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Reviews Categories | Filters, Audio: (DSP and others) | Vectronics VEC-820 CW Filter Kit Help

Reviews Summary for Vectronics VEC-820 CW Filter Kit
Vectronics VEC-820 CW Filter Kit Reviews: 7 Average rating: 4.0/5 MSRP: $35
Description: The VEC-820K Electronic Kit gives an incredibly narrow 80 Hz bandwidth and extremely steep skirts with no ringing for razor sharp selectivity. It will pull CW signals out of interference in any ham radio band. You simply plug the kit into your radio phone jack to drive phones or between audio stages for full speaker operation. You can select three bandwidths: 80, 110, 180 Hz. Noise is down at least 60 dB one octave from center frequency for 80 Hz bandwidth. Center frequency is 750 Hz. The kit's 8 poles active IC filtering uses low Q cascaded stages. Stops ringing. No impedance matching needed. No insertion loss. The kit uses a 9 volt battery (not included). The kit measures 1 x 3 x 3 inches.
Product is in production.
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KE8AOL Rating: 5/5 Jan 19, 2017 10:07 Send this review to a friend
Works surprisingly well  Time owned: 0 to 3 months
Found one of these kits on ebay for about $20, including shipping. Let me preface my review by stating that this kit is probably old stock, likely years old. I am using it with an old DX-300 general coverage receiver. I am writing this review because these still occasionally appear for sale on the internet.

Parts were complete and correct. Although they were lumped into a small rat's nest, all were in good shape. I recommend verifying the values of the tiny resistors with an ohmmeter and separating them ahead of assembly.

Minor complaints about the quality:
---The pc foil bubbles easily if you're not careful with the soldering iron.
---The IC socket pins were a bit reluctant to take solder. If you feel able to very thinly tin these ahead of installation, I recommend doing so.
---The Switchcraft sliding switch has silver-plated terminals and they were tarnished. This is anticipated in the instructions and they call for sanding the terminals before soldering ... nostalgic!

I put the kit together in about 1 hour. The instructions are well written and theory is provided. Parts layout, schematic, etc., are provided and nothing is really left to the imagination; it is written for the novice.

On initial fire-up, there was an awful howl in the audio. It turned out to be a hair-like bridge of solder between two IC pins. Once the bridge was removed, the filter worked quite well. For those who have never used a filter like this, it does take a bit of getting used to. When on the narrowest setting, a novice might easily tune by and miss a CW signal if moving the tuning knob too fast. There is a bit of a whistle that progresses with filtration, but I find it quite tolerable.

Specifically to those who might use this with an old receiver that drifts or is otherwise unstable, you might find the narrowest setting a challenge when your receiver moves off frequency.

Bottom line is that for $20, I have a great CW audio filter with a very useful selection of filtering and I can hear CW much better.
N5ZKZ Rating: 3/5 Jun 25, 2012 09:57 Send this review to a friend
fantastic design, dissapointing quality.  Time owned: 0 to 3 months
the design of the filter is top notch, works great.
the quality of the parts was a different story.
1. some kind of fiber board (not glass and epoxy like earlier kits).
2. printed paper labels for the front and back panels?
3. Screw terminals for the audio input? Really?! these run the risk of shorting. replace it with a 1/8" audio jack, its cheaper than hunting down vintage terminals from the 30's.

I would and do recommend the filter because it is a good solid design and will literally filter out EVERYTHING, it's good. great job on the design.

but skip the case, looks like a 3rd grader put it together.
KB8LZG Rating: 3/5 Jun 9, 2012 11:57 Send this review to a friend
Kit works OK but.......  Time owned: 0 to 3 months
I ordered one of these the end of April and was told it was back ordered, I was unimpressed with that but I waited. I had forgotten that I ordered it, then the first of June, I got an email from UPS a package was in rout to me. I seen that it was the kit I had ordered in April.
Got it and put it together, it didn't work. I wrote them, not asking for help because I can fix it myself, just informing them I was not happy and did not have the time right then to "fix" it so IF I had time I would let them know what was wrong whit the KIT.
I found there was 4 resistors in the kit that were the wrong value, it was a orange band instead or a yellow band. My eyesight is not as good as it used to be and I did not see it right off, my fluke told me the values. I replaced them with some I had here and it worked.
Going to get the right parts when I have time to order them.

I see that most of the reviews are a few years old so I think things have changed there.
You can make your own mind up.

Over a month to get after ordered.
Have to trouble shoot kit to find problem.
Kit has wrong parts causing it to not operate.

It does however work nicely and as they say, after I repaired mine.
I am using it and will continue to use it as it is a nice little filter.
M0RNA Rating: 4/5 Dec 31, 2008 09:40 Send this review to a friend
Works well  Time owned: 0 to 3 months
I purchased the kit and the separate case for use with an FT817. I am not a regular constructor of kits, but found the instructions to be clear and helpful. I built the kit, and housed it in the case in a few hours, and was pleased when it worked first time.

Tuning around the bands, I was pleased at the way that the desired signal was boosted when tuned in properly to ~750Hz using the VFO or RIT. Adjacent signals were still audible to some extent, but greatly attenuated. This filter definitely seems to boost weak signals to quite a comfortable level, and the 3 filter widths are all usable and pleasant to listen through. NB: It is of central importance to select a CW side tone note of 750Hz.

I would give this kit a 5/5 except for the fact that there was no knob included with the kit for the filter selection switch and I am not certain if this was deliberate or an oversight.
N6MUK Rating: 4/5 Jan 7, 2008 10:25 Send this review to a friend
Its a really good, solid CW filter  Time owned: more than 12 months
It's about as good as an old school audio cw band pass filter can get!

1) The widest (180 Hz) setting is perfect for cleaning up a wide open pass band for scanning/ signal searching. If you have a rig that lacks audio selectivity, this is necessary.

2) The medium (110 Hz) setting is only occasionally useful to me because my rigs have inboard filtering that I prefer when the band is not too crowded.

3) The narrowest (80 Hz) setting is impressive and useful. Once I got used to it, really can't live without it. It will ring a bit. Sometimes the cw note, if weak and noisy, will set off a bit of a howl. Its actually pretty tame and not very troublesome. Sometimes, a weak cw signal that is barely hearable, will pop out of the noise when perfectly centered through this 80 Hz filter and become easy copy. You must tune carefully and your receiver's RIT is useful for this.

This filter really shines when used in combination with a rig's existing IF filtering. It is important to check the center frequency of your rigs filters to make sure they are 750 Hz or close to that. You cant adjust the center of the Vectronix pass band; its fixed at 750 Hz.

Overall a great and cost effective addition to the shack!
KC9CS Rating: 5/5 Jan 28, 2007 15:52 Send this review to a friend
Works well, fun kit!  Time owned: 0 to 3 months
I build a lot of QRP equipment from kits. This kit only took a couple of hours to build, and that included some modifications and getting it into a cabinet. The kit I built was the upgrade from the VEC-820 listed above..mine was the VEC-821 called the Super CW Filter Kit. I think it's essentially the same as the 820 but includes a 1 watt audio amplifier for driving a speaker. I modified the kit with a switch to be able to switch between headphones or an internal speaker in the cabinet. All the listed parts were in the kit (although the kit took nearly 2 months on backorder--ordered it the last week of November, it arrived in late January) and I sorted them and checked the inventory list. I typically save egg cartons for my small parts when I build, the egg sections can be written on with pen or marker for the parts identity and this makes the build go quicker. 43 individual electronic parts make up the kit, then you have the IC sockets (3) a rotary switch and some other hardware. Following the manual you should be able to put this together without a problem IF you identify the parts correctly and place them correctly. Some of the resistors are very tiny and I needed magnifiers to see the color bands well enough. As each part is placed, check it off in the manual as in the old Heathkit manuals. One thing the manual wasn't very clear on is the connections to the speaker, and the input from your radio. In fact, a speaker isn't included, nor are any input jacks, probably because each persons needs will be different. In my case, I made a fast dash to the nearby Radio Shack store for 1/8" chassis mount stereo phono jacks for the input. The kit comes with a 9 volt battery clip but the kit will run on anything from 9-18 volts. I'd suggest a miniature female plug and the mating male plug to get power from a 12v battery source since I run all my QRP rigs from a single 12v 750mA/hour battery.
The kit does contain some polystyrene capacitors and newcomers should be careful with not applying too much heat in soldering these in...they're fragile. how does it work? Great! There's a bypass position on the switch and switching the filter into the audio circuit one can hear a distinct difference both in audio bandwidth and noise. The kit has a noise reduction circuit and it drops noise 15 db. When switching to the first position the bandwidth is 180hz, second position is 100 hz and the last 80 hz. I sensed only a wee little bit of ringing in the 80hz position and it was not offensive. In fact, sometimes switching through the various positions would reveal a station 'hiding' under the QRM/QRN of a nearby signal. Pretty nifty, especially for low tech QRP rigs. The CW tone is pleasant, and centered about 750hz. Switching from the bypass position to the filtered position also activates the 1 watt audio amplifier and the audio boost is noticeable. This bit of audio boost is essential to some QRP rigs which typically use only headphones and are somewhat finicky about the audio impedance they see. This kit solves that problem, although you can't expect it to drive a very large speaker with any results.

Bottom line: the kit does what it says it will do, and it does it very well. It separates interfering signals and can make the difference in hearing or not hearing a station. And it is inexpensive. It's not a full featured DSP, but it will benefit the QRP operator in pulling those signals out. All in all a fun kit that works!
K2JN Rating: 4/5 Apr 13, 2004 18:54 Send this review to a friend
Inexpensive CW audio filter  Time owned: 0 to 3 months
The Vectronics VEC-820 is an inexpensive audio filter that utilizes an eight-pole active filter design. The project can be purchased as a simple board kit for about $20. An additional $15 gets you a nice cabinet with extra connectors to complete the project. Components provided in the kit are fairly decent quality and the printed circuit board is medium grade in quality. At a careful pace, the kit can be completed in one evening by the average kit builder. There are only 27 components, including two LM747 op-amp chips. I chose to take my time and complete the kit in several evenings making sure to double check some of the hard wiring to connectors and switches. In addition, novice kit builders should take extra care so as not to apply too much heat when soldering the eight polystyrene capacitors.

Instructions are fairly easy to follow and both the board kit and the case kit come with separate manuals. The case uses a self-stick aluminum-look labels to add that commercial feel. I wasnt too fond of the labels since they are easy to scratch or can come loose if applied incorrectly.

When complete, the kit provides a 2-position screw terminal for input and a monaural jack for output. I hooked up my filter to my Lowe HF-150 using a pair of Kenwood HS-6 head phones. Filtering response was fairly decent on all settings and optimized for 750-800 Hz tone. Ringing was not noticeable on 180 Hz, and minimal on 110 Hz and 80 Hz bandwidth settings. Running some tests on the 40-meter band, I found the 180 and 110 Hz settings most suitable to my ears.

Overall, Id give this kit a 2-thumbs-up. Its inexpensive, easy to build and will suite most needs for CW operators who need extra selectivity without paying a fortune.

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