Re: Topband: Bev wire under a path?
You could also shorten the Beverage length with loading coil(s) and run coax under the gravel if thats a possible option. Since the coils slow down the wave a bit you have to factor in the velocity factor so the electrical length doesnt flip the directivity at around a .5 VF. Using Slinkys for a continuously loaded element Ive reduced a well performing Beverage to 175' which calculates to a .59 VF. Its 5 of the 3" diameter Slinkys in series and a 1200 Ohm resistor for my granite ground. Carl KM1H - Original Message - From: "W2RU - Bud Hippisley" To: "Neil G0JHC" Cc: Sent: Friday, January 06, 2012 9:05 AM Subject: Re: Topband: Bev wire under a path? My Northwest Beverage does exactly what you are proposing. It crosses a shared gravel driveway that leads to my home. Fortunately, there are small trees on each side of the driveway (in fact, they hold up segments of the Beverage), so I simply ran my Beverage wire down one tree, across the driveway in a trench a few inches deep, and back up the tree on the other side. I recommend strongly — especially if the ground ever freezes at your QTH — that you put the underground portion of the Beverage wire in a length of PVC tubing and leave a little slack in that portion of the wire. Along with some of our neighbours on this same driveway, we learned the hard way a few years ago that even direct burial power lines *break* due to the repeated stresses caused by vehicular traffic and frost heaves in the area of the wires if some form of rigid conduit isn't used. And the farther down you can place the wire, the less likely it is to gradually work its way back up to the surface over time. I'm sure there's some signal loss and impedance bumps caused by the earth's proximity, but it's still a whole lot better than not being able to have a NW Beverage at all! Bud, W2RU On Jan 6, 2012, at 8:23 AM, Neil G0JHC wrote: > I currently have a 585ft Bev, which at around 200ft has to pass over > a > gravel track which is 12-15ft wide. I am contemplating...burying the wire > 2 or 3 " > under the gravel track. I am using WD1-a wire. > > Has anyone any experience of the effect on performance. I will be burying > approx. 2-3% of its total length. > Neil G0JHC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4126 - Release Date: 01/06/12 ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: looking for suggestions for rcv antenna for this years CQWW 160SSB
First, thanks to Mike W0BTU for directing me to this forum. Last year was just my second attempt to work the CQWW and I guess I did fairly good for a newbie...Single Op Low Power, 1st in Florida, 2nd in Call area 4, 7th in US and 11th in North America. BUT only worked a handful of DX out of Europe. The few I did work asked me why I wasn't answering all the stations they could hear calling me. The vertical tower I used the last two years gets out great, but doesn't hear as well. I only operate from sunset to sunrise in this contest because I am using the 466 ft tower at the radio station where I work. Daytime there the tower is hot with about 10 amps of RF from our 3.1kw AM daytimer. There is 100kw FM out of a 10bay ERI dual polarized stack at the top of the tower. I do suspect the FM causes some suppression of signals on my rcvr because when the FM signs off at midnight, I do get better contact numbers per hour. I get great signal reports from almost everyone I've worked on this BIG STICK. I just pull the knife blade from the AM ATU and connect with a coax balun directly to the station ground system and the copper strap to the tower. It's 36' wide on each side. LOTS OF STEEL up there. loads up great with very low swr. Especially up near 1.9 This year I just got a chain link fence finished around the entire 5 acres. SO I considered putting up a loop for receive. It would be a total of 2050 feet. Would take about 300 feet of coax to center feed it at the back of the property. I calculated the cost of building around 100 2x2 A Frames to get the loop up about 30 feet, and would tie wrap the A frames to the fence posts... the lumber and hardware alone would be over a grand! and that does not include the cost of coax and the 2050 feet of wire! I've read a lot of the articles on the Beverage including the ones from the 20's... and after reading Mike's info and at his suggestion I looked up the archives on Beverages here on the forum.Looks like running a Beverage across the 250 ft wide ground system for the AM would not be a good idea? Course I would have an excellent ground source at the SW end of the Beverage and could easily have a full wave aimed NE at Europe. Another thought would be to hang a fullwave extended Zep(fed with ladder line) from the station tower. I can climb the tower and hang a pulley at any height I want. Then I could pull the Zep up late in the afternoon. I might even be able to leave it up after trying it out a weekend before. The lower end would go to a 40 ft push up mast at the NE corner of the chain link fence. One of my ham club friends plotted the loop with EZNEC...and is going to run plots of 4 different configurations of the Zep..(based on different positions up the tower from 100' to 250'. SO SUGGESTIONS ANYONE? Thanks Cal Zethmayr W4GMH Crestview, FL. W4GMH at cox.net if you want to contact me off the list. I can send you some google earth pix of the layout. ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Anybody has used Hi-Z for sale?
Ignacy, why is Hi-Z not selling? Has the patent issue resurfaced? 73, Joe K2XX On 1/6/2012 4:51 PM, Ignacy Misztal wrote: > HI-Z is not selling so I am asking whether anybody has used Hi-Z for sale? > All except HI-Z 8, for which I have no space. > Ignacy, NO9E > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > > > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: HiZ Delay and Preamp Boxes
I know that some people swear by vents. But I personally have had terrible results venting my Beverage antenna control enclosures. The enclosed relay has froze up more than once from condensation, caused by humid air getting inside and freezing (usually in the dark and in the dead of winter). But since I switched to sealed plastic gasketed-lid enclosures, that problem completely went away. They have clear lids, and I've never seen condensation inside. One thing that helps maintain the seal is completely filling all connectors with silicone dielectric compound. Only my F connectors are waterproof; I use tip plugs/jacks for the antenna and ground connectors. I force that stuff into all the connectors until it appears inside the box at the other ends. As the pressure differential between the inside and outside of the enclosure changes with temperature and barometric pressure, this non-hardening compound moves in or out, maintaining the seal. And I usually add more of that whenever I disconnect and reconnect anything. Also, just before putting on the lids, I heat up in inside with a heat gun to help eliminate any moisture. And I don't use desiccant. Never have. If at some point in the future I ever did see condensation, though, I would add a small desiccant packet before I would ever drill vents of any size, large or small. Complete details with part numbers at this URL (scroll down past the transformer photos): http://www.w0btu.com/Beverage_antennas.html#Beverage_Antenna_Transformers I know, I can already hear the keyboard clicks of all the people that are going to tell me that I should use sealed DIP relays and vent my enclosures. :-) 73, Mike www.w0btu.com On Fri, Jan 6, 2012 at 12:51 AM, Dennis W0JX wrote: > ... > As for the new preamps, while the company states that they are > water-proof, there is the possibility that humid air will condense inside > and create water. Every beverage transformer box that I have built in this > humid Ohio location has had corrosion problems from condensed humidity > inside the “sealed” boxes. Water always finds a way in. So I plan to > ventilate them... > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Anybody has used Hi-Z for sale?
HI-Z is not selling so I am asking whether anybody has used Hi-Z for sale? All except HI-Z 8, for which I have no space. Ignacy, NO9E ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: BC filter follow-up
Jim Brown wrote: > > Attenuation at the top of the band (near cutoff) is the toughest to > achieve, the Clifton filter looks awfully good, and the cost is quite > reasonable. If I had your problem, that would be my choice. > > 73, Jim K9YC The Clifton filter is a Chebyshev, with only 14 dB attenuation at 1.7 MHz. What you really want is an elliptic function filter, of which there are several available. These can provide much more attenuation at 1.7 MHz. Rick N6RK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Half or Quarter Wave??
On 1/5/2012 8:35 AM, paul ecker wrote: > Have a LDG Z11Pro auto tuner at base of pine tree that vertical leg runs up. > 4:1 balun at base of vertical feeding RG-213 coax to shack. I don't understand why the 4:1 balun, or the remoting the tuner to the base of the tree -- the feedpoint ought to be pretty close to 40-50 ohms as it is, and not terribly far from resonance, so the SWR with it feeding 50 ohm coax ought to be fairly low (less than 4:1). With this sort of condition, RG8 from the feedpoint to a tuner in the shack ought to provide a very low loss condition and handle legal ham power. As it is, that 4:1 impedance transformation is likely to be adding loss rather than reducing it. 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Fwd: Re: Bev wire under a path?
A buried wire is a transmission line. When a transmission line is very short compared to a quarter wavelength, its usually considered to have practically no transmission line properties of its own except for a small amount of resistance. Three primary factors are at play when using a very short transmission line (a buried insulated wire or coaxial cable) to connect two sections of a Beverage antenna: Dielectric loss - a directly buried insulated wire will have more dielectric loss than a coaxial cable or a wire enclosed in a plastic conduit. A very short directly buried insulated wire might have insignificant dielectric loss (it wouldn't be difficult to measure this). Mismatch loss - a very short transmission line (a buried wire in a conduit or a coaxial cable) has negligible mismatch loss. When a transmission line is very short (compared to a quarter wavelength), its characteristic impedance has little consequence to the circuit in which it is operating. Velocity factor - minimizing the length of a coaxial cable, using high velocity factor coaxial cable (such as cable TV hardline), or using a very short buried wire in a conduit will minimize the phase delay between the two interconnected segments of a Beverage antenna. Using tennis balls to center the wire in the plastic conduit as recommended by KV4FZ will further reduce the phase delay of a buried wire. 73 Frank W3LPL Original message >Date: Fri, 06 Jan 2012 12:33:09 -0400 >From: Herb Schoenbohm >Subject: Topband: Fwd: Re: Bev wire under a path? >To: TopBand List > > > > >On 1/6/2012 10:33 AM, Ryszard Tymkiewicz wrote: >> > > >> Neil& All, >> I was using this kind of passing roads quite oftenusually the distance >> was 3 meters in a soil. It was not affecting 160m but on 80m I noticed >> a difference , probably a capcitance to a ground was significant. >> In my main QTH where I have a lot of houses and tracks around >> I'm using thin wire 0,7 mm and a support in 50 % are just trees 3-7m high. >> Its easy to throw a reel of such wire over a tree. >> >> 73 Rys >> SP5EWY > > > >If looses are noticeable due to ground effect trench attenuation you can >use a bigger conduit and a bunch of tennis balls with a hole drilled in >the center as insulators to greatly improve the VF in an underground bridge. > >Just a thought. > >Herb Schoenbohm, KV4FZ > >___ >UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: BC filter follow-up
On 1/6/2012 6:05 AM, N1BUG wrote: > I am guessing my primary problem is mixing of signals in the mid to > low part of the BC band, and will most likely opt for the filter > with the best attenuation at those frequencies. I do not seem to > hear anything particularly strong at the upper end of the BC band > anyway. Attenuation at the top of the band (near cutoff) is the toughest to achieve, the Clifton filter looks awfully good, and the cost is quite reasonable. If I had your problem, that would be my choice. 73, Jim K9YC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Fwd: Re: Bev wire under a path?
On 1/6/2012 10:33 AM, Ryszard Tymkiewicz wrote: > > Neil& All, > I was using this kind of passing roads quite oftenusually the distance > was 3 meters in a soil. It was not affecting 160m but on 80m I noticed > a difference , probably a capcitance to a ground was significant. > In my main QTH where I have a lot of houses and tracks around > I'm using thin wire 0,7 mm and a support in 50 % are just trees 3-7m high. > Its easy to throw a reel of such wire over a tree. > > 73 Rys > SP5EWY If looses are noticeable due to ground effect trench attenuation you can use a bigger conduit and a bunch of tennis balls with a hole drilled in the center as insulators to greatly improve the VF in an underground bridge. Just a thought. Herb Schoenbohm, KV4FZ ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Half or Quarter Wave??
Hi Paul and fellow Topbanders, The answer IMHO is leave it at 1/4 wavelength. Adding wire to a 1/2 wl antenna will make a Hi-Z point at the feed point which your tuner could have problems matching. Also you will have more horizontal energy which is fine for "Near Vertical" communications, but not for DXing where you want as much of the signal as possible in the vertical wire. Similarly a 3/8 wl inverted-L will also warm more clouds than DX receivers. As to ground or elevated radials, I agree with one other reply stating that additional radials from the feedpoint across, not around, your lot should reduce ground losses and increase transmitted signal strength. 73 & GL George K8GG > New to the list and new to 160M. I have a 1/4 wave Inverted L that I have > finally got the bugs out of and it seems to be working fine. Vertical leg > is 45' and horizontal run is 86' for a total length of 131'. Have a LDG > Z11Pro auto tuner at base of pine tree that vertical leg runs up. 4:1 > balun at base of vertical feeding RG-213 coax to shack. I have a 250', > three strand Deer fence around the lot that I am using all three strands > as my radial system. > > > --- Question is should I leave well enough alone or would I get better > results on 160M by extending the horizontal leg, to > 1/2 wavelength length?? > > 73 and Tnx > Paul > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Bev wire under a path?
Bud is right for a single wire beverage, where matching is not important, but dont expect to have a good f/back ratio with a 2-wire. However the gravel will help a little as it is non conductive, but the 15ft length of wire on the ground will cause a big Z discontinuity with unknown effects on the matching which of course adversely affects the reflection xfmr and terminations. You are getting good f/back on your bev at present, shame to spoil it (except the EZNEC analysis showed loops to work at least as well, or better). I ran a WD1 beverage for 30ft at 20ft high over a stream and it was terrible. I use a duct myself for the same reasons as Bud because my NE/SW beverages cross the footpath buried for 8ft just under surface, wire in water pipe, but it is not a tricky 2-way bev. Do try it by all means, it will be interesting to see what happens, but if worse, surely you can get some wooden posts or something each side of the road which are better than a thin pole. 73 John. - Original Message - From: "W2RU - Bud Hippisley" To: "Neil G0JHC" Cc: Sent: Friday, January 06, 2012 2:05 PM Subject: Re: Topband: Bev wire under a path? My Northwest Beverage does exactly what you are proposing. It crosses a shared gravel driveway that leads to my home. Fortunately, there are small trees on each side of the driveway (in fact, they hold up segments of the Beverage), so I simply ran my Beverage wire down one tree, across the driveway in a trench a few inches deep, and back up the tree on the other side. I recommend strongly — especially if the ground ever freezes at your QTH — that you put the underground portion of the Beverage wire in a length of PVC tubing and leave a little slack in that portion of the wire. Along with some of our neighbours on this same driveway, we learned the hard way a few years ago that even direct burial power lines *break* due to the repeated stresses caused by vehicular traffic and frost heaves in the area of the wires if some form of rigid conduit isn't used. And the farther down you can place the wire, the less likely it is to gradually work its way back up to the surface over time. I'm sure there's some signal loss and impedance bumps caused by the earth's proximity, but it's still a whole lot better than not being able to have a NW Beverage at all! Bud, W2RU On Jan 6, 2012, at 8:23 AM, Neil G0JHC wrote: > I currently have a 585ft Bev, which at around 200ft has to pass over > a > gravel track which is 12-15ft wide. I am contemplating...burying the wire > 2 or 3 " > under the gravel track. I am using WD1-a wire. > > Has anyone any experience of the effect on performance. I will be burying > approx. 2-3% of its total length. > Neil G0JHC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Bev wire under a path?
Re: Topband: Half or Quarter Wave??
Paul, I would stay with a 1/4 wave setup. By extending the horizontal wire so that the total antenna length is a 1/2 wave sounds like a good idea BUT at a height of 45 feet above ground on 160 meters. I would think more of your power will be getting dumped into the ground then what you are dumping now. I use to put up a half wave wire vertical with a 5 foot balloon. Played great BUT only good for a quick weekend and the tuner parts running 1500 Watts were massive because of the very very high voltages. You should see some improvement in your current setup if you move the vertical wire away from your tree. There is allot of water in that tree even frozen which a am sure sucking the RF right out of the antenna. If you want to do anything to the ANTENNA TYPE change the "L" to a "T" by attaching another horizontal wire at the "L" junction point or moving your vertical section (away from the tree) to the center of the horizontal wire you have up now. Just make sure the horizontal wire is the same length from the vertical tie point to both ends. Why? The setup you have now is giving you mostly high angle radiation which is good for local contacts. An inverted-L for 160 meters should have around a 70 foot vertical section to compete for DX operation. Again your current "L" setup will work but not as well as a "T" same vertical height for DX operations. The feed point impedance with the "T" will still be very low, as it is still being feed around the 1/4 wave current point so you won't have to deal with very high voltages. You might need a loading coil depending on how long you can make the horizontal wires. The amount of power radiating off the "L" or "T" should be about the same BUT remember you will be getting allot more at low angles with the "T". The next area of improvement I would work on is the radial system. Elevated radials are nice but to be really effective need to be tuned. To isolate the antenna from the ground losses takes allot of radials. If you have the room place as many radials as you can on the ground. Slit the soil to cover the wire and hope for the best. If your limited to how much wire you have allot of short radials around the antenna base is better then one, two or three long ones. Best of Luck, Rich AA2MF rlcarie...@verizon.net On Jan 6, 2012, at 12:30 AM, paulk...@aol.com wrote: > Before doing anything else, consider a more robust tuner at the base, that > is a high-current area whether the antenna is 1/2 or 3/8 WL. A simple L > network tuner with a #12 or #14 air-wound inductor and a variable capacitor > with at least 1000V spacing will provide much better performance IMHO. You > can very easily compare performance with the LDG with a simple RF Ammeter > at the tuner output. I have the Z-11 Pro and even a fairly modest home > brew manual tuner produces stronger currents at the base of my inverted L. > > I assume your deer fence is elevated, perhaps 6' or so, I'd consider > installing some insulators along the span of the top wire around your lot at > about the 50' point and add a couple more wires diagonally across the lot for > a > total of 4 50' elevated radials, even if they are asymmetric around the > base of the vertical. Many have reported much better performance with > length that approximates the vertical height of the L. Be open to other > ideas > from the group on the overall length adjustment, it has been discussed at > length, no pun intended. > > Paul, K5AF > > In a message dated 1/5/2012 10:38:43 P.M. Central Standard Time, > ecke...@yahoo.com writes: > > New to the list and new to 160M. I have a 1/4 wave Inverted L that I have > finally got the bugs out of and it seems to be working fine. Vertical leg > is 45' and horizontal run is 86' for a total length of 131'. Have a LDG > Z11Pro auto tuner at base of pine tree that vertical leg runs up. 4:1 balun > at > base of vertical feeding RG-213 coax to shack. I have a 250', three strand > Deer fence around the lot that I am using all three strands as my radial > system. > > > --- Question is should I leave well enough alone or would I get better > results on 160M by extending the horizontal leg, to 1/2 wavelength length?? > > 73 and Tnx > Paul > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: BC filter follow-up
Thanks to everyone who sent suggestions on my problem. Those who did not receive a personal thank-you note is because mail to you bounced. I thought it might be helpful to post a follow-up with links. In no particular order: http://www.arraysolutions.com/Products/BCB%20RF%20Filters.htm http://www.n1nc.org/Filters/160meter/ http://www.cliftonlaboratories.com/z10020_am_medium_wave_band_reject_filter.htm http://www.dlwc.com/ http://www.rescueelectronics.com/RF_Filters.html (note: may be able to custom build HPF) http://www.parelectronics.com/bcst-hpf-specs.php http://www.universal-radio.com/catalog/filters/4426.html http://www.morganmfg.us/radio-products/bcb-interference-filters/ http://yu1lm.qrpradio.com/bp%20yu1lm.htm http://www.cliftonlaboratories.com/z10022a_high_pass_filter.htm http://www.ac0c.com/main/page_antennas__homebrew_clifton_labs_z10022a.html ... Final comments on my specific issue: The overwhelming consensus is I should not be having anywhere near this magnitude of problem with skywave signals. I agree! But I have been chasing this on and off for years and have been unable to identify a specific problem with my station. I don't know what else to do but throw money at the problem and hope to cover up the symptoms of what surely is an equipment malfunction. I have ruled out building. I build a lot of stuff, but filters would seem to require test equipment I do not have access to. Flying blind is usually a good way to crash. :-) I am guessing my primary problem is mixing of signals in the mid to low part of the BC band, and will most likely opt for the filter with the best attenuation at those frequencies. I do not seem to hear anything particularly strong at the upper end of the BC band anyway. 73, Paul N1BUG ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Bev wire under a path?
My Northwest Beverage does exactly what you are proposing. It crosses a shared gravel driveway that leads to my home. Fortunately, there are small trees on each side of the driveway (in fact, they hold up segments of the Beverage), so I simply ran my Beverage wire down one tree, across the driveway in a trench a few inches deep, and back up the tree on the other side. I recommend strongly — especially if the ground ever freezes at your QTH — that you put the underground portion of the Beverage wire in a length of PVC tubing and leave a little slack in that portion of the wire. Along with some of our neighbours on this same driveway, we learned the hard way a few years ago that even direct burial power lines *break* due to the repeated stresses caused by vehicular traffic and frost heaves in the area of the wires if some form of rigid conduit isn't used. And the farther down you can place the wire, the less likely it is to gradually work its way back up to the surface over time. I'm sure there's some signal loss and impedance bumps caused by the earth's proximity, but it's still a whole lot better than not being able to have a NW Beverage at all! Bud, W2RU On Jan 6, 2012, at 8:23 AM, Neil G0JHC wrote: > I currently have a 585ft Bev, which at around 200ft has to pass over a > gravel track which is 12-15ft wide. I am contemplating...burying the wire 2 > or 3 " > under the gravel track. I am using WD1-a wire. > > Has anyone any experience of the effect on performance. I will be burying > approx. 2-3% of its total length. > Neil G0JHC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Noise Canceller
Hi all, Try to read and listen http://translate.google.com/translate?hl=en&rurl=translate.google.com&sl=ru&u=http://dl2kq.de/ant/3-15.htm (en) or http://dl2kq.de/ant/3-15d.htm (de) 73 de Igor, DL2KQ ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Bev wire under a path?
I currently have a 585ft Bev, which at around 200ft has to pass over a gravel track which is 12-15ft wide. Currently I have installed 2 poles either side of the path. These poles are 20ft high (so a horse box can pass under). I have had to guy the poles due to strong winds here by the sea. They look unsightly and draw attention to the Bev. The Bev is 6 to 8ft in height apart from this section which slopes up and down from the poles to cross the road at a height of 20ft for 15ft.the slope is gradual on either side of the poles until it returns to 6-8ft. The Bev seems to work fine. I am contemplating doing away with the poles and burying the wire 2 or 3 " under the gravel track. I am using WD1-a wire. Has anyone any experience of the effect on performance. I will be burying approx. 2-3% of its total length. Thanks for your comments and experiences. Neil G0JHC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: MFJ Noise Canceller 1026/1025
> I wouldn't worry about an S-unit of noise increase, especially on 160. > > That's bound to happen with any active device like the MFJ-1025; and with > the normal BG noise level on 160, I don't think it'll keep you from hearing > anything. Many of the DX stations I have worked for "new ones" would have been totally inaudible if my noise floor had been an S-unit higher. Both my present and former MFJ-1026 units had the high noise floor. As noted in my post about filters and IMD yesterday, the solution is to use a preamp ahead of the noise canceller. You need to feed it high enough level from the antenna such that you hear/see no increase in noise when the unit is engaged. 73, Paul N1BUG ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
