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Reviews Categories | Ham radio kits | Hagerty Radio Company Direct Digital VFO Help


Reviews Summary for Hagerty Radio Company Direct Digital VFO
Hagerty Radio Company Direct Digital VFO Reviews: 6 Average rating: 5.0/5 MSRP: $150.00
Description: AD9951 based DDS vfo kit
Product is in production.
More info: http://www.wa1ffl.com
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You can write your own review of the Hagerty Radio Company Direct Digital VFO.

KG7RS Rating: 5/5 Feb 12, 2012 09:34 Send this review to a friend
Attention Boat Anchor Ops!  Time owned: 0 to 3 months
Hi Folks,
I found Jim's DDS VFO board and companion driver amp board while searching for a solution to the age-old instability problem inherent in many old tube-type VFO's driving vintage transmitters. I've owed and used many of the old VFO's which have produced varying on-air results. At a minimum, most I've found produced a less-than-desirable CW note - especially chirp. This may have been acceptable back in the good old days, but is rather embarrassing on the air today. Frequency drift is another issue, although less of a problem in my experience. Although these issues are of minimal concern on AM, they have played havoc with my CW operation with classic tube transmitters, something I dearly enjoy. One of the solutions to vintage VFO issues is using crystals. Original FT-243 types with their relatively large quartz blanks are the best bet for vintage transmitters - some of which can run substantial crystal current causing heating and contributes to instability once again. I've ordered several custom-made crystals from ICM but FT-243 crystals are no longer being manufactured and the smaller HC/6 type crystals with larger diameter pins currently available are expensive. The considerably smaller quartz blank still shows the results of heating in some transmitters. These are the issues which have prompted me to take a good look at modern DDS VFO designs. I suspect many boat anchor ops have experienced similar problems getting old rigs on the air. I regularly hear chirpy signals on the old 40 meter novice band!

Jim Hagerty produces a very high quality, well-designed DDS VFO board which, when combined with his companion driver amplifier board, will produce an extremely stable HF signal at around 20V p-p. This output level is higher than many vintage VFO's and has demonstrated that it will easily drive most vintage tube transmitters I've tested with it. These include my beloved Heathkit DX-40, Hallicrafters HT-40 and even my homebrew 6AG7/6L6 simply by plugging in the VFO output cable into the transmitter crystal socket. I found that it does not have sufficient output to drive my WRL Globe Scout 65B on the third or fourth harmonic of 7Mhz, such as would normally be used on 15 & 10 meters respectively. This transmitter need lots of drive amplitude as the 6V6 oscillator tube in the first stage also functions as a multiplier. Some of the other WRL models may be similar so research is suggested if one plans to use these boards with one of these fine old transmitters. Certainly the VFO level could be further amplified through a 3rd stage of the builder's design. My VFO does have sufficient drive for my Globe Scout on 160 & 80 using a 1.8Mhz signal and on 40 & 20 using a 7Mhz signal.

The DDS VFO output is very clean thanks to Jim's use of 2 filter stages on the VFO board and a large toroidal matching transformer on the output of the driver amp board. I've viewed the signal on my oscilloscope and the waveform looks perfect, with some minor distortion beginning well above 21Mhz. As most ops will use this VFO between 1.8 & 7Mhz in this application, this is not an issue. By design, the signal output is rock stable - no drift and a good CW note. I've received numerous on-air comments expressing amazement that my DX-40 sounds like a modern transceiver. In fact, it appears I've become quite the on-air ambassador for Hagerty Radio once I explain that I'm driving my rig with a modern DDS signal source!

As mentioned, the finished VFO project consists of two separate boards - the DDS VFO board and a driver amplifier board. A third LCD module board rounds out the package. The VFO board is a very high quality multi-layer PWB and care has been taken in its design with a separate RF ground layer. Due to the multiple layers, soldering can be a little more difficult than the average kit board due to the heat sink effects. Be sure to follow Jim's advice by cleaning the board to remove oxides which can impede thermal transfer from your iron. The single layer, double-sided drive amp board is conventional and easily soldered as usual. The DDS IC and several chip caps are surface mount and although I wouldn't foresee the chips being difficult to solder, the DDS chip is very tiny and has a very fine lead pitch. Fortunately, Jim offers the board kit with all the surface mount parts pre-installed except one surface mount transformer package which was very easy to solder down. The remaining components are all thru-hole types. The board has a single ground pad which is intended to serve as a ground for several function switches, 3 leads to the LCD display and one pin of the frequency encoder. Jim suggests installing a discarded component lead to serve as a post to which the myriad connecting wires are "wrapped & stacked" then soldered. I found a better way is to mount an old-style phenolic terminal strip to one of the board stand-offs, run a single wire from the ground pin to one of the terminals, then install the myriad ground wires to one or more of the terminals as needed. Otherwise, construction and layout are straightforward and simple.

I connected the output of the VFO board to the input of the driver amp board with a short piece of RG-174 mini coaxial cable. The LCD display module is wired with 14 individual wires - instructions are clearly provided. My kit came with, for a modest premium, a nice optical encoder without click detents which tunes like a conventional VFO. A click detent mechanical encoder is provided standard. There are 4 wires to connect the encoder and again, the instructions provided are clear. A SPST NO pushbutton switch (user provided) is needed to control the frequency step selection - from 1 hz to 1Mhz. When the button is pressed and held, step selection is made by rotating the encoder (VFO tuning knob) to select the step, then the button is released. The VFO board features a "key" pad and I installed a 1/4" phone jack on the rear panel that when shorted enables VFO RF output, when open, the VFO output is off. I also installed a front-panel SPST toggle switch in parallel with the key line for "spotting" the VFO signal in my receiver.

Beyond these basic components, the VFO board has several other features which may or may not be used depending on builder preference. These include a selectable offset for either SSB or CW and a "CAL" function which allows dialing out frequency display error due to on-board clock oscillator tolerance. The board includes selectable memories too. All of these functions can be added simply by connecting appropriate user-supplied toggle or pushbutton switches. Although I chose not to use the memory functions in my completed VFO, it would be a nice feature as the unit defaults to 10Mhz upon power up. Setting a memory each for 1.8, 3.5 & 7Mhz would be a nice feature. Also, the CAL function is saved by memory and using CAL ensures dead-on frequency display. The VFO package requires a 12VDC power source at around 250mA. I used a Jameco 12VDC 1A regulated wall-wart power supply which actually outputs 12.6VDC, is well filtered and well-regulated thanks to an internal 3-terminal regulator IC.

It appears the design has a low susceptibility to nearby RF fields, RF feedback and other issues which may exist in the average ham shack. My VFO is well shielded inside an aluminum enclosure and I have not noted any glitches, malfunctions or strange effects. Although my station is well grounded, I tested this VFO under all kinds of conditions and it appears unfazed by strong RF.

Choice of enclosures is entirely up to the builder and I chose a sloping front aluminum cabinet and finished it with black wrinkle paint to add a touch of "vintage" to a thoroughly modern circuit. You can see my version of this VFO by looking up my callsign on QRZ.com.

In researching the field of contenders while planning this project, I found at least 2 other DDS VFO boards out there. Both are interesting and appear to have varying virtues and shortcomings. One in particular features fixed "bands" at 1.8, 3.5 & 7mhz and includes a 2nd line on the LCD display to show the transmitter operating frequency after multiplication by pushbutton selection of X1, X2, etc. This would be a very useful feature for boat anchor ops and I hope Jim will consider offering this feature on his design - perhaps only requiring a program change in the firmware. The level of on-board filtering provided, careful use of separate RF and digital grounds and attention to circuit detail makes Jim's board stand above the field in my opinion.

So, is using a modern DDS circuit for frequency control of antique and vintage transmitters "cheating"? Unless one is a diehard purist I'd say no! Operating with this VFO and a little vintage novice transmitter is truly a pleasure. In fact, I spent several hours last night on 40 meter CW participating in the SKCC WES "contest" using Jim's VFO to drive my DX-40 along with a Hammarlund HQ-160. A fun time indeed.

My hat's off to Jim Hagerty for a very well done DDS product design and a sincere thank you on behalf of myself and other long-suffering boat anchor ops. Jim's support & correspondence was greatly appreciated.

73, John, KG7RS, Mesa, AZ
 
W5SXD Rating: 5/5 Apr 20, 2011 19:44 Send this review to a friend
Well done!  Time owned: more than 12 months
Very nice!

I've built four of Jim's boards, two of the original design and two of the current design. Although I can't comment on the VFO features in his processor, the synthesiser and filters are top notch. I use these in another project just for the synthesiser and filters, controlling them from my own processor on a seperate board.

Realy well done!

Richard W5SXD
 
KB7OCY Rating: 5/5 Sep 5, 2010 17:36 Send this review to a friend
Excellent!  Time owned: 0 to 3 months
I was looking for a VFO as an alternative to using crystals on an old HT-9 transmitter when I stumbled across Jim Hagerty's solid state, digital VFO and display. His kit arrived with all parts neatly and orderly arrainged along with excellent assembly instructions. By carefully following the instructions, the kit worked perfect the first time! Jim was very helpful with answering any questions I had during assembly. He is a very nice man, indeed. I can say my experience building this kit was excellent. I would certainly recommend Jim's VFO kit to others. The specifications are generously conservative as mine has a flat response from 200khz to 30mhz into a 50 ohm load. The VFO lent itself quite well into a 19" rack which includes the W1FB solid state vacuum-tube tunable interface which I "wide-banded" to cover 160 through 40 meters and has an output of 90V P-P into a 5k load. I can't wait to experience this nifty little combination!

Regards,
Henry Hurrass
KB7OCY
 
N4BBQ Rating: 5/5 Nov 17, 2009 08:37 Send this review to a friend
Awesome Product  Time owned: 0 to 3 months
I purchased this kit for a future home brew project and it built up easy, has a very high-quality circuit board, and outputs a very clean signal. Can't wait to get it into action.

I recommend this VFO kit highly and Jim is very quick to answer e-mail.
 
WN5Y Rating: 5/5 May 16, 2009 16:17 Send this review to a friend
Best DDS kit available  Time owned: 3 to 6 months
I have built several DDS VFOs. When I saw Hagerty's article in QEX, I was very impressed. Very clean output (as shown by the pic of the SA scan), no SMT parts to mount, and incredible support from Jim. The kit is very easy to put together and worked first time for me, which is unusual (I can mess up the simplest of kits). I had a receiver with two offsets that I wanted to switch on the fly. Jim made the necessary changes in a very short time and sent me a new processor with no charge. The switches are intuitive to use and I found it very easy to learn and remember even when away from the DDS for a while. You save $50 with this kit from not having to mount any SMT parts (sending it away, paying labor and shipping). I have trouble with surface mount parts and have no desire to solder any DDS chip. So I figured the real cost of this kit at only $100. Considering the quality of the DDS VFO, it is a bargain. Jim uses a 4 layer board (manufacturers recommendation, everyone else uses 2 layer boards) that results in a very clean and reliable DDS. I highly recommend this kit. Order it, spend an afternoon putting it together, connect to your favorite rig, and start working the DX! I did, and couldn't be happier.
 
WB6VHK Rating: 5/5 Jan 24, 2009 16:03 Send this review to a friend
DDS VFO KIT  Time owned: 0 to 3 months
I was looking over the last few years for a good dds vfo to install in an older radio (Atlas) that I wanted to improve. After a few dissapointing experiences with some other inexpensive kits, I almost gave up. A few months ago, I was surprised to see the WA1FFL kit advertised in CQ magazine. I purchased one online and two days later it was at my door. It took about an hour to build the main board and another half hour to wire up the display and a few buttons for testing. It worked perfect the first time I turned it on! I am giving this kit a solid "5" rating as I am very impressed with the quality of the board and components and found Jim Hagerty (the owner of the company)to be one of the most helpfull people I have ever met! When I installed it in my radio I was amazed at how clean of a signal it produces, Very few birdies anywhere. I plan on buying another one for another project soon. Thanks jim!
 


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