--------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100000 Date: 08/31/96 From: BILL RISTER Time: 11:11am \/To: TOM WALKER (Read 8 times) Subj: Low Budget Antennas-1 On 08-30-96 TOM WALKER wrote to BOB FIKE... TW> I would just concider you Lucky. It is really difficult to actually TW> have solder Stick to a Steel Coat Hanger. Particualrly with a 75 TW> watt iron. =VBG= Methinks some think it's melding when it's actually just "hanging around." ___ * OFFLINE 1.56 --- Maximus/2 3.01 * Origin: The Politically Incorrect! [OS/2, V34+] (1:106/1010) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100001 Date: 08/31/96 From: THOM LACOSTA Time: 11:32am \/To: ALL (Read 8 times) Subj: Old Time Rig Mailling list Hello All! I've started a mailling list that might be of some interest to those that own amateur radio equipment no longer in production. Here's some info on the list: Discussions concerning Amateur Radio Equipment no longer in production The OTRIG mailing list is designed to be a forum for discussions concerning amateur radio equipment that is no longer in production. It is expected that members of the list will not only post messages concerning equipment of older vintage that is for sale, but also equipment that they desire to obtain. Questions and answers concerning modifications are encouraged. Participants are from around the world; please keep polite especially if someone makes what looks like to us a silly mistake. Language: English Requests for subscriptions to this list MUST be addressed to: listserv@fablotz.min.net in the body of your message have: subscribe otrig Posts to this list are addressed to: otrig-l@fablotz.min.net Thom LaCosta K3HRN thom@fido261.qis.net Our Business is Business --- * Origin: HQ AmberNet & Netland (1:261/3000) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100002 Date: 08/29/96 From: PAUL WILLIAMS Time: 10:51pm \/To: ALL (Read 8 times) Subj: Antenna Specs Does anyone have the specs for a Larsen K~lrod model FB-136? I can't find my larsen reference (from '88 >: ) to look this one up. Would like to use it for base use. (ham & ems) I should get a reply if sent, but mail to/from this system may be a bit erratic in the near future. The sysop is going to a mail only system and I'm in the throws of setting up a point system using terminate 3. Thanks, Paul KB5IVG ... "Watch your tongue if you don't want K'vin drooling on you" - Joost The preceding nonsense was brought to you courtesy of AVENUE BBS at 9608.29:22:51 --- FMail 1.02 * Origin: Electronic Avenue * San Antonio, TX * 210-333-0060 (1:387/510) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100003 Date: 08/30/96 From: WAYNE SAROSI Time: 07:43pm \/To: BOB FIKE (Read 8 times) Subj: Low Budget Antennas-1 In a message to Wayne Sarosi <29 Aug 96 2:50> Bob Fike wrote: BF> Hmmmmm, I'm confused. I'v made 3 antennas just like this one with BF> coat hangers. They soldered up just fine. Used a 75 watt BF> soldering iron and silver solder with no problems. To keep the BF> rust off, used blue Crylon paint (no metal in the paint) to BF> finish the job. Oh well I guess ignorance is bliss. I didn't know BF> you coldn't solder a coat hanger to a PL-259. Antennas have been BF> working fine for abt 2 years now. ;-) Nope. You can't solder with Tin-lead solder a coat hanger to anything. Silver solder is different and I'm suprized you can do it with a 75w iron. And i have never been able to solder with tin-lead solder a coat hanger to a PL-259 even with a propane torch. Silver solder is different and most amateurs don't have it. It gets too hot and screws up the connector. Just a thought. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100004 Date: 08/30/96 From: WAYNE SAROSI Time: 07:48pm \/To: BOB FIKE (Read 8 times) Subj: cheap antennas In a message to Wayne Sarosi <29 Aug 96 3:05> Bob Fike wrote: BF> Good series Wayne. Been a avid follower of home made antennas BF> since I started the hobby. Can make some very effective antennas BF> at very low cost, and learn how they work to boot. Unfortunatly BF> it is just abt the only thing we can build now a days. Short of BF> buying a SMT pick and place machine, and a reflow furnace. hi hi TNX. Been working on a few more postings and will post them soon. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100005 Date: 08/30/96 From: WAYNE SAROSI Time: 07:50pm \/To: BOB FIKE (Read 8 times) Subj: Corner Reflector In a message to Wayne Sarosi <29 Aug 96 3:11> Bob Fike wrote: BF> Got anything in your series abt making a nice corner reflector BF> ant. for 2m or 70cm? I hear some chicken wire can be used also BF> for this antenna. Been thinking abt making one for some time now. 2m? forget it unless you have the room. 70 cm. Easy. Will do. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100006 Date: 08/31/96 From: WAYNE SAROSI Time: 08:07pm \/To: BILL EWALD (Read 8 times) Subj: Loopy Antennas In a message to Wayne Sarosi <29 Aug 96 8:07> Bill Ewald wrote: >WS> Now stretch the dipole to one wave and place the traps at one wave >WS> dipoles bend the antenna into a loop such that the tip ends meet and >WS> you have a full wave loop antenna with traps. At 20m the antenna would >WS> know no better, but at 15 and 10m what is it? I don't really know. BE> Seems like I'll just have to try putting a trap in the loop, and BE> see what happens... Let us know what happens. Remember that the trap will block the higher frequency and the loop will not be complete. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100007 Date: 08/31/96 From: WAYNE SAROSI Time: 08:11pm \/To: HARVEY HARBICHT (Read 8 times) Subj: Low Budget In a message to Wayne Sarosi <29 Aug 96 0:09> Harvey Harbicht wrote: HH> Instead of hangers, I'm working with HH> that aluminum ground wire (#8 size?) HH> that RS sells. It needs external support for lengths over 3-4 feet or so HH> (I'm using PVC pipe [see note below]) HH> but it's very very easy to work with. HH> The wire won't solder, but all you have HH> to do is bash the ends flat, drill HH> little holes and use nuts and bolts. Very easy. Sound easy enough. HH> [note:] I put a 6 inch piece of the PVC in the microwave with a glass of HH> water. The water boiled. The PVC stayed cold. So I believe it's RF HH> transparent/safe. At around S-Band, which is within the frequency of the microwave oven, the PVC will conduct. At C-Band and especially above that, you can use PVC tubing for wave guide. Granted, it's not very good but it works. >>The hardest part is going to be the SO-239 connector center pin. HH> I thought about that. My plan is to solder a heavy piece of paperclip HH> to the center pin and BOLT it to the aluminum rod(s). HH> Questions: HH> What do the elements of a beam do to HH> the radiating element (beside "beam" HH> it I mean)? Do they change the impedence, the resonance or both? In a passive antenna beam like a yagi or quad, the parasitic elements just resonate if cut properly. the impedance is a function of the driven element and matching. Resonance is a function of physical length and diameter. So, if cut correctly per design, the passive elements will pose no problem to the Driven Element. HH> So many different dimensions for the RE HH> of a quad beam! One plan says 1005/f. HH> One says 984/f. One says 234/f and then multiply that by 4. Another says HH> 986/f. There are more. What is right? The reflector should be between 4-6% longer than the Driven element. By converting 300/fMHz to feet you get 984/fMHz for a full wave. HH> My master plan is: HH> Make a simple 2-meter loop and use it for a while as a kind of HH> bidirectional antenna. Make it into a cubical quad a little later. HH> Add more elements even later. HH> Am I going to have to retune the DE every time I add something or HH> can I just space everything 1/4 wave HH> and have it work? My 2 main problems HH> with a beam (beside turning space) are Probably a small bit but not much at worst. If cut correctly, not at all. HH> My IC2000H handbook says the SWR must be *BELOW 1.5:1* so the beam HH> has to be quite resonate. HH> Some of the repeaters I want to hit have inputs above 147 and some have HH> inputs below 145. So.......the beam has HH> to be below 1.5:1 or better from 144 HH> to 148. That can be tough depending on surrounding antennas. Your setup will dictate that. I have made several beams that were <1.5:1 from 142-150. Thus it can be done. HH> I was playing with a "real" 2-meter 4 element beam for a while. HH> The SWR readings HH> when the antenna was 10 feet or more off the ground looked like this: HH> | HH> 3 | HH> 2 \ /\ / HH> 1.5 \ / \ / HH> 1.4 \/ \ / HH> 1.3 \ / HH> 1.2 \ / HH> 1.1 \/ HH> 144 145 146 147 148 HH> But when it was 6 feet or lower it was VERY low from 143 to 149. HH> Is this normal? That's the second one HH> I've had that did that. It looks like HH> I'm going to MAKE a beam. Most HF beams require the antenna to be a 1/2 wave off the ground for best results. At 2m that would be around 40". I would look into other objects like fences, homes, etc that could mess up the reading at 6' in height off the ground. I have found that if I tune an antenna at 6' off the ground I tune it to 1.5 to 1.8:1 SWR. When I get it up the tower, with help on tuning, I adjust the SWR to fit the situation of a multi-antenna installation. Bingo! it fits and works with great results. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100008 Date: 08/31/96 From: WAYNE SAROSI Time: 08:45pm \/To: BRUCE LEGRANDE (Read 8 times) Subj: DF'n In a message to Wayne Sarosi <30 Aug 96 1:33> Bruce LeGrande wrote: MC> I have a different approach to direction finding (found in another old MC> QST.) It involves shielding your ht, and MC> using the "Body Effect". The ht is WS> Hmmm. Interesting. Is the duck inside the downspout such that it WS> shields the antenna except for the opening at the top? That BL> Would the HT necessarily have to be inside the gutter, or could BL> one build a shield just around the 'duck' and have the bottom BL> closed with a slip on end that has a BNC bulkhead connector BL> through it to connect the antenna to ? BL> Then what if you used one of those telescoping quarter waves with BL> the BNC (instead of the 'duck') to adjust the ammount of antenna BL> presented to the signal. It would seem like this would make the BL> unit a bit more stable, and sturdy, BL> although slightly more costly to build. Hard to tell. I'm waiting on a reply so I can get more info. Basically it looks like you shield the antenna pattern save the top end of the 'donut' thus it provide direction if pointed at the suspect signal. The use of the telescoping antenna is that the less extended the less it picks up. Kind of like your commercial FM portable. The theory behind using an omni antenna for direction finding is to home in on the strongest signal by trial and error. Numb the antenna by shortening it and do the same again until the point comes where you remove the antenna at close range. The point of this is the signal and the receiver. The only tool you have is the antenna which you can control. Kind of a hearing aid and volume control. BL> And what if copperclad was used instead of alum'. Seems like, in BL> essence, we're talking about the same theory as that of a BL> waveguide, although much scaled down ? I have done tests with different materials such as aluminum, stainless steel and copper and found no difference in dipoles at VHF and UHF frequencies. Waveguide theory at VHF is out the door concerning material and a size like this. Shielded rooms use Steel. Some screen rooms use copper screening. Just a thought. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2) --------------- FIDO MESSAGE AREA==> TOPIC: 188 HAM TECH Ref: DD100009 Date: 08/31/96 From: WAYNE SAROSI Time: 09:09pm \/To: BRUCE LEGRANDE (Read 8 times) Subj: FM antenna 88-108 In a message to Wayne Sarosi <30 Aug 96 2:13> Bruce LeGrande wrote: > WS> [HAM_TECH LOW BUDGET ANTENNAS - 5] > WS> Although this isn't ham_tech related, this antenna will come in > WS> handy for anyone who listens to Commercial FM (88-108 MHz) and has > WS> a couple of stations that just don't quite make it using the > WS> internal antenna or a wire dipole inside the house. > WS> | 5 feet | > WS> ___________________________________________ ___ > WS> (____________________ _____________________) ___ 4-6 > WS> inches 1 inch BL> Looks basically like what I bought from RS a few years ago (don't BL> know if they still stock it or not), but theirs used very small BL> solid rods so the band was much sharper. I like your idea of BL> using the copper tube better! Theirs was also an omni, as it was BL> bent into an S shape (as viewed from top). What is your opinion BL> on doing that with this one ? What would it do to the feedpoint imp ? I'm not familar with the RS design as I don't look at their antennas very much save TV antennas. Most of their purchases are not of RS design. The copper tubing was just a good purchase at the time. You can use aluminum tubing with no problem. A dipole is not quite omni as you know. My design is a dipole. I believe I am familar with that design now that I think about it. It reminds me of the antennas the elderly use with their motorcoaches. Use mine and you'll get much better results. To make it onmi just place it vertical. FM commercial uses circular polarization anyhow. -WS --- * Origin: Editor HTL, Moderator HAM_TECH (Quick 1:374/73.2)