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Post by bluemax on Oct 17, 2017 11:59:08 GMT -5
I had a very interesting contact the other night on a LSB CB frequency. I was on my classic Robyn SB520D and found myself tuning in each of the transmitting stations on different ends of my clarifier. Up, down, up again, down, oops missed him - UP. OK you get it. So I tuned in simulcast on my Ranger Superstar. After adjusting both radios to an acceptable frequency and volume, I was able to hear the exchange rather seamlessly. I used the Robyn for the station that was less off center (on my end) and the Ranger for the station that was almost at the extreme capability of the Robyn. So it dawned on me that there is a huge difference in fine tune capability. But since only the Ranger has a frequency counter, I don't know how much range I have on the Robyn. Thinking back to other sideband oldtimers, I would say that none of those radios had the fine tune range of the new stuff. Was there an acceptable standard in the 70's or thereabouts or did certain radios have much better range even then? And does anyone know what that range might be on the SB520D? I think I'm struggling with understanding how crystal tuning and VFO tuning overlap in this instance.
In any case it was a very interesting radio adventure.
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Post by Sandbagger on Oct 17, 2017 17:39:34 GMT -5
I had a very interesting contact the other night on a LSB CB frequency. I was on my classic Robyn SB520D and found myself tuning in each of the transmitting stations on different ends of my clarifier. Up, down, up again, down, oops missed him - UP. OK you get it. So I tuned in simulcast on my Ranger Superstar. After adjusting both radios to an acceptable frequency and volume, I was able to hear the exchange rather seamlessly. I used the Robyn for the station that was less off center (on my end) and the Ranger for the station that was almost at the extreme capability of the Robyn. So it dawned on me that there is a huge difference in fine tune capability. But since only the Ranger has a frequency counter, I don't know how much range I have on the Robyn. Thinking back to other sideband oldtimers, I would say that none of those radios had the fine tune range of the new stuff. Was there an acceptable standard in the 70's or thereabouts or did certain radios have much better range even then? And does anyone know what that range might be on the SB520D? I think I'm struggling with understanding how crystal tuning and VFO tuning overlap in this instance. In any case it was a very interesting radio adventure. What you witnessed is the primary reason why locked on transmit, receive only clarifiers are a BAD idea. They're ok if only 2 stations are in a QSO. But add in a third or, like you, someone just listening, and if the two stations aren't transmitting on the same frequency, you have to shift the clarifier to each station when they transmit. The two stations talking don't care because they can simply tune to each other. But anyone else will have to shift back and forth as each station takes a turn on the TX switch. That being said, the FCC originally allowed for a +/- .005% frequency tolerance to be legally "on-frequency". What does that mean? It means that for instance, if you take channel 13, 27.115 Mhz. To be within tolerance means that you can go from 27.1136 to 27.1164, or about +/- 1.4 Khz. That tolerance spec was originally designed to take into account frequency drift due to crystal aging and other frequency determining parts shifting value. But it also allowed CB makers to deliberately design SSB clarifiers to shift within that tolerance and remain legal. So the typical 70's vintage SSB rigs normally had a +/- 1 to about 1.3 Khz clarifier range. Which was enough to track stations that might have drifted away from center frequency and, more importantly, allowed a group of people to net their frequencies together at the same place. Yea, guys would often endlessly argue about who's radio was closer to being truly "on-frequency". But it didn't really matter what that frequency truly was as long as everyone was on the same frequency. When the 40 channel radios started being produced in 1977, the FCC mandated that the clarifier would only shift receive frequency. Transmit frequency would remain "locked on". The thinking here was that the "newfangled" PLL synthesizers had tighter frequency tolerances, so the TX/RX synchronized shifting clarifiers would not be necessary. But they were wrong. Radios could still vary enough to require tuning in with the clarifier. But now 6 different people could be on 6 different frequencies and everyone would have to tune their clarifiers when the next person spoke. So most likely your Robyn, if it was never modified for extended frequency range, will probably move about +/- 1.4 Khz max. Due to aging, the range could be lopsided, going further one way than the other.
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Post by SIX-SHOOTER on Oct 17, 2017 19:26:48 GMT -5
If you did not already know now you understand why a Browning Golden Eagle is a bad choice for a SSB radio.It's the same issue they have always had when it comes to tuning in other stations on SSB.It's a losing game & for those who try & use them it drives some of them cray enough that they will sell the Browning thinking something is wrong with it when it's just the reality of how they were designed & built.
SIX-SHOOTER
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Post by bluemax on Oct 18, 2017 12:45:03 GMT -5
I've noticed that the Ranger can ALMOST fine tune all the way between set channel frequencies. Not quite overlapping, but close. If there's a 10kHz difference, say Ch13 to Ch14, I can tune up from 13 and down from 14 and get pretty close to center. Sometimes it's hard to zero in on a frequency without trying both. So I might have a +/- 4 to 4.5kHz range on that radio. Big Difference!
And I remember some old ham radios that an uncle had were basically coarse/fine tuning up and down the entire band like all analog radios used to be. You can imagine how long it took to monitor a band that way.
Thanks.
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Sandbagger
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Post by Sandbagger on Oct 19, 2017 8:34:38 GMT -5
I've noticed that the Ranger can ALMOST fine tune all the way between set channel frequencies. Not quite overlapping, but close. If there's a 10kHz difference, say Ch13 to Ch14, I can tune up from 13 and down from 14 and get pretty close to center. Sometimes it's hard to zero in on a frequency without trying both. So I might have a +/- 4 to 4.5kHz range on that radio. Big Difference! And I remember some old ham radios that an uncle had were basically coarse/fine tuning up and down the entire band like all analog radios used to be. You can imagine how long it took to monitor a band that way. Thanks. Remember, there's a difference between what LEGAL CB radios were allowed to do with respect to frequency shift, and what EXPORT radios typically are set up for. It makes perfect sense to have a coarse clarifier that tunes +/- 5 Khz, to fill in the spaces between channels. And many previously legal CB radios can be modified to extend their tuning range in a similar fashion.
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Post by Sandbagger on Oct 19, 2017 8:37:06 GMT -5
If you did not already know now you understand why a Browning Golden Eagle is a bad choice for a SSB radio.It's the same issue they have always had when it comes to tuning in other stations on SSB.It's a losing game & for those who try & use them it drives some of them cray enough that they will sell the Browning thinking something is wrong with it when it's just the reality of how they were designed & built. SIX-SHOOTER The Browning Mk III was not a good choice for SSB. The trouble tuning people in (they first had to tune to you, and then you had to tune to them. Netting with several people was an exercise in frustration), was only part of the issue. The receiver BFO drifted around pretty badly, which made the whole experience less than enjoyable.
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Post by SIX-SHOOTER on Oct 19, 2017 23:49:16 GMT -5
If you did not already know now you understand why a Browning Golden Eagle is a bad choice for a SSB radio.It's the same issue they have always had when it comes to tuning in other stations on SSB.It's a losing game & for those who try & use them it drives some of them cray enough that they will sell the Browning thinking something is wrong with it when it's just the reality of how they were designed & built. SIX-SHOOTER The Browning Mk III was not a good choice for SSB. The trouble tuning people in (they first had to tune to you, and then you had to tune to them. Netting with several people was an exercise in frustration), was only part of the issue. The receiver BFO drifted around pretty badly, which made the whole experience less than enjoyable. I have owned all of the Browning Base radios with SSB & I'd say without a doubt that NONE of them are good SSB radios.I love my MK IVA but when I want to talk SSB I either switch to my DAK Mark X or to my President Madison without hesitation.Both of those are AWESOME SSB radios & AM as well. SIX-SHOOTER
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Sandbagger
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Post by Sandbagger on Oct 20, 2017 12:47:44 GMT -5
The Browning Mk III was not a good choice for SSB. The trouble tuning people in (they first had to tune to you, and then you had to tune to them. Netting with several people was an exercise in frustration), was only part of the issue. The receiver BFO drifted around pretty badly, which made the whole experience less than enjoyable. I have owned all of the Browning Base radios with SSB & I'd say without a doubt that NONE of them are good SSB radios.I love my MK IVA but when I want to talk SSB I either switch to my DAK Mark X or to my President Madison without hesitation.Both of those are AWESOME SSB radios & AM as well. SIX-SHOOTER Yea, I would tend to agree. The prestige and notoriety of running a Browning, is based on AM usage. The Tram D201 is a far better SSB radio (of the "premium" rigs), and there are others out there that are far better SSB performers. Most notable on the list are the CPI-2000 and Stoner Pro-40. But the Uniden based radios, like the Madison and Cobra 2000 do a great job as well. Even the dinky Realistic TRC-465 does a nice job on SSB.
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