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1000 foot longwire antenna's
In article
, wrote: On Mar 3, 4:35*am, Telamon wrote: In article , wrote: dxAce raised the point that he would prefer to upgrade to a 1000 foot antenna rather than upgrade to a better radio. This is a bit like which came first? the chicken or the egg? I have had extensive experience of using 1000ft longwires or beverage antenna's on my DXpeditions over the years and indeed they do pull in the signals something awesome. But they also pull in more interfering stations that want to blot out your faint DX target, and also whatever QRM/RFI noise is floating around, they pull more of that in too. So at the end of the day it still means it is better to DX with a top end radio that suppresses and minimises the offending signals and QRM that are interfering with your faint DX target. Over the years I gradually upgraded my radio's to what I thought was the ultimate, a Drake R8B. I was quite satisfied with that until I was loaned a Rohde & Schwarz. Although the R & S did not have any more bells and whistles than my Drake, it was so clearly superior to my R8B that from then on I hankered after a better radio. The R&S just pulled in faint stations that did not even register on the R8B and then was also better able to resolve to audibility stations that were interfered with much better than the R8B. So I watched developments and then my good friend Guy pointed me towards the Icom IC-756PROIII, which I later acquired. This radio was indeed better than my R8B, see: http://www.dxing.info/equipment/icom_ic756_plimmer.dxSo the 756Pro3 has really proved itself in the field, culminating in the catch of a lifetime: 1410 Khz, CFUN, Vancouver BC, Canada, some 14,000 miles away from the Seefontein DX site. Whether or not I would have got this catch on my old R8B is a moot point - I don't think so as it was extremely faint and on the border of audibility, and my DX mates didn't get it either. So I am happy that the 756Pro3 paid for itself and that is why I am now upgrading to the new Icom IC-7700 which should be here in April. If I get only one more rare catch I will be satisfied that the 7700 has been a worthwhile investment. But to keep things in perspective, I think the things that are important to good DX reception are, in order of importance: 1st.] A decent antenna, the best you can afford or rig up. 2nd.] Location. Most of us live in the city or suburbs and are either in condo's or on limited size plots, so our options are limited. That is why serious DXer's go to a lot of trouble and expense to find the "ideal" DX location. When you find a decent place, the results are VERY rewarding. 3rd.] The radio. again, get the best you can afford. The results just get better and better. I would liken our hobby to any sport. If you take golf and Tiger Woods for example. He has only the latest and most expensive cutting edge equipment. If he gets the latest $3000 putter and it allows him that extra inch nearer the hole, he is satisfied. So it is with radio gear and antenna's. Have fun and good DX You bring up a good argument but tangled in it are a number of factors that all affect reception. The chicken and egg question is easy. The antenna is the egg and it comes first. All antennas are not created equal and are designed to achieve certian objectives in reception just like radios. In the extreme the antenna can be highly directional where the desired signal can be specifically enlarged relative to other signals and noise. In the radio it is mainly blocking and bandpass filtering. Both antenna directionality and gain or radio gain, blocking, and selectivity can get you where you want to go to get that DX. I'm familiar with Rohde & Schwarz signal generators but not their receivers. You don't mention the model number of the receiver but I can speculate on a few things. One would be cost. Chances are the R&S receiver costs 10 to 30 times the Drake. Two would be that the R&S would not have such niceties as sync detection or tone controls. I don't think going to ham transceivers is the way to go unless you are a ham or are working toward being one. I'm not interested in being a ham and I don't want to buy a transceiver. DSP can be a good thing but it depends on how it is engineered. I have both kinds of radios and the DSP type appears to have no advantage in AM mode. The DSP radio does appear to work better for SSB. I would expect that for digital modes the DSP would clearly be superior. Here the crucial parameter at play I believe is bandwidth. Designed properly DSP IF and AF filtering is generally much better than analog and so in application where this is more important the DSP radios can perform better. Anyone who has operated a radio with several filters has most likely noticed that as you decrease the bandwidth the receiver noise floor drops improving signal to noise. Since DSP filters can have very steep walls and depth over analog filtering you would expect improved signal to noise and better reception where narrow bandwidths are in play. There are always performance tradeoffs and you only address what a DX'er might want and certainly not what I would want in a receiver. What I want is good performance and good sound. Many DSP implementations have lousy sound quality with a lot of distortion. Here I noticed that with DSP you can have a signal in the clear without the pops and hiss and yet not be able to understand what is being said. I have listened to tapes of DSP radio reception and noticed that besides not being able to understand many of the words in speech that it was very difficult to listen to the recordings after a while. Even when I had a transcript of what was said and replayed the DSP recordings over again I still could not make out some of the words. I also found it very tiring to listen to DSP sound. I'll take the pops, whistles, and hiss over the DSP distortion anytime. Here is an observation I have made on DSP sound. Have you ever listed to a coast to coast show with one of those reverse speech guys on? I don't know about other people but sometimes listening to DSP SW recordings was not unlike listening to those reverse speech recordings. Telemon, I didn't deal in detail about the 1000 ft beverage antenna, because the subject of antenna's is vast and the number of huge technical tomes written on the subject will keep you going for the rest of your life. I see you have a poor opinion of DSP receivers, so I can only presume you experienced the faults of the early models that only had 16 bit engines. My 756Pro3 has a 24 bit engine with 32 bit processor and I assure you suffers from none of the problems you mention that applied to the earlier offerings like the JRC NRD545D. I wrote a detailed description of my experiences of the 756Pro3's audio and filter at: http://www.dxing.info/community/view...607b7f67e8ff1a ab600e79c4f I assure you the audio on the 756Pro3 is top notch, only thing it lacks is a synch detector. Rohde & Schwarz did indeed make receivers for HF, the last of them being the EK895, which unfortunately was so expensive that it could only be affordable to professional and government operations. They don't make stand alone receivers anymore, only modular HF units that fit into a more comprehensive monitoring PC run station. The R&S EK receiver I had use of for several months was the analogue model just before the EK895 - it's performance was just awesome. It's outstanding performance was not due to any fancy pre-amps, but rather superb circuitry, high quality components and build, and top notch filters. In performance the only hobby radio that ever came near it in performance was my pals Drake R7A. Both these receivers could resolve DX signals that my R8B couldn't. Of course it's different tricks for different dicks. What I am looking for in a top end receiver is a complete overkill for the fella that just want's to potter around and get good sound out of AM HF broadcasts. OHIM (Oh hell it's Monday) enjoy your radio and good listening Yeah, this should be an exciting week. I didn't mean to convey the impression that DSP receivers are just no good. My RX340 sounds just fine but I prefer the sound of the R8B for AM signals. The RX340 works really well on SSB but this is different program material than what is on AM mode the broadcasters use. No question that DSP is the way to go on digital signals as the software filters are much faster, sharper, and deeper than the analog and so you can get much better error rate ratio. I think DSP is clearly better for SSB voice also but when it comes to listening to AM mode broadcast that's where it has some drawbacks and these can be minimized but they are not going to be biased that way in a ham transceiver where the emphasis is on SSB. I think that a really good sounding DSP receiver for AM broadcast can be made if it is designed with that mode in mind. -- Telamon Ventura, California |
1000 foot longwire antenna's
With Drake SPR-4, R8, and R8B receivers, I have observed where adjacent
channel spatter can seemingly obliterate weaker stations. I think this is a function of the AGC recovery time. Even though there are selectable AGC rates on the Drake receivers, I think a longer than usual decay time could cause this problem. Another thing that can cause the effect is having early stages in a receiver generate the AGC voltage. This is not good.............you need to have all AGC voltages generated by stages that follow the high selectivity portions of the receiver. I found this out the hard way, in my early receiver design days. I don't notice this effect with the Drake R7 receiver or the TR7 transceiver. These receivers don't have the smooth, swirly audio / AGC characteristic of the R8 either. This characteristic is what gives the R8 its pleasant audio recovery. As a final example, the Icom R75 is very good when it comes to demodulating a weak signal next to a very strong adjacent channel signal..................the problem here is that its hard AGC characteristic gives me what I would refer to as earstrain. Just not very pleasant to listen to over long periods of time. A decay characteristic of 150 to 200 milliseconds seems to be a good compromise. I've never played with R&S receivers, but I have played with Racal, Harris, Collins, Cubic, etc. All of these receivers are designed for life and death situations, and they all seem to handle that adjacent channel issue very well. Pete wrote in message ... Telemon, I didn't deal in detail about the 1000 ft beverage antenna, because the subject of antenna's is vast and the number of huge technical tomes written on the subject will keep you going for the rest of your life. I see you have a poor opinion of DSP receivers, so I can only presume you experienced the faults of the early models that only had 16 bit engines. My 756Pro3 has a 24 bit engine with 32 bit processor and I assure you suffers from none of the problems you mention that applied to the earlier offerings like the JRC NRD545D. I wrote a detailed description of my experiences of the 756Pro3's audio and filter at: http://www.dxing.info/community/view...aab60 0e79c4f I assure you the audio on the 756Pro3 is top notch, only thing it lacks is a synch detector. Rohde & Schwarz did indeed make receivers for HF, the last of them being the EK895, which unfortunately was so expensive that it could only be affordable to professional and government operations. They don't make stand alone receivers anymore, only modular HF units that fit into a more comprehensive monitoring PC run station. The R&S EK receiver I had use of for several months was the analogue model just before the EK895 - it's performance was just awesome. It's outstanding performance was not due to any fancy pre-amps, but rather superb circuitry, high quality components and build, and top notch filters. In performance the only hobby radio that ever came near it in performance was my pals Drake R7A. Both these receivers could resolve DX signals that my R8B couldn't. Of course it's different tricks for different dicks. What I am looking for in a top end receiver is a complete overkill for the fella that just want's to potter around and get good sound out of AM HF broadcasts. OHIM (Oh hell it's Monday) enjoy your radio and good listening John Plimmer, Montagu, Western Cape Province, South Africa South 33 d 47 m 32 s, East 20 d 07 m 32 s RX Icom IC-756 PRO III with MW mods Drake SW8 & ERGO software Sony 7600D, GE SRIII, Redsun RP2100 BW XCR 30, Sangean 803A. Antenna's RF Systems DX 1 Pro Mk II, Datong AD-270 Kiwa MW Loop, PAORDT Roelof mini-whip http://www.dxing.info/about/dxers/plimmer.dx On Mar 3, 4:35 am, Telamon wrote: In article , wrote: dxAce raised the point that he would prefer to upgrade to a 1000 foot antenna rather than upgrade to a better radio. This is a bit like which came first? the chicken or the egg? I have had extensive experience of using 1000ft longwires or beverage antenna's on my DXpeditions over the years and indeed they do pull in the signals something awesome. But they also pull in more interfering stations that want to blot out your faint DX target, and also whatever QRM/RFI noise is floating around, they pull more of that in too. So at the end of the day it still means it is better to DX with a top end radio that suppresses and minimises the offending signals and QRM that are interfering with your faint DX target. Over the years I gradually upgraded my radio's to what I thought was the ultimate, a Drake R8B. I was quite satisfied with that until I was loaned a Rohde & Schwarz. Although the R & S did not have any more bells and whistles than my Drake, it was so clearly superior to my R8B that from then on I hankered after a better radio. The R&S just pulled in faint stations that did not even register on the R8B and then was also better able to resolve to audibility stations that were interfered with much better than the R8B. So I watched developments and then my good friend Guy pointed me towards the Icom IC-756PROIII, which I later acquired. This radio was indeed better than my R8B, see: http://www.dxing.info/equipment/icom_ic756_plimmer.dxSo the 756Pro3 has really proved itself in the field, culminating in the catch of a lifetime: 1410 Khz, CFUN, Vancouver BC, Canada, some 14,000 miles away from the Seefontein DX site. Whether or not I would have got this catch on my old R8B is a moot point - I don't think so as it was extremely faint and on the border of audibility, and my DX mates didn't get it either. So I am happy that the 756Pro3 paid for itself and that is why I am now upgrading to the new Icom IC-7700 which should be here in April. If I get only one more rare catch I will be satisfied that the 7700 has been a worthwhile investment. But to keep things in perspective, I think the things that are important to good DX reception are, in order of importance: 1st.] A decent antenna, the best you can afford or rig up. 2nd.] Location. Most of us live in the city or suburbs and are either in condo's or on limited size plots, so our options are limited. That is why serious DXer's go to a lot of trouble and expense to find the "ideal" DX location. When you find a decent place, the results are VERY rewarding. 3rd.] The radio. again, get the best you can afford. The results just get better and better. I would liken our hobby to any sport. If you take golf and Tiger Woods for example. He has only the latest and most expensive cutting edge equipment. If he gets the latest $3000 putter and it allows him that extra inch nearer the hole, he is satisfied. So it is with radio gear and antenna's. Have fun and good DX You bring up a good argument but tangled in it are a number of factors that all affect reception. The chicken and egg question is easy. The antenna is the egg and it comes first. All antennas are not created equal and are designed to achieve certian objectives in reception just like radios. In the extreme the antenna can be highly directional where the desired signal can be specifically enlarged relative to other signals and noise. In the radio it is mainly blocking and bandpass filtering. Both antenna directionality and gain or radio gain, blocking, and selectivity can get you where you want to go to get that DX. I'm familiar with Rohde & Schwarz signal generators but not their receivers. You don't mention the model number of the receiver but I can speculate on a few things. One would be cost. Chances are the R&S receiver costs 10 to 30 times the Drake. Two would be that the R&S would not have such niceties as sync detection or tone controls. I don't think going to ham transceivers is the way to go unless you are a ham or are working toward being one. I'm not interested in being a ham and I don't want to buy a transceiver. DSP can be a good thing but it depends on how it is engineered. I have both kinds of radios and the DSP type appears to have no advantage in AM mode. The DSP radio does appear to work better for SSB. I would expect that for digital modes the DSP would clearly be superior. Here the crucial parameter at play I believe is bandwidth. Designed properly DSP IF and AF filtering is generally much better than analog and so in application where this is more important the DSP radios can perform better. Anyone who has operated a radio with several filters has most likely noticed that as you decrease the bandwidth the receiver noise floor drops improving signal to noise. Since DSP filters can have very steep walls and depth over analog filtering you would expect improved signal to noise and better reception where narrow bandwidths are in play. There are always performance tradeoffs and you only address what a DX'er might want and certainly not what I would want in a receiver. What I want is good performance and good sound. Many DSP implementations have lousy sound quality with a lot of distortion. Here I noticed that with DSP you can have a signal in the clear without the pops and hiss and yet not be able to understand what is being said. I have listened to tapes of DSP radio reception and noticed that besides not being able to understand many of the words in speech that it was very difficult to listen to the recordings after a while. Even when I had a transcript of what was said and replayed the DSP recordings over again I still could not make out some of the words. I also found it very tiring to listen to DSP sound. I'll take the pops, whistles, and hiss over the DSP distortion anytime. Here is an observation I have made on DSP sound. Have you ever listed to a coast to coast show with one of those reverse speech guys on? I don't know about other people but sometimes listening to DSP SW recordings was not unlike listening to those reverse speech recordings. -- Telamon Ventura, California- Hide quoted text - - Show quoted text - |
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