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Re: radio shack roll up antenna as counterpoise
Lazaro Munoz
I tried the radio shack swl radio antenna as a counterpoise to a
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Maldol whip antenna. Interstingly using the MJF analyzer, mine shoeda resonance of 25M rolled up or extended, however it will show different reactance depending on the amount that is rolled up (duh! it acts a coil). Next I set the frequency on the MFJ to a working frequency of 28.500Mhz and rolled out until it showed an SWR of 1.1! and I marked the spot with red tape, it I did not check the length but I can if someon is interested. The reactance was 0 and the resistance was 100 ohms, I guess you can actually transmit with just the SWL antenna!? I figured that if it was tuned it would act as tuned counterpoise when attached to ground side of the Maldol. It seems to me that the idea of using a "counterpoise" as opposed to a "ground plane" is in reality just turning your quarter wave whip into a lazy dipole. I just threaded it through the retainting slot that mates with the BNC dimples and connected it up. I will get some lug in the future to make it easier to connect it but for now it works ok since it have ha nice snug fit. I am able to get the FT817 down to 2-1 bars on the SWR meter by adjusting the whip length. I might be able to get it down to 0 by adjusting the counterpoise length, but I am a bit lazy right now. Have fun fellow experimenter, laz -- k2laz On Wed, 16 May 2001, Sharyl - W3VET wrote:
By the way for those who don't know, |
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Re: inflatable antennas
David Perry
Just a thought here. If we could get a large inflatable mast, such as the
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2.5 m ones used by yachties as danbouys, could we not wind a coil round the bottom, then tape wire up the shaft and use? To collapse, deflate the item, pop in bag or pocket and go home! If we could find or get made, some, say, 5 m shafts we would be in business with good sized verticals. paddling pools use 5m shafts, but in circles of course. A 5m shaft of diameter, sa, 3 inches, would not take too much puff to blow up. Thoughts or help? David/ G4YVM ----- Original Message -----
From: <julian@...> To: <FT817@...> Sent: Thursday, May 17, 2001 12:25 PM Subject: [FT817] Re: More Antennas Just for fun, I connected the ATX to my IC-756PRO. On the otherthe food court nearest to the Yaesu booth. 439.125 simplex. To unsubscribe from this group, send an email to:Questions ) see
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Re: Battery Connectors and wiring.
--- In FT817@y..., KG4CHX@A... wrote:
While experimenting I found the following voltage drops under fullDoes it really matter? According to K6XX analysis of current drain during transmit, the current drawn by the power amplifier is largely unaffected by voltage. As a result, that 1 watt that we could conceivable recover by replacing the power connectors will just result in 1 watt more power dissipation in the MOSFETs. Or am I missing something? -- Brian N0KZ |
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Battery Connectors and wiring.
I really like Barry's new cover and battery charger jack, nice job. I
am sure they spent some hours figuring that out with the limited space. If you have followed some of my earlier posts on connectors and wire in rig you know that there exists some voltage drop in harness. I was intimadated at first but determined to eliminate aa much voltage drop as possible. I was able to remove the connector on PC board by using solder wick on pins. I then experimented with maximum wire size that would fit in hole {orginal is 30 gauge and has over 100MV drop from battery}. If you are carefull you can use 22 gauge, it just barley fits, I used 22 gauge with .006 thick teflon insulation. I then installed a Deans Ultra plug and socket, more on this later. I now have 1.3MV drop under full load from battery to board!. While experimenting I found the following voltage drops under full load: Battery Tray 200MV! New Connector 35 MV Wire from connnector to PC board 100MV Wire from batery to connector 100MV You can see that if you are using the battery tray and stock wiring. This is all lost in heat energy. 2amp X .5 volts = 1 watt lost to voltage drop!! If you do not want to tackle taking off wire from board, another member suggested soldering leads to bottom of board bridging the parallel positive and negative feed with larger wire, 20 gauge will work for this and you can remove for warranty work. Deans connectors: The Ultra I used is going to be my new connector for ARIES and all portable packs. I measured less than 100 MV at 20 amp load, it a tight fit in batery compartment requiring some trimming plastic case. Their standard 2,3 or 4 pin connectors all exhibitted 5MV or less under load and fit easily in battery compartment. The Ultra connector is overkill but I had some from my R/C flying and standardized on these for the shack. For ARIES work the Amderson Power Pole Connector is almost as good and easier to find. I have some pig tails to convert to Power Poles for ARIES box. If you do either wire mod and use W4RT's cover with charging jack you will have the an easily chargable pack and virtually 0 voltage loss. If there is enough interes I will order a supply of Deans connectors and offer to group at cost, as I did on the molex connectors. .73 Tim O'Rourke KG4CHX |
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Re: chalk line antenna (any length)
F.B. Nutter, Jr.
Has anyone thought of using an inexpensive fly fishing reel. I have used
them in the past for dipoles & long wires & they work great. Also large fishing snap swivels come in handy with a wire antenna. 73, Fil W8FIL Sharyl - W3VET wrote: Bonnie Wrote:www.I've found that you don't need to reel out the entire wire. In fact,the spool can be reeled in to any suitable length... and even
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Re: Cheap Hams
Ed Juge/NM
That's a CYA situation. In truth, most manufacturers will honor the
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warranty on a modified radio provided the mod didn't cause its problem and is not likely to cause one in the future. The one glaring exception (and there well could be others) used to be Collins Radio. When you sent them one for even the most minor repair, they would not return it to you until it met new gear specifications (without ANY mods) and that was typically a multi-hundred-dollar tab. 73... Ed, W5EJ ----- Original Message -----
From: "Mel Farrer" <mfarrer@...> To: <FT817@...> Sent: Thursday, May 17, 2001 12:27 PM Subject: RE: [FT817] Cheap Hams unsubscribethe food court nearest to the Yaesu booth. 439.125 simplex. To unsubscribe from this group, send an email to:Questions ) see
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Re: Don't ground your counterpoise (keep it elevated)
Stephen M. King
From: "KQ6XA" <xtalradio@...>
To: <FT817@...> Sent: Thursday, May 17, 2001 4:47 AM Subject: [FT817] Don't ground your counterpoise (keep it elevated) Julian G4ILO wroteI would like to see this discussion left here.Surely the more efficient ground coupling shouldWell, Julian, do you think maybe we should continue this discussion on I have read reports here about the MP-1 and the difference in performance between using it close to the ground or using it elevated even a little bit and the elevated position seems to work better -- perhaps this is because more of the counterpoise is also above the ground? 73, Stephen W3SMK |
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Re: Cheap Hams
Mel Farrer
unsubscribe
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-----Original Message-----
From: Keith [mailto:n6jpa@...] Sent: Monday, April 23, 2001 3:32 PM To: FT817@... Subject: Re: [FT817] Cheap Hams Hi, What annoys me is that Yaesu voids your warranty if you modify the radio in any way, including the green wire modification. Yaesu should have designed the radio for either alkaline or rechargeable battery use. Just my 2 cents. Keith On 23 Apr 2001, at 21:40, FT817@... wrote: It annoys me that hams are cheap as all get-out, unwilling to buy a -- Best Regards, Keith ========================================================= NW Radio Page. Freeware Site. ======================================================== To unsubscribe from this group, send an email to: FT817-unsubscribe@... and for a great FAQ ( Frequently Asked Questions ) see Your use of Yahoo! Groups is subject to |
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Re: Digest Number 398
Terry McClary
From: "Sharyl - W3VET" <w3vet@...>--- There is a seasoning I haven't heard of in quite a few years. The thought of the smell still makes me nauseous. Terry WB8SJQ |
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Re: Antennas
David Perry
Metal Supermarkets. See yellow pages.
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David ----- Original Message -----
From: <julian@...> To: <FT817@...> Sent: Wednesday, May 16, 2001 10:00 PM Subject: [FT817] Re: Antennas For those with an ATU a cheaper and probably lighter solution (thethe food court nearest to the Yaesu booth. 439.125 simplex. To unsubscribe from this group, send an email to:Questions ) see
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Re: Antennas
David Perry
yeah, fare comment.
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David ----- Original Message -----
From: <julian@...> To: <FT817@...> Sent: Wednesday, May 16, 2001 9:55 PM Subject: [FT817] Re: Antennas NW Cumbria. I guess the mid-point between us would be round aboutthe food court nearest to the Yaesu booth. 439.125 simplex. To unsubscribe from this group, send an email to:Questions ) see
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Re: Digest Number 399
The MP-1 is made and sold in the USA. Details from
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www.superantennas.com. You can order over the phone by credit card - the antenna arrived quite quickly. I might be persuaded to sell mine, but as others are claiming good results with it I would like to spend some more time trying to get it to work satisfactorily. Julian, G4ILO --- In FT817@y..., "Gavin Stirling" <gavin.stirling@t...> wrote:
What's the difference between an MP1 and the ATX Walkabout antenna? |
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Re: More Antennas
Just for fun, I connected the ATX to my IC-756PRO. On the other
antenna socket was my 5 band vertical. On the spectrum display I could then quickly check the difference in received signal strength and estimate the difference in dB. The ATX was 18 to 20dB down on the vertical. Of course, my little ATX stand had only a short feeder so it had to be indoors with the 756PRO. That might have affected the signal strength a bit. Nevertheless it is perhaps not so surprising that it is hard to work DX. With the 5W out from the FT-817, it is a bit like running 100 - 200mW on the vertical. Of course, you may not need more power than that to make the QSO if only the DX station could hear you call in the first place. Julian, G4ILO |
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Re: RT Systems Cat software is out!
Gary Mitchelson
I have it for the VR-500 and have been happy with it.
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-----Original Message-----
From: thomas4174@... [mailto:thomas4174@...] Sent: Wednesday, May 16, 2001 10:49 PM To: FT817@... Subject: [FT817] RT Systems Cat software is out! RT Systems have just posted their computer control software for the FT-817. I have the software for the Icom IC-Q7A and it works pretty well. Has anyone tried the FT-817 software yet? It seems the company wants $25 with $5 shipping up front, with no chance to see what you're getting. Comments??? ***____FLASH_____** FT-817 users GET TOGETHER at Dayton Hamvention Saturday at 3PM. Meet at the food court nearest to the Yaesu booth. 439.125 simplex. To unsubscribe from this group, send an email to: FT817-unsubscribe@... and for a great FAQ ( Frequently Asked Questions ) see Your use of Yahoo! Groups is subject to |
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Re: More Antennas
Demetre Valaris - SV1UY
--- In FT817@y..., julian@t... wrote:
That URL should be , I think.Hi Julian, This discussion is getting better and better. OK I have seen and corrected the URL in another message. Tks anyway. As for the wire element dipole, although it might be lighter, you cannot hang it on bushes and still work as good as a taller mast. OK if there are plenty of tall trees around, then a wire dipole is the best antenna, but if you walk on a mountain that has few trees, then the W3FF portable dipole is very good because it needs a single mounting point and it can at least be kept 3 - 6 meters above ground. Also if you have a light mast you can operate while walking, although the whole structure is big, but nevertheless operative. (Hmm better keep away from the men in white suits, hi hi hi!!!). Another reason for using it with a mast is that you can handle the dipole as a sloper or even as a vertical dipole (well nearly). Overall it is a better performer than a whip vertical, but of course the whip is much lighter and if one uses a trailing counterpoise, it is nearly as a vertical dipole, but with all the limitations we both know! (fluctuating SWR as we walk etc). The handheld dipole does not have these problems at all. I always try to carry in my bag a thin wire dipole, such as a half version of Bonnie`s MINIBAC and whenever possible I hang it between 2 tall trees and tune it with my ZM-2. I have only used it once though because at the moment I am more interested in Pedestrian Mobile operation (walking portable) than stationary portable operation. I also carry my ATX, which is permanently strapped on the FT-871`s carry case, because it makes a perfect and lightweight emergency set and I have worked with it quite a bit of NVIS (by holding the ATX nearly horizontal with a counterpoise), i.e. on 40m I have talked to Crete, and the South of Greece and even to the North covering distances of about 400~700kms and got a 5-7 most of the time. I even got 5-5 my a mobile station in the South of Greece. I also talked to Europe and got 5-4, and 5-7 on 21 and 28 MHZ. Unfortunatelly no DX with the ATX yet, but I have not tried enough maybe only once I tried New Zealand and I could not be heard but when I changed to the MP-1 I managed the QSO. Also once I called some Japanese stations on 10 meters from the top of Mt. Ymittos, but no joy. Since the I gave up on using the ATX for DX. That is all for now Julian and I must tell you again that I do enjoy this thread. I think it is very constructive. 73 de Demetre SV1UY |
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Re: Don't ground your counterpoise (keep it elevated)
--- In FT817@y..., "KQ6XA" <xtalradio@a...> wrote:
Well, Julian, do you think maybe we should continue this discussionon a more appropriate forum like HFpack?I don't think all the members of this group are members of HFpack, and some of them may be interested in reading the thread to its completion. But, the my main point is this:efficient as elevated groundplane verticals or vertical dipoles. The oldWhat this implies, at least to me, is the counterpoise is acting not as a ground plane but as a radiating element. Actually I suspected that might be happening, and it would explain why the adjustment and positioning of the counterpoise is so touchy. It might be interesting to see what results could be achieved by a full size dipole with *both* elements lying on the ground. It might prove/disprove the argument of those who claim the ATX is little better than a dummy load. I live in an area of the most conductive soil in North America(salt marsh island---25metres from salt water). I have tested bothgrounded radials and elevated radial verticals here (portable, pedestrian,and fixed antennas). The elevated ones always win by 6~20dB, dependingon frequency and configuration.Yes, my own elevated radial trapped vertical is many dB better than the ATX. But then the vertical element is a lot bigger. Julian, G4ILO |
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Don't ground your counterpoise (keep it elevated)
Julian G4ILO wrote
Surely the more efficient ground coupling shouldWell, Julian, do you think maybe we should continue this discussion on a more appropriate forum like HFpack? But, the my main point is this: Especially for QRP (like the FT817), it is important not to waste power by delivering that power into the resistive earth soil ground. HF grounded-radial quarterwave verticals simply are not as efficient as elevated groundplane verticals or vertical dipoles. The old theories about the HF benefit of buried ground radials have fallen down under real world testing. I live in an area of the most conductive soil in North America (salt marsh island---25metres from salt water). I have tested both grounded radials and elevated radial verticals here (portable, pedestrian, and fixed antennas). The elevated ones always win by 6~20dB, depending on frequency and configuration. So... if you want to radiate your little portable 5W signal into the air, get your antenna as up as high above the earth ground as practical! Bonnie KQ6XA |
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Re: More Antennas
That URL should be , I think.
It's a neat idea and I've saved the page for further study. But if you're prepared to carry a mast that big around would you lose anything by simply using it to support a thin wire inverted V or other type of wire-based antenna, which would be lighter? Julian, G4ILO --- In FT817@y..., "Demetre Valaris - SV1UY" <sv1uy@s...> wrote: Hi guys and gals,[snip] |
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