Re: Topband: Dual band shunt-feeding tower on 160/80
Jeff, You will have problems with attempting to shunt feed a 100 foot grounded tower on 80 since it approaches a grounded half wave radiator and just to long on 80. The solution for this is to make a decoupling sleeve on the tower by elevating the 80 meter feed up the tower and bring down several skirt wires at the 40 foot level that are a least a 1/4 wave long on 80. You can bring them to the ground and run the extra lengths out parallel and insulated from the ground. This will allow you to shunt feet above the skirt attachment point. The only problem with this is that it will impact the 160 mete feed and you may have to have a HV switch to disconnect the unused band. So report that just connecting the 80 meter coax braid up the tower and fanning out some radials at that point can work. But again why screw up a perfectly good 160 meter vertical when you can hang 80 meter slopers from it with less impact and not so much hassle? Herb Schoenbohm, KV4FZ On 8/25/2013 11:43 PM, Jeff Blaine wrote: A buddy of mine has a 100’ 25G tower and wants to run it on both 160/80. I’m thinking a par of shunts will work for that? If you have done this, I would be interested in your comments on the general implementation. Thanks! 73/jeff/ac0c www.ac0c.com alpha-charlie-zero-charlie _ Topband Reflector _ Topband Reflector
Re: Topband: 160 meter activity
On 08/26/2013 12:26 AM, Mike Waters wrote: Bill, The stations on the RBN are automatic, and work even when unattended. They are not like the DX clusters which require a manual post. Call CQ and see. :-) 73, Mike www.w0btu.com http://www.w0btu.com Hi Mike, Thanks. Yes..I thought everybody who knows what RBN is also knows that the stations *automatically* post the information on the RBN server. I thought I made an efficient use of words. I did make the call and was not heard. I did see some activity on the RBN and I was able to hear the North American stations that were posted there AND I heard one or two that were NOT posted there. Do they call the receive stations skimmers? I'm sure the skimmers are 'plagued' with the same noise problems all of us face. And there is the matter of 'lobes' in the antenna patterns - intentional or not. There are a lot of reasons why skimmers might miss some signals. One of them is low power and another could involve the antenna. It may not radiate well and it may not radiate well in the direction of skimmers that could otherwise hear. Not all of the skimmers are on 160 meters. I hope to be be doing some more serious antenna work before snow. I do sometimes get heard and pretty much always - on the other bands with that antenna. Meanwhile I will keep trying. Puzzle pieces keep falling into place. I discovered a 'bad' patch cord in the station. It was obvious instantly when I put it in the antenna circuit. As Tim the ToolMan Allen says - Oy? 73, Bill KU8H _ Topband Reflector
Re: Topband: Anyone have a boat load of J-310s?
Thanks, Andy I understand your IP and trade-secret issues. That's an interesting approach. I'll have to give it some thought, although I don't expect to be building preamps anytime in the foreseeable future. Was just curious why so many J-310/309. Now I understand. Have a good afternoon! 73, Charlie, K4OTV -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Andy Ikin Sent: Monday, August 26, 2013 6:29 AM To: Charlie Cunningham Cc: Topband Reflector Subject: Re: Topband: Anyone have a boat load of J-310s? Charlie wrote on Aug. 26. Your preamp sounds very interesting! It must be fairly elaborate, if it uses 8 of the J309 FETS! I'd be interested in the circuit! Charlie, I don't disclose circuit diagrams for commercial reasons. However the design is a push-pull using 4 fets in parallel to increase the gm and reduce the channel resistance, hence lower the noise. 73 Andrew G8LUG _ Topband Reflector _ Topband Reflector
Re: Topband: Dual band shunt-feeding tower on 160/80
I've done exactly what Herb suggested: hung a sloper for 80M off the side of my 160M shunt-fed tower. Neither antenna knows the other is there and both work pretty well - meaning I'm satisfied with what I get out of them. Interesting. I have tried verticals, slopers, inverted V's and other 80 meter antennas on or near my 160 meter tower with little success. The impedance of any such antenna seems to be severely altered by the nearby tower. I suspect it depends on the electrical length of the tower. Mine is close to an electrical half wave on 80 - 100 feet of Rohn 25 with a 7 element 6 meter yagi, approximately 30 foot boom sitting at 103 feet. At one point in time the 160 meter shunt feed could be made to provide an excellent match on 80 simply by changing the series capacitance. However, after I cut down several nearby trees that no longer works. 73, Paul N1BUG _ Topband Reflector
Re: Topband: 160 meter activity
To use a preamplifier or not (in a signal estimation) it seems to me it is equivalent as to speak: to use the antenna for RX or not, to use radio or to listen shout by a throat from mountain... I exaggerate. But our radio and its functions are created to help the operators. I sometimes switch off a preamplifier on TOP, sometimes I switch on the amplifier on my Beverages. If on GP I do not hear DX, during too time on BV with the amplifier I will be copy signa S9 that what signal S I should give to this station? More often my official report more conditional if I hear station more S6. P.S. In ours QTH 160m still sleeps. Yesterday on 80m was audible V31MA (S3-4) which were heard by my signal unfortunately. 73! de Eugene RA0FF http://dx.bgtelecom.ru http://www.qsl.net/ra0ff/ Воскресенье, 25 августа 2013, 16:44 -07:00 от Bob Kupps n...@yahoo.com: Well I applaud your making the effort at giving an honest report. It seems to me that 599 is reported far too casually these days and I certainly attempt to give honest reports even in a (non contest) pile up. Although R reports are fairly easy - I give 3 if I'm struggling, 4 if I have to pay attention and 5 if it's easy. But S reports, especially on the low bands where we are often using preamps, attenuators or both make an objective report a bit tougher. The other night I was chatting with my pal W6YA on 20. My 100 watts to a 5/5 stack always gets a better report on his K3 than his 1500W to a 4 el gets on my K3 until he finally said that he always uses his preamp on the high bands because the K3 S meter is factory calibrated with the preamp on, and he like I strive to give meaningful reports. Anyway, I would be interested in how other ops (who care) try to give meaningful reports - objective vs subjective. Also my compliments to N4ZR and the RBN guys who are providing a great service to the ham DX community in this regard. 73 Bob HS0ZIA From: John Harden jh...@bellsouth.net To: topband@contesting.com Sent: Sunday, August 25, 2013 9:17 PM Subject: Topband: 160 meter activity 160 is really picking up here. I called CQ on 1824.5 this morning here in Atlanta at 1030 Z. VK3ZL came back to me with a 599 report and I gave him an honest 579. The band has been open for some time at this QTH. However, the RX antenna is the Hi-Z 4-8 PRO, 8 vertical array (with 4 antennas active at any time). No doubt I hear signals others cannot hear. I do HIGHLY recommend it.. 73, John, W4NU _ Topband Reflector _ Topband Reflector _ Topband Reflector
