OK, let me understand this. the idea was to take 0-150MHz add a 60Hz sync signal to keep the VCR happy, store it to tape through the Video IN jack then on output simply remove the 60Hz and you basically have coming out what you put in? So simple its silly! I once used a Hi-Fi VCR to capture 8 hours of FM DX audio. Hardly genius.
From: [email protected] [mailto:[email protected]] On Behalf Of Mark Connelly Sent: Friday, February 21, 2014 4:56 PM To: [email protected]; [email protected]; [email protected]; [email protected] Subject: [CapeDX] Perseus captures from 1991 I finally got around to going through a box of VHS videotapes from the late '80s / early '90s spectrum capture experiments, as originally developed by Craig Healy (NG1U), and mentioned in this article: http://chowdanet.com/markc/webpage/WA1ION/vcrdx.pdf There were about 6 tapes in the box. Two of these, when played into a receiver, had reasonable performance. One of these was the tape Craig had originally supplied me. This was made at his QTH near Providence, RI. The whole AM band is captured. Sensitivity on the lower half was quite low so it's primarily the local stations such as 630, 790, and 920. Some skip signals can be heard on the upper half of the dial. I still have to review the tape to determine the exact date and times of recording. Items on a news / sports station, possibly with some Google follow-up, will nail down the date. At some point in the recording there should be a time check on one station or another. I looked into the lower shortwave spectrum but noted little in the way of "real" (non-birdie) signals, so no CHU or WWV assistance on the time. The second tape was one I made at Billerica, MA in April 1991 during the "wee hours" of the morning: 0643-1043 UTC. Because 50 kW WRKO on 680 is only 2.8 miles / 4.5 km from the receiving site, a notch filter for 680 was inserted ahead of the VCR input. Usable sensitivity for the capture came in starting around 800 kHz and up. One thing that must be kept in mind is that this primitive version of spectrum capture had a rather small dynamic range: only about 30 to 40 dB from a hashy noise floor up to the level of a strong local on the verge of causing distortion and spurs. The tapes, obviously, are not going to produce much in the way of weaker signal DX. Before the tapes have a chance to deteriorate, I'm porting at least some of the contents over to Perseus files. This also gives a ready method for sharing the experiment results with others. I reset the computer date/time so that the Perseus time-stamping is relatively close to the occurrence of the original recordings. After I get all this stuff digitized, I'll go over it for any interesting audio clips. Though the "VCR DX" method became known to the MW DX world about a quarter century ago, it is widely believed that, as far back as the JFK administration, "spook" agencies such as the NSA were able to store substantial RF bandwidths for later review. Broadcast studio grade videotape, or something similar but custom-designed, was used. Converters allowed any chunk of spectrum to be heterodyned to the baseband range (0-3 MHz?) the tapes could accommodate. The late Gordon Nelson (WA1UXQ) seemed aware of it. Maybe some tapes will show up at a Fort Meade, MD fleamarket / yard sale so we can tune around and hear stuff like Belize 834 and Bermuda 1235 once again, as well as Murray-the-K on WINS proclaiming his status as the Fifth Beatle. Mark Connelly, WA1ION South Yarmouth, MA __._,_.___ <http://groups.yahoo.com/group/CapeDX/post;_ylc=X3oDMTJxc2p2bmY0BF9TAzk3MzU5 NzE0BGdycElkAzIyODgxMDM4BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2MDg4BHNlYwNmdHIE c2xrA3JwbHkEc3RpbWUDMTM5MzAxOTc2Mw--?act=reply&messageNum=6088> Reply via web post <mailto:[email protected]?subject=Re%3A%20Perseus%20captures%20from%201991> Reply to sender <mailto:[email protected]?subject=Re%3A%20Perseus%20captures%20from%201 991> Reply to group <http://groups.yahoo.com/group/CapeDX/post;_ylc=X3oDMTJmaHJ1NWhqBF9TAzk3MzU5 NzE0BGdycElkAzIyODgxMDM4BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNudHBjBHN0 aW1lAzEzOTMwMTk3NjM-> Start a New Topic <http://groups.yahoo.com/group/CapeDX/message/6088;_ylc=X3oDMTM1dGM4cjUyBF9T Azk3MzU5NzE0BGdycElkAzIyODgxMDM4BGdycHNwSWQDMTcwNTA2MzEwOARtc2dJZAM2MDg4BHNl YwNmdHIEc2xrA3Z0cGMEc3RpbWUDMTM5MzAxOTc2MwR0cGNJZAM2MDg4> Messages in this topic (1) <http://groups.yahoo.com/group/CapeDX;_ylc=X3oDMTJmZGc5OG04BF9TAzk3MzU5NzE0B GdycElkAzIyODgxMDM4BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDdnRsBHNsawN2Z2hwBHN0aW1lA zEzOTMwMTk3NjM-> Visit Your Group <http://groups.yahoo.com/;_ylc=X3oDMTJlbnI3cWI4BF9TAzk3MzU5NzE0BGdycElkAzIyO DgxMDM4BGdycHNwSWQDMTcwNTA2MzEwOARzZWMDZnRyBHNsawNnZnAEc3RpbWUDMTM5MzAxOTc2M w--> Yahoo! Groups . <http://info.yahoo.com/privacy/us/yahoo/groups/details.html> Privacy . <mailto:[email protected]?subject=Unsubscribe> Unsubscribe . <http://info.yahoo.com/legal/us/yahoo/utos/terms/> Terms of Use . <http://geo.yahoo.com/serv?s=97359714/grpId=22881038/grpspId=1705063108/msgI d=6088/stime=1393019763> __,_._,___ _______________________________________________ IRCA mailing list [email protected] http://montreal.kotalampi.com/mailman/listinfo/irca Opinions expressed in messages on this mailing list are those of the original contributors and do not necessarily reflect the opinion of the IRCA, its editors, publishing staff, or officers For more information: http://www.ircaonline.org To Post a message: [email protected]
