Bruce, Funny this should come up. I was doing some research on what kind of luck folks had with Ramsey preamps and came upon this link... http://www.worldwidedx.com/home-brew-mods/35101-ramsey-pr40-440mhz-preamp-kit.html I don't think this guys application used a diplexer and my 70cm antenna will be strictly receive as well but this struck me as kind of what you were talking about doing with the ARR unit. 73, Michael, W4HIJ Bruce Robertson wrote: > I'm grateful to everyone who has contributed to this discussion. > > It strikes me that the greatest improvement we could make to hand-held > yagis would be to somehow integrate a low noise preamp circuit very > close to the 70cm port. I have an indoor-style ARR preamp that I've > thought of connecting to the boom with cable ties. A powersupply using > AA batteries and a DC to DC buck-boost chip from, e.g., Maxim, would > keep the whole thing light. (Alternatively, I see that the max voltage > for my ARR is pretty high: I might get away with a pair of Nicad '9v' > batteries.) > > Like so much of amateur radio, it's more of a challenge of > construction than anything else. > > Has anyone experimented with this sort of improvement? > > 73, VE9QRP > Bruce > > On Wed, Oct 21, 2009 at 8:21 AM, Allan Saul <al...@rfdesign.co.za> wrote: > >> Quite a lot of guys are using the handy Arrow Model 10W >> duplexer for the handheld 146/437 antenna and mine arrived here >> today so I thought I would put it on the network analyser >> and see how it performs..... >> >> >From the Radio cable to the 2m antenna connector an Insertion Loss of >> 0.75dB was measured with a rejection of 57dB at 70cm. The VSWR at 2m was >> 1.24:1 >> >> >From the Radio cable to the 70cm antenna connector an Insertion Loss of >> 1.2dB was measured with an attenuation of 56dB on the 2m signal. The VSWR >> at 70cm was 1.29:1 >> >> The VSWR on the 2m port was 1.21:1 and on the 70cm port was 1.20:1 >> >> For those guys wanting to look at the actual plots they can be found here >> http://www.rfdesign.co.za/default.asp?pageID=785423593&filePath=D:\SoftPage_V5\files\5645456\Download-Library\Amateur-Radio\ZS1LS\Mode-J-Filter >> >> 73's >> Allan ZS1LS >> >> >> >> >> >> _______________________________________________ >> Sent via amsat...@amsat.org. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> >> > _______________________________________________ > Sent via amsat...@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > ------------------------------------------------------------------------ > > > No virus found in this incoming message. > Checked by AVG - www.avg.com > Version: 8.5.423 / Virus Database: 270.14.25/2450 - Release Date: 10/21/09 > 16:44:00 > >
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