Keyboard Shortcuts
ctrl + shift + ? :
Show all keyboard shortcuts
ctrl + g :
Navigate to a group
ctrl + shift + f :
Find
ctrl + / :
Quick actions
esc to dismiss
Likes
- Ft817
- Messages
Search
|
/PM whip + counterpoise = dipole antenna
John wrote:
raises questions what an antenna like the MP-1...The MP-1 vertical and its counterpoise both are somewhat equal and opposite radiating parts of a lazy vertically polarized dipole. Really somewhat eliptically polarized :-) The use of the word "counterpoise" fell out of favor for many fixed applications on HF, and was replaced by more accurate descriptives. Recently, the word counterpoise has been re-invigorated for use with /PM [Pedestrian Mobile such as FT-817 on HF] applications. These days, counterpoise simply refers to a drooping or dragging wire connected to the radio case. But this humble quarterwave dragging wire is contributing just as importantly to the radiation efficiency of the "dipole" as the gleaming machined quarterwave tuned antenna rod. Bonnie KQ6XA |
|
Re: Steel tape counterpoise
Brian B. Riley, N1BQ
toggle quoted message
Show quoted text
-----Original Message-----Yeah! Right! But you know damned well it almost always took twice as much T as the FMs said it would take! Especially when dealing with the hardwoods of a certain tropical wonderland .... ... and another thing ... I never could stand nuouc mam! Makes me want to ralph just remembering it! Let's hear it for the "date pudding" or "ham and muthers" cheers ... bbr |
|
Re: radio shack roll up antenna as counterpoise
John --
The discussion...raises questions whatThe $64,000 Question? The article doesn't put it quite this way, but here's the gist, I think: Clearly the counterpoise radiates, unless you've gone out of your way to waste the radiation, which is the point that Bonnie KQ6XA has been making repeatedly. But unlike an orthodox dipole, a lot of that radiation is involved in heavy interaction with the "radiator" radiation, with phase reinforcement or cancellation, secondary effects of ground reflection and coupling, and so on. One possible outcome is a very eccentric radiation pattern. But it may be possible to smooth that out by redistributing and spreading out the interaction through multiple radials or counterpoises, capacitance hats, and so on. In the limit, this is a disk, of course; but still a radiator, although with the "flattest" interactions with the vertical element. Thus the classic advice to use as many radials (the best approximation to a disk) as your patience will allow. So an MP-1 with a proper single-wire elevated counterpoise is just a half-loaded dipole with a radiation pattern to make your hair stand on end. An MP-1 *without* a proper elevated counterpoise is just a waste of watts. :-) That's how I read it, anyway. Frank AB2KT |
|
New RATS FT-817 Control Software Update 1.2.0
Mark A. Smith
I have updated the RATS FT-817 control software to 1.2.0. This new version
fixes a problem when reading the frequency from the radio during mode changes. Also added the ability to minimize the interface down to the LCD display only with control provided via the computers keyboard. Any feedback would be greatly appreciated. 73 The website is: Mark KB5KYX |
|
Re: radio shack roll up antenna as counterpoise
John O. Newell
Frank AB2KT --
Tnx for the link. This keeps getting funnier. I was reading that page last night, but only got to #1. I really enjoy Cebik's articles, though I confess I don't always understand it all. The discussion on the page you mention raises questions what an antenna like the MP-1 (or the AP-10) with the appropriate "counterpoise" <slap me! :-)> really is, and which part of it is really doing the radiating (if the "counterpoise" is the correct length)??? Only at #7 now, maybe the answer lies further on! Tnx es 73 John Newell |
|
Re: FT-817 power lead plug?
Tom Griffin
On Thu, 17 May 2001 20:06:45 -0400, I wrote about Re: [FT817] Re:
FT-817 power lead plug?: On Thu, 17 May 2001 23:28:41 -0000, you wrote about [FT817] Re: FT-817 part 171-3222 right angle, black with white tipOops, 1.7 x 4.75mm - sorry www.mouser.com73 Tom K4IIJ |
|
Re: FT-817 power lead plug?
Tom Griffin
On Thu, 17 May 2001 23:28:41 -0000, you wrote about [FT817] Re: FT-817
power lead plug?: It's a 4,00mm x 1,70mm plug. The same plug used by many of theMouser catalog #601, pg 108, part 171-3221 right angle, black part 171-3222 right angle, black with white tip www.mouser.com 73 Tom K4IIJ |
|
Re: FT-817 power lead plug?
Maplin part no. AR22Y seems to be OK, though this is listed in the
toggle quoted message
Show quoted text
catalog as 4.0mm x 1.7mm. You also need a lead AQ81C. The wire looks a tad on the thin side for a possible 2 amps transmit, but I haven't found a source for a plug you can attach your own wire to. Doubtless the dealers will sell an official Yaesu power lead, which probably also has a fuse in it. Julian, G4ILO --- In FT817@y..., "David Henn" <drhenn@y...> wrote:
Hello, |
|
Re: radio shack roll up antenna as counterpoise
also. Iusing a "counterpoise" as opposed toHa! Glad someone said it out loud -- this has been my surmise would be interested in hearing from someone who's better versed inantenna theory whether or not this is in fact correct! is very interesting on this point. Frank AB2KT |
|
Atlas 210x manual and new group
Sharyl - W3VET
I've scanned in the entire Atlas-210x manual for a fellow ham.
Perhaps someone else can use this. It's a series of GIF files encapsulated in a ZIP file It's 2.7M. You can join the new Egroup at: and get it from the files section. Or download directly from: Warning! It's 2.7M 73 Sharyl |
|
Re: Battery Connectors and wiring.
Which battery technology are we talking about? When NiMH batteries
sag below 1.1 volts per cell at 2 amps draw, they are about 95% drained (based on the discharge graphs I have on hand), and it drops off quickly from there, below 1 volt at about 97% of capacity. So between 8.8 volts and 8.0 volts (where the radio shuts down) you have about 2% of the usable capacity of the NiMH cells. So the difference between shut off at 8.5 volts (stock) and 8.0 volts (after modification) is less than 2% of the capacity of the cell. Call that maybe 30 seconds of extra transmit time per recharge. I'm not trying to troll here. Are my numbers right? If they are, I don't see that there is an argument to be made for replacing the power connectors and resoldering new leads to the board. In terms of reliability, a dedicated NiMH pack (like the Maha) is going to be better than the battery tray, simply because soldered cells are going to last longer than spring contacts, and because heating up the NiMH cells from the power dissipation in the battery tray will unnecessarily shorten their useful lifetime. But I don't see voltage drop as being very important, otherwise. -- Brian N0KZ --- In FT817@y..., don@h... wrote: Well - yes - I think you are missing something - let's say - since Ibetween the battery and the load to say .15 volts, then the battery could gothe available battery capacity.to drainvoltage drop!!Does it really matter? According to K6XX analysis of current largelyduring transmit, the current drawn by the power amplifier is unaffected by voltage. As a result, that 1 watt that we couldresult |
|
Re: Z11 batteries
Elliott
Hi All:
toggle quoted message
Show quoted text
I just purchased a Z11 and have yet to assemble it. I charged 2 9v NiCads and they were about 16.2 volts. I check with the Z11 manufacturer and he told me that the maximum voltage that the unit could handle was around 24 volts. With a little use, the batteries should quickly drop below the "normal" 14v operating level. I will let you know if any smoke appears when I get it going! 72 Elliott WA6TLA Bill Terry wrote: Hey Guys |
|
Re: More Antennas (W3FF URL)
Demetre Valaris - SV1UY
--- In FT817@y..., "F.B. Nutter, Jr." <fbnjr@m...> wrote:
The W3FF link doesn't work for me.Hi Fil, The correct link is I realized my mistake and sent immediatelly a correcting message, but obviously some guys have not noticed it!! Sorry about that. 73 de Demetre SV1UY |
|
Service Manual - Repair support ?
Hi,
as I have a broken 817 on my desk, I need some more information than the circuit diagrams that come with the manual. Any hint ? Or can someone tell me, why the display is flashing and AF is muted ? When I pull "UL" high, the flashing stops -> PLL does not lock. Why does it have 2 DDS chips ? What is "LD","VCV" ? Why do I do that ? 73s, Falk - DL3DAZ |
|
Re: inflatable antennas
Chris
Not for us smokers, i'd be there all day...
toggle quoted message
Show quoted text
Chris ----- Original Message -----
From: David Perry To: FT817@... Sent: Thursday, May 17, 2001 8:00 PM Subject: Re: [FT817] inflatable antennas Just a thought here. If we could get a large inflatable mast, such as the 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 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 > > > ***____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 > > > Yahoo! Groups Sponsor www. ***____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 the Yahoo! Terms of Service. |
to navigate to use esc to dismiss