigan ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Why there are any VF-1s left on the planet is a mystery to me. I owned a couple of them, beginning in 1959, and they were absolutely dreadful. Guaranteed to drift and chirp. You could always tell who was using a VF-1 when you heard the CW signal. The Eico 722 was a good stable VFO and I still run into one of them from time to time. A pair of VF-1s make a nice set of nostalgia bookends, but that's about the extent of their usefulness. 73, K8AC - Original Message - From: Gary Winkelman thewink...@gmail.com To: drakelist@zerobeat.net Sent: Tuesday, January 05, 2010 9:25 AM Subject: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot. Could that be somewhat remedied by replacing some of the components with newer ones? TNX in advance for any advise! Gary N2UM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Ye olde diode
This'll take you back a piece.. I've been looking, without success, for a cross reference on a couple of vintage diodes from an old power supply.. would appreciate a reply from anyone who might give me a cross reference or ratings specs on: MR1033B MR1034B Thanks a bunch Doc ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Ye olde diode
Doc - Both those diodes cross to an NTE156, which is a 1000 PIV @ 2A rectifier. IF your device actually NEEDS 2A, then a 1N5408 (3A) would be an inexpensive replacement. If you actually need less than 1A, a 1N4007 is even cheaper and easier to find. What are they used in? Drake? For future reference ... http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com HaloNet wrote: This'll take you back a piece.. I've been looking, without success, for a cross reference on a couple of vintage diodes from an old power supply.. would appreciate a reply from anyone who might give me a cross reference or ratings specs on: MR1033B MR1034B Thanks a bunch Doc ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Floyd - Now that's a mean thing to say! :-) I used a VF-1 for several years handling traffic on CW, (very picky ops re signal quality, especially high speed,) with no problems. See January 2008 ER. There ARE several identified ways for the VF-1 to go astray however, aside from the obvious quality kit assembly / soldering. One, it needs it's own regulated power supply, no borrowing power from the transmitter. Two, it needs a GOOD selected 6AU6A, or better still a 6AH6. And, C, it needs a reasonable (30 min) warmup. 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com K8AC wrote: Why there are any VF-1s left on the planet is a mystery to me. I owned a couple of them, beginning in 1959, and they were absolutely dreadful. Guaranteed to drift and chirp. You could always tell who was using a VF-1 when you heard the CW signal. The Eico 722 was a good stable VFO and I still run into one of them from time to time. A pair of VF-1s make a nice set of nostalgia bookends, but that's about the extent of their usefulness. 73, K8AC - Original Message - From: Gary Winkelman thewink...@gmail.com To: drakelist@zerobeat.net Sent: Tuesday, January 05, 2010 9:25 AM Subject: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot. Could that be somewhat remedied by replacing some of the components with newer ones? TNX in advance for any advise! Gary N2UM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Gary, I'm not familiar with the VF-1 but I have an Eico model 722 VFO in which I've replaced the electrolytic capacitors. It has its own AC supply. I haven't tried to use it on the air yet so I can't say anything about how much it drifts. It should be possible to correct drifting by using capacitors with temperature coefficients that corrects for temperature drift of other components in the oscillator circuit. Old carbon composition resistors may be a problem as well. They tend to absorb moisture and increase in value. If you find any that are off in value, replace them with good RF quality film resistors. The 722 also uses cathode keying. Rather than changing a cathode keyed VFO to grid block keying, my approach would be to use a sequential keyer that turns on the VFO, then keys the transmitter a couple of milliseconds later, then on key up turns off the transmitter first, and lastly turns off the VFO. That gets rid of chirps, and it eliminates key clicks as well if the rise and fall times of the stages following the VFO are controlled. I think shaped grid block keying works best for amplifiers rather than VFOs. If you try to start a VFO slowly, you could get a major chirp, or it might not start at all. In my view, control of rise and fall time is best done in the stages following the oscillator. If you do what Collins did in the 310B (I have one and it is a beautiful CW rig) and run the VFO at one half of the operating frequency (of the lowest band in the case of the 310B), you can leave it running and just key the following multiplier(s) and amplifier. That avoids the problem of a back wave from a constantly running VFO at the operating frequency. It would also avoid the problem of having to key both a negative and a positive line (I'm assuming your 2-NT uses grid block keying and that's why you are thinking of converting a VFO to that.) 73, Bob AD3K -Original Message- From: drakelist-boun...@zerobeat.net [mailto:drakelist- boun...@zerobeat.net] On Behalf Of Gary Winkelman Sent: Tuesday, January 05, 2010 9:26 AM To: drakelist@zerobeat.net Subject: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO I'm looking for a VFO for my new to me 2-NT. I've read where several older VFOs will work with some modifications, mainly converting to grid block keying. Has anyone had experience with the old Heathkit VF-1? I believe it has to be modified for grid block keying but I'm not exactly sure how to accomplish that. I also understand that they are known to drift a lot. Could that be somewhat remedied by replacing some of the components with newer ones? TNX in advance for any advise! Gary N2UM ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Years ago, many years ago actually, I bought a VF-1 at a hamfest in Springfield Ohio for a buck. I used it with a home brew 1625 CW transmitter for my very first ever 160 meter contact around 1977. Only compalint I had was a phone call from a local ham for having bad key clicks! Gary___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
[Drakelist] Diode from a Galaxy far, far away...
Thanks, Garey, for reply.. I've got an old Galaxy 2000 power supply torn apart and wanted to replace both caps and diodes but couldn't find any cross-references on those rectifiers. I had some diodes used in the L4B but it looks like they won't handle the Galaxy load.. I don't know if you're familiar with the Galaxy 2000 design but it's a comparatively small 2 kw linear running 10 paralell 6HF5's in a grounded cathode design with peak plate currents around 2.5 amps.. big bang in a small package! By the way, I just finished a recap of that L4B and posted it on the Halo.net site at this link .. http://mysite.verizon.net/halo.net/halo05c.html Any idea where I might be able to pick up a few feet of the high voltage wire used in the L4B? Thanks again, Doc = Doc - Both those diodes cross to an NTE156, which is a 1000 PIV @ 2A rectifier. IF your device actually NEEDS 2A, then a 1N5408 (3A) would be an inexpensive replacement. If you actually need less than 1A, a 1N4007 is even cheaper and easier to find. What are they used in? Drake? For future reference ... http://nte01.nteinc.com/nte/NTExRefSemiProd.nsf/$$Search?OpenForm 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 4-B, C-Line TR-4/C Service Supplement CDs www.k4oah.com HaloNet wrote: This'll take you back a piece.. I've been looking, without success, for a cross reference on a couple of vintage diodes from an old power supply.. would appreciate a reply from anyone who might give me a cross reference or ratings specs on: MR1033B MR1034B Thanks a bunch Doc ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Drake 2-NT to Heathkit VF-1 VFO
Likewise I'm using a HA5 with fine results John K5MO ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] Ye olde diode
Hi Doc. I thought those numbers rang some bells. They are Motorola numbers. And from my trusty Motorola Semiconductor Data Book (1970) here are the specs: MR1033B Peak repetitive reverse voltage: 300 V Non-repetitive reverse voltage: 400 V RMS Reverse voltage: 210 V Average repetitive forward current: 3 A Peak repetitive forward current: 25 A MR1034B Peak repetitive reverse voltage: 400 V Non-repetitive reverse voltage: 500 V RMS Reverse voltage: 280 V Average repetitive forward current: 3 A Peak repetitive forward current: 25 A Both of these can be replaced by a 1N4722. Actually, the 1N4722 is direct substitute for the MR1034B. The 1N4721 has lower voltage ratings. You could most likely substitute a 1N5403 for the MR1033B and a 1N5404 for the MR1034B. Or as Garey pointed out, a 1N5408 could most likely substituted for either or them. I hope this helps. 73 - Mark N1VQW ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
