Re: Topband: Antenna matching question
Tom, I have an amplifier with a pair of 3-400Zs I built in the 60s. When I built it it was for 20, 15 and 10 meters. I used 3 of the 5 positions of a BC375 tuning unit switch. Everything work fine. I added 160, 80 and 40 meters. 160 was switched in and out with a RJ-1a vacuum relay. When I went to 20 and up meters the switch contacts arced. I added another RJ-1a to short out the unused lower band coils. I switch the RJ-1a's in and out with 2 mini toggle switches. One says 160---other bands, the other switch says low bands---high bands. It works fine on all bands. At that time 3-400Zs were new from Eimac $34.00 each. 73 Price W0RI >> If this is only 160-40 you probably won't have a series resonance issue with >> unused turns, but if you cover a wide range you will want to progressively >> short the large coil taps. This is why band switches that do not short (like >> the old National amp) and why large roller inductors mess up on higher bands. > > > If you mean the NCL-2000 I suggest looking at the schematic again. Or did > National make another ham amp that Ive missed?? > Here you go, Carl That's the wrong way to do a bandswitch. It does not pick up and hold the lower band contacts when switched to higher bands. This allows the taps to build up high voltages on lower band taps when working higher bands. Switches should be pick up and hold, or progressively shorting. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna matching question
If this is only 160-40 you probably won't have a series resonance issue with unused turns, but if you cover a wide range you will want to progressively short the large coil taps. This is why band switches that do not short (like the old National amp) and why large roller inductors mess up on higher bands. If you mean the NCL-2000 I suggest looking at the schematic again. Or did National make another ham amp that Ive missed?? Here you go, Carl http://www.arizona-am.net/PHOENIX/W7CPA/W7CPA%20NCL-2000%20BS%20Before.jpg That's the wrong way to do a bandswitch. It does not pick up and hold the lower band contacts when switched to higher bands. This allows the taps to build up high voltages on lower band taps when working higher bands. Switches should be pick up and hold, or progressively shorting. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna matching question
- Original Message - From: "Tom W8JI" To: "Bill Wichers" ; Sent: Tuesday, March 18, 2014 5:33 PM Subject: Re: Topband: Antenna matching question You mention keeping the highest impedance part "clean" electrically, which would make me think putting the small coil nearest the anteanna would be best. Whichever part of the inductor is shunted out is essentially just adding stray capacitance, that keeps the shorted turns part of the inductors towards the feedline. Since most or all of the large inductor will be shorted out when on 40M, it will act essentially as extra capacitance in the matching network on that band.> That's why tank systems in amplifiers have the ten meter coil near the high impedance end. If this is only 160-40 you probably won't have a series resonance issue with unused turns, but if you cover a wide range you will want to progressively short the large coil taps. This is why band switches that do not short (like the old National amp) and why large roller inductors mess up on higher bands. If you mean the NCL-2000 I suggest looking at the schematic again. Or did National make another ham amp that Ive missed?? Carl KM1H _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
Many have tested various grades of RG-6 shield integrity from HF to microwave in a lab enviroment. It does vary, even at HF and low VHF so I suggest sticking to a name brand and getting the best you can afford as it is more likely to be better over time. Even a single braid varies in percentage of coverage, mo is mo betta and quad shield doesnt cost much more. Be very sure you get the proper connectors that are for the cable you pick. Carl - Original Message - From: "Bill Wichers" To: Sent: Tuesday, March 18, 2014 4:18 PM Subject: Re: Topband: Andrew RG6 specs ? Regarding the copper clad steel (CCS) center conductor, you can easily get RG6 with a solid bare copper (BC) center conductor too. BC center conductor is important for security cameras (which are baseband), and for satellite applications (which send DC over the center conductor to power the LNB at the dish). Since the satellite guys especially are also a very large market, there are lots of good BC center conductor RG6 variants to choose from at good prices. Regarding the braid in the shield, Tom actually did some testing on that some time ago. I think he took a piece of the dielectric with the bonded foil ONLY (no braid) and measured essentially the same amount of leakage as the "regular" coax with the braid. I remember being surprised at that since I'd always thought of the foil as the high-frequency shield and the braid for the lower frequency part. I agree with you that I don't think I'd trust the light-braid RG6 variants for TX though since I'd be concerned about heating. Even though the foil is a good shield, there just isn't much metal there to carry the higher currents associated with transmitting. BTW, you can even get RG6 with copper braid if you need solderability. It tends to be a lot more expensive though. -Bill [snip] loss doesn't matter for an RX antenna, but shielding does. Many CATV coax cables have shielding that is optimized for VHF/UHF, but not so great at MF (160M). Many also have a copper clad center conductor, which is fine for VHF/UHF, but more loss than copper at MF, which makes it less wonderful for TX. Take a look at the shield of any coax that you hope to use on MF and HF. If it's foil plus a thin braid, it will be lossy at MF/HF, and won't be a very good shield. If the SWR on the line is low, it may or may not handle much power. [snip] _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4336 / Virus Database: 3722/7210 - Release Date: 03/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna matching question
You mention keeping the highest impedance part "clean" electrically, which would make me think putting the small coil nearest the anteanna would be best. Whichever part of the inductor is shunted out is essentially just adding stray capacitance, that keeps the shorted turns part of the inductors towards the feedline. Since most or all of the large inductor will be shorted out when on 40M, it will act essentially as extra capacitance in the matching network on that band.> That's why tank systems in amplifiers have the ten meter coil near the high impedance end. If this is only 160-40 you probably won't have a series resonance issue with unused turns, but if you cover a wide range you will want to progressively short the large coil taps. This is why band switches that do not short (like the old National amp) and why large roller inductors mess up on higher bands. 160-40 is less of an issue than 80 or 160 through 10. 73 Tom _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A newbie question
Tom ole buddy.. Call me on the secret Zilla line and let's chat. We can hook a brother up !! :- On Tuesday, March 18, 2014, wrote: > To all,,, I am relatively new to 160,,, I work the vhf/uhf/Eme > spectrum,so I am used to weak signal work,, I just moved to arizona,and > decided to try 160!!,. I had no problem working the HS0 yesterday morning , > but I could not hear the XV7 this morning,,I heard a lot of my "neighbors" > working him... Could anyone give me any info on his xmit power and what > type of receiving antenna those of you who worked him, were using?? > Thanks!! > Sent on the Sprint® Now Network from my BlackBerry® > _ > Topband Reflector Archives - http://www.contesting.com/_topband > -- >From the iPad _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna matching question
The inductors are homebrew, but beefy. Basically I use 1/8" thick G10 phenolic
with holes drilled in a cross vise (to maintain spacing), 8 gauge wire for the
windings, and three aluminum brackets shaped like this \___/ arranged like a
triangle on each end to hold the G10 in place. It ends up making a very sturdy
assembly with an almost entirely air core. I'm not worried about heating and
there isn't much conductive material in the area of the coil. The mounting
plate for the matching network is glastic ('micarta'), and the entire thing is
in a large PVC electrical enclosure.
You mention keeping the highest impedance part "clean" electrically, which
would make me think putting the small coil nearest the anteanna would be best.
Whichever part of the inductor is shunted out is essentially just adding stray
capacitance, that keeps the shorted turns part of the inductors towards the
feedline. Since most or all of the large inductor will be shorted out when on
40M, it will act essentially as extra capacitance in the matching network on
that band.
The capacitors and vacuum relays are Russian surplus with 15kV ratings. I
expect around 7kv or so at the base of the antenna while transmitting.
I should probably post a pic of one of the inductors sometime. It's a simple
construction method that is very robust and easy to do at home even if you
don't have machine shop facilities handy.
-Bill
>
> It really depends on the parts.
>
> We always want the highest impedance part of the system to have the least
> unnecessary stuff hanging from it, and to have the highest voltage rating
> for contacts and arc paths.
_
Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
Regarding the copper clad steel (CCS) center conductor, you can easily get RG6 with a solid bare copper (BC) center conductor too. BC center conductor is important for security cameras (which are baseband), and for satellite applications (which send DC over the center conductor to power the LNB at the dish). Since the satellite guys especially are also a very large market, there are lots of good BC center conductor RG6 variants to choose from at good prices. Regarding the braid in the shield, Tom actually did some testing on that some time ago. I think he took a piece of the dielectric with the bonded foil ONLY (no braid) and measured essentially the same amount of leakage as the "regular" coax with the braid. I remember being surprised at that since I'd always thought of the foil as the high-frequency shield and the braid for the lower frequency part. I agree with you that I don't think I'd trust the light-braid RG6 variants for TX though since I'd be concerned about heating. Even though the foil is a good shield, there just isn't much metal there to carry the higher currents associated with transmitting. BTW, you can even get RG6 with copper braid if you need solderability. It tends to be a lot more expensive though. -Bill [snip] > loss doesn't matter for an RX antenna, but shielding does. Many CATV coax > cables have shielding that is optimized for VHF/UHF, but not so great at MF > (160M). Many also have a copper clad center conductor, which is fine for > VHF/UHF, but more loss than copper at MF, which makes it less wonderful > for TX. > > Take a look at the shield of any coax that you hope to use on MF and HF. > If it's foil plus a thin braid, it will be lossy at MF/HF, and won't be a > very good > shield. If the SWR on the line is low, it may or may not handle much power. [snip] _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
Commscope owns Andrew, likely just a different name imprinted on the jacket. Carl KM1H - Original Message - From: "Mike Waters" To: Sent: Tuesday, March 18, 2014 2:10 PM Subject: Re: Topband: Andrew RG6 specs ? You could also use that stuff to feed your TX antenna. I do here. If it's like the Commscope CATV F-6 coax I have, it'll handle about 3 kW continuously on 160. 73, Mike www.w0btu.com ... http://www.oocities.org/yanpingma2000/mocsy-catalog.pdf Page 6? _ Topband Reflector Archives - http://www.contesting.com/_topband - No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4336 / Virus Database: 3722/7210 - Release Date: 03/18/14 _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
On 3/18/2014 11:10 AM, Mike Waters wrote: You could also use that stuff to feed your TX antenna. I do here. If it's like the Commscope CATV F-6 coax I have, it'll handle about 3 kW continuously on 160 Mike, RG numbers for coax no longer mean much in terms of a specification. There are dozens of RG-6 cables in the Belden catalog, many very different from each other, each optimized for different uses. For all practical purposes, loss doesn't matter for an RX antenna, but shielding does. Many CATV coax cables have shielding that is optimized for VHF/UHF, but not so great at MF (160M). Many also have a copper clad center conductor, which is fine for VHF/UHF, but more loss than copper at MF, which makes it less wonderful for TX. Take a look at the shield of any coax that you hope to use on MF and HF. If it's foil plus a thin braid, it will be lossy at MF/HF, and won't be a very good shield. If the SWR on the line is low, it may or may not handle much power. There ARE cables labeled RG6 with a solid copper center and one or even two dense copper braid shields. Belden makes at least two, and several years ago, I bought a surplus spool of a similar cable with Pasternak's name on it, at a good price. 73, Jim K9YC _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A newbie question
Hi Tom, Welcome to topband! As you gain experience you will encounter many situations where your transmit antenna is inadequate for receiving. An excellent receiving antenna can provide as much as 10 dB improvement compared to an omnidirectional vertical transmitting antenna, not only in terms of signal to noise ratio, but also significantly improved ability to receive through pileup QRM and intentional or accidental QRM. Do you have adequate space for a receiving antenna? As with all things involving antennas, size matters... The highest performance receiving arrays such as the Hi-Z monoband active 8-circle array (200 foot diameter) or the W8JI/W5ZN/N4HY passive 8-circle array (350 foot diameter) require an acre or more well away from transmitting antennas. They provide truly astounding receiving improvement, but the expense and effort to install them is much greater than for smaller arrays. Small receiving antennas including the Array Solutions SAL-30, K9AY loops or flag antennas offer significant improvement at modest effort and cost, but they require only a 36 foot diameter circle. Perhaps the simplest receiving antenna is a Beverage, offering quite good performance for an investment of only a few hours work but they require at least 500 feet of length to obtain significant performance improvement compared to the popular small receiving arrays. W8JI has perhaps the largest Beverage array in use on topband, three 900 foot phased Beverages spaced 300 feet from each other. 73 Frank W3LPL - Original Message - From: wa8...@wa8wzg.net To: "TopBand" Sent: Tuesday, March 18, 2014 3:45:53 PM Subject: Topband: A newbie question To all,,, I am relatively new to 160,,, I work the vhf/uhf/Eme spectrum,so I am used to weak signal work,, I just moved to arizona,and decided to try 160!!,. I had no problem working the HS0 yesterday morning , but I could not hear the XV7 this morning,,I heard a lot of my "neighbors" working him... Could anyone give me any info on his xmit power and what type of receiving antenna those of you who worked him, were using?? Thanks!! Sent on the Sprint® Now Network from my BlackBerry® _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Antenna matching question
Here's my question: the large inductor is much higher Q on 160 than the small inductor (large inductor is about 4.5" diameter, small one about 2" diameter). Would it be better to have the large inductor connected to the antenna and the small one to the feed (the two inductors would still be in series), or the other way around? My original thinking was that it wouldn't really matter since they're in series, and due to the tap selection arrangement the same distributed capacitance is in the circuit regardless. Can anyone think of a reason why the arrangement of which inductor was in which position would make any practical difference in this system that I may have missed? It really depends on the parts. We always want the highest impedance part of the system to have the least unnecessary stuff hanging from it, and to have the highest voltage rating for contacts and arc paths. _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A newbie question
Tom, I worked XV7BM at 1328z this morning about 10 minutes before our SR. When I worked him, he was 559, but within 10 minutes he was 579! I'm running about 1400 watts out to a 70 ft vertical with (2) 50 ft top hat wires. I have over 100 135 ft ground radials. My RX antenna is a HI-Z 4 SQ antenna that works great! It increases the signal about one S unit, but also rejects noise off the sides and back. It has helped me greatly in hearing DX on 80m & 160m. Ray, N6VR Chino, Valley North Central AZ On Tue, Mar 18, 2014 at 9:20 AM, wrote: > I worked XV7BM on 160 at my sunrise (about 1400z) this morning, running > about 900w, and transmitting/receiving on the same antenna, a half-sloper > off a 110' tower. He was peaking over s-9 when I worked him. > > All the same facts applied to my QSO with HS0ZKX yesterday. > > Now if only XZ1Z would appear tomorrow morning... > > Good luck! > > 73, > Jim W1YY > Kingston, WA > > -Original Message- From: wa8...@wa8wzg.net > Sent: Tuesday, March 18, 2014 8:45 AM > To: TopBand > Subject: Topband: A newbie question > > > To all,,, I am relatively new to 160,,, I work the vhf/uhf/Eme > spectrum,so I am used to weak signal work,, I just moved to arizona,and > decided to try 160!!,. I had no problem working the HS0 yesterday morning , > but I could not hear the XV7 this morning,,I heard a lot of my "neighbors" > working him... Could anyone give me any info on his xmit power and what > type of receiving antenna those of you who worked him, were using?? > Thanks!! > Sent on the Sprint® Now Network from my BlackBerry® > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
You could also use that stuff to feed your TX antenna. I do here. If it's like the Commscope CATV F-6 coax I have, it'll handle about 3 kW continuously on 160. 73, Mike www.w0btu.com ... http://www.oocities.org/yanpingma2000/mocsy-catalog.pdf Page 6? > _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: Andrew RG6 specs ?
... http://www.oocities.org/yanpingma2000/mocsy-catalog.pdf Page 6? 73ss Carsten, DL6LAU Am 18.03.14 18:52, schrieb Charles Stackhouse: I just bought a 1000ft spool of unused Andrew AD6TS-BF type 6 coax (?RG6) to use as Beverage feedline. I can't find any specs on the Internet. Does anyone on this list have any information about this coax. Many thanks. Charlie W2GN _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Andrew RG6 specs ?
I just bought a 1000ft spool of unused Andrew AD6TS-BF type 6 coax (?RG6) to use as Beverage feedline. I can't find any specs on the Internet. Does anyone on this list have any information about this coax. Many thanks. Charlie W2GN _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: Antenna matching question
I'm working on a new matching network for my vertical. The vertical is a wire cage of approx. 82 feet high, and I use it on 160, 80 and 40 meters. The matching network is a low-pass L network. The new matching network is remotely tunable with 5 different capacitors selected by vacuum relays and two tapped inductors adjusted with motorized rotary switches. One inductor is large (about 45 uH), most of which is needed for loading on 160 and less is needed on 80 but I have 6 taps to choose from. The smaller inductor (about 2 uH) is used mostly for 40, but also to "fine tune" the large inductor since the large inductor is almost 2 uH per turn. The inductors are in series between the antenna and feed with motorized rotary switches to select the taps, one switch per inductor, 6 taps per inductor. Taps are set to be "about right" for the bands I use on the antenna so the matching network is adjustable but within certain ranges - it's not a "match anything" network, it's specific to t his antenna. Here's my question: the large inductor is much higher Q on 160 than the small inductor (large inductor is about 4.5" diameter, small one about 2" diameter). Would it be better to have the large inductor connected to the antenna and the small one to the feed (the two inductors would still be in series), or the other way around? My original thinking was that it wouldn't really matter since they're in series, and due to the tap selection arrangement the same distributed capacitance is in the circuit regardless. Can anyone think of a reason why the arrangement of which inductor was in which position would make any practical difference in this system that I may have missed? -Bill _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: A newbie question
I worked XV7BM on 160 at my sunrise (about 1400z) this morning, running about 900w, and transmitting/receiving on the same antenna, a half-sloper off a 110' tower. He was peaking over s-9 when I worked him. All the same facts applied to my QSO with HS0ZKX yesterday. Now if only XZ1Z would appear tomorrow morning... Good luck! 73, Jim W1YY Kingston, WA -Original Message- From: wa8...@wa8wzg.net Sent: Tuesday, March 18, 2014 8:45 AM To: TopBand Subject: Topband: A newbie question To all,,, I am relatively new to 160,,, I work the vhf/uhf/Eme spectrum,so I am used to weak signal work,, I just moved to arizona,and decided to try 160!!,. I had no problem working the HS0 yesterday morning , but I could not hear the XV7 this morning,,I heard a lot of my "neighbors" working him... Could anyone give me any info on his xmit power and what type of receiving antenna those of you who worked him, were using?? Thanks!! Sent on the Sprint® Now Network from my BlackBerry® _ Topband Reflector Archives - http://www.contesting.com/_topband _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: (no subject)
I see somebody is trying to sell a copy or two for 369.00 on Amazon and Ebay.LOL Mike W0MU On 3/18/2014 4:08 AM, la...@otterstad.dk wrote: Low Profile Amateur Radio: Operating a Ham Station from Almost Anywhere _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: A newbie question
To all,,, I am relatively new to 160,,, I work the vhf/uhf/Eme spectrum,so I am used to weak signal work,, I just moved to arizona,and decided to try 160!!,. I had no problem working the HS0 yesterday morning , but I could not hear the XV7 this morning,,I heard a lot of my "neighbors" working him... Could anyone give me any info on his xmit power and what type of receiving antenna those of you who worked him, were using?? Thanks!! Sent on the Sprint® Now Network from my BlackBerry® _ Topband Reflector Archives - http://www.contesting.com/_topband
Re: Topband: PZ1AA
Update on the PZ1AA situation for the CQ 160 CW contest. Stations that have this callsign in their log will have the QSO not count. There is no penalty associated with removing the QSO. It will be counted as a "duplicate" QSO. 73 Tree N6TR CQ 160 Log Checker On Wed, Feb 5, 2014 at 5:52 AM, Don Kirk wrote: > Now that the CQWW 160 meter CW contest log submission deadline is past, > here is an update from Ramon (PZ5RA) about PZ1AA. > --- > This morning I got a call from the authorities and they told me they have > never submitted this call. So it was a pirate or a fake. > --- > 73, > Don (wd8dsb) > _ > Topband Reflector Archives - http://www.contesting.com/_topband > _ Topband Reflector Archives - http://www.contesting.com/_topband
Topband: (no subject)
Low Profile Amateur Radio: Operating a Ham Station from Almost Anywhere . Sold out at ARRL. Anybody has one collecting dust ? 73 Rag LA5HE mail2web - Check your email from the web at http://link.mail2web.com/mail2web _ Topband Reflector Archives - http://www.contesting.com/_topband
